vector control of a 3-phase ac induction motor using

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Application Note

Vector Control of a 3-Phase AC Induction Motor Using FMC16100 MCU

AN024702-1006

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AN024702-1006

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Information IntegrityThe information contained within this document has been verified according to the general principles of electrical and mechanical engineering. Any applicable source code illustrated in the document was either written by an authorized ZiLOG employee or licensed consultant. Permission to use these codes in any form, besides the intended application, must be approved through a license agreement between both parties. ZiLOG will not be responsible for any code(s) used beyond the intended application. Contact the local ZiLOG Sales Office to obtain necessary license agreements.

Document Disclaimer©2006 by ZiLOG, Inc. All rights reserved. Information in this publication concerning the devices, applications, or technology described is intended to suggest possible uses and may be superseded. ZiLOG, INC. DOES NOT ASSUME LIABILITY FOR OR PROVIDE A REPRESENTATION OF ACCURACY OF THE INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED IN THIS DOCUMENT. ZiLOG ALSO DOES NOT ASSUME LIABILITY FOR INTELLECTUAL PROPERTY INFRINGEMENT RELATED IN ANY MANNER TO USE OF INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED HEREIN OR OTHERWISE. Except with the express written approval ZiLOG, use of information, devices, or technology as critical components of life support systems is not authorized. No licenses or other rights are conveyed, implicitly or otherwise, by this document under any intellectual property rights.

Version DisclaimerApplication Notes are tested with the version of ZDS II available at the time of release. Subsequent releases of ZDS II may require you to modify Application Note code to restore its function.

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AN024702-1006 Revision History

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Application Note Vector Control of a 3-Phase AC Induction Motor Using FMC16100 MCU

Revision HistoryEach instance in the Revision History reflects a change to this document from its previous revision. For more details, refer to the corresponding pages or appropri-ate links given in the table below.

Date Revision Level Section\Description Page No

October 2006

02 Table 6, replaced eZ80® CPU withZ8 Encore!® and eZ80® CPU User Manual (UM0077) with eZ8 CPU User Manual (UM0128).

29

July 2006 01 All Initial Release All

AN024702-1006 Table of Contents

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Table of ContentsList of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vList of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viAbstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Z8 Encore!® MC Flash Microcontrollers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Description of Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Application Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Software Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Variables and Declarations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Main Event Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Subfunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Software Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Appendix A—References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Appendix B—Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Appendix C—Schematic Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Appendix D—Flowcharts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

AN024702-1006 List of Figures

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List of FiguresFigure 1. Washing Machine Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 2. Washing Machine Motor with Tachogenerator . . . . . . . . . . . . . . . . . . . 5

Figure 3. Modular Controller and XP Command Module . . . . . . . . . . . . . . . . . . 5

Figure 4. Hardware Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 5. Current Sense Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 6. Overcurrent Sense Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 7. Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 8. Sampling Space Vector PWM Current (State = 3) . . . . . . . . . . . . . . . 15

Figure 9. Space Vector PWM States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 10. Phase Current Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 11. Park Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 12. Inverse Park Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 13. Inverse Clarke Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 14. PWM Space Vector Modulation (Ground Reference) . . . . . . . . . . . 23

Figure 15. PWM Space Vector Modulation (Neutral Reference) . . . . . . . . . . . . 24

Figure 16. High-Voltage Main Board Schematic . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 17. FMC16 Control Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 18. HV Gate Drive Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Figure 19. HV Power Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 20. Washing Machine Interface Module Schematic . . . . . . . . . . . . . . . . 35

Figure 21. DAC Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 22. XP Command Module Schematic (Connects to Washing Machine Module) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 23. Flowchart for the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 24. Flowchart for the PWM ISR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

AN024702-1006 List of Tables

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List of TablesTable 1. Sample Interpretation by PWM State . . . . . . . . . . . . . . . . . . . . . . . . . 16

Table 2. PWM Duty Cycle by State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Table 3. Initialization Execution Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Table 4. Main Loop (ISR) Execution Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Table 5. Subfunction Execution Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Table 6. List of References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Table 7. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

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AbstractThe 3-phase alternating current (AC) induction motors are mechanically simple, rugged, highly reliable, lower in cost per horsepower than DC motors, and capable of more torque and efficiency than single-phase AC motors. A 3-phase AC induction motor can be controlled by varying its inputs according to a mathematical model of the rotor flux field in a complex vector space (Vector Control). Vector Control provides efficient and accurate control of the motor’s speed and torque.

