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ITC132 high-voltage micro to motor interface

Posted: 07 Dec 2000     Print Version  Bookmark and Share


By Bill Lucas and Warren Schultz An IGBT power stage that is designed to run 3 phase AC Induction motors with input signals from an ASB124 Motion Control Development Board is presented here.

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1MOTOROLA AN1606 ITC132 High Voltage Micro to Motor Interface By Bill Lucas and Warren Schultz An IGBT power stage that is designed to run 3 phase AC Induction motors with input signals from an ASB124 Motion Control Development Board is presented here. It is intended to facilitate code development for the 68HC908MR24. Power ratings include motors up to 1 Horsepower and DC bus voltages up to 380 volts. Figure 1. ITC132 -- High Voltage Micro to Motor Interface CAUTION! ITC132 motor control development boards are capable of operating at dangerous voltages and capable of supplying dangerous amounts of power to rotating machines. To facilitate safe operation, input power for the High Voltage Rail should come from a current limited DC laboratory power supply. Before moving scope probes, making connections, etc., it is generally advisable to power down the high voltage supply. When high voltage is applied, using only one hand for operating the test setup minimizes the possibility of electrical shock. Operation in lab setups that have grounded tables and/or chairs should be avoided. Wearing safety glasses, avoiding ties and jewelry, and using shields are also advisable. EVALUATION BOARD DESCRIPTION A summary of the information required to use systems development board number ITC132 is presented as follows. A discussion of the design appears under the heading Design Considerations. Function The evaluation board shown in Figure 1 is designed to provide an optically isolated interface between microcomputers and induction motors up to 1 horsepower. It accepts 6 logic inputs which control 3 IGBT Half-Bridge outputs, and is arranged such that a logic ZERO at the input turns on the corresponding power transistor. The inputs are directly tied to opto isolator input diodes, and require an ability to sink 25 mA. This type of configuration is applicable to pulse width modulated (PWM) systems where the PWM signal is generated in a microcomputer, digital signal processor, or other digital system. It is suitable for driving induction motors up to 1 HP off DC bus voltages up to 380 volts. In addition to controlling the motor, current sense, bus voltage, and temperature feedback signals are provided. This board is designed to interface directly with Motorola ASB124 motion control development boards. Order this document by AN1606/D MOTOROLA SEMICONDUCTOR APPLICATION NOTE ) Motorola, Inc. 1998 REV 1 AN1606 2 MOTOROLA Electrical Characteristics The following electrical characteristics apply to operation at 25 degrees Celsius, and unless otherwise specified, HV Rail = 320 VDC. Table 1. Electrical Characteristics Characteristic Symbol Min Typ Max Units DC Rail Voltage HV Rail 12 380 Volts Gate Drive Supply Voltage +18 V 16.2 19.8 Volts Logic Supply Voltage +5 V 4.75 5.25 Volts Peak Phase Current IPK 10 Amps Continuous Phase Current IM 5 Amps Input Current @ VIN = 0 V Iin -25 mA Quiescent Current +5 V +18 V HV Rail ICC 25 125 1 mA mA mA Bus Current Sense Voltage Isense 250 mV/A Temperature Sense Voltage Vtemp .65 Volts Bus Voltage Sense Voltage Vbus 5 mV/V Power Dissipation PDISS 50 Watts AN1606 3MOTOROLA Content Board contents are described by the following schematic and parts list. A