* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download PNIMNiPE_nr56 - Instytut Maszyn, Napędów i Pomiarów
Power factor wikipedia , lookup
Audio power wikipedia , lookup
Electrification wikipedia , lookup
Control system wikipedia , lookup
Electrical ballast wikipedia , lookup
Resilient control systems wikipedia , lookup
Current source wikipedia , lookup
Electric power system wikipedia , lookup
Resistive opto-isolator wikipedia , lookup
Electrical grid wikipedia , lookup
Power inverter wikipedia , lookup
Power engineering wikipedia , lookup
Power MOSFET wikipedia , lookup
Amtrak's 25 Hz traction power system wikipedia , lookup
History of electric power transmission wikipedia , lookup
Electrical substation wikipedia , lookup
Three-phase electric power wikipedia , lookup
Mercury-arc valve wikipedia , lookup
Voltage regulator wikipedia , lookup
Surge protector wikipedia , lookup
Stray voltage wikipedia , lookup
Opto-isolator wikipedia , lookup
Variable-frequency drive wikipedia , lookup
Buck converter wikipedia , lookup
Voltage optimisation wikipedia , lookup
Switched-mode power supply wikipedia , lookup
Alternating current wikipedia , lookup
Nr 64 Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej Nr 64 Studia i Materiały Nr 30 2010 PWM rectifier, integrated power module, hardware design, TMX320R2812, auto-code generation Michał KNAPCZYK*, Krzysztof PIEŃKOWSKI** THREE-PHASE PWM RECTIFIER BASED ON INTEGRATED POWER MODULE AND FIXED-POINT DIGITAL SIGNAL PROCESSOR FOR RAPID PROTOTYPING ISSUES The paper presents a laboratory test-bench with a three-phase two-level PWM rectifier. The setup is based on a 3.3kW integrated power module and a 32-bit fixed-point digital signal processor with a Simulink auto coder for rapid prototyping of control strategies. The setup has been diversified into separate modules for different tasks: grid voltage and grid current measurement modules, hardware dead-time block with IGBT gate signal inverted logic driver, analogue signal processing block for sensor-to-processor interface, auxiliary control electronics and power circuits with overvoltage and overload protections. These modules assembled in unit provide entire functionality of the laboratory setup with the PWM rectifier for flexible and fast implementation of control strategies either for their further development or for the purpose of didactics. In order to demonstrate the operation of the proposed test-bench Sliding-Mode Voltage Oriented Control with -PWM has been implemented to control the PWM rectifier. Numerous experimental results have been presented and discussed. 1. INTRODUCTION Modern power electronics devices for commercial use are controlled by numerous types of microcontrollers. A code of newly developed and thoroughly tested control algorithms is next optimized to be run within a possibly lowest time-consuming microprocessor routine. However research and development phase of design of new control schemes for power electronics equipment requires versatile and flexible control units usually based on fast fix-point or even floating-point digital signal processors. These are usually mounted on evaluation boards equipped with dedicated peripherals like PWM __________ * 3cap Technologies GmbH, 85764 Oberschleißheim, Germany, [email protected] Politechnika Wrocławska, Instytut Maszyn, Napedów i Pomiarów Elektrycznych, ul. Smoluchowskiego 19, 50-370 Wrocław, Poland, [email protected]. ** 2 modules for control of power electronics devices, ADC converters, general purpose inputs and outputs, as well as RAM or EEPROM for flashing the software and recording diagnostics alerts. They provide communication with PC usually via a standard serial or USB port. In field of high quality energy conversion integrated power modules have recently revolutionized the design of modern power converters. For high power conversion the semiconductor structures are designed as integrated modules containing SCR or GTO legs. In range up to medium power ratings complete IGBT- or MOSFET-based three-phase two-level and multi-level converters are available. Further improvements in design of power modules have led to integration of protective electronics with the semiconductor structure inside its package or outside it in case of its tiny dimensions [1,2,3]. Such intelligent power modules are protected against overloading, over/under-voltage and over-heating [6,7,8,11]. This paper describes a design of a laboratory test-bench with the three-phase two-level PWM rectifier based on 3.3 kW IGBT power module FS10R06VL4 with EiceDRIVER 6ED003E06-F and evaluation board eZdsp R2812 with TMX320R2812 digital signal processor. The presented design process providing increased quality of system performance has been significantly improved in comparison with the previous hardware setup presented by authors in [4]. 