Until now, Vector Control has been the domain of digital signal processors (DSPs), digital signal controllers (DSCs), and a few 32-bit and 16-bit microcontrollers. Constant cost pressure and increased consumer expectations have driven design engineers to seek minimal hardware solutions that extract maximum performance from motors used in consumer goods.

This application note demonstrates how ZiLOG's Z8 Encore!® MC 8-bit microcontroller is used to implement Vector Control of an AC induction motor.

Z8 Encore!® MC Flash MicrocontrollersZiLOG’s Z8FMC16100 Series Flash MCU is based on ZiLOG’s advanced eZ8 8-bit CPU core and is optimized for motor control applications. It supports control of single and multiphase variable speed motors. Target applications are consumer appliances, HVAC, factory automation, refrigeration, and automotive applications, among others.

To rotate a 3-phase motor three AC voltage signals must be supplied, phase-shifted 120° from each other. To control a 3-phase motor the MCU must provide 6 Pulse Width Modulation (PWM) outputs. The Z8FMC16100 Series Flash MCU features a flexible PWM module with three complementary pairs or six independent PWM outputs supporting deadband operation and fault protection trip input. These features provide multiphase control capability for various motor types and ensure safe operation of the motor by providing immediate shutdown of the PWM pins during a fault condition.

DiscussionAn electric motor consists of a stationary frame (stator) in which a rotating component (rotor) is mounted on a shaft and bearings. In a 3-phase AC induction motor, the stator is laced with three sets of inductor windings energized by three AC voltage inputs that are phase-offset 120° from each other, producing a rotating field of magnetic flux inside the motor. This field creates an induced magnetic flux in short passive windings on the rotor. The stator field exerts magnetic force on the rotor flux field, resulting in torque on the output shaft.

AN024702-1006 Abstract

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In a 3-phase motor control application, the input to the motor is produced by a 3-phase inverter bridge. A bridge contains three complimentary source/drain transistor pairs which connect either ground or high-voltage DC to each of its three outputs in response to digital control signals from the microcontroller. The microcontroller uses PWM on the bridge control signals to generate three approximately sinusoidal AC waveforms on the bridge outputs, with the required 120° phase offset.

The duty cycle of each microcontroller PWM output is varied to control the period and amplitude of the generated AC signal, which in turn determines the speed and torque of the motor. The microcontroller senses the resulting AC current and motor speed and periodically adjusts the AC signal waveform, increasing or decreasing torque to maintain the appropriate motor speed. For more information on motor control, see documents listed in Appendix A—References on page 29.

Theory of OperationIn this application, the FMC16100 microcontroller’s PWM module is configured as three complementary output pairs. Each output pair controls one complementary source/drain transistor pair in the inverter bridge. The PWM module is configured to insert a 0.6 µS deadband between ON states to prevent leakage that might occur if one transistor in a pair turns on before the other is fully off.

Each PWM output pair produces a stream of complementary on/off pulses to activate the corresponding source or drain transistor in the inverter bridge. The voltage of each bridge output varies with the source/drain pulse duty cycle.

The period of each PWM cycle is configured to be 50 µS and the PWM module generates an interrupt request at the end of each cycle. The PWM interrupt service routine (ISR) leaves the PWM interrupt disabled while it executes, and is tuned to execute within 200 µS to 250 µS. Therefore, the PWM ISR is executed every five PWM cycles or 250 µS.

The PWM ISR controls all of the ongoing application program functions after initialization. The primary goal of the ISR is to update the duty cycle value for each PWM channel as needed to produce the appropriate AC waveforms at the inverter bridge outputs.