pin by pin circuit description follows in the next section. Table 2. Parts List Item Quantity Reference Part 1 6 C1, C3, C5, C7, C9, C11 22 5F SMT 2 8 C2, C4, C6, C8, C10, C12, C18, C21 .1 5F Ceramic 3 1 C13 470 5F, 450 VDC 4 2 C14, C15 .022 5F 5 3 C16, C17, C19 .O1 5F 6 1 C20 470 5F, 35 VDC 7 1 C22 .33 5F Ceramic 8 1 Q1, D1, Q2, D2, Q3, D3, Q4, D4, Q5, D5, Q6, D6 MHPM6B10A60D 9 6 D7, D10, D13, D16, D19, D22 MUR1100E 10 7 D8, D11, D14, D17, D20, D23, D26 1N914 11 6 D9, D12, D15, D18, D21, D24 MBR160 12 2 D25, D27 MV57124A (RED LED) 13 6 FEET 14 6 ISO1, ISO2, ISO3, ISO4, ISO5, ISO6 HCPL0453 15 2 ISO8, ISO7 MOC8106 16 1 Q7 MPSA06 17 1 Q8 2N3904 18 6 R1, R7, R13, R19, R25, R31 2.2 OHMS 19 6 R2, R8, R14, R20, R26, R32 5.6K 20 11 R3, R9, R15, R21, R27, R33, R48, R52, R53, R54 100 21 7 R4, R10, R16, R22, R28, R34, R41 10K 22 6 R5, R11, R17, R23, R29, R35 22 23 6 R6, R12, R18, R24, R30, R36 180 24 2 R37, R40 390K 25 1 R38 1.5K 26 1 R42 3.9K 27 4 R39, R43, R50, R51 270 28 2 R44, R49 820 29 1 R45 220 30 1 R46 .01 31 1 R47 10 32 4 TP1, TP2, TP3, GND TEST POINTS 33 6 U1, U2, U3, U4, U5, U6 MC33153 34 1 U7 MC33072 35 4 LARGE SCREW TERMINAL (DOUBLE) 36 1 14 PIN RIBBON CONNECTOR 37 1 16 PIN RIBBON CONNECTOR 38 5 MEDIUM SCREW TERMINAL (DOUBLE) 39 1 ITC132 PC BOARD 40 1 HEAT SINK AAVID 61010 (1.6) AN1606 4 MOTOROLA VCC FLT IN GND DSAT GATE SENS GND 8 5 1 2 6 7 4 3 MC33153 MBR160 D9 R3 100 R5 22 C2C1 22 mF 0.1 mF + R2 5.6 K HCPL0453 5 68 ISO1 D7 3 2 1N914D8 +18 V +5.0 V R4 10 K 2.2 R1 180 R6 MUR1100E Atop Atop Q1 1 2 16 D1 PHASE A HV RAIL U1 MHPM6B10A60D VCC FLT IN GND DSAT GATE SENS GND 8 5 1 2 6 7 4 3 MC33153 MBR160 D12 R9 100 R11 22 C4C3 22 mF 0.1 mF R8 5.6 K HCPL0453 5 68 ISO2 D10 3 2 1N914D11 +18 V +5.0 V R10 10 K 2.2 R7 180 R12 MUR1100E Abot Abot Q2 15 14 D2 I SENSE U2 VCC FLT IN GND DSAT GATE SENS GND 8 5 1 2 6 7 4 3 MC33153 MBR160 D15 R15 100 R17 22 C6C5 22 mF 0.1 mF + R14 5.6 K HCPL0453 5 68 ISO3 D13 3 2 1N914D14 +18 V +5.0 V R16 10 K 2.2 R13 180 R18 MUR1100E Btop Btop Q3 4 5 16 D3 PHASE B HV RAIL U3 VCC FLT IN GND DSAT GATE SENS GND 8 5 1 2 6 7 4 3 MC33153 MBR160 D18 R21 100 R23 22 C8C7 22 mF 0.1 mF R20 5.6 K HCPL0453 5 68 ISO4 D16 3 2 1N914D17 +18 V +5.0 V R22 10 K 2.2 R19 180 R24 MUR1100E Bbot Bbot Q4 12 11 D4 I SENSE U4 VCC FLT IN GND DSAT GATE SENS GND 8 5 1 2 6 7 4 3 MC33153 MBR160 D21 R27 100 R29 22 C10C9 22 mF 0.1 mF + R26 5.6 K HCPL0453 5 68 ISO5 D19 3 2 1N914D20 +18 V +5.0 V R28 10 K 2.2 R25 180 R30 MUR1100E Ctop Ctop Q5 6 7 16 D5 PHASE C HV RAIL U5 VCC FLT IN GND DSAT GATE SENS GND 8 5 1 2 6 7 4 3 MC33153 MBR160 D24 R33 100 R35 22 C12C11 22 mF 0.1 mF R32 5.6 K HCPL0453 5 68 ISO6 D22 3 2 1N914D23 +18 V +5.0 V R34 10 K 2.2 R31 180 R36 MUR1100E Cbot Cbot Q6 10 9 D6 I SENSE U6 Figure 2. Schematic AN1606 5MOTOROLA + - - + R37 390 K R40 390 K R42 3.9 K I SENSE +5.0 V AGND AGND TP1 TP2 TP3 VEE VEE R48 100 R47 10 R46 0.01 C17 0.01 mF Q8 2N3904 TRIM R43 270 R44 820 R45 220 C16 0.01 mF C15 0.022 mF C14 0.022 mF C13 470 mF 450 VDC ISO7 MOC8106 CS+ R41 10 K C21 0.1 mF D25 Q7 MPSA06 MC33072 5 6 +18 V +5.0 V Phase A Phase B Phase C AGND I sense HV RTN CS- R49 820 4 1 3 2 U7A MC33072 1 2 4 5 VEE +18 V M1 FAN + - A TRIM R50 270 ISO8 MOC8106 2 1 4 5 87 U7B HV RAIL +18 +18 +18 C20 470 mF RTN RTN RTN C18 0.1 mF +5.0 +5.0 GND GND C22 0.33 mF Vtemp +18 & HV ON R38 1.5 K R39 270 D26 1N914 D27 +5.0 ON R51 270 C19 0.01 mF HV RAIL Vbus A B C R52 100 R53 100 R54 100 + Figure 3. Schematic AN1606 6 MOTOROLA Pin By Pin Description Inputs and outputs are grouped into four connectors. Two connectors are provided for inputs, +5 V, and ground. One consists of screw terminals and the other is for ribbon cable. Either can be used, they are wired in parallel. Outputs to the motor, +18 V, and the High Voltage Rail are supplied on a large screw connector. Returns for the High Voltage Rail and +18 V are also on this connector. Feedback signals are grouped togetheron a separate ribbon cable connector. In addition, two through hole pads have been placed immediately adjacent to R46 for easy access to the current feedback resistor. Ribbon connector pinouts are shown in Figure 4. 