2. DESIGN OF LABORATORY SETUP WITH PWM RECTIFIER The PWM voltage-source rectifier requires for its proper operation the exact information about grid voltages, grid currents and the output DC voltage (Fig.1). Fig.1. Diagram of proposed experimental setup of PWM rectifier 3 2.1. INTEGRATED POWER MODULE The power unit of the proposed prototype of the PWM rectifier is based on the 3.3 kW IGBT power module by EUPEC/INFINEON with the electronic interface EiceDRIVER™ 6ED003E06-F [11]. The reason of the widespread use of the IGBT transistors is their voltage-based control because practically no power is taken during the switching process unlike in case of SCRs or GTOs. The crucial problem in realization of the driver system for the transistor-based two-level bridge is a floating reference voltage for gate signals of the upper-side transistors. The problem has been overcome by the application of a dedicated IGBT driver IR2136S of International Rectifier using the boot-strap technique. Fig.2 presents the three-phase IGBT power module mounted on a heat-sink with additional protective electronics. Fig.2. EiceDRIVER 6ED003E06-F: overview (left); block diagram [11] (right) The FS10R06VL4 power module presented in Fig.3 provides the maximal DC-link voltage Udcmax=300V and the maximal DC-link current Idcmax=10A. The minimum deadtime for the IGBT transistors in each leg of the converter is Tdead=1.8s. Fig.3. EUPEC module FS10R06VL4 consisting of six IGBTs integrated in gel-filled package 4 Fig.4 presents the detailed functional diagram of the proposed laboratory setup of the PWM rectifier with the FS10R06VL4 integrated power module containing six IGBT transistors with respective shunt diodes, the IR2136S IGBT driver and the LM393M voltage comparators. The on-board electronics is supplied with 15VDC. This electronic interface provides short-circuit, under/over-voltage and over-current protection by a shunt resistor, the IR driver and comparators. In case of power modules which are equipped with NTC temperature sensor in their internal structure EiceDRIVER can also provide an over-temperature protection [11]. P1/CON9 - CONTROL 1 2 3 4 5 6 7 8 9 BYG20J NC BYG20J BYG20J 1 VCC VB1 HO1 2 3 4 5 6 7 8 100k MCL4148 VS1 27 82 10u 26 82 FS10R06VL4 VB2 HO2 FLT 28 VS2 24 23 10u 9 82 22 MCL4148 11 ITRIP VB3 EN HO3 RCIN VS3 20 19 10n 0.1u 10u 15k 18 EU 10n VSS LO1 LO2 0.1u 13 COM LO3 G1 16 + - 270 G2 G3 EV G4 G5 EW G6 15 82 14 15k IR2136S 0.1u 120 15k 15k N (-) LM393M 68k 15k 10n 12 SUPPLY 15V 15k 82 0.1u 47u MCL4148 U V W 82 2 1 P (+) 560k 10 P2/CON2 HIN1 HIN2 HIN3 LIN1 LIN2 LIN3 33m 2.2k NTC LM393M (optional) 8.2k 33k 33k + - 0.1u 2.2k 15k 0.1u 0.1u 100k 0.1u 560k 10n Fig.4. Detailed diagram of EiceDRIVER 6ED003E06-F with FS10R06VL4 6-pack module [11] Table 1 presents selected electrical characteristics of the proposed FS10R06VL4 power module with its driver circuit 6ED003E06-F. Table 1. Selected parameters of EiceDRIVER 6ED003E06-F with FS10R06VL4 6-pack module DC-link voltage Udc: DC-link current Idc (@TC=25°C) Collector-emitter voltage UCE Maximal switching frequency fswitch Minimal PWM ratio Total power dissipation Ptot (@TC=25°C) Minimal dead-time for IGBTs in one leg Tdead Driver supply voltage Uin 360V 10A 600V 15kHz 0.1 78W 1.8s 15V 5 2.2. VOLTAGE AND CURRENT SENSORS In the proposed laboratory setup with the PWM rectifier voltage and current transducers offered by LEM have been applied. The operation of these sensors is based on Hall-effect to provide galvanic separation between the microprocessor and the power module, as well as to provide high linearity and accuracy of voltage and current sensing [9]. Fig.5 presents prototype boards with LV25-P sensors for grid and DC-link voltage measurement and grid current transducers LA50-P. The voltage measuring range in case of