The PWM duty cycle values are derived from a feedback loop based on rotor speed and rotor flux position. The stator current waveform is determined by sampling two phases of the inverter output current and reconstructing the third phase.

The rotor speed is sampled by a counter/timer configured to measure the period of a magnetic position sensor on the motor. The measured speed is periodically compared to the requested speed received through UART from an external controller. The resulting speed command value is used to create a rotation reference frame expressed as a two-phase direct/quadrature (DQ) vector.

AN024702-1006 Discussion

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The resulting vector is regulated to produce the necessary flux and torque amplitude in the output vector.

An inverse Park transform is used to rotate the reference frame relative to the rotor position. Then an inverse Clarke transform is used to convert the rotated two-phase reference frame back into a 3-phase expression. At the same time, the vector’s position is classified into one of six states, each corresponding to one sixth of the vector circle.

When the ISR calculates duty cycles for the three PWM channels, one phase is left unmodulated (ON or OFF for the whole PWM cycle), and the flux vector is encoded by modulating the other two phases. This reduces switching losses by one third. The two phases to be modulated depend on the flux vector’s state position. After the PWM space vector calculation is complete, the corresponding PWM registers are updated. For more details on the software implementation, see Software Implementation on page 11.

Description of ComponentsIn addition to the Z8 Encore!® MC microcontroller, this design uses the following major components:

• Z8 Encore! XP® microcontroller

• Insulated-gate bipolar transistors (IGBTs)

• I2C interfaced 8-bit digital-to-analog converter (DAC)

• Washing Machine Motor

Z8 Encore! XP® MicrocontrollerThis application employs the Z8 Encore! XP® 8-pin MCUs internal precision oscillator, 10-bit analog-to-digital converter (ADC), I/O, and UART features to demonstrate the washing machine application user interface. User commands are transmitted to the Z8 Encore!® MC MPU as serial data. In theory, this allows very complex control commands to be transmitted. The demonstrated user interface consists of a potentiometer for speed control, a pushbutton command input, and a pushbutton to reset the Z8 Encore! XP® MCU.

Two 6N137 single-channel optocouplers transmit UART command signals while electrically isolating the user command module from the high-voltage modules.

Insulated-Gate Bipolar TransistorsSix 6SGS5N60RUFD IGBTs are used under PWM control to generate the required 3-phase AC motor drive current from a high-voltage DC supply. Although these IGBTs are rated for momentary short-circuit operation, the Z8 Encore!® MC PWM deadband feature is used to reduce leakage when the IGBTs are switched.


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Three IR21064S high-side and low-side gate drivers are used to convert the Z8 Encore!® MC microcontroller’s CMOS PWM outputs into signals with the voltage needed to drive the IGBT gate inputs.

Digital-to-Analog ConverterThe Z8 Encore!® MC microcontroller’s I2C interface is used with a DAC5574 digital-to-analog-converter to generate up to 4 analog test outputs based on internal program values. This allows the internal values to be directly compared to the motor controller’s output waveform on an oscilloscope.

MotorThe motor is a 3-phase AC Induction motor used in washing machine applications as illustrated in Figure 1.

The application motor is illustrated in Figure 2 on page 5. The motor has the following specifications:

• Rated Power: 500 W

• RPM max: 15,000 rpm

• Max current: 2.8 Arms

• Continuous current: 1.5 Arms

• DC Bus Voltage: 350 Vdc

The motor windings are connected in the Wye configuration for this application.

The back side of the motor has an integrated Tachogenerator, which consists of an 16-pole magnet mounted on the shaft and a single-phase winding mounted on the housing. This produces a sine wave signal whose voltage and frequency are proportional to the motor speed. The interface to the Z8FMC16100 is a simple transistor circuit that squares off the sine wave into 3.3 V digital pulses going to Timer 0 in Capture Restart mode. This gives 8 pulses per revolution.

Figure 1. Washing Machine Application


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Application HardwareThe application electronic components and circuitry are divided among several printed circuit modules that attach to a main board mounted on a heat sink and a separate user command module, as illustrated in Figure 3.

