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Transcript
UM0243 User manual Universal motor control starter kit Introduction The UMC Starter Kit is considered to be a complete reference system for the universal motor drive. From a hardware and software point of view, the kit is ideal for the development of universal motor driving or, more generally, the development of phase angle control. With the supplied PC GUI, the control type can be chosen between open or closed loop (PI controller) and the control parameters easily modified. The whole system consists of two boards (main and PC interface boards) and the PC GUI software which also serves to get measurements from the board such as current, firing angle, speed. December 2006 Rev 2 1/29 www.st.com www.BDTIC.com/ST Contents UM0243 Contents 1 Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Phase control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 Description of parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 PC software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1 5 6 Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5.1 Stand alone mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5.2 PC driven mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5.3 Frequency measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.4 Open and closed loop control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 6.1 Testing points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 6.2 Current sense and overcurrent detection . . . . . . . . . . . . . . . . . . . . . . . . . 25 6.3 Using BTA12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 6.4 Working at 60Hz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 7 Temperature limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 8 Package contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2/29 www.BDTIC.com/ST UM0243 1 Getting started Getting started Warning: The Kit is not electrically isolated from the AC input. The MCU is directly linked to the mains voltage. No insulation is ensured between the accessible parts and the high voltage. The STEVAL-IHM007V1 Kit must be used with care and only by persons qualified for working with electricity at mains voltage levels. All measurement equipment must be isolated from the mains before powering the board. When using an oscilloscope with the Kit, it has to be isolated from the AC line. This prevents a shock from occurring as a result of touching any SINGLE point in the circuit, but does NOT prevent shocks when touching TWO or MORE points in the circuit. When programming the MCU through the In-Dart connector, make sure the board is plugged into an insulated mains plug to avoid computer damage. For correct operation of the UMC Starter Kit, use the following procedure (please refer to Figure 1 and Figure 2): 1. Connect the two boards using the appropriate connector (SCI); 2. Connect the PC interface board to the PC serial port through a serial connector; 3. Power on to the PC interface board through JP2 or J3(5V) connector (PC interface board); 4. Attach jumper J4 (HW[Stand Alone] / SW[PC-driven]) on the main board; 5. Connect the motor to the Motor connector (main board); 6. Connect the motor feedback sensor to JP4 / Hall Sensor(Hall Effect Sensor) or J5 / Tacho(Tachometer) connectors (main board); 7. Put a jumper on SW2/Hall Tacho depending on the speed sensor used, according to the silkscreen (main board); 8. Connect the mains power to Mains connector (main board); 9. Open UMC Application window. From the Options software button, set the serial port and the basic / advanced user mode (see Software help for further details); 10. Click Connect software button. Now the kit is ready to be driven by the GUI. In stand alone use, skip steps 1, 2, 3, 4 (no jumper on J4), 9 and 10, regulate the speed through the potentiometer POT1 (speed increases in a clockwise direction) before connecting (switching on) the main power. The motor will start running according to the default parameters and to the potentiometer value. Push SW3 ON/OFF switch to turn off (on). The following figures show the block diagrams of the Main board and the PC Interface. 