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Renewable Energy Technologies in Asia: A Regional Research and Dissemination Programme PHASE II For Photovoltaic Applications Training Manual Prepared by Solar Laboratory 01 Mac Dinh Chi St., 1 District Ho Chi Minh City SR Vietnam CONTENTS Page Lesson 1 Overview of Development of Inverter. By Phys. Trinh Quang Dung 01 Lesson 2 Renewable Hybrid Power Supply Unit Smart 1000 a combination of Charger - Inverter UPS Unit By Phys.Trinh Quang Dung Eng. Nguyen Truong Duc Eng. Le Sy Thang 09 Lesson 3 Sine-Square and Sine-Modification Inverter By Eng. Tran Phi Cong 26 Lesson 4 High Frequency Inverter. By Eng. Nguyen Truong Duc Eng. Tran Phi Cong 35 Lesson 5 True Sine Inverter. By Eng. Le Si Thang 42 Lesson 6 Computer Designing of Inverter. By Eng. Nguyen Truong Duc 50 REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam LESSON 1 OVERVIEW OF DEVELOPMENT OF INVETER I. BRIEF HISTORY AND TECHNICAL DEVELOPMENT 1.1 Motor Generator Inverter: Since 1940 inverter has appeared and the first uses were in the Second World War. This time together with a development of electronic lamps, the need of high DC voltage had been requested. During the time of world war’s II when Navy Ships ran on DC power only then DC source was urgently needed. That time, the Invertor was Rotary Inverter. In fact this was a motor generator, which could convert 12 VDC, 27 VDC, into 110 VAC, 220 VAC and it was only way to convert DC voltage into AC voltage. The most popular brand of that era was Redi – Line. Over half of century passed but Redi – Lines still appear in use in the country - side around us. These rugged units were quite reliable, strong enough and produced AC voltage with a low efficiency about 50%. The Rotary Inverter had many disadvantages as very high start current of 20A – 30A and no stable out put voltage. It also could not have start up surge capacity, which limited applications of inductive loads as fan, pump, compressor etc… Because of their quite high reliability, Blue Bird Rotary Inverter still had been produced until the late of 1970’s and early 1980’s. 1.2 Electronic Sine Square Inverter. Trip-lite company founded in 1992 was the first produced a unique automobile headlight, which has been Invented by Graham Tripped. Later, the product line expanded to include Electronic Inverter. In that era, the early units used mechanical vibrator to oscillate DC power into square waveform AC, the mechanic vibrator when it oscillates which turning on and off continuously contact-points to make square wave current. This kind of Inverter could response only one defined load and short lifetime because of contact points easy damaged. Solid-state semiconductor devices were born in middle of 20 century, which supported to new generations of Inverte: Full – Electronic Inverter in the early 1960’s. The solidstate transistors replaced the mechanical vibrator, which maintains longer lifetime of the unit. This 1 event declared a termination of Rotary Inverter Technology as well as mechanic vibration system. Since this point, the motor – generators no longer produced anywhere. Although that, unregulated square wave design of this kind Inverter could not go over and many technical problems were still open as unstable output voltage, no surge power, no frequency control etc… This time Inverter could response only for resistive loads but they was not possible to run reactive loads as motor, Ice – creamaker, pump, microware oven etc… These weak points limited applications of Inverter and they had almost fallen in forgetting of people. Later on a design of frequency control was applied to allow a steady draw, which had improved the time-by-time and formed modified sine wave, which is still very popular for today. On basic of this technology, Tripp lite has produced power Inverter, UPS devices (Uninterruptible Power Supply). The company provides products in worldwide market. In 1979 Vanner inc. introduced the first 1000W sine modified wave Inverter thanks to it’s parented power transistor drive technique. That time it was a big achievement and subrising, because of an unheard efficiency of 87%. The first application of this Inverter was used in ambulances. Few years later, the application was expanded into various types of vehicles including remote television vans. After that following the market request, product line expanded with 2200W and 3000W Inverter. After the world energy crisis in 1973, Renewable Energy Sources have been mentioned and attracted energy policy markers. One of the urgent request was how to produce high quality AC electricity from RE and one again the companies, researchers, engineers have jumped in a competition of Inverter Technology. During 1980’s there were two companies manufacturing Inverter in USA for the world market: Heart interface and GTO Electronics. There were some others in Europe and Asia but they were small. In 1986 Heart split off to form Trace Engineering, which later became a famous Inverter manufacture in the world. The Heart Inverter had a battery charger /converter built in and was the pioneer reached highest efficiency that time over 90%. Another strong point of it’s specification was the surge power had got three times. In 1986 one of the Inverter models included a microprocessor control was mentioned. On the technical point of view, we could classify that the first generation Inverters used Metered Darlington Technology. This special circuit metered base current to power a transistor proportional to load. The magnetic design increased efficiency. Second – generation Inverters used FETs (Field Effect Transistors), since FETs have almost no switching losses, efficiency was markedly improved. In the last decade of 20th century, the Inverter Technology has strongly developed with a big worldwide competition. In 1987 Exeltech was founded and manufactured High Frequency Sin Ware Inverter. It claims the first redundant Inverter system, “hot” swappable capability and modular design. This kind of Inverter do not used big transformator that why they have quite small size, much lighter and convenience for mobile application. Stat-power Technologies Corporation head quartered in British, Columbia, Canada was founded in 1988 also manufactured M.S.W Inverters using High Frequency design. The company provided portable power for remote regions. 2 In 1990 IC (Integrated circuits) were applied which allowed the creation of energy management system and microprocessor in Inverter Technology. The first microprocessor controlled Inverter/Charger was introduced in 1993. The advantages of M.S.W Technology are efficiency and relatively economical cost although that the M. S. W Inverter however, still cannot run all kinds of loads because of poor peak voltage regulation and the fact that the AC output is not a pure sin wave. Beside this, M. S. wave Inverter also makes interference to loads in some cases. Trace Engineering developed and patented improvements to the modified sine wave technology in their sine wave series Inverter. While not a true sine wave, the output is a multi – step approximation that results in fewer load incompatibilities. The charger is more efficient and results lower AC. This sine wave series Inverter still has several other features as including an automatic generator start/stop, a battery temperature sensor and three independency set voltage relays. Trace Engineering has covered big part of the global market that why in South Africa the name “Trace” it means “Inverter” In 1995 Stat-power introduced a pure sine PV Series Inverter wave Inverter/Charger using high Frequency Switching Techniques, they were successful in producing a high output charger with a power factor approaching “1”. This is almost not distortion at the DC port in both Inverter and charger mode which could be viewed as a technological milestone. Pure Sine Wave Inverter opens a new era and any limitation of use is remained. Although that Pure Sine Wave Technology just in start, we expect a quick development to sweep out some barriers as high cost, difficult to maintained etc… and catching a potential world market. The Pure Sine Wave Inverters have given good chance for grid – connected design as well as synchronous of several Pure Sine Wave Inverter to increase power. We could say that since 1995 a “boom” of competition for Inverter manufacturing. Millions solar roofs, thousands of wind farms, micro-hydro projects which have requested big amount of Inverters. Thanks to the revolution of Renewable Energy in world wide together with big manufactures, a lot of new electronic companies as Steca, Leomics, AST, Zenit have jumped in the exciting market. Nowadays appearing a variable service of Inverters as Inverter for solar pump, for AC solar module for grid – connected use etc… The smallest Inverter is one supplying for AC module which size is only 108 x108 x30mm or 220x70x20mm. Output power only 80W – 100W and catching an efficiency of 94%. They are introduced by Trace Engineering USA and OK service company of Neither Land. 3 The larger pure sine Inverter has already built up to a of power of 20 KVA and surge power 200% . It runs big advanced micro processor control with soft start. The efficiency gets over 90%. Stable output voltage and frequency, full protection for overload and short circuit, current mode control, automatic low battery shutdown to protect battery, variable speed fan cooling. It’s weight is 250 kg and could operates in poor condition up to 450C and relative humidity 95%. AC Module Inverter II. DEVELOPMENT INVERTER IN VIETNAM During 1985 –1990 on network and three all main cities. An urgent power from battery or an electronic company Divu and introduced Divu with a max power of surge power and responded only for resistive loads. Vietnam had not enough Electricity nights per week were black out in of Market request was given: AC Inverter. During 1987 – 1990 an HCM City jumped in product – line Inverter. It was sin square Inverter 300w. The quality was poor, no SPECIFICATIONS OF LEONICS TRUE SINE INVERTER The efficiency was low about 60%. Later on in short time the imported Inverters from Taiwan AND South East Asia and Copy imported – Inverter covered quite small and poor market that time there for Divu company also stopped their product. 