Figure 2. Washing Machine Motor with Tachogenerator

Figure 3. Modular Controller and XP Command Module

AN024702-1006 Application Hardware

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Figure 4 is a block diagram of the application hardware design, showing the logical position of each module in the controller.

The following sections briefly describe each module of the application hardware. The schematics are shown in Appendix C—Schematic Diagrams on page 31.

High-Voltage Main Board and Power StageThe main board serves as the connector backplane for all the other controller modules. It also provides the high-voltage power stage that converts the single-phase AC supply to the 3-phase motor control output under PWM control. The schematic for the main board module is illustrated in Figure 16 on page 31.

Figure 4. Hardware Block Diagram

ACPower

HV Main Board

Power Stage3 Phase ACInduction

Motor

HVPower

Module

HVDrive

Module

FMC16ControlModule

User Interface

XPCommand

Module

WashingMachineInterfaceModule

DACModule


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The power stage section rectifies and filters the single-phase AC supply to provide a high-voltage DC bus supply. This section also contains the six IGBTs used under PWM control to generate the 3-phase AC motor drive current.

The MPU is powered after the AC supply is connected, but a normally-open relay withholds DC power from the IGBTs until the MPU has started and the application software has completed its necessary startup functions. The application then uses an I/O port output to enable a simple transistor driver that closes the relay, powering the IGBTs.

High-Voltage Power Supply ModuleThe schematic for the power supply module is shown in Figure 19 on page 34. This module uses an LNK304G IC to convert rectified AC from the power stage to generate the application’s 120 mA, 12 V supply. This 12 V supply is then regulated by a UA78M33 IC to provide the 3.3 V supply.

High-Voltage Gate Drive ModuleThe schematic for the gate drive module is shown in Figure 18 on page 33.This module contains three IR21064S high-side and low-side gate drivers that convert the Z8 Encore!® MC microcontroller PWM outputs into the voltage needed to drive the IGBT gate inputs.

FMC16100 MPU Control ModuleThe schematic for the MPU module is shown in Figure 17 on page 32. This module contains the Z8 Encore!® MC microcontroller, a 20 MHz ceramic resonator, ZiLOG 6-pin DBG interface, and the off-chip components of the high-voltage current sense and overcurrent detection circuits.


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Figure 5 illustrates the overall current sense circuit, including some power stage components and components internal to the MPU. Vref is the internal reference voltage of the MPU analog-to-digital converter and the full scale input range. At zero current (zero voltage across Rsense) the output of the Op Amp is at 1/2Vref, this centers the current waveform at one half of the full input range of the ADC.

R1 = 10 KΩ

R2 = 100 KΩ

Gain = 10

Vref = 2 V

C1 = unused

C2 = 120 pF

The Resistive Divider also forms a Low Pass Filter (LPF) to take out the diode reverse recovery current spike in the current sense signal. Since this is usually in the MHz frequency range a single pole LPF is sufficient set at a couple of hundred kHz. As the Operational Amplifier circuit already has a LPF this is more important for the following comparator circuit.

Figure 5. Current Sense Circuit

Rsense =Vref

2 × Gain × I_max = 10 kΩ ×2V

2 × 10 × 8A = 0.0125 Ω (0.020 used)


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The Cutoff Frequency is calculated as follows:

Figure 6 illustrates the overall schematic for the overcurrent sense circuit, likewise including some power stage components and components internal to the MPU.

R3 and R4 set the overcurrent trip threshold. Since this is a DC value, a bypass capacitor (C3) of 0.1 μF is used.