3/29 www.BDTIC.com/ST Getting started UM0243 Figure 1. Main board layout Tacho Hall sensor J5 JP4 SW2 Hall/Tacho ON/OFF button Fuse ST7LITE35 POT1 General Switch ICC connector ® Figure 2. MAINS connector SCI connector Motor connector PC interface board layout Main board Connector Optocouplers PC Serial Connector ST3232 JP2 Power Supply Connector Isolated DC/DC Supply J3 Power Aux Connector 4/29 www.BDTIC.com/ST Cooling area Sensing amplifier (bottom side) ACST8 HW/SW J4 Capacitive Power Supply UM0243 2 Phase control Phase control The speed control of universal motor in AC mode is performed by varying the firing angle delay of a triac, thus varying the RMS voltage seen by the motor. In detail, the triac is switched on after the mains voltage zero crossing with a delay between 0° and 180°, that is between 0 and 10 ms if working at 50Hz, or 0 and 8.3ms if working at 60Hz. The current is thus supplied from the mains to the load for a part of each half mains period: the current starts flowing through the load as soon as the triac is turned on and is stopped at the next triac current zero crossing. The power fed to the load varies depending on the firing angle delay: the lower the angle, the higher the power. The kind of control performed is symmetrical, i.e. the firing angle is kept constant within a period of the mains voltage. Figure 3. Phase angle partialization Pulse Length Firing Angle Zero Crossing TRIAC Driving Control Signal 5/29 www.BDTIC.com/ST Description of parameters 3 UM0243 Description of parameters In PC-driven mode all the parameters can be changed in real time (see: Section 4 on page 8). However, when the system works in stand alone mode, parameters such as maximum and minimum firing angles, pulse length, maximum current allowed, soft start duration, cycle change duration, open loop (OL) or closed loop (CL) control, target angle (if in OL), target speed (if in CL), minimum and maximum speed (CL) are set in the UMC.h file. These default values can be modified in the UMC.h file, after which the project should be rebuilt and the microcontroller reprogrammed. Otherwise, the only parameters that can be changed while the program is running are the target angle (OL) or the target speed (CL), and this can be obtained by rotating the potentiometer POT1 on the main board (see Figure 1). Below is a brief description of the parameters: ● Soft Start: this expresses in how many periods of Mains the Firing Angle reaches the Target Angle starting from Alpha Max angle. ● Pulse Length: duration of the firing pulse; the range is [50: 500] µs ● Measured Current: selects the type of current measurement: on the mains zero crossing or the maximum value. ● Current limitation: if the selected current measurement type is Max current, this value sets the maximum allowed current flowing through the motor. If the load current reaches this value for a time longer than 1.5ms the motor is stopped. The user should be aware that the current is measured only during the positive wave of current if the selected measured current is the maximum value. ● Alpha Min: minimum firing angle allowed; range [4° : (Alpha Max-1)]. ● Alpha Max: maximum firing angle allowed; range [(Alpha Min+1) : 167°(50Hz), 162°(60Hz)]. ● Soft Variation: it expresses in how many periods of Mains the Firing Angle (OL) or the target speed (CL) reach a new Target Angle (OL) or a new target speed (CL) starting from the actual value. ● Ki: integration factor in PI speed control (CL). ● kp: proportional factor in PI speed control (CL). ● Pulses Per Revolution: it indicates the number of encoder pulses per shaft round, if this value is not correctly set, the measured speed will not be correct, thus compromising the CL control. ● Target Speed Min/Max: minimum/maximum target speed; the value of the changing speed knob, in PC driven mode, and, in stand alone and CL mode, the value read from the potentiometer change accordingly to these parameters. ● Filtering: number of acquisitions whose average gives the measurement. 