LV25-P is set up using carefully selected shunt power resistors. The current measuring range for LA50-P can be easily adjusted by setting an appropriate number of turns of a current cable round a transducer’s core. Fig.5. Prototype boards with transducer for AC-DC voltages (left) and ac currents sensing (right) Fig.6 shows a coupling and scaling interface for the transducers and the DSP. Since the analog-to-digital converter (ADC) of the DSP requires positive input signals in range from 0 to 3V the offset signals have been added to the scaled output signals of the proposed transducers. The matching circuit is based on inverting operational amplifiers TL074 and RC low-pass filters for the anti-aliasing purpose. For the maximum protection of the DSP the inputs of the ADC channels have been equipped with the 1N5711 Schottky barrier diodes operating as voltage limiters. Fig.6. Scaling interface between voltage and transducers and analog-to-digital converter of DSP 6 2.3. OPTOCOUPLERS, DEAD TIME AND POSITIVE-TO-NEGATIVE LOGIC CONVERTER For galvanic separation between the power module with its interface electronics and the microprocessor-based control system fast logic gate opto-couplers HCPL-2211 have been applied. The hardware dead-time module has been designed using SN7414 Schmitt-trigger inverters, SN5406 buffers with open-collector outputs and the RC branches. Besides providing blinking time the proposed circuit inverses control signal to negative logic routine. Despite its sensitiveness to changes of ambient temperature the circuit shown in Fig.7 provides satisfactorily stable functionality at typical laboratory conditions. There are six independent circuits for each of six IGBTs. +15V 7805 +5V TMX320R2812 HCPL-2211 GPIO (PWM) ACTIVE HIGH SN7414D C1 SN7406D B1 SN7414D A1 to IGBT ACTIVE LOW Fig.7. Opto-coupler, dead time and positive-to-negative logic converter (left); signal routine (right) Fig.8 (left) presents the prototype board with the complete set of circuits presented in Fig.7 for one IGBT. The parameters of the RC branch have been tuned in order to make signals reach a Schmitt-trigger’s threshold in 2s as shown in Fig.8 (right). C1 C2 Fig.8. Evaluation board with optocouplers and hardware dead-time (left); measured control signals for one leg of IGBT module (right) 7 2.4. FAULT PROTECTION SYSTEM AND LINE POWER ADAPTER The proposed prototype of the PWM rectifier has been equipped with software and hardware protection systems against hazardous effects of any possible faults or power overshoots. As it is shown in Fig.9, in case of short-circuit or overvoltage the power module should be cut off from the supply line throughout respectively varistors, fuses and a relay. Moreover a brief unexpected collapse of the low DC voltage supplying the DSP and control electronics causes the cut-off of the power module and safe discharge of the DC-link capacitor thru a discharging resistor. Fig.9. Overview of protective equipment of proposed setup of PWM rectifier In order to provide a low DC input voltage for auxiliary electronics and sensors a power adapter has been designed. Fig.10 presents its application with a wiring diagram. For safety reasons the power module supply voltage of 15VDC is provided separately. Fig.10. Power adapter for DC low voltage: front view (left); schematic diagram (right) 8 2.5. TMX320R2812 DIGITAL SIGNAL PROCESSOR For the realization of the control tasks in the experimental setup of the PWM rectifier an evaluation board eZdsp™ R2812 by Spectrum Digital® based on TMX320R2812 Digital Signal Processor by Texas Instruments has been chosen. Fig.11 presents the front view of the DSP applied in the proposed setup of the PWM rectifier. The block diagram beside shows the DSP’s internal functionality. Fig.11. eZdsp board based on TMX320R2812 DSP by Texas Instruments [10] The TMX320R2812 is the fixed-point, 32-bit data word microprocessor with two overlapping data and program address spaces, 18K words on-chip RAM, 128K words on-chip FLASH, 64K words off-chip SRAM, 30MHz clock (maximal rate up to 150MHz), 56 multiplexed digital inputs/outputs, 12-bit 16-channel analog-to-digital converter (80ns), 45 interrupts divided into 8 levels of priority, 5V supply voltage and two Event Managers including a hardware 2-level/3-level PWM modulator. The DSP is embedded