For R4 = 10, R3 is selected as:

Figure 6. Overcurrent Sense Circuit

ƒc =1

2π × R1 || R2 × C2=

12π × 5 kΩ × 120 pF = 256 kHz

R3 = R4 ×(Vref + I_max × Rsense)

(Vref – I_max × Rsense)= 10 kΩ ×

(2V + 10A × 0.02 Ω)

(2V – 10A × 0.02 Ω)= 12.2 kΩ ≈12.4 kΩ


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Washing Machine Interface ModuleThis module provides the speed control interface between the modular controller and the washing machine. It consists of the following parts:

• Optoisolated UART command interface

• Motor tachometer/turn sensor

The optoisolator section ensures the electrical isolation of the user command module from the high-voltage module, and also serves to multiplex the FMC16100 RXD and TXD signals onto a single isolated DATA signal that connects to the remote Z8 Encore! XP® user command module. Power and ground for the user side of the optoisolator section are provided by the user command module.

The tachometer/turn sensor section converts the analog rotor-sense signal from the AC motor to a logic-level DC pulse stream suitable for the Z8 Encore!® MC timer/counter input.

DAC Test Output ModuleThis module contains a DAC5574IDGS DAC whose I2C serial interface is driven by the Z8 Encore!® MC microcontroller. The controller software transmits selected internal values to the DAC, which converts those digital values to one of four analog outputs. This allows, for example, the internal reconstructed waveform to be compared on an oscilloscope to the actual AC output from the power stage.

Z8 Encore! XP® Command Module (External)The Z8 Encore! XP® user command module is separate and remote from the modular controller. It requires a separate 12 V power supply, which it regulates to 5 V and 3.3 V for its own use. The module’s clock source is the Z8 Encore! XP® MPU’s internal precision oscillator. The module includes a 6-pin DBG header, a reset pushbutton switch, an input pushbutton, and an input potentiometer for speed control. Command values derived from the input are transmitted to the controller main board through a single data line connected to both the TXD and RXD pin of the Z8 Encore! XP® UART. The main board connector also supplies 5 V and GND signals to power the user side of the optoisolator section of the washing machine interface module.


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Software ImplementationFigure 7 illustrates the functional block diagram of the Vector Control application.

Variables and DeclarationsDeclarations set the PWM frequency, the Timer 0 scaling for the Tachogenerator, and the modulation values. All variables are declared as global for speed of execution and simplicity of code.

All variables are unsigned. All signed values have separate variables of the form Name for positive and nName for negative contents. One of these variables is always zero. Using unsigned math speeds up execution but makes the algorithms longer in code.

The ADC inputs are treated as 8 bits and the PWM output is 8 bits. Internal computations generally have 4 extra bits of precision especially in the control loops that use PI (Proportional Integral) compensators, this prevents rounding from affecting integrator precision. For Inverse Park Transform (vector rotation) the concept of a quadrant is used to determine calculations on the unsigned values.

Figure 7. Functional Block Diagram

AN024702-1006 Software Implementation

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The program uses a 128-value sine lookup table, Sine_Table[128]. This table represents sine values from 0 to 90 Degrees, or approximately 0.7 Degree steps. Stepping through the table in the forward direction gives sine values from 0 to 90 Degrees and stepping through the table in the reverse direction gives cosine val-ues from 0 to 90 Degrees. This along with knowledge of the quadrant of the angle of interest (Theta) allows full reconstruction of sine and cosine values for any angle between 0 and 360 Degrees.

The polarity table, Polarity_table[8], contains bit masks used to set the polar-ity bits in the PWMCTL1 register. A 1 bit causes the corresponding channel to start the next PWM cycle in the ON state. A 0 bit causes the channel to start in the OFF state.

The ripple compensation table, ripple_table[256], contains pre-calculated bus voltage ripple compensation factors. See Bus Ripple Compensation on page 20.

InitializationThe following initializations are performed when main() is executed:

Option BitsThe options bits set the PWM Polarity and the WDT default mode.

OscillatorOscillator initialization consists of sending an unlock sequence to the oscillator control register then enabling the external oscillator circuit. After allowing a setting time of 50 ms the oscillator control register is unlocked again 20 MHz External Ceramic Resonator

Digital OutputPB7 is used as a digital test pin for code development. This allows testing of the speed of routines and to check out conditional branching of routines.

ComparatorUsed for Overcurrent shutdown.