4 A serious research and good design of Inverter has been done by AST Company during 1986 – 1989. In 1990 AST Company put it’s products in local market with two ranges: 300W and 600W sin modified wave Inverter with stabilizes output voltage 220V ± 5% and full – protection system. Since 1995 thanks to open – door policy, the economic of Vietnam going on fastly and Renewable Energy Sources as solar, wind, micro hydro have strongly developed. One again Inverter has become “hot” request for remote, mountainous regions as well as on Island and country side A lot of electronic companies have put in market their Inverters as RoBo, Solar, Hansin etc…. The common disadvantages of the Market – Inverter are poor quality, high stand by current or low efficiency. AST company is still pioneer among them for quality and the company has continuously done research and improved design and quality. AST is also leading ahead in manufacturing UPS devices and Auto Stabilizations. The company networks have distributors and agencies along the country and sell out 5000 products/month approximately. Solarlab is a National Laboratory belongs to Vietnam National Center for Sciences and Technologies. It is a pioneer and leader of PV development of Vietnam. To serve own activities, Solarlab has researched on Inverter – Technology since 1990 and has Introduced the first “ SOLARSTAT” equipment in the Solar Station and Cultural House at Tam Thon Hiep District HCM City in Vietnam end of 1990. The SOLARSTAT kept “Industrial Model and Design” issued by Department of Invention and Properties of Vietnam during 1992 – 1998. The SOLARSTAT is a heart of Battery Charging Center and Cultural House, It consists of four Charging Channels by solar modules and a built in sin square Inverter of 300W. Later on, Solarlab has continuously developed and improved quality of it’s Inverters with 500W and 1000W. The Inverters of Solar lab SOLAR START manufactured specially for PV. Applications that why the quality and energy saving are priorities. The stand by current of Solarlab’s Inverter usually was 2/3 of the market Inverter and high surge power. During last 10 years. Solar lab put in operation about 60 SOLARSTAT along the country. In 1993 nine SOLARSTATs Certification of Solar start were exported to Republic of Mali in Africa according cooperation with FONDEM France and one SOLARSTAT was exported to Lao P.D.R in order of MOSTE Vietnam in 1997. The SOLARSTATs provide electrical power for various PV. Applications as Telecommunication repeaters, Satellite – Para ball Receiver – Transmitter Cultural Houses, Solar House, and Local Radio Broadcasting Center etc… In 1996 Solar lab designed a first High Frequency Inverter in Vietnam following a research program funded by Sida Sweden. The product was 50W only but it could not become a real product because of lacking imported FETs Since 1997, AST Company and Tectrans Viet Enterprise has joined to design and manufactured Smart product with the range of 300W, 500W and 1000W. For short time of 2 years, Smart 300, 500 and 1000 were improved much good design and quality. It is front of Smart back of Smart 5 a Hybrid Power Supplied unit built in a power - full good sine modified Inverter. Surge power gets 200% and unheard efficiency of 90% Full protection as well as UPS function guaranteed. Frequency controlled, stabilized AC output voltage ± 5%, Hybrid Charging Control process and Battery Metter System are very competitive advantages of the Smart product – line. Smart 1000 run all kinds of load as: water pump, photocopy machine, glass cutter etc… Especially it response also fun, refregenerator too. 2000’s is a good start of the product -line of smart with 14 units were exported to Thailand, Philippine and Germany. APPENDIX: SMART SYSTEM 6 7 Grid-connected Inverter 8 REGIONAL TRAINING COURSE ON “INVERTER TECHNOLOGY” 16-20 OCTOBER, 2000 HCMC LESSON 2 RENEWABLE HYBRID POWER SUPPLY UNIT SMART 1000 I. INTRODUCTION: Smart 1000 is a Renewable Hybrid Power Supply Unit, which has manufactured by AST electronic CO. & TECTRANS VIET Enterprise. It is an intelligent equipment, which has many advantages and conveniences for Use. The UPS function allows Smart 1000 can operates everywhere catching network. Especially in the domain of communication and informatics applications the continuous power all of time is very important fact. Which guarantee dropping out communication signal and losing database. On input source, Smart has a wide range of choice whatever: grid reconnected, Solar module, Wind, micro hydro generator as well as Diesel generator… which makes Smart becomes a power source everywhere and every time. You know, solar radiating is everywhere in Vietnam and almost everywhere in the world. Furthermore, Solar power is a renewable and infinite power. Therefore Producers of Smart has designed Smart 1000 use solar power is a basic power source. Besides, others renewable are Wind power, hydroelectric power has been used too. Smart 1000 can use in mountainous, remote area as well as in island... In mountainous where has much solar radiating and waterfalls you can use solar power and hydroelectric power to charge battery and use other applications. In coastal region or island where have much solar radiating and wind you can use solar power and wind power. With countryside you can use solar power and diesel generator… Now, in Vietnam Smart 1000 has used on cultural boats and health service boats. Smart 1000 has been exported to some countries in ASIA. For example: Thailand, Philippine … and it’s going to export to Germany on next time. It expect a big market future thanks its advantage II. DESIGN AND OPERATION 2.1 Description Mobile independent hybrid power station for 12V DC and 110/230V AC, 50 Hz, built-in mains charge (AC 230 V) and solar charger regulator (DC 12V) for solar modules up to 500Wp (40A) charging capacity, DC/AC inverter (modified sine wave) with rated 9 power capacity: 1000 W (surge power capacity = 2000 W), built-in uninterrupted power supply (UPS) device for safe supply during power cuts, multiple connections for 12V DC power charging systems (wind, hydro, generator), main and battery voltage indicator, charging current indicator, system protection for low and overload, 12V DC mains adaptor, switch-able 1.5–3–4.5–6 –7.5–9–12V, 1 cigarette lighter socket for 12V DC and 4 AC safety sockets for 110/230V, system mounted in a roller rack in ready-to-use performance for direct connection of 12V DC battery bank (180Ah – 400Ah); weight without battery bank ≈ 30 Kg. Smart 1000 is a mobile intelligent hybrid power supply and control unit for AC and DC appliances in home, offices and remote dwellings. It’s an AC power source for anytime and everywhere Smart 1000 is an ideal and unique equipment for reliable energy supply in isolated area with selected and approved components, guaranteeing: high power quality, high reliability, quiet operation, multiple possibilities. Smart 1000 is a ready-to-connect unit, simple to install, easy to use and requires no maintenance. Charging power sources for Smart 1000 are besides grid or generator - a set of two qualities certified solar modules in combination with a sophisticated and highly efficient wind generator. Smart 1000 is capable of supplying power for: Lighting, Refrigeration, Air Conditioning, House hold Appliances, Tools, Communication Equipment, Radio, TV, Video, Computer, Charging Facility for DC source, etc. Smart 1000 is used with Power sources Renewable Energies: Solar Module 100Wp300Wp, Wind power Air 403, Micro Hydro Gurgler PT02 (150W-300W), Grid 220V, and Generator 500W-3000W. Hybrid Power Station is a hybrid power supply uses different sources of renewable energies. The equipment consists of three parts as following: Charger Regulator * Solar & Grid * Power 12 VDC Storage System For Loading: - TV - Lighting - Computer - House appliances U.P.S / Inverter 12V / 220 VAC 220V 50Hz(60Hz) Fig ure 1: The Block Scheme of Hybrid Power Station 10 The charging process of Charger Regulator for Solar and Grid is built in. And the Generator, Micro Hydro, Wind had the control charging regulator themselves. The full protection system allows the equipment auto-operates to against most of troubles keeping high reliability of the equipment. § Energy charging The charging of Hybrid Power Station can be applied with many variable kinds up to local conditions such as Grid, Diesel Engine, Micro Hydro, Wind or Solar Generator. We can use single or Hybrid Energy Power at the same time for charging. However, the most important charging principle is a total charging current must not to be over a limit of: 30Amax for