6/29 www.BDTIC.com/ST UM0243 Description of parameters Here follows an example of the UMC.h file with a brief description. /****************************************************************************** File name : C:\temp\UMC\source\umc.h Author : UMC GUI Application Description : UMC Parameters Creation : Monday, November 14, 2005 12:01:35 *******************************************************************************/ #ifndef __C5A1372E_D06C_47ED_AEF2_67EDD76C3079__ #define __C5A1372E_D06C_47ED_AEF2_67EDD76C3079__ #define UMC_OPEN_LOOP #define UMC_CLOSED_LOOP 0x0001 0x0002 #define UMC_MAX_CURRENT #define UMC_ZERO_CROSSING /* CONTROL SETTINGS */ #define UMC_O_C_LOOP 0x0000 0x0001 UMC_OPEN_LOOP /* This has to be changed into UMC_CLOSED_LOOP if necessary*/ #define UMC_PULSES_PER_REVOLUTION 0x0008 /*Corresponding to parameter Pulses Per Revolution on the GUI*/ #define UMC_SOFT_START 0x0032 /*Corresponding to parameter Soft Start on the GUI*/ #define UMC_PULSE_LENGTH 0x00C8/*Corresponding to parameter Pulse Length on the GUI*/ #define UMC_OVER_CURRENT 0x0080 /*Corresponding to parameter Current Limitation on the GUI*/ #define UMC_ALPHA_MIN #define UMC_ALPHA_MAX #define UMC_MEASURED_CURRENT 0x000A 0x00A7 UMC_ZERO_CROSSING /* This has to be changed into UMC_MAX_CURRENT if necessary*/ #define UMC_SOFT_VARIATION 0x0032 #define UMC_TARGET_ANGLE 0x0000 /*Corresponding Target Angle, knob /*Corresponding Target Speed, knob #define UMC_TARGET_FREQUENCY 0x270D #define UMC_KI #define UMC_KP #define UMC_CL_MIN_SPEED loop*/ #define UMC_CL_MAX_SPEED 0x0002 0x0019 0x1388 to of to of parameter the GUI in open loop*/ parameter the GUI in closed loop*/ /*Corresponding to parameter Min, close to the knob of the GUI in open 0x2710 /*Corresponding to parameter Min, close to the knob of the GUI in open loop*/ (unsigned long)(UMC_CL_MIN_SPEED) * #define UMC_CL_MIN_FREQ UMC_PULSES_PER_REVOLUTION / 60 #define UMC_CL_FREQUENCY_STEP (unsigned long)(UMC_CL_MAX_SPEED - UMC_CL_MIN_SPEED) * UMC_PULSES_PER_REVOLUTION / 60 #define UMC_FILTERING 0x0008 /*Corresponding to parameter Filterign in the Acquisition Setting of the GUI*/ #endif /* __C5A1372E_D06C_47ED_AEF2_67EDD76C3079__ */ For parameters not described in this paragraph, please refer to UMC GUI Help. 7/29 www.BDTIC.com/ST PC software 4 UM0243 PC software For a better tuning of parameters and for acquisition purposes, a PC interface has been developed. In Figure 4 and Figure 5 the Open Loop and Closed Loop windows are shown respectively. Please launch the UMC Setup file and follow the instructions for the software installation. Once the software has been installed, select the correct COM port from the Options section and click the connect button to get started with the software. Then choose the Advanced or Basic Mode, where the latter case has a reduced set of user-parameters. Then you can choose both the control parameters and the control mode before starting the motor. The communication is synchronized by means of a CTS signal (hardware handshake), which is set at a high level by firmware only when PC communication is allowed. Ensure that this signal is correctly managed by the PC otherwise communication failures may occur. For further details please refer to the UMC Application help. Figure 4. GUI - open loop mode 8/29 www.BDTIC.com/ST UM0243 PC software Figure 5. 