Op AmpFor current sensing using a single current sense resistor. The op Amp is used to offset the ground referenced current sense signal to 1 V (half of the 2 V reference) and the voltage is gained up by a factor of 10. For a sense resistor value of 20 mOhms and a current of +/-4A gained up by 10 this represents a 1 V signal that can swing +/- 0.8 V.


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ADCUsed for sampling current and DC Bus Voltage.

RelayThe main relay is normally open so the high-voltage power supply is disabled while the microcontroller starts up. The relay initialization pauses for three seconds before closing the relay to make sure the high-voltage bus capacitors can precharge through a resistor. After closing the relay, the program waits another second to allow the relay contacts to settle.

Current CalibrationOnce the peripherals are enabled and have settled out 8 samples of the current sense channel are taken with zero current. The average of these samples are used to zero out any offsets in the circuit.

UARTThe UART is configured for 9600 baud, 1 start bit, 8 data bits, and 1 stop bit. UART transmit and receive are tied together for single wire communication. The 3 wires are ground, data, and 5 V. The UART service routine updates every 2 ms. The service routine is set up for just receiving data in this application. A more elaborate communication link could be implemented with this hardware.

I2CI2C is used for an external EEPROM for logging product data. For testing purposes the I2C interface is used to send data to a 4 Channel DAC. In this implementation a single channel of the DAC is updated every 250 μs so that one parameter can be monitored in real time. This provides a method for troubleshooting and code development, and field orientation tuning using an oscilloscope. To control the DAC the Z8FMC16100 is set up as the I2C Master at 384 kbps, 2.6 μs per bit. All data is sent to DAC channel A.

Timer0Timer 0 is used in Capture Restart Mode, the encoder input rising edge is used to trigger the Capture. If the timer rolls over then the maximum timer count of 0xFFFF is used setting it to the minimum speed.

PWM ModuleThe 3-phase PWM module is set up in Edge Aligned PWM and the PWM polarity is controlled to Allow Space Vector Modulation and current sampling and reconstruction. Each PWM pair is set up in complementary mode with 12 clock


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cycles of deadband (0.6 μs). The PWM reload event triggers an ADC conversion. This is used for current reconstruction.

PWM InterruptThe PWM reload interrupt is enabled. The PWM ISR constitutes the program control loop. PWM interrupts are disabled during the ISR until the ISR is complete.

Main Event LoopAfter initializations are complete, program control drops into an infinite ‘do nothing’ loop. All subsequent program functions are performed by the PWM interrupt service routine (ISR), so this ISR is in effect the main event loop. The PWM ISR is executed on every fifth PWM cycle.

Current SampleThe PWM interrupt is configured to automatically start an ADC conversion that samples the high-voltage current, so the PWM ISR begins with an ADC conversion already in progress. The PWM interrupt is edge-aligned, and the sample takes place before the PWM state change propagates to the inverter bridge gates. Thus, this first sample captures the current at the end of the just-completed PWM cycle.

After reading the first sample, the ISR immediately begins another ADC conversion. This second sample captures the current at the beginning of the new PWM cycle. This is illustrated in Figure 8 on page 15. Phase currents are then reconstructed from these samples.


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I2C Send Address and Start BitSends the address byte used by the DAC to establish communication. This action begins a side-process of the PWM ISR. I2C-related instructions are inserted at intervals to set up and transmit one test value per ISR loop to an external DAC.

Phase Current ReconstructionPhase current reconstruction is based on the two current samples previously obtained plus the PWM space vector State. The State value is updated at the end of each ISR pass to reflect the stator flux vector angle arrived at in that pass. State positions are shown in Figure 9 on page 16. The State determines how each current sample is interpreted, as shown in Table 1 on page 16. In this table, the variables I_a, nI_a, I_b, nI_b, I_c, and nI_c represent the positive and negative current variables for phases A, B, and C.