H.P.S Smart 1000 The user should read carefully the catalogues when charging with Wind, Micro Hydro before connecting into H.P.S Smart 1000. TECTRANS-VIET is willing supply Synchronous Renewable Energy Sources such as Solar, Wind, Micro Hydro sources that are suitable with the equipment Smart For charging we must connect in exactly positions. Grid connects to AC-in, Solar into Solar-in, Wind or Micro Hydro into Wind/ Hydro-in, Generator into Generator in. The important note is a right connection to ⊕ and of DC sources. For Grid charging, turn on AC power contact to Charger. § Use DC power: To use DC power, turning on the contact DC power ON, lighting indicator indicates 12V DC is on DC-out. When Battery voltage gets lower than 10.5V, empty indicator lighting on and DC source auto cutting off to protect Battery Bank. When the Battery Bank is full charged, DC source will auto Reset (or press Reset button). DC source can also supply from contact cigarette in the backside, note follow correct pole ⊕ and printed in equipment. § Use AC power: The UPS/ Inverter provides a continuing power of 500W or 1000W with voltage 220V AC ± 5% 50Hz (or 60Hz) for: TV, Video, Lighting, Computer use. Surge power is 1000Wmax with and 1500Wmax with Smart 1000 SS in 5 seconds. Inverter supplies AC 110V - 220V with Sine modification waveform. So, when use H.P.S for running motors which have high inductive characteristic, please carefully ask expert about the equipment. When the Smart connects to a Grid power, AC source connected directly with network. If the AC source suddenly interrupts the UPS function will be auto-change to Inverter within 1 second. When AC source disconnect by overload or short circuit, please check carefully and repair to be sure troubles overcame, and turn off AC contact then turn on, AC source will be reset. When using with invertors, the loading must turning on slowly to avoid suddenly heavy loading for Smart. 11 § Indication systems: AC Power: lighting at ON position and AC voltage. DC Power: lighting at ON position and DC voltage. Charger: ° Grid Power Led will be lighting if charges by Grid on AC - in 220V AC. ° Solar Power Led will be lighting if charging by Solar Modules on Solar in 12 V DC. ° Diesel Power Led will be lighting if charging by Generator 12VDC on Diesel input. ° Wind / M. Hydro Led will be lighting if charging by Wind or Micro Hydro, Generator ON Wind / M.Hydro in 12VDC Battery: ° Full Led (100%) will be lighting if the voltage of Battery Bank is 12.5V. ° Normal Led (60%) will be lighting if the voltage of Battery Bank is 12V. ° Low Led (30%) will be lighting if the voltage of Battery Bank is 11V. ° Empty Led (10%) will be lighting if the voltage of Battery Bank under 10.5V and cut off DC-out. Ammeter: showing charge – current into Battery Bank if equipment is charging by any energy sources: 50Amax for Smart 1000 VDC meter: show voltage in the two pales of Battery Bank from Storage Systems capacity 200 AH / 300 AH. VAC meter: show voltage 220V AC ± 5%, 50 Hz or 60 Hz. This voltage will appear when inverter is using or the Smart connecting to Grid. § Protection systems: Smart 1000 is high reliability with full protection systems, includes: > Against overload and short circuit on outside. > Against inverse charging on Solar in. > Against overcharge. > Against exhausted Battery Bank. Low voltage disconnection 2.2 Design 2.2.1 Block Scheme Oscillator 50 Hz UPS controller 220V AC INPUT 12V DC OUTPUT Ejection controller protection block 220V AC OUTPUT Driver and Tower Solar Regular V DC INPUT Diesel source Wind/M. hydro Rectifier DC Ampere Meter Charging indicator system Overcharge Protection Battery 12state Indicator system Store battery Bank 12V DC 100/200 Ah Transformer inverter DC Voltage Meter AC Voltage Meter AC AC Ampere Amper Meter e 110V AC OUTPUT 2.2.2 Block function • Solar regular, Diesel source, Wind / M-hydro block: there are energy charging sources, the charging of Hybrid power station can be applied with many variable kinds up to local conditions such as Solar, Diesel, win and Micro Hydro. • Charging indicator system block: include Leds such as Solar Power Led, Generator power Led… to indicate energy charging and charging state. For example: Solar Power Led lighting if charging by Solar Modules, Generator power Led lighting if charging by Diesel generator… • DC Ampere meter block: show current charge for battery. • Overcharge Protection block: Overcharge Protection. • Battery state indicator system: include Leds to indicate Battery state. When battery is full, the FULL LED will be lighting. When voltage of battery is low the LOW LED will be lighting… • DC voltage meter: display battery voltage. • Store battery bank block: Battery bank from storage systems capacity 100/200Ah • Low voltage disconnection block: disconnect to load when battery is Low voltage • Oscillator 50 Hz block: change DC voltage input to 50Hz potential pulse. • Ejection controller protection block: against overload and short circuit on outside • Driver and power amplifier block: control power amplifier to amplify 50Hz potential pulse before it goes into transformer. To intensify output capacity • Transformer Inverter block: change 50Hz potential pulse to 110/220V AC output • AC voltage meter: display AC voltage output. • UPS controller block: control UPS mode. When the Smart connects to a grid power, AC source connect directly with network. If AC source suddenly interrupts the UPS function will be auto-change to Inverter within 1 second. 2.3 Principle Circuit 2.3.1 Main circuit OPTO 220V AC IN Gate 1k 220/50v Vcc RELAY 1 K A IN TRANS C1815 Vcc 470/0.5w Gate 5k6 RELAY 2 OUT 1K 1k 15v AC 220V AC IN TRANS 13 +B MAIN CIRCUIT SW LM317 3.3/1W 10/5W 10/5W D613 Vin A1013 2 Vcc 560 1 220/50v 6k8 470k +Vout ADJ 100/100v 3 6k8 220/50v 2k2 6k8 9v 6k8 6k8 103 5k 10 103 3v TS 1MF 15k 18v 1MF 2k2 C1815 15k Text 4007 Text 103 10MF 15V 2k2 C1815 6v R6 100MF 100 (60N06 * 6) 1K A1015 R1 4054 10 2k2 4054 10/5W C1815 +B 6V R6 100MF (60N06 *6) 100 1K A1015 4054 10 4054 4M/250v R1 Main circuit contains Power supply circuit and associate circuits to apply power and associate other circuit together. Power supply circuit: In Principle of Inverter changes DC to AC voltage. To do that, it needs a stable oscillator 50 Hz. So that, request for power supply is voltage and current supply must is very stable. Therefore in Power supply circuit must have Voltage stabilizer and current stabilizer. In circuit, power supply on B+ through A1013, C1815 and D613 transistor to pin 1 of LM317 will create a voltage and current stable on output pin 3 2.3.2 Oscillatory circuit 14 An oscillation at 12800 Hz was created IC 555 on pin 3 and conducted to pin 1 of IC 4520. After that, it will be divided to have a signal with 800 Hz frequency. This signal was send pin 9 and on output at pin 14 we have a signal with 50 Hz frequency. Then it will be modulate to have DR1, DR2 signals. They are conducted to two amplifier-powers. Each one contains six mosfet-transistors (60N06). They were in parallel together. DR1, DR2 signals drive two amplifier-powers to have a sine signal with 50 Hz frequency. Amplifier-powers’ outputs were conducted to primary coil of transformer and on secondary coil we have a 220/110V AC. 15 50HZ800HZ DAT CS IN/LINE DONG BO 4 2 R CVolt TRIG 5 10K 68K 1 Q DIS GND 8 VCC THR GND GND 3 6 VCC 104 10 3K9 9 DIODE RES1 POT1 U?C LM324 10K 10K 10MF 470K 12 8 CAP 13 RES1 R DIODE 10K U?A 4520 Q3 Q2 Q1 Q0 14 5K6 220K GND 6 5 4 3 GND 10K 2 1 7 DIODE U?D LM324 EN CLK GND 7 555 CAP POT1 U? ZENER3 GND VCC R U?B 4520 14 13 12 11 7 Q3 Q2 Q1 Q0 10K U? DIODE 100K 33K GND 51K DIODE 5 6 CAP U?B MC4558 6V 47K 6V 3K3 470K DIODE 103 3K3 470K 3 1 2 7 6V A ELECTRO1 DIODE LM393 1 U?B LM393 2 3 LM324 5 11 6 4 U?A 8 4 47K 104 GND 6V 103 220K 68K 7 10K 103 U? 12 13 1 2 10K 6V 22K U?D 4011 10K 8 GNDCAP 9 104 VCC 11 3 U? 5 GND U?B 4011 RES1 222 DIEU CHE DR2 16 U?C 4011 10 POT1 RES1 6 47K U?A 4011 4 GND 5K6 222 DR1 RES1 PLUG VCC OSC CIRCUIT U?B 220K LM324 EN CLK 5 DIODE 4.7MF 6 LED 15 U? SCR VCC 10 9 U? 2.3.3 Transfer circuit Function of this circuit is to transfer between inverter and UPS mode. In circuit we used OP-AMP LM339 makes comparing circuit to detect signal from grid electricity. Duty of this circuit control relay 1 and relay 2 to decide automatically supply energy to load from grid electricity or Inverter. Transistor A1013 will control charging battery from grid electricity. TRANSFER CIRCUIT 820K 14 8 6 VR02 33K VCC NPN 10K 5K6 LM339 12 10K GND 104 4 4 4K7 U?A 220K 104 15 22MF LM324 14 GND Z Z1 Z0 Y Y1 Y0 3 5 330K LM339 DIODE VCC GND 10K NPN GND DIODE 1 2 U?B 13 12 X1 X0 X DIODE 13 10 0.47MF 11 6K8 3 D 11 CAP 9 10 11 6 C B A INH 2 1 104 7 VEE VCB DIODE 560K 10K GND 6V 51K U? 10K DIODE VCC U? GND 5 7 6 4053 LM324 DIODE 6V D 2K2/1.2W 14 VCC LM324 100K 100K 104 C 10 100K 8 9 GND 10K 51K DIODE 47K 13 51K BD2 12 104 1K TRANS1 223 10K BD1 LM324 2.3.4 Display circuit Showing operation state of system by leds. In this circuit, we used OP-AMP LM339 compare input signals with correlative reference signals. They will control leds when input signals change. DISPLAY CIRCUIT 4007 +B 1.5K 10MF TS Charging GRID 3V 10K 1MF 1.5k 10K 3 17 TS Full 5 10K 2 4 1.5k 12 6V LM339 Normal TS 1.5K Normal .5k TS 800HZ C1815 5K6 102 51K 10K 10K A 5 2 SYN NPN GND VCC 3 2K7 220K 4 50hz U? A1015 5K6 LM339 LM339 PLUG DIODE 680K 10MF 22K 2K2 39K 22K 10MF 33K TS CHARGE 9 7 1 2K2 1K C 1K5 B 2K2 DIODE 104 COMPARE 103 5K6 5K6 120K VR01 1M 0.47MF IN/LINE VCC B> C 2.3.5 DC and charging control circuit. Function of this circuit is to control charge for battery. It can cut off overload and overcharge state. When voltage of battery is low, A1015 transistor will active to control charging for battery. When battery is full on LM393’s output has a signal to control C1815 transistor on pin B and this transistor active to supply 12V DC to load. At the time, it cut off charging for battery. CHARGE CONTROL CIRCUIT DIODE SCR PLUG B1K5 47MF PLUG A1013 U? TRANS3 SCR 9V RES1 GND 4K7 GND 33K GND DIODE GND DIODE 1K/1W U?B U?D TRANS3 PLUG 5 12 7 14 13 6 5K6 224 47K LM324 RES1 LM324 330K 6V PLUG 2K2 220MF 3K3 PLUG U? DIODE 1K5 DIODE C1815 U? 18 1 2 DIODE GND 47K GND 33K 330R 22K RES1RES1 15K LED 50K 39K 11 PLUG 10K 8K2 3 LM324 12V 2K2 U?A 47MF PLUGDIODE VCC 33K 100K 4 ZENER2 GND DIODE 1 33MF GND 2 GND VCC 3K9 3K3 GND U? 2.4 Circuit board. All circuits of Smart were divided into several small circuit boards. It is easy to fit and repair. Include: - Main board. - Osc board. - Transfer board. - Charge board. - DC out board. - Display board. - AC charge board. 