4.1 Closed loop mode Acquisition The acquisition takes place after having pushed the appropriate button on the right side of the GUI window. The Underflow and Overflow bars inform the user respectively whether acquisition samples are missing (communication problems), or if the application is too slow for samples to be processed. In the latter case the user should adjust the acquisition time by using the Time bar (Acquisition Settings menu) if necessary. After having stopped the acquisition, the Plot button is enabled. Clicking this button displays a plot based on the parameters in the Acquisition Data menu, as shown in Figure 6. At the same time, a log file containing the acquired samples of the three parameters is produced. Note: During start up and, in open loop, when the target angle is varied, the firing angle plot may result in a ramp with different slopes, the first one being steeper. Actually, the firing angle variation is linear with time and the actual slope is constant. The steeper part of the plot is in fact due to some missing acquired sampling (both in the plot and in the log file) and this is due to the fact that when the Set button is pushed, set and get commands are sent to the microcontroller preventing it from sending acquired data. 9/29 www.BDTIC.com/ST PC software UM0243 Figure 6. GUI - plot window 10/29 www.BDTIC.com/ST UM0243 5 Firmware Firmware The development toolset used is SOFTEC STVD7 ver 3.2.1. The workspace is opened by opening the UMC.stw file. If any modification to the source files or to the umc.h file has been made, the project has to be rebuilt, thus generating a new umc.s19 file. This file is used to program the microcontroller. The firmware has been developed in order to work both in stand alone mode (HW) and in PC driven mode (SW) depending on jumper J4. By reading the value of pin PA2 one of the two working modes is selected. Below is a brief description of the firmware flow in the two cases: 5.1 1. Defaults Loading (service_routines.c): default parameters are loaded; they can be changed by PC interface in PC driven mode. 2. Peripheral Initialization (ADC_10bit.c, lite_timer_8bit.c, sci.c): – ADC → ADC on, channel converted is channel 0 (hw potentiometer). – Lite Timer →Input Capture and Time base (1ms) interrupts enabled for tachometer or Hall effect sensor period measurement for motor speed computing. – SCI →1 Start bit, 8 Data bits, 1 Stop bit, baud rate equal to 19200. 3. Ports Initialization (ports.c). 4. Mains Frequency Detection (mains.c). 5. Reading of Pin PA2 (mains.c): by means of a jumper this pin is connected to ground in PC-driven mode or to a switch in stand alone mode. Stand alone mode As soon as stand alone mode has been detected, the motor is turned on. The first interrupt request is the one coming from pin PB5, the zero-crossing mains voltage detection pin, the sensitivity has been set so that both rising and falling edges of the signal generate the interrupt request. As soon as this interrupt is served, the PWM AR Timer is switched on in order to start counting the firing angle delay and then, if a falling edge occurs, the Analog to Digital Converter is set in order to convert the value coming from the potentiometer. Otherwise, on the rising edge, the A/D converter is configured for the current measuring and if required, the soft variation of the firing angle is implemented. The triac activation is controlled by PWM AR Timer. On its interrupt routine, the measurement of the period maximum current is also performed. A flowchart for stand alone mode is shown in Figure 7. 11/29 www.BDTIC.com/ST Firmware UM0243 Figure 7. Firmware flowchart - stand alone mode Start: Ports & Peripheral Initialization Mains freq detection PA2 set ÆStand Alone Mode Pin PA2 reading Motor ON PA2 interrupt Compute new angle/speed from potentiometer reading Conversion PeriodÆ freq Waiting for interrupt PB5 falling edge (ZVS) Pot reading Motor ON/OFF PWM/AR Timer interrupt Soft start/soft variation management TRIAC turn ON Over Current Computing Compute potentiometer mean 5.2 Lite Timer interrupt Period Measurement PC driven mode The flow chart during PC driven mode is shown in Figure 8. Compared to the stand alone mode, here the SCI communication handling is present. 