on an evaluation board presented in Fig.12 with the interface electronics for the transducers and two external 8-bit digital-to-analog converters (DAC) for monitoring of inner control variables direct on an oscilloscope. Fig.12. DSP socket with interface electronics (Fig.6) (left); pin layout for PWM and DACs (right) 9 2.6. OVERVIEW OF PWM RECTIFIER PROTOTYPE The complete laboratory setup of the PWM rectifier consists of the six component boards presented in the previous sections assembled one on another and connected as shown in Fig.13 to provide the functionality depicted in Fig.1. Fig.13. Overview of assembled prototype of PWM rectifier on test-bench 3. SIMULINK MODEL FOR AUTO-CODE GENERATION The idea of Sliding-Mode Voltage Oriented Control (SM-VOC) for the PWM rectifier described in details in [5] is the decomposition of the grid current vector ig based on the Park transformation into the two rectangular components igd and igq -q) coordinate frame oriented with the grid voltage vector as depicted in Fig.14 (left). Fig.14 (right) presents a block diagram of the proposed control method. Fig.14. Sliding-Mode Voltage Oriented Control: vector decomposition (left); block diagram (right) 10 Fig.15 demonstrates the Simulink model of Sliding-Mode Voltage Oriented Control presented in Fig.14 (right) realized with help of Target for TI C2000™ toolbox including C28x IQmath Library for fast fixed-point arithmetic. SM-VOC R2812 eZdsp voltage C281 x A 5 ADC A5 egAB A4 A4 egBC A0 A0 igA A1 A1 igB A3 A3 udc analog -to -digital converter egAB current angle egBC angle egd igA egq igB igd Input1 left igq Input2 right scaling DACleft DACright Out to SCOPE reference currents id *, iq * computation signal offset cancelation egd id* egq id* sd id phi*(rad) 0 phi * u0* switching fcn for d -axis iq* PI d a s1* q b s2* angle c s3* iq* sq 820 switching fcn for q -axis udc * C281 x to IGBTs iq i_load GPIO DO u0 Digital Output To switches Fig.15. Target for TI C2000 model of Sliding-Mode Voltage Oriented Control for auto-coding Fig.16 presents one of applications of the fixed-point IQmath arithmetic model of selected parts of Sliding-Mode Voltage Oriented Control for real-time auto-coding. reference currents id *, iq * computation 4 u0* egd egq id* i_load A IQmath Y B IQNdiv IQN / IQN 1 1 id * 1 egd phi*(rad) u0* 5 i_load A IQmath Y BIQNmpy IQN x IQN iq* 2 egq 3 phi *(rad ) A IQmath Y BIQNmpy IQN x IQN 1 A IQmath Y BIQNmpy IQN x IQN 2 A IQmath Y B IQNdiv IQN / IQN 2 iq * Fig.16. Target for TI C2000 model of Sliding-Mode Voltage Oriented Control for auto-coding Texas Instruments IQmath Library is set of highly optimized and high precision mathematical function library to port the floating-point algorithm into fixed-point code on TMS320C28x devices. These routines are typically used in computationally intensive real-time applications where optimal execution speed and high accuracy is critical. The TI IQmath library shortens significantly the time of DSP application development [10]. 11 4. SELECTED EXPERIMENTAL RESULTS The experiments have been carried out using the parameters presented in Table 2. Due to the properties of the power module of the PWM rectifier presented in Table 1 the experimental verification has been performed at a reduced grid voltage. Table 2. Parameters of experimental setup with PWM rectifier Grid phase voltage eg: Grid voltage frequency fg: Grid resistance Rg: Choke inductance Lg: DC-link capacitance Cd: DC-link nominal voltage Udc: Load resistance Rload: SM-VOC sampling rate: 38V 50Hz 100m 11.3mH 1000F 100V 35 35s Fig.17 (left) presents a measured phase grid voltage and three-phase sinusoidal grid currents at step change of a converter load (Rload=35) and at unity power factor condition (UPF). Fig.17 (right) shows the grid currents in the (d-q) coordinate frame at step change of converter load derived with help of DACs. igC igB igA egA Fig.17. Experimental results of Sliding-Mode Voltage Oriented Control for proposed PWM rectifier: phase grid voltage and three-phase grid currents at step load change and unity power factor (left); grid currents in (d-q) coordinate frame at step change of converter load (right) The transient of the DC-link voltage at step change of converter load is shown in Fig.18 (left). Since the measured phase grid voltage is corrupted with