2.4.1 Main board. It’s the motherboard to combine several small circuit boards together. For example: OSC board, transfer board and charge board. 19 2.4.2 OSC board. It contain oscillator and divide circuit to create a signal at 50 Hz frequency. 20 2.4.3 Transfer board. It contains transfer circuit. 21 2.4.4 Besides, we have some circuit boards. For example: charge board, DC out board, Display board and charge board. 22 23 24 2.5 Technical specification. Equipment Smart 1000 SS AC Voltage DC Voltage Wave form Power Continue Surge Sine 230V/110V ± Modificatio 1000 W 5% 10,5 V ÷14V n 50 Hz or 60 Hz Battery Bank I Charge 300 Ah 1500W/5sec 400 Ah 35A max Integrated control-battery system in “plug and play” performance installed a mobile roller rack, optional 12 or 24 DC. • Powerful battery bank: 12 – 180 to 400Ah. • High cycle charge battery bank in low maintenance or maintenance-free performance. • Built-in DC/AC inverter 230/ 110V, optional in 50 or 60 Hz performance, 1000W continuous power, 2000W peak surge power. • 12V system with step wave inverter • Built-in main charge (230V) and solar charge regulator optional 12V DC for solar module up to 5000W charging capacity • Built-in uninterrupted power supply (UPS) device activated when connected with public grid. • Multiple connections for 12V DC power charging system (Wind, Hydro, Generator) • Mains and battery voltage indicators. Protection against • Current indicator for AC grid charging and DC charging source. • Battery protection against over and low load. • Multiple outlets for 230/110V AC and 12V. • Prepared for direct connection with selected solar, Wind, and Hydro generators. 25 REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam LESSON 3 SINE SQUARE AND SINE MODIFICATION INVERTER More and more technologies, or circuit designs have involved in the quest for creating higher power AC from low voltage DC sources. This lesson will examine some design techniques in which we already done. I. LOW FREQUENCY TRANSFORMER BASED INVERTER. The following technologies are based on low frequency switching of the low DC voltage, applying the DC pulses to a step- up transformer. Two common technologies are the PUSH_PULL technology is suitable for production of Square and Modified Square ware and sine-ware outputs. The block diagram of a low frequency transformer based inverter is shown below. 12VDC BATTEY 12VAC Low frequency Transistor Switches 120VAC Low frequency Transformer AC Loads (Push-pull or Bridge) SQUARE WARE AND MODIFIED SQUAREWAVE INVERTER. It is called SQUAREWAVE INVERTER because of its shape of the output waveform. (See figure 1) 120 VAC RMS Figure 1,Square Wave output Wave Square wave inverter were the “ Original Electronic “ inverter .The first versions such as Tripplits used a mechanical vibrator type switch to break –up the low DC voltage into pulses are then applied to a step-up transformer. With the advent of semiconductor switch, the mechanical vibrator was completely replaced by “ Solid-state “ transistor switches. Figure 2 is a common circuit referred to as “ PUSH_PULL “ technology to produce a square wave output. 26 Transformer Trasistor Switch Battery Negative AC Output Square Wave Battery Poaitive Battery Negative Trasistor Switch Figure 2. The basic theory of a Push-Pull design is as follow: the top Switching transistor closed and causes current to flow from the battery negative through the up-half primary transformer to the battery positive. This action indices a step-up voltage on the secondary side of the transformer. (See figure 4A). After a period of time, the switch Flip-Flop. The top switch opens and then the bottom switch closes allowing current to flow in the appositive direction. (See figure 4B) This cycle continues and higher AC voltage is obtained from secondary port of the transformer. The Turn radio of transformer decides the output voltage, the more turns on secondary side, the higher voltage is obtained. (Figure 4A + 4B). Transistor Switch Closet Battery negative Battery negative induced curent CurentFlow Battery positive AC output Square wave AC output Square wave Battery positive CurentFlow induced curent Battery negative Battery negative Figure 4A Figure 4 b Transistor Switch Closet The major problem with the Push-Pull approach is that the current in the transformer has to susdely reverse directions. This cause a large reduction in efficiency as well as potential for large transients, thus degrading the waveform, Another drawback is the transformer that require for the Push-Pull design must have two-primaries, The output pulse is directly related to battery voltage Since the radio of transformer is fixed, any charge in battery voltage would effect the peak output voltage .for square wave, RMS voltage is equal to peak voltage and as a result power output is depended on battery voltage. Finally, most square wave inverters have mediocre efficiency (typical about 80 %) and the idle draw is relatively high. II. MODIFIED SQUARE WAVE INVERTERS. The addition of an extra winding in the transformer along with few other parts allows output of a MODIFIED SQUAREWAVE (often referred to as a modified SINE-WAVE by marketing types) while still utilizing a push-pull technology) 27 170Vol Peak 120VAC RMS Pulse height equal to battery voltage times the turn radio of the output transformer and dependent on battery voltage Figure 5 Modified Square Wave and Off-Time. The switching cycle is identical to that described in the section on square wave inverters, except for one additional step .In the switching cycle, another step is added which clear out the transformer reducing the problems associated with the suddeed change in current direction. This is accomplished by the off time shorting winding shown in figure 6 .As one switch opens and before the second switch closes, the switch across the shorting winding closes, effectively removing the current from the transformer. This would be like slowing a car to stop and then shifting to reverse, much better than the situation mentioned previously. Off-time shorting provides a better zero crossing of the waveform, which equates to better zero crossing of the waveform, which equates to better ability to operate electronic devices. Improved efficiency and lower total harmonic distortion of the waveform are other benefits. Several manufactures accomplish off –teme shorting by placing a solid –siste switch directly across the AC output lines. This approach works, however the switch is not isolated from the AC output line, and as a result it is subject to abuse from transients, which can be caused by reactive loads (I.e. electric motor) Utilizing a shorting winding in the transformer is preferable due to the isolation provided from the AC output Transistor Switch Battery negative Battery positive AC output Square wave Transistor Switch Battery negative Transistor Switch Figure 6 Push-Pull The major advantage to a modified square wave is the ability to regulate RMS voltage by means of varying the pulse width, and off-time period. The pulse width variation method of regulation is referred to as pulse width modulation or PWM The idea behind RMS regulation is to keep the area inside the wave from equal at all times (figure 7A). Since the peak voltage, or pulse height is a product of battery voltage and the transformer ratio, when the prak* voltage increases the area inside the pulse will increase if the pulse width remains the same. With a square wave inverter, nothing can be 28 affected about this increasing RMS voltage. But PWM control allows the width of the pulse to be narrowed, thus maintaining a constant area in sine the waveform (Figure 7 B) Peak voltage Peak voltage Peak voltage 120VAC RMS C On the other hand, ifA the battery voltage decrease, the RMS voltage would also B Nominal Battery Voltage High Battery Voltage Low Battery Voltage decrease if the pulse width remains the same .In this case .RMS voltage regulation may be achieved by the pulse width (Figure 7C). Changing of pulse –width accomplished by controlling the on and off time of the transistor switch. Realistically, there is a point where the zero time is no longer presented as the pulse –width is increase and essentially a square wave is present. Beyond this, the RMS voltage becomes unregulated. Modified square wave inverters are great improvement over square wave types they offer good voltage regulation, lower total harmonic distortion and better overall efficiency. Electric motors operate much better from a modified square wave and most electronic equipment will operate with less problems III. DESIGN AND OPERATION 3.1 General Specification of an Inverter The most important specifications are following: 1. Input voltage 2. Output voltage 3. Output power 4. Stability of the output frequency under loading condition 5. Stability of the output voltage under loading condition. 