14 12 10 8 6 4 2 13 11 9 7 5 3 1 GND Cbot Ctop Bbot Btop Abot Atop GND GND GND GND GND +5 +5 INPUT J1 14 12 10 8 6 4 2 13 11 9 7 5 3 1 AGND Vtemp N/C N/C Phase C Phase B Phase A Vbus GND GND GND GND GND GND FEEDBACK J2 1615 AGNDI sense TOP VIEW Figure 4. Connector Pinouts Inputs: Inputs Atop, Abot, Btop, Bbot, Ctop, and Cbot are logic inputs. A logic 0 turns on the input's corresponding output transistor, i.e., a logic 0 applied to input Atop turns on output transistor Atop, etc. Logic levels are standard 5 volts, with sink currents that are typically 20 mA. They are pulled up to +5 volts with 10K ohm resistors. Therefore, in the absence of any inputs all output transistors are turned off. +5: 5 volt power is supplied along with input signals from a control board. It is included on the input connectors for this reason. GND: The input connectors contain a ground that is common to the controller's digital ground. It is labeled GND. HV RAIL: HV RAIL is the motor power connection. It is intended for use with current limited, line isolated, laboratory power supplies. Acceptable input voltage range is +12 to +380 VDC. It is located at the top of the output connector. HV RETURN: HV RETURN is the power supply return for the motor power supply HV RAIL. +18: +18 is the gate drive supply. Its tolerance is 16.2 to 19.8 VDC. RTN: Two terminals on the output connector are labeled RTN. They are connected together, either one may be used as the +18 volt gate drive supply's return. The other can be used for instrument grounds. These terminals are common to the motor power supply return, HV RETURN, but do not have its current carrying capability. They should not be used for connecting the motor power supply. Motor Outputs: Motor output terminals are labeled Aout, Bout, and Cout. They can be used to drive a 3 phase induction motor, 3 phase brushless DC motor, a reversible brush DC motor, or 3 brush DC motors unidirectionally. Isense: Isense is a current sense feedback voltage that appears on pin 15 of connector J2. It is derived from a .01 ohm low inductance surface mount sense resistor that is in series with the ground return. The voltage across this resistor is opto isolated and amplified with a nominal gain of 25. Isense, therefore, represents return current with a scale factor of approximately 250 mV/Amp. This signal is isolated with a simple open loop opto coupler, and is therefore not particularly AN1606 7MOTOROLA accurate. A spot on the board adjacent to R50 is provided to trim this output. Software trim techniques can also be used to improve accuracy. Vbus: Vbus is a bus voltage feedback signal that appears on pin 13 of connector J2. It is derived from the High Voltage Rail and like Isense is isolated with an open loop opto coupler. It also has provision for a trim resistor, which is located adjacent to R43. Vtemp: A temperature output signal derived from a forward biased diode's VF appears on connector J2 at pin 12. The diode, in transistor Q8, is mounted such that it measures ambient temperature. Two tests points immediately adjacent to Q8 are intended to make it easy to