Figure 8. Sampling Space Vector PWM Current (State = 3)

A1

0

1

0

1

0

B

C

PWM PERIOD PWM PERIOD

Current Sample 1 Current Sample 2


16


Using Kirchoff’s current Law and assuming no zero sequence currents (zero sequence currents are only possible in an imbalanced Delta wound motor not in a

Figure 9. Space Vector PWM States

Table 1. Sample Interpretation by PWM State

PWM StateCurrent Sample 1

VariableCurrent Sample 2

Variable

0 nI_c nI_b

1 I_b I_a

2 nI_a nI_c

3 I_c I_b

4 nI_b nI_a

5 I_a I_c

6 (Not Used)

7 (Not Used)

180°

120°

360°

300°

240°

60°

STATE 3

STATE 2

STATE 4 STATE 5

STATE 1

VB -VC

VC -VB

VA-VA STATE 0


17


Wye winding), the sum of three phase currents equals zero. The third current can be derived from the other two samples using the following equation:

I_a + I_b + I_c = 0

The oscillograph in Figure 10 compares a reconstructed waveform as output to the DAC at 1 A/330 mV (top trace) to the original waveform as read by a current probe at 1 A/10 mV.

Test for End of PWM PeriodThis action begins another side-process of the PWM ISR. PWM interrupts remain disabled until the main loop ISR returns. However, at several times during the main loop, the program polls the IRQ0 register to see if a PWM request is pending. If so, the program clears the request and increments a counter. Near the end of the main loop, this event counter is used to delay completion of the process until four PWM request events have occurred, in addition to the one that began the loop. This process ensures a five-event main loop cycle (250 μs total) without the need for precise timing of each main loop routine.

Figure 10. Phase Current Reconstruction


18


Clarke TransformA Clarke transform produces a 2-phase (direct and quadrature) representation of the reconstructed 3-phase stator flux vector. Then a quadrant test is applied to the reference currents I_ds and I_qs to determine which quadrant the currents are in. This result is used later in the Park Transform to rotate the 2-phase vector. The equation for the Clarke Transform is:

Angle UpdateThe angle Theta is updated through the following equation:

Theta = Theta + Speed + Slip

Where:

Theta = rotor flux angle relative to the stator phase A winding

Speed = speed (frequency) of the rotor in terms of the update rate of the control loop

Slip = slip speed (frequency) required to produce the proper rotor flux

Sine and Cosine LookupSine and Cosine values are generated from an unsigned table of sine values from 0 to 90 degrees contained in a 128 value table (90 Degrees/128steps = 0.7 Degrees/step) Two values are taken from the table one at angle stored in the variable Sin_1 and one at 128-angle stored in the variable Sin_2.

I2C Send Control Byte to DACSends the control byte used by the DAC to select the DAC output channel.

Park Transform—Vector RotationThe Park transform rotates the two phase currents referred to the stationary reference frame of the stator to the rotating reference frame of the rotor flux. This is illustrated by Figure 11 on page 19. The equation for the Park Transform is:

I_dr = I_ds × cos(Theta) + I_qs × sin(Theta)

I_qr = –I_ds × sin(Theta) + I_qs × cos(Theta)

I_qs = (I_b + I_c)2√3

I_ds = I_a – (I_b + I_c)12


19


I2C Send MSB to DACSends the 8 bit data used by the DAC. This is the internal value that is sent to the DAC board to allow display of internal values as voltages on the oscilloscope. The implemented routine sends data to one channel of the DAC updated at the loop rate. This allows real time display of reference or feedback values.

I_d RegulatorRegulator that controls the direct component of the current vector. This is regulated by a simple PI regulator.

I_q RegulatorRegulator that controls the quadrature component of the current vector. This is regulated by a simple PI regulator.

Figure 11. Park Transform

I_qr

I_qs

I_dr

I_dsTheta


20


Quadrant TestA quadrant test is applied to the reference currents I_dr and I_qr to determine which quadrant the currents are in. This result is used later in the Inverse Park Transform to rotate the 2-phase vector. Reference currents I_dr and I_qr are calculated in the Speed_reg() subroutine.

I2C Send LS Byte to DACThe DAC is only 8-bits resolution so this is a don’t care byte required by the DAC.