6. Wave form on output gate and deformation. 7. Efficiency 8. Protection scheme (overload, low input voltage etc…) Nowadays on the market there are several types of Inverter using SCR or transistor. Some type are using transformation, some not using transformation. Example: The type using SCR gives high efficiency, impulse – resistance capacity is higher but the exciting cut – off under heavy power is more complicate and it involves an over current during the starting that make SCR unable to cut – off. The output impulse is not sinusoidal; getting a sinusoidal impulse will make high loss in the filter. The type-using transistor is limited by output power but the circuit is more simple and is easy to operate. It unable to give a good impulse, bad efficiency at the line polarity, good impulse at the on – off polarity. The types not using transformation 29 have disadvantage in low output power and high cost, due to not using transformation the current loss is low under the not – loading condition. 3.2 Classification & block scheme There are some Inverter-types as following: a. Using SCR series inversion b. Using SCR parallel inversion c. Using impulse inversion d. Using current feed – back transistor e. Using voltage feed – back transistor f. Using both current and voltage feed – back transistor g. Using feed – back transistor with separate exciter or using amplifier – exciter IC for transistor. h. Using high frequency DC Inverter with an exciter to Control Mospet Generally, in three types using SCR the output impulse is rectangular. To have a sinusoidal impulse it needs a filter. Types 4, 5, and 6, using transistor give output impulse almost sinusoidal, it’s frequency and form tightly depends on the load. Type 7 gives rectangular output impulse almost sinusoidal, it’s frequency is relatively stable under the various loading condition but the form is strongly depends on the load. Analyzed the advantages and disadvantages of above presented types. The step – method may use. Transistor has following advantages: - More economical, low cost - Good output impulse form: The filter is simple, low harmony distortion. - High frequency stability - High efficiency due to the transistor operates at D condition. - Possible of stabilization of the output voltage by means of limiting the exciting impulse amplitude for transistor. General block – scheme: This scheme is now using in SOLAR LAB 30 Fig. 1 Block scheme of an Inverter - Block 1: Multi – Harmony oscillator or oscillator outputting a rectangular 50Hz impulse. - Block 2: Single circuit stabilizer, used to create impulse amplitude for each half – period of excitation. It is possible to control amplitude by means of feed – back from block 3, 4. - Block 5a, 5b: Excitation cascade for the power output transistor. - Block 6a, 6b: Power transistors, connected depending on the output power - Bock 7: consists of under – voltage and over current protections and an accumulator charger. - LC: Output filter (AC) 3.3 Electrical Circuit Scheme The actual Inverter scheme is showed below: Oscillator creating Q1, Q2. IC 4047 with capacitor C1 and adjustable resistor VR1 creates an impulse with frequency of 100 Hz at position 13 and then this frequency will be divided into 50Hz at position 10, 11. Single circuit stabilizer consists of: Amplifier IC 4081 and transistors Q7, Q8, Q9, Q10. To create an impulse with amplitude is that enough for the excitation cascade. To control the impulse amplitude of the single stabilizer, a voltage of 10V is taken from transformation, and then via a rectifier is passed to the position 9 and 10 (U 2). The amplifier takes signal from 7 gives to 2, 6 (U 3). By this way the impulse amplitude giving to the stabilizer is stable. Excitation cascade of power transistor is a 31 transistor H 1061. Power transistors are connected by Darlington type, each side consist of three transistor s 3055 with a disturbance protection Output transformation is winded such as suitable for the voltage of 12V or 24V. Voltage at the outlet is 110V and 220V; the power must reach the range of 300W ÷ 500W A regulator for adjusting the output voltage is available here. There is also a batteries protection circuit for the case of overload and voltage drop lower then 11V. Voltage for the power cascade (6) is feeded directly because of heavy current. Voltage for the oscillator and blocks 1,2,3,4,5 is given from the relay. The protection circuit controls relay winding. As the voltage becomes lower than 11V. The control transistor will cut – off the voltage to the relay, so the blocks 1,2,3,4,5 will not operate, in consequence the Inverter will stop working. To make the Inverter work again, it needs to charge the battery and push the SET button for feeding the relay. When the relay is energized, it’[s contacts will be closed, so block 1,2,3,4,5 will be energized and it make the Inverter work again. 32 33 REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam LESSON 4 HIGH FREQUENCY INVERTERS I. INTRODUCTION: High frequency inverter is another approach to creating higher power AC from low DC voltage. The name HIGH FREQUENCY refers to the speed at which the transistors switch on and off. II. OPERATION: This type of inverter creates low DC voltage from battery power through a transistor switching stage to change it to AC square wave and then apply it to a high frequency step-up transformer (which made-up of by Ferrite core) to creates high AC voltage. Now, this high AC voltage is then be rectified (change back to DC), apply to a low frequency switcher (H-BRIDGE) creates Utility power AC. II.1 Block diagram: (Figure 1) Battery 12VDC High Frequency Transistor Switches High Frequency Transforme r High Frequency Rectifier High Frequency Switcher 170VDC Low Frequency Transistor Switches 120VAC AC Load (Bridge) High frequency inverters may be either modified square or sine wave output. Drawbacks to the high frequency approach are poor source ability for starting motors and other reactive loads, and the fact that there is transistor switches on the AC output which are not isolated from the AC load. Transients, which may be created by reactive loads, can cause failure in the output transistors. Additionally in general the battery negative is not isolated from the AC outlet neutral in a High Frequency inverter. The transistor-switching configuration is a H-BRIDGE switch layout with the transformer replaced the high voltage power supply, often utilizing a fly back configuration (Figure 12). The high voltage switcher takes a low voltage DC input and produces a higher voltage DC output. The positive and negative ends of the high voltage supply are then alternately connected to the AC output lines by the bridge and output is pulse width modulated. This provides excellent voltage regulation. . Transistor Switch 170Volts Transistor Switch HighVoltage Switcher + - 35 0 Volts AC Output Modified Square Wave Figure 2: HF Inverter with H-BRIDGE Technology The voltage being switched in a HF inverter is the high voltage DC .In a low frequency transformer based H-BRIDGE; the low voltage from the battery was switched through a transformer. Off time shorting is provided in the high frequency approach by closing the two transistors across the AC output on the Zero volt side of the high voltage switcher. Remember, the switcher must off-time short between switch changes. The three figures below show the states of the switches in one cycle of the high frequency inverter. Since the H-BRIDGE switcher has already been discussed only a graphic depiction of the output switch states and current flow is shown. Figure 3, 4,5 Transistor Switch Curent flow 170Volts 0 Volts HighVoltage Switcher + AC Output Modified Square Wave - Transistor Switch Battery Positive Battery Negative Figure 3 AC Output Transistor Switch 170Volts HighVoltage Switcher + 0 Volts - Transistor Switch AC Output Battery Positive Transistor Switch Battery Negative Curent flow Figure 4 36 170Volts HighVoltage Switcher 0 Volts The main advantage behind frequency switchchers is the very light in weight and physical size is small. Disadvantages of HF inverters are poor surge ability due to the characteristics of the switching power section supplying the bridge (limits their usage to motor load) Lack of isolation between the transistor and AC loads makes them very vulnerable to transients caused by reactive loads since there is no transformer to isolate and act as a “ flywheel “ to oppose fast changes in output current. HF inverter exhibits high idle current because the high voltage switcher runs constantly and this also often causes interference with TV’s radios. etc. II. 2 Sine wave output inverters Just as with modified square wave and square wave output inverters, multiple approaches and topologies have deloped to produce sine wave output inverters. These inverters are desirable in that they will run loads more like the utility grid. The downfall is complexity and expense in building some types of this inverter. A Sine wave is shown in figure 14 along with several key points of the waveform. II. 3 Rotary inverters The earliest type of DC to AC inverters was the ROTARY INVERTER. Essentially this piece of equipment was a DC motor that turned an AC generator. The rotary inverter has the advantage of producing a very nice sine wave output at the expense of low efficiency (typical 60 %) and very kigh idle power consumption. II. 4 Ferro-resonant transformer inverters The Ferro-resonant sine wave output inverter takes advantage of the inductive characteristics of certain transformers. An inductor is a coil of wire that has the ability to store energy and to oppose changes in current within a circuit. An inductor acts like a magnetic “ Flywheel “. In other words if voltage is suddenly applied to inductor, the inductor will react by attemping to slowdown the resulting current rise. Conversely, if the current is already flowing through the inductor and is suddenly removed, the inductor will reacts by releasing it stored current and attempt to stop the current from going to zero. (The electromotive field force of inductor expands and collapses) As the result the fall time of the current is prolonged. This reaction acts to impede the changes in current. Unfortunately, inductance causes the transformer to have a relatively low efficiency (Typically about 50%) and the waveform is very sensitivity to loads 37 II. 4. 