low-order harmonics (mainly the third), this grid voltage distortion is also penetrating into the DC-link 12 voltage making it oscillate. However there is no fourth wire in the system and the influence of the third harmonic is thus cancelled and the grid currents remain sinusoidal. Fig.18 (right) presents the rectifier input line-to-line PWM voltage produced with help of the delta-modulation (-PWM) for SM-VOC. Since the grid voltage is reduced the presence of voltage drops over IGBTs is thus distinct. Fig.18. Experimental results of Sliding-Mode Voltage Oriented Control for proposed PWM rectifier: transient of DC-link voltage (left); rectifier input PWM voltage under delta-modulation (right) 5. CONCLUSIONS The paper presents a thorough design of the experimental setup of the PWM rectifier based on a DSP control unit. For the proper operation the PWM rectifier requires feedback information about all state variables. Hence the voltage and current sensors with its auxiliary electronic have been constructed and examined. The real-time application of the Sliding-Mode Voltage Oriented Control (SM-VOC) for the PWM rectifier requires a faster and more efficient digital signal processor than in case of its linear counterpart (VOC) to achieve the comparable quality of the control process. This is due to the fact that Sliding-Mode Control of the PWM rectifiers uses the delta-modulation that is realized on-line at each calculation step of the control algorithm. In contrary, SV-PWM is realized in a separate hardware module (Event Manager) at a definable rate regardless of a control algorithm rate. However as it was shown in this paper it is possible to implement the proposed sliding-mode-control technique in TMX320R2812 DPS which is dedicated for power electronics applications. The proper selection of values of the choke inductance and the DC-link capacitor, as well as neglecting a sensorless control in the algorithm provide the satisfactory performance of the sliding-mode-based control techniques using the proposed digital controller. 13 REFERENCES [1] FREYBERG M., HERMWILLE M., HONG U.-S., LI J., SEMIX and SKYPER – an intelligent IGBT module with adaptable driver, The 28th Annual Conference of the IEEE Industrial Electronics Society IECON’02, Seville, 2002. [2] KANELIS K., LORENZ L., STOLZE T., New Low Cost IGBT-Modules, Proceedings on International Conferences ZM Communications GmbH PCIM’01, Nuremberg, 2001. [3] KANSCHAT P., STOLZE T., PASSE T., RŰTHING H., UMBACH F., HELLMUND O., 600V IGBT3-Technology in New Low Cost Modules for Consumer Drives Applications, Proceedings on International Conferences ZM Communications GmbH PCIM’03, Nuremberg, 2003. [4] KNAPCZYK M., PIEŃKOWSKI K., Hardware Application of AC/DC Converter Based on Intelligent Power Module and DSP Controller, Scientific Papers of the Institute of Electrical Machines, Drives and Metrology of the Wroclaw University of Technology, No. 59, Studies and Research, No. 26, Wroclaw, 2006, pp.182-193. [5] KNAPCZYK M., PIEŃKOWSKI K., Robust Current Control Technique for Boos-Type AC-DC line-side Converter with Sliding-Mode Voltage Observer, Scientific Papers of the Institute of Electrical Machines, Drives and Metrology of the Wrocław University of Technology, No. 57, Studies and Research, No. 25, Wroclaw, 2005, pp.381-392. [6] LASKA T., MÜNZER M., RUPP R., RÜTHING H., Review of Power Semiconductor Switches for Hybrid and Fuel Cell Automotive Applications, 1st Conference on Automotive Power Electronics, APE'06, Paris, 2006. [7] LORENZ L., KANELIS K., Design Proposal for Low Power Drives, Proceedings on International Conferences ZM Communications GmbH PCIM’01, Nuremberg, 2001. [8] PASSE T., STOLZE T., LIANG Z., IGBT modules for low cost consumer applications, Proceedings on International Conferences ZM Communications GmbH PCIM’02, Nuremberg, 2002. [9] QIU D. Y., YIP S. C., CHUNG H., HUI S. Y., On the Use of Current Sensors for the Control of Power Converters, IEEE Transactions on Power Electronics, vol.18, no.4, July 2003, pp.1047-1055. [10] Texas Instruments, Code Composer Studio IDE Manuals, IQmath Library, TMS320C28x Manuals, User Guides and Application Reports, www.ti.com. [11] ZHIHONG L., KEGGENHOFF R., EiceDRIVER™ 6ED003E06-F - Evaluation Board for EasyPACK750 – Datasheet and Application, EUPEC GmbH, July 2003.