12/29 www.BDTIC.com/ST UM0243 Firmware Figure 8. Firmware flowchart - PC driven mode Start: Ports & Peripheral Initialization Pin PA2 reading PB5 falling edge (ZVS) PA2 reset ÆPC GUI driven Mode SCI communication handling PI control each 10ms (if CL) Conversion PeriodÆ freq Waiting for interrupt Current measurement (if ZC current) Acquired frame transmission (if in acquisition) SCI interrupt Set SCI flag (Communication handled on main routine) PB5 rising edge (ZVS) CTS Enable Soft start/soft variation management PWM/AR Timer interrupt TRIAC turn ON Over Current Computing CTS Disable Lite Timer interrupt Period Measurement 5.3 Frequency measurement The reading of the motor speed is achieved in two steps. First, the period measurement is performed thanks to the Input Capture feature of the 8-bit Lite Timer, and then a period to frequency conversion is executed. When a transition on the feedback signal (tachometer or Hall sensor) occurs, an interrupt is generated by the Lite Timer peripheral and the value of the Lite Timer counter is latched in the LTICR register. In order to make the system less sensitive to eventual dissymmetry on the signal duty-cycle, only high to low transitions are taken into account. The Lite Timer Input Capture (LTIC) feature of the Lite Timer, together with the possibility of generating an interrupt when the upcounter overflows (LTTB1 Interrupt), precisely measures the period of the Hall sensor signal. Considering, in fact, Figure 9, it is possible to draw the following mathematical relationship: TH = ((250 − Capture 1) + Capture 2 + 250 ⋅ ( N − 1)) ⋅ 32 f OSC N >0 (5.3.1) where TH represents the feedback signal period, Capture 1 and Capture 2 indicate the values of Counter 1 at the edges of the Hall sensor signal and N is the number of LTTB1 interrupt events between the two feedback signal falling edges taken into account. 13/29 www.BDTIC.com/ST Firmware UM0243 Figure 9. Feedback signal semi-period measuring (N>0) LTTB1 Int LTTB1 Int LTTB1 Int 249 Counter1 Capture 1 Capture 2 t LTIC Int LTIC Int LTIC Int (Discarded) Hall sensor output t The relation (5.3.1) is valid only under the condition N>0 and therefore it can not be used to measure frequencies higher than 500Hz. In this case the formula to be used, deduced by observing Figure 10, is (5.3.2) : Figure 10. Hall sensor signal semi-period measuring (N=0) 249 LTTB1 Int LTTB1 LTTB1 Capture 2 Counter1 Capture 1 LTIC Int LTIC Int LTIC Int t Hall sensor output t TH = (Capture 2 − Capture 1) ⋅ 32 f OSC (5.3.2) Note that in both (5.3.1) and (5.3.2) TH is computed with a resolution equal to is 4 µsec at 8MHz fOSC. 32 which f OSC It can be seen that in order to measure the Hall sensor semi-period correctly, the LTIC and LTTB1 ISRs must be executed by the microcontroller core in the same order in which the related interrupts events occurred. This would normally happen if no other interrupts service routines are executing. However in our software, a third interrupt source is enabled (PWM update event), so a potentially erroneous situation could arise due to the interrupt priority mechanism. Figure 11 describes two possible situations when multiple interrupts occur: 14/29 www.BDTIC.com/ST UM0243 Firmware Figure 11. Multiple interrupt pending situation LTTB1 LTTB1 249 249 Captured value << 125 Counter 1 Captured value >> 125 Counter 1 t t LTIC Int LTIC Int Hall sensor output t PWM OVF ISR execution t t PWM OVF ISR execution t Due to the higher interrupt priority of LTIC with respect to LTTB1, in both cases the LTIC ISR is executed before LTTB1 ISR. In this case, the value stored in the LTICR is used to reconstruct the correct sequence. If the content