1 Circuit description: Right in center of circuit is IC 1, controlling the “PWM” Pulse width modulation) .It contains a saw tooth generator, 2 differential amplifiers and a comparator to modulate the PWM. It also has a comparator to control the cut-off timing, a 5 v reference and 2 output control: push-pull or 1 of 2. The components at pin 5 and 6 are to put the operation frequency of converter on 25 KHz. This frequency is selected to get the Max output from transformer. . The PWM puts the pulse which has the width change from pin 9 and 10, these pins are damped by 3 parallel of IC 2 to trigger the gate of Mosfet Q1 + Q2 through 10 Ohm resistor Mostfet Q1 + Q2 energizers the primary of transformer T1. Which is connected to +12V, each mosfet is energized by a square wave so that when Q1 is conducted, Q2 is opened and when Q1 Is opened, Q2 is conducted. The ratio of transformer increases the output voltage from the secondary coil of Transformer. 2 zener diodes ZD1 + ZD2 keep Q1 + Q2 from over-voltage. This zener diode operates as follow: When mosfet opened, transformer will have a transient voltage on the drain of mosfet. When this voltage is over the breakdown voltage of Zener (75v) is reacts by turn on the mosfet to keep the transient voltage… The silicon diode that is in series with zener diode are to control the negative voltage. BOÄÑAÛ O DC-DC GOÙ I ' H ' SOÙ NG VUOÂ NG B3 340v Q5 Q3 B5 R1 B4 +12V +12V T1 Q1 ~ - B1 Q4 + B6 + ~ Q2 Q6 R2 B7 100 385vw B2 0v R B8 B1-Boäkích ñoâ i B4,B5,B6,B7,Boäkích coå ng caù ch l i II. 4. 2 Feedback voltage; B8-Boäsinh soù ng xung vuoâ ng ñi eà u chæ nh B2-Boäkhuyeá ch ñaïi quaùdoø ng B3-Hoà i tieá p caù h li The voltage divider which is consists of R1 = 1.2 M ohm and R2 = 3.3 K ohm are used to control the current of high voltage DC from the converter and to energized the operation amplifier IC5a. This OP-AMP energizes IC 4 (optocoupler). This IC4 isolates the output voltage from input and energizes IC3b another OP-AMP IC5b (inside LM358) s not used. - Trim pot VR1is used to adjust DC from IC4 in order to have high voltage out. - Voltage DC from VR1 is amplified by IC 36 and feed through differential amplifier IC! Across Diode D8 to control the trigger PWM of mosfets when DC voltage is over +340v, energized voltage decrease, pulse-width increases until output voltage is corrected. 38 - Notice that 12V is not feed to IC5 and HV of IC4 because HV of IC4 is needed to be free. There fore these pins are supplied an isolated DC voltage by Transformer T2. This transformer is energized at frequency of 1 MHz through C=. 0047 Mf by Q 15 + Q 16 .The secondary of TX T2 is rectifier by bridge D20 –D23 (1n4148) and filtered by 0,1 Mf. Output voltage is regulated by zener diode ZD7 = 12V before supply to IC4 and IC5. II. 4. 3 Current limited The drain pins of inverter DC – IC3a controls DC. It controls the dropping voltage across R=430 M ohm that is connected between Q1 + Q2 and negative port (0V). IC3a amplifier this dropping voltage by 391 and only small amount voltage drops across resistor just before over current happen. The output of IC 3 is feed Ed back to pin 16 of IC 1 through diode D7. This would stop the comparator voltage of IC3 when the current over 30A. II. 4. 4 Stand-off time In the push-pull class of inverter, there would be stand off time, if not the mostfet or power transistor would short. This action can easily happen because 2 mosfet can open at same moment. The comparator of stand off time at pin 4 controls the output of the push-pull at pin 9 & 10 occur at the same time by delaying the output when one pin are low from the other. The standoff time increases when the first charge to start first C =10 Mf between 13, 14 and 4 discharge. This action causes the stand off time 100 % at pin 9 and 10.When capacitor charges through R=47k to ground, standoff time discharge to ground level. To prevent the over-voltage of the battery, it is necessary to keep the level of pin 2 of IC1 at low. Check the voltage of battery by a voltage divider 10K –12K when the voltage of battery below 10V, the output port of 9 + 10 is close to turn off the circuit. II. 4. 5 The h output Q3 BUK655 Q5 BUK655 340V 1N4148 1N4148 1N4148 1N4148 T3 T5 1.2M Y 100 pf 240VAC output 220k 220k 100 pf 100mf Q4 1N4148 BUK655 Q6 1N4148 BUK655 1N4148 1N4148 T4 T6 3.3k 100 pf X 220k 220k 560 pf 39 560 pf 100 pf 560 pf 560 pf As mentioned above 4 mosfet are connected in “ H “ figure through HV. Mosfet Q Q3 - Q4 - Q5 - Q6 are trigged by the trigger of analog transformer to isolate from low voltage, the gate trigger of Q3 is include transformer T3, Diode Ñ + D10, Transistor Q7, Zener diode ZD3, R = 220 Ohm and capacitor C = 100 mf. To energize Q3, the frequency of 1 Mhz is apply to primary of T3, The output voltage from secondary ports are rectified by Diode D and filtered by C = 100 mf. The DC output is fed back through D1o to gate of Q3. When Zener diode ZD8 zener at 15V of gate Q3 -- then T3 open. . To de-energize Q3, 1Mhz signal is turn off, but this action is not fast enough. Q7 operates - Capacitor 100 Mfd charges through 220 K – until base of Q7 turn below 0.7 v to the Emitter -- Q7 rapidly opened to ground the capacitor voltage of gate Q3 to turn it off immediately. As previous described Q3 + Q6 are push – pull and Q4 + Q5 are push-pull. The series transformer T3 + T6 --- T4 + T5 are energized sequently. To energize transformer T3 + T6, it is necessary to have the series of 1 MHz signal every 10 us in only 70% time (T1 = 70%) = 7 us .IC5 oscillated series 50 Hz that is needed for 1 Mhz. IC6 is a timer circuit 7555 that vibrates at 1 KHz and trigged IC 6. A decade counter CD 4017 with 10 output that decode 5 –6 – 7 0f IC 8 were connected to OR circuit by diodes D17, D18, D19, to control the high output of NAND (IC10a) Three high output in only 10% or 30% of time. After reversed by IC 10a, the output is high in 0% of time as already dad IC 10a triggers pin 8 + 11 of IC 10 b + IC 10c, pins 1 + 13 of IC 10b + IC 10c are connected to complement output Q + Q every time it get clock-pulse from 5 of IC 8 every 10 us the reset input of IC 10b + IC 10c are connected to 1MHz oscillator IC 7 incorporated with another timer LM 7555. IC10b and IC10c can only send signals 1MHz when other 2 inputs are high. This occurs in 70% of time in each 10us sequently. The supply voltage is 12 VDC from the battery through Fuse 30A is connected directly to transformer T1. The low path is connected to switch S1 and resistor 10 Ohm; Capacitor 2200 mf in parallel with supply path is used to regulate the current to inverter. One LED in parallel with supply is to inform the power supply is on and remember LED must be in series with resistor 2.2K Ohm. This document s include: - Schematic diagram of Inverter - PC board for assembling. 