remove and reconnect with a twisted pair of wires. Connected to a twisted pair, Q8 can be placed on the heat sink or motor. Phase Voltage Feedback: Phase voltage feedback signals Phase A, Phase B, & Phase C are also included on feedback connector J2. They are located on pins 2, 4, and 6, and terminated with resistors 52, 53, and 54. This board does not provide any signals to these pins. It does provide a solder pad for each phase, labeled A, B, & C, which make it convenient to wire circuitry from the breadboard area to these points. The breadboard area has hole patterns in which 2 LEM LA 25-NP current sensors will fit. AGND: A separate ground is provided for the analog signals. It is labeled AGND. AGND and GND are tied together on ASB124 control boards. If a different input source is used, it may be necessary to tie GND & AGND together. Pads for that purpose are located immediately to the left of the +5 V indicator light. Test Points TP1-TP3: Test points TP1, TP2, & TP3 provide access to feedback signals for Temperature, Motor Bus voltage, and Motor Bus current. TP1 is connected to the forward biased diode that is used for measuring temperature. Its ground is the analog ground AGND. TP2 is connected to the opto coupled output signal for Motor Bus voltage, and TP3 is connected to the opto coupled output signal for Motor Bus current. Both are also referenced to AGND. APPLICATION EXAMPLE An application example shown in Figure 5 illustrates system connections to an ASB124 control board and an induction motor. This arrangement can be run stand alone, or the ASB124 can be connected to an MMDS or MMEVS system for code development. The two boards are designed such that the Drive and Feedback ribbon connectors line up. Cables are supplied with the ASB124 board. Once they are plugged in it is only a matter of connecting power supply and motor leads to get a system up and running. It is important to note that the HV RAIL motor power input is a positive DC voltage that is intended to come from a current limited laboratory power supply. MOTION CONTROL DEVELOPMENT BOARD HIGH VOLTAGE MICRO TO MOTOR INTERFACE 7.5-15 VDC DRIVE FEEDBACK MOTOROLA ASB124 MOTOROLA ITC132 INDUCTION MOTOR +320 VDC +18 VDC HV RAIL HV RTN Aout Bout Cout +18 RTN RTN GND B+ Figure 5. Application Example AN1606 8 MOTOROLA An important application's consideration occurs at power up and power down. When the controller's power is off, all of its outputs look like logic lows. In order not to turn-on all six IGBT's simultaneously, it is necessary to avoid completely powering an ITC132 power stage when its controller is unpowered. This is accomplished by supplying the +5 volts that powers the opto inputs from the controller. On ASB124 controllers, this +5 volts is switched off at reset in order to disable ITC132 power stage inputs when power to the controller is not present. DESIGN CONSIDERATIONS A simplified schematic of one phase is illustrated in Figure 6. Top and Bottom inputs are opto coupled to inverting gate drivers. This arrangement isolates the inputs from the high voltage power stage, making it suitable for use with microcomputer development tools. It also facilitates board layout and improves noise immunity, since each gate drive can be returned directly to the emitter of its corresponding IGBT. To make things simpler, the IGBT's have a 6 volt gate threshold, making negative gate bias unnecessary. The MC33153 gate drivers have an undervoltage lockout that is designed for the 6 volt threshold. +18 V +5.0 V Atop +18 V +5.0 V Abot R1 2.2 D7 R2 5.6 K R6 180 D8 R7 2.2 D10 R8 5.6 K C1 C3 R12 180 D11 