of the LTICR is lower than 125, it is assumed that the LTTB1 event occurred just before an LTIC event so that the Lite Timer overflow counter must be incremented before the semi-period computation. However, if the LTICR contains a value higher than 125, it is assumed that the LTIC occurred just before a Lite timer overflow (LTTB1 event). In this case, the overflow counter must not be incremented before the semi-period computation but it will be taken into account at the next LTIC event. After the period measurements have been carried out, they are stored in the measure array, whose depth is equal to the parameter "filtering". Successively, in the main loop, an average of the stored measurements is performed and the period to frequency conversion is carried out. Function Compute_division( ) provides conversion optimization in terms of execution time for frequencies higher than 35Hz. 5.4 Open and closed loop control When the Open Loop control strategy is selected, the firing angle is the control parameter. It can be changed by potentiometer in Stand Alone Mode or by a control in the PC GUI (refer to Figure 4) if PC-driven. However, when the Closed Loop control strategy is selected, the control parameter is the target speed. In this case, in order to make the actual speed equal to the target speed by adjusting the firing angle, a PI controller has been implemented. The general formula for an analog PI regulator is: t u (t ) = K P * e(t ) + K I * ∫ e(τ )dτ (5.4.1) 0 15/29 www.BDTIC.com/ST Firmware UM0243 where: u(t) is the driving signal e(t) is the error signal, difference between the actual feedback frequency and the target feedback frequency. Kp, K1 are respectively the proportional and the integral constants. In the case of digital regulators the above equation becomes: n u (n ) = K P * e(n ) + K I * T * ∑ e(i ) i =0 (5.4.2) where: u(n) is the driving signal sampled at the instant nT e(n) is the error signal sampled at the instant nT Kp, K1, KD are respectively the proportional and the integral constants T is the sampling time. We can also write: n +1 u (n + 1) = K P * e(n + 1) + K I * T * ∑ e(i ) i =0 (5.4.3) and, subtracting equation (5.4.3) from (5.4.2): n ⎡ n +1 ⎤ u (n + 1) − u (n ) = K P * [e(n + 1) − e(n )] + K I * T * ⎢∑ e(i ) − ∑ e(i )⎥ i =0 ⎣ i =0 ⎦ simplifying: ∆u (n ) = K P * ∆e(n ) + K I * T * e(n ) (5.4.4) Equation (5.4.4) shows the variation of the firing angle ∆u (n ) at the instant nT due to the error in the same instant (term e(n ) ) and to its variation at the instants nT and (n-1)T (terms ∆e(n ) and ∆e(n ) − ∆e(n − 1) ). [ ] In the "PI" routine, the error is first computed and based on it, the variation of the firing angle is calculated according to equation (5.4.4). The coefficients must be adjusted for a given motor type. This can be easily achieved with the PC GUI. 16/29 www.BDTIC.com/ST UM0243 6 Hardware description Hardware description Two separate boards have been developed: the main board and the PC interface one. In Figures 13 and 14 the schematics of the boards are shown. At first glance, the main characteristics are: ● A capacitive power supply to reduce the overall cost of the system. This supply can source an average current lower than 20mA. ● Control Unit consisting of an ST7Lite35 device and external circuitry. ● An ACST8-8C AC Switch. This device is driven by means of a bipolar transistor in order to guarantee the proper working in the whole extended temperature range using only one MCU pin. In fact the turn-on current needed is equal to 35mA in nominal conditions, but it increases up to 70mA for a -20°C junction temperature. Nevertheless if no further MCU pins are needed for other purposes, the ACST switch can be directly driven using 3 HS pins connected in parallel. A noise suppressor (R7 and C7, see Figure 13) has been connected in parallel with the device in order to increase IEC61000-4-4 immunity. ● Two