40 REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam LESSON 5 TRUE SINE INVERTER I. INTRODUCTION. After almost 50 years of development, nowadays sine modified Inverters technology is still popular and covered the global market. These Inverters are quite simple, easy for manufacturing, maintenance and an economic price, although that, disadvantages of this kind of inverter are many. First of all they response only for resistive loads. The inductive and relative loads could not run on them as fan, motor, pump, compressor act … One being technical baries is unregulated sine square wave and uncontrolled frequency which not allow to make sixnonization among them to increase power from several Inverter as well as grid connected. Today, a lot application need high confident frequency – band and accurate synchronization and big power act... The sine-modified wave could not response well. True sine wave has been born in this situation to put away all limitations of S.MW Inverter. True sine wave technology is a mille – store of development, which satisfies all requirement of development global market. Every kinds of loads, no limited power range, high confident frequency –band and high efficiency of over 90% are basic advantages of true sine wave inverter. It also response well for high technology equipments in field of telecommunication, informatics without any interference. T.S.W Inverter is ideal product for renewable energy development with grid-on /off technology. II. DESIGN AND OPERATION Design idea: For creating a standard AC source from 12VDC is quite complicated with several requirements such as: Stable voltage, low coefficient of distortion, and no drop – power and high conversion efficiency. Transmitting energy from DC source with frequency 0Hz into AC 50Hz. It could not use line near method but it must carry by high frequency more than 20kHz then on output it is filtered to get energy 50Hz. 42 1. Block of scheme: Feedback Modulator 2 Oscillator creating standard sine signal 50Hz 3 Waveform correction 5 4 Oscillator creating trigger pulse 20Khz Low voltage 9 Protector Overload 10 Indicator Driver 6 Feedback Output 220V/50Hz 8 Filter 7 Amp -power 1 Battery 12V Operation of working blocks: - Block 1: Battery 12 VDC is a DC power source for changing and supplying energy to other working blocks. - Block 2: Creating standard sine signal 50Hz it is most important block using as a basic signal. - Block 3: This is the most important to have true sine form reference and compensation feedback signal from load with standard sine signal to create appropriate wave 50Hz to distribute to splitting two channel. - Block 4: Oscillate for creating triangle puls with high frequency 20kHz, carrying sine wave 50Hz to output terminals of the regulation blocks. - Block 5: Modulation of appropriate wave and triangle pulse 20kHz to get square pulse 20kHz with different width. - Block 6: Driving square pulse 20kHz to fit input pulse of power amplifier. - Block 7: Power – amplifier consists of two branches operates by driving pulses to create output power. This block decides working power of inverter. 43 - Block 8: 50Hz filters, filtering high frequency signal into frequency signal 50Hz which be feedback to block 3 for recorrection of waveform. - Block 9: Disconnecting power when getting any trouble as overload, low voltage, short circuit to protect inverter. - Block 10: Indicator indicating all working states of inverter. Operation of the blocks are controlled by waveform on output of each. 2. Design: 2.1. Design principle: Block scheme consists of two parts: - Regulation / controlling block - Power amplifier block 2.1.1 Usually the regulation-controlled block is designed in following scheme which is easy finding out devices on market. There are many ways of design to get standard sine signal some design methods are introduced hereby. a. Analog method: The circuit use two IC 1458 to create sine function the first gate create square wave 50Hz, two following gates create triangle wave from square wave and calibrate incorrect wave form. The fourth gate amplifier signal to combine isolated resistance output. The circuit design is simple, devices are easy to find out competitive price. Although that, accurate of circuit is not high and it needs to use Bi – power source crested standard sine. The balance of passive elements is very difficult. b. Digital method: 44 BoÄPHAÙ T SOÙ NG KIEÅ U BÖÔÙ C Vcc 8 4 3 7 6 5 Q 2 ¼ 4042 D 7555 2 8 7 D Q 10 13 ¼ 4042 D Q ¼ 4042 14 11 D ¼ 4042 Q 4 1 IC 555 oscillates to create startup pulse (ck). Out put gate F.F using responding resistance to pull up getting step wave. It is called step wave creative circuit. After that, they are carried out to calibrated circuit them we have standard sine U U t t R1 Vi op-am R2 V out Following advanced technology today, some manufacturer order makes special compact devices for themselves. It is a security way of knows how and it makes difficulty for maintenance of lacking replaced devices on the market. 2.1.2 Power amplifier: There are many designs to do power amplifier. The most important for designer is getting optimum design which must follow the devices appearing on the market. We propose some schemes for choice a. Half – bridge inverter Unfiltered Output Filter 45 Filtered Output With this scheme, which gives high quality of waveform, high transmitting speed waveform has not been split of in channels. It requests transistor devices Bi–pole, which can stand in high voltage. b. Full – bridge inverter Unfiltered Output Filtered Output Filter Speed of change has shape of half – bridge but output waveform was channel split off. This circuit is well for big power range, allowing using lower voltage devices and saving energy. But UPS devices are suitable for this circuit 2.2 Principle Scheme: consists of: - Sine wave oscillator board Modulator board Chopper board Power amplifier board 3. Definite principle of operating block: 3.1 Circuit creates sine wave IC 555 oscillates to create square wave 50Hz to make clock pulse IC 2 (4520), this pulse is taken carried out by gate Q0 of IC2 with frequency 20kHz. It drives modulator and recorrect waveform. Output gate Q1 of IC2 makes pulse clock for IC3 to create pulse 800Hz on output gate Q3 and pulse 50Hz is taken out at sixth pin of IC4, which is a signal to drive IC6. Op-amp 1 amplifies feedback Voltage from load past to fourteenth pin of IC6. At pin14, 13, and 12 of IC6 can be display switch, when pin 14 links 13 opamp 2 amplifies IC5 has function to decode BCD 3 line into out 8 lines combining op-amp 2 to create step sine wave which has amplitude Vp – p = 12V. 3.2 Modulator and channel splitting off (see above principle diagram) 46 IC1 recorrects step wave form to become standard sine wave 50Hz. IC2 takes out feed back signal from load to reference and compensate with standard sine signal then creating distortion sine wave as following chart: IC 3 Osculate to create triangle pulse high frequency 20kHz. This signal goes together detective sine wave into IC4 IC5 to modulate and channel splitting of A and B channels which driver 2 power amplifying channels. III. TECHNOLOGICAL PARAMETERS: DC input voltage: 9V – 14.5V distortion rat < 3 % AC output voltage: 220C AC ±5% P = 1000W (if overload 1500W, Inverter stands 1.5s and overload to 2000W to be 50ms) Stable frequency f = 50Hz ± 0.5% 47 REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam LESSON 6 COMPUTER DESIGNING OF INVERTER I. INTRODUCTION: Designing with the support of computer has developed so long, it assists us to save much of time. Design with the support of computer reach the high exactness if being done by hand it is very difficult to reach, it is the tool for quick design. One of the works, which the electronic worker should do well, is to draw the printed circuit board to weld and install all kinds of electric circuit. If having to do this work in craft there will be a lot of restrains. Presently there have been a lot of software running on computer which can be in charge well this work. I.1 Software used to design electricity, electronics. The software which are used to design the electronic circuit there are many, normally they combine in couple to be a group that is Orcad/SDT for Schematic design tool called SDT, to be used commonly with Orcad/PCB to compare and create the premise for Orcad/PCB when establishing the Printed Circuit Board called PCB. It means that Orcad/PCB will base on the draw of Orcad/SDT to design automatically the circuit lines, location of the accessories in order later to give a printed circuit board in the preeminent manner. It can stipulate the names of the following software: - Software: PROTEL-AUTOTRAX OF AUSTRALIA. - Software: CIRCUIT MAKER which is the computer program for drawing design - imitation of the electric circuit running on WINDOWS. - ULT CAP SCHEMATIC DESIGN TOOL. - ULT PAK of Lab Center. - SMART. - QUICK ROUTE running on the media of Windows. - Easy Professional with the sub-program. * Pulsar for imitation. * Analyzer for analysis and imitation of the linear circuit. * Z match for analysis of the Smith diagram in high frequency. I.2 Software used in Vietnam There are a lot of software lists, but we collect Orcad due to the following reasons: - Orcad imported into Vietnam so long, there are many users therefore it has been propagated widely. - There are so many software in the market, easily for set-up. 50 -- - Orcad does not require about the structure of machinery. It can run on IBM, PC XT, AT Computer or relevant circuits suitable with IBM. In the field of electricity and electronics the software of ORCAD for designing electronic circuit, this software settles for two basic matters for making the electric drawing that is Orcad STD-Schematic Design Tool and designing Orcad PCB Printed Circuit Board but this software is just in the form of drawing with a preeminent design to automatically run the networks to connects the accessories with each other. In order to calculate the design of the electronic circuit we should use further PSPISE. It has the effect to settle the mathematics for circuit theory. Capacity of Orcad is also very strong: - To have capacity for automatic and manual design. - To have a big library. - It can be revolving and symmetric partially. - It can be elastic the connecting wire and bus when moving the objectives. - It can move and wipe the objectives or blocks. - It can carry out repeating the orders quickly. - It can display the squared net. - There are 05 launching levels. - The user can foist over 100 adding-up orders. - Not to limit the classified drawings. - It can display directly the directories of library. - Statement can set up in horizontal line and it can set up in vertical line. - It can print on the paper of size from A to E and there are a lot of particulars you will refer further. For the old software Orcad running in the environment DOS therefore if wanting to use it we should study some orders, nowadays we have had Orcad running in the environment of Windows therefore the use is easier. II. DESIGN: II.1. Design of Inverter. We will use the software to draw Electronic Circuit: Orcad/SDT in order to carry out drawing 01 simple Inverter. In order to be able to draw the electric circuit of Inverter by computer we should understand function and usage of the orders in menu: Again Block Conditions Delete Edit Find Get Hardcopy Jump Library Macro Place 51 -- Quit Repeat Set Tag Zoom After appearance in the left corner of the screen a menu board is arranged to lengthwise. There are three ways to develop the orders in Menu as follows: 1- To press the key of the initial character of that order. 