D12 R9 100 R11 22 Q2 D2 R46 0.01 HV RTN PHASE A D9 R3 100 R5 22 Q1 D1 HV RAIL Figure 6. Phase A -- Simplified Schematic From a systems point of view, using opto couplers for both top and bottom gate drives is a very effective strategy for minimizing design time. Even though in many applications opto's are not necessary for the lower half-bridge gate drives, they are very effective at keeping conducted noise from microcontrollers. Since it is noise management that typically takes the most design time, the improved noise robustness of an opto coupled topology can get products to market more quickly. To further improve noise robustness, several components in addition to opto couplers are used. Referring again to Figure 6, diodes D8 & D11 hold the opto's off with a lower impedance when the inputs are high. Resistors R1 & R7 protect the 18 volt gate drive supply from di/dt induced voltage transients. Although unnecessary for rectification, diode D10 serves the same function on the lower gate drive. Between the driver output and IGBT gates, two resistors and a diode are used instead of a single gate drive resistor. The additional components allow turning the IGBT's on slower than they are turned off. Due to the characteristics of the freewheeling diodes, this arrangement produces less noise than a single resistor. In situations where either layout or freewheeling diode softness characteristics have not been optimized, it is also advisable to add a Schottky diode between the MC33153's output and ground pins. The upper gate drive bootstrapped power supply has a 22 5F surface mount storage capacitor. This value has been chosen for Induction motor drives that use sine wave or third harmonic pulse width modulation. Space vector modulation and Brushless DC motor drives will work better with larger storage capacitors. Pads are provided on the board for adding larger capacitors if they are needed. CONCLUSION The ITC132 High Voltage Micro to Motor Interface is part of a motor control tool set that significantly reduces design and development time. It accepts signals from an ASB124 Motion Control Development Board, and provides a 3 phase power output that is capable of running motors up to 1 horsepower. AN1606 9MOTOROLA NOTES AN1606 10 MOTOROLA NOTES AN1606 11MOTOROLA Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. "Typical" parameters which may be provided in Motorola datasheetsand/orspecificationscananddovaryindifferentapplicationsandactualperformancemayvaryovertime. Alloperatingparameters,including"Typicals" must be validated for each customer application by customer's technical experts. Motorola does not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applicationsintended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury ordeath may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyershall indemnify and holdMotorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer. AN1606 12 MOTOROLA Mfax is a trademark of Motorola, Inc. How to reach us: USA/EUROPE/Locations Not Listed: Motorola Literature Distribution; JAPAN: Nippon Motorola Ltd.; SPD, Strategic Planning Office, 141, P.O. Box 5405, Denver, Colorado 80217. 1-303-675-2140 or 1-800-441-2447 4-32-1 Nishi-Gotanda, Shinagawa-ku, Tokyo, Japan. 81-3-5487-8488 Customer Focus Center: 1-800-521-6274 MfaxTM: - TOUCHTONE 1-602-244-6609 ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; 8B Tai Ping Industrial Park, Motorola Fax Back System - US & Canada ONLY 1-800-774-1848 51 Ting Kok Road, Tai Po, N.T., Hong Kong. 852-26629298 - HOME PAGE: AN1606/D

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