speed sensor nets for a Hall effect sensor or a Tachometer. ● A Current Sensing circuit. ● A Zero Crossing Network providing the Control Unit with a TTL signal in accordance with the zero crossing of the mains. This network is realized with a bipolar transistor, but a resistor topology could also have been used (see Figure 12), but, in this case, the firmware must handle somehow the dissymmetry compensation in order to avoid DC current injection through the motor. Figure 12. Resistor based ZCN VDD MCU Mains PB5 R 160K R 160K C 100pF 17/29 www.BDTIC.com/ST 4 3 2 1 HEADER 4 JP7 TACHO 2 1 J5 JP4 1 2 3 Hall sensor R20 10K R17 10K Univ ersal motor 2 1 JP2 JP1 R19 10K R14 10K CTS RXD TXD 1N4148 D4 Vdd5 MAINS 2 1 2 R15 33K R16 1K BC337-25 3 Q4 1 Vdd5 C8 1n 1 TP7 R9 470K R7 Q2 47 1 ACST8 R3 0.047R 5W C6 1uF 220V~ C7 1n 220V R8 470K C13 68n SO7K300 NC L 10n x2 C3 8A/250V C14 N.C. TP7 R5 2.2K R6 47 47 SW2 1 2 2 TP3 TP2 TP2 HALL TACHO 3 1 D3 1N4148 TP3 68 TP6 TP6 D2 1N4148 C4 1000u/10V C2 100nF TP5 TP5 50K RESET Vdd5 150nF C9 POT NTC 1 2 J3 Vdd5 POT RXD PB5/ZC NTC pin Current Sense C5 100nF Current Ref 2 Target Speed SPEED SENSOR POT1 Q3 BC547B PB5/ZC Triac driv ing Current Ref R22 R21 Vdd5 D1 6.2V 1W 1 F1 1 3 1 TP1 TP1 1 3 N U1 PA0(HS)/LTIC OSC2 OSC1/CLKIN R18 56K Vdd5 R12 10K R13 100K 3 2 4 7 U2 C10 2.2nF NTC pin 6 1 TP4 TP4 R10 100K TS1851ID Vdd5 ST7LITE 35 PA1(HS)/ATIC SCK/AIN1/PB1 PA2(HS)/ATPWM0 MISO/AIN2/PB2 PA3(HS)/ATPWM1 MOSI/AIN3/PB3 PA4(HS)/ATPWM2 CLKIN/AIN4/PB4 PA5(HS)/ATPWM3/ICCDATA AIN5/PB5 PA6/MCO/ICCCLK RDI/AIN6/PB6 PA7(HS)/TDO SS/AIN0/PB0 RESET Vdd Vss R11 10K 10 9 8 7 6 5 4 3 2 1 11 12 13 14 15 16 17 18 19 20 HW/SW 2 1 J4 Vdd5 SCL Current Sense R4 22K SW3 RESET SDA GPSwitch TXD SCL SDA CTS ON/OFF 1 2 3 4 5 6 7 8 9 10 10nF C11 ON/OFF J2 SW4 GPSwitch Triac driv ing Q1 3 BC547C 1 Programming Interf ace 2 R1 100K Vdd5 2 C1 1n 2 1 www.BDTIC.com/ST 1 SPEED SENSOR + - 18/29 1 Hardware description UM0243 Figure 13. Main board schematic UM0243 Hardware description Figure 14. PC interface board schematic VIN GND U6 LM78L05ACZ 3 C8 1 VOUT Vdd5 Vdd5 U1 ISOLATED 4 Vin DC/DC Vo 5 2 1uF C1 +5V +5V 1 GND 1uF / 16V JP2 1 2 VCC5 C2 100nF 16V 7 0V VCC5 NME0505D 0V HEADER 2 C3 + C4 1u / 16V J3 1uF/16V U2 1 2 + C5 1uF/16V 1 2 3 4 5 6 7 8 aux-v oltage TXD JP1 + C6 1uF/16V P1 VCC GND T1OUT R1IN R1OUT T1IN T2IN R2OUT C+ V+ C1C2+ C2VT2OUT R2IN 16 15 14 13 12 11 10 9 0V RXD_Insulated CTS_Insulated RXD 4 3 2 1 ST3232/SO CTS 1 6 2 7 3 8 4 9 5 PC Interf ace C7 0V + 1uF/16V HEADER 4 Tx_Insulated 0V VCC5 CTS Vdd5 VCC5 VCC5 R101 R3 10K RXD Vdd5 2.2K R4 1K R100 1 4 U4 U5 2 3 Tx_Insulated 2 SFh615A R2 1K 4 1.8K TXD R1 2.2K CTS_Insulated 1 4 U3 1 3 RXD_Insulated 2 3 SFh615A SFH615A 0V 0V In Figure 15 the picture of the main board shows the main parts. Figure 15. Main board 1 2 3 4 5 6 7 8 10 Note: 9 See below for a description of labeled board components. 19/29 www.BDTIC.com/ST Hardware description 1. Tachometer sensor connector 2. Hall Effect sensor connector 3. Off/On push button (only in stand alone mode) UM0243 4. This jumper detects stand alone(no jumper present)/pc driven mode (jumper present) 5. Potentiometer for speed/ firing angle changing (if the system works in stand alone mode) 6. General switch 7. PC interface connector 8. NTC connector 9. Motor connector 10. Mains power connector 11. Testing points 6.1 Testing points Some testing points are present on the board thus allowing the user to directly obtain and measure waveforms. Here follows a list of these points and of the expected waveforms. ● TP1: Vdd - 5V ● TP2: ground ● TP3: zero crossing signal - 0:5V square wave at 50 or 60Hz ● TP4: current sense (output signal of the OP-Amp) - see Figure 16, 17, 18 ● TP5: speed sensor feedback - see Figure 20 ● TP6: triac driving signal - see Figure 21 ● TP7: ACST8 output - see Figure 22, 23 In all the figures below, channel C1 represents the zero crossing signal (@ 50Hz) and channel C3 pin PA4, i.e. the triac driving signal before the transistor, this in order to give an idea of the firing angle used in the examples. Besides the waveforms on the testing points, Figure 19 has been added in order to show the current on the ACST switch. 