2- To use the arrow key to move the light bar to the order which we want to call and press Enter key. 3- To use MOUSE to move the arrow and order which we want to call and to click the left knot of MOUSE. 4- A lot of main orders in Menu with the subordinate orders and various effects. From subordinate Menu, when wanting to return main Menu, press ECS key until main Menu re-appears (or to click the right knot of Mouse). II.2. The design steps of Inverter. II.2.1 Design of block diagram: Inverter is the machine to transform electricity from DC to AC so it should have the frequency oscillator 50Hz, this signal need to be sufficiently big to excite for the capacity of transistors together with transformer (to excite for these transistors to turn off/on to the rhythm 50Hz) to create the secondary rate of the revolving voltage transformer therefore in circuits should have the impulse amplitudes rating between primary and secondary rate of the transformer output depending on the DC voltage input from the said conditions we can construct the block diagram of an inverter as follows: Block diagram of Inverter: 1 2a 3 4 5a 6a LOAD 2b 5b 6b 7 52 -- Block 1: Multi-harmony oscillator or oscillator outputting a rectangular 50 Hz impulse. Block 2: Single circuit stabilizer, used to create an impulse amplitude for each halfperiod of excitation. It is possible to control amplitude by means of feedback from block 3, 4. Block 5a, 5b: Excitation cascade for the power output transistor. Block 6a, 6b: Power transistors, connected depending on the out put power. Block 7: Consists of under-voltage and over current protections and an accumulator charger. LC: Output filter (AC). From the said block diagram we commence to design the electric circuit. Block 1: Oscillator creating Q, Q: In order to create two signals of opposite phases for frequency 50Hz we have more various ways, we can use the oscillating circuit to combine between transistors and accumulator, inductive wire, resistance, or usage of IC 555, but these circuit should be settled in stability the complex frequency therefore I see that we can use IC4047 to make the oscillating circuit and also dividing frequency, we have the signal in the position 13 with frequency 100Hz divided into 50Hz to position No.: 10 and 11 but opposite with the remaining phase. So, in order to draw the said circuit we commence the following steps: Step 1: Drawing IC a- Pressing Enter for three times to call main Menu b- From main menu - collect Get c- From the Get dialog line, to type 4047 and press Enter on the screen appearing symbol IC d- To use Mouse or arrow to move the symbol to the location where you want to set-up and press P key. The symbol will change the color. To move cursor out the location for continuity to call other accessories, to press <ESC> key to escape and Enter to return main Menu. VCC Y U1 Y 1 RST RX CX RCC 13 11 10 OSC RET +T -T AST AST Q Q 4047 9 2 1 5k VR1 1 + .33 C1 3 12 8 6 4 5 1 Y 1 Y + .1 C2 1 Y Step 2: To draw resistor, rheostat: 53 -- 10k R1 a- From main Menu to call Get b- From the dialog line to type into Resistor or R and Enter. The screen appears the symbol of resistor and subordinate menu c- To use mouse or arrow key to move the symbol to location where needing to locate and pressing P key, the symbol will change the color in case wanting to rotate the symbol we press R key (Routate) to rotate the symbol and to press P key for location d- To move cursor out the location to call continuously the other accessories. To press ESC key to escape and Enter to call main Menu. Step 3: To draw Vr a- From main Menu to collect get b- From the dialog line to call Get, to type into Vr and Enter. The screen appears the symbol of rheostat and subordinate menu c- To use Mouse or arrow key to move the symbol to the foot of R and press P key. The symbol will change color, if needing to rotate the accessory to press R key d- To move cursor out the location to call continuously the other accessory. 4/. To draw accumulator C1, C2. a- From main Menu, to collect get b- From dialog line Get, to type into Cap and Enter. The screen appears the symbol of accumulator and subordinate menu c- To use Mouse or arrow key to move the symbol to foot 1 and 3 of IC to press key (when needing to press R key to collect the characteristic pole of the accumulator) to press P key the symbol will change color d- To use Mouse or arrow key to move the symbol to foot 5 of IC to press P key the symbol will change color (when necessary to press R key to collect characteristic pole of the accumulator). Step5: To draw Mass of accumulator and IC a- From main Menu to call Get, b- From dialog line Get, to type into GND power and Enter. The screen appears the symbol mass and subordinate menu c- To press arrow key or Mouse to move the symbol to the foot of IC d- To press P key to confirm. The symbol will change the color e- To move cursor out the location to call continuously the other accessories, to press ESC key to escape and Enter to return main Menu. Step 6: To mark Vcc a- From main Menu, to collect Place. A subordinate menu appears b- To collect power. The screen appears symbol Vcc at the location of cursor and a subordinate menu c- To use arrow key or mouse to move the symbol to any location near IC and to collect place (pressing P key) the symbol will change color 54 -- d- To move cursor out the location to call the other components, to press ESC to escape and Enter to return main menu. Step 7: To draw circuit line: a- From main menu, to collect Place to appear subordinate menu b- From subordinate menu, to collect Wire or BUS or Dashed line (accordingly) and appear a order line. Begin Find jump Zoom Escape. c- To use Mouse or arrow key to move cursor to the point for commencing drawing. For example to draw the line connecting the feet 9, 12, 8 and mass, to locate cursor at the foot No. 9 of IC and to press <B> key (begin > the screen appears the order line. Begin End New Find Jump Zoom escape d- To use Mouse or cursor to draw circuit. When drawing a white line appears following the location of cursor moving. (To connect to foot 12, foot 8 then connect mass located before that), to press key <End> the drawing line will change color e- To press key ESC to escape and enter to return main menu f- To repeat the practices from a to e to draw the other circuit lines Step 8: To draw the point connecting circuit: a- From main menu to collect Place appearing subordinate menu b- From subordinate menu, to collect Junction c- The screen appears the symbol at the position of cursor and subordinate menu: place Find Jump Zoom escape d- To use Mouse or cursor to move cursor to the location which wanting to collect (for example the cutting point between foot 12 with the connecting line of foot 9 and mass and to press P key the symbol will change color. e- To continue moving the symbol to point of foot 8 to cut with the connecting line between foot 9 and mass and to press P key the symbol will change color. f- To move cursor out the location to press ESC key to escape and Enter to return main menu. Step 9: Remark the exit and entry port of the circuit: a- From main menu, to collect Place to call subordinate menu b- From subordinate menu, to collect TEXT c- From question <Test?> to type into oscillation and Enter the screen will appear the word oscillation at the location of cursor and order line. Place Orientation value larger smaller find Jump Zoom escape d- To use arrow key or Mouse to move the word to fixed location and press <P> key. Then to move cursor to the other location. To press ESC to escape and Enter to return main menu. II. 2 Save of drawing In order to save the drawing, to carry out the practices as follows: 1. From main menu, to collect Quit to call subordinate menu. 55 -- 2. From subordinate menu, to collect Write to file. 3. From the dialog Write file? To type into the name which wants to name for the drawing in attachment of the enlarging part and Enter the drawing save into an information book. Note * If calling not correctly the name of accessory, in same screen it will inform the words <NOT FOUND>. Therefore, if not to understand clearly what the accessory wants to call, from the dialog Get? To press Enter key to call library. From the dialog <Which library?> to collect Device.Lib. to collect continuously Serene order the list will appear for reference. * Or from main menu to call Library, a page of item listed the names of component concerning the drawing, we can refer and collect correctly the names of the desired components. 56 --