20/29 www.BDTIC.com/ST UM0243 Hardware description Figure 16. TP4 - Current Sense Signal (C2), 168° firing angle. Note: The signal is different from zero only during half a period of the mains waveform. Figure 17. TP4 - Current Sense Signal (C2), firing angle is decreasing 21/29 www.BDTIC.com/ST Hardware description UM0243 Figure 18. TP4 - Current Sense Signal (C2), 6° firing angle Figure 19. C1 - zero crossing signal. C2 - ACST driving signal. C4 - ACST switch current. 22/29 www.BDTIC.com/ST UM0243 Hardware description Figure 20. TP5 - Speed sensor feedback signal (C2), 3500 RPM Figure 21. TP6 - Triac Driving Signal (C2) 23/29 www.BDTIC.com/ST Hardware description UM0243 Figure 22. TP7 - ACST Output-COM voltage (C2) with firing angle equal to 167° Figure 23. TP7 - ACST Output-COM voltage (C2) with firing angle equal to 90° 24/29 www.BDTIC.com/ST UM0243 6.2 Hardware description Current sense and overcurrent detection The voltage created by the current flowing through the sensing resistor R3 (0.047 Ohm) is amplified by ten so that the maximum detectable current is about 10A. The protection against overcurrent only takes place when the max current instead of the zero crossing current is measured. This parameter can be changed by software or, in stand alone mode, by modifying the umc.h file. In case the max current is the parameter measured, the value is acquired each 500µs and the protection takes place (motor is switched off) only if three consecutive values exceed the maximum allowed, this is in order to reduce measurement noise. Measurement of maximum current is carried out during main power's positive half waveform. 6.3 Using BTA12 It's possible to place a BTA12-800CW (12 Amps RMS) Triac instead of the ACST8-8C. In this case a S07K300 varistor must be connected in parallel with the triac for over-voltages protection (see Figure 24). Figure 24. Schematic variation when BTA12 is used. N R22 0.047 Current Ref R19 R26 1n BTA12-800CW Q9 Triac driving 56 U S07K300 J4 47 1 2 Universal motor 6.4 Working at 60Hz Please note that the kit works at 60Hz under nominal voltage supply conditions (i.e. 110V). For lower voltage values the capacitive power supply stage has to be modified, since it has been designed to work in the range 110V/230V. 25/29 www.BDTIC.com/ST Temperature limitation 7 UM0243 Temperature limitation Since the microcontroller uses its internal oscillator and PLL, which are temperature dependent, and since the system's correct behavior is strictly related to the oscillation frequency, the system has to be considered to operate in the temperature range that involves a maximum frequency deviation of: ● ±3% from the nominal 8MHz frequency if working at 50Hz or ● -2%:+3% from the nominal 8MHz frequency if working at 60Hz For higher frequencies the SCI communication with the PC fails, but the control still operates correctly. Otherwise, the microcontroller needs to be recalibrated or an external oscillator must be used. Automatic real time calibration can also be implemented (refer to AN1324 for further information). 26/29 www.BDTIC.com/ST UM0243 8 Package contents Package contents The following material is supplied in the package: ● UMC Main board ● PC interface board ● One connector main board - PC interface board 27/29 www.BDTIC.com/ST Revision history 9 UM0243 Revision history Table 1. Document revision history Date Revision Changes 08-Sep-2006 1 Initial release. 14-Dec-2006 2 Safety warning added Section 1 on page 3 28/29 www.BDTIC.com/ST UM0243 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. 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