Read Bus VoltageThe bus voltage is sampled through the microcontroller’s ADC. Currently this is used for ripple compensation, but it could also be included in field weakening calculations or used for over-voltage shutdown protection.

Bus Ripple CompensationThis routine tracks changes in the bus voltage and looks up a precalculated ripple compensation factor which is inversely proportional to the ADC sample of the bus voltage. The PWM duty cycle is scaled by this factor to compensate for variations in the DC bus voltage, so that a smaller factor value corresponds to a reduced PWM duty cycle. This clamps the output waveform to a nominal voltage.

This application uses a nominal bus voltage of 225 VDC. At this voltage, the output factor is 255 (full scale, no compensation). The factor scales down to 0 at 375 VDC or higher, providing an overvoltage shutdown. Between 225 VDC and 375 VDC, the lookup table values are calculated using the following equation:

Inverse Park Transform—Vector RotationThe Inverse Park transform rotates the two phase voltages referred to the rotating reference frame of the rotor flux to the stationary reference frame of the stator. This is illustrated by Figure 12 on page 21. The equation for the Inverse Park Transform is:

V_ds = V_dr × cos(Theta) – V_qr × sin(Theta)

V_qs = V_dr × sin(Theta) + V_qr × cos(Theta)

pwm_correction = × 255ADC_vbus_nom

ADC_vbus


21


I2C Send Stop Bit to DACA stop bit is sent to terminate the I2C communication.

Inverse Clarke TransformThe Inverse Clarke Transform converts the two phase voltages of the rotated DQ reference frame to the ABC reference frame of the stator windings. This is illustrated by Figure 13 on page 22. The equation for the Inverse Clarke Transform is:

Figure 12. Inverse Park Transform

V_qr

V_qs

V_dr

V_dsTheta

V_b = (V_qs)12

2√3(V_ds) +

V_c = (V_qs)12

2√3(V_ds) –

V_a = V_ds


22


PWM Space Vector ModulationSpace Vector Modulation starts with the 6 states that represent the 6 voltage vectors VA, –VC, VB, –VA, VC, and –VB. Table 2 shows the PWM duty cycle calculation used for each state. States 6 and 7 represent the unmodulated phase (OFF or ON).

Figure 13. Inverse Clarke Transform

Table 2. PWM Duty Cycle by State

PWM State

PWM Duty Cycle

Phase A Phase B Phase C

0 100% 100%– V_b 100%– V_c

1 V_a V_b 0%

2 100%– V_a 100% 100%– V_c

I_b

I_q

I_c

I_a=I_d


23


Figure 14 illustrates an example of PWM space vector modulation at a PWM magnitude of 75 out of 125, referenced to DC Ground.

3 0% V_b V_c

4 100%– V_a 100%– V_b 100%

5 V_a 0% V_c

6 0 0 0

7 100% 100% 100%

Figure 14. PWM Space Vector Modulation (Ground Reference)

Table 2. PWM Duty Cycle by State (Continued)

PWM State

PWM Duty Cycle

Phase A Phase B Phase C


24


Figure 15 illustrates an example of PWM space vector modulation at a PWM magnitude of 75 out of 125, referenced to Neutral.

Watchdog Timer RefreshRefreshes the Watchdog Timer once every loop update (250 μs). A reset occurs if the oscillator or a fault in the code disrupts operation for more than 200 ms.

Subfunction Service RoutineThe subfunctions are subroutines that don’t need to be updated every time the PWM ISR executes. There are ten subroutine calls arranged in a round-robin sequence so that only one call is executed per ISR loop. Therefore, each call is executed once every 2 ms. Not all round robin slots are needed for the currently implemented subfunctions. The remaining slots are available for future expansion.

Subfunctions

Tachometer UpdateThe Tachometer update routine looks at the latest Capture Value from Timer 0. The routine checks for a roll-over, if it detects a roll-over then the maximum counter value of 0xFFFF is used to calculate speed. Also a rate limit is put on the variable Speed_step to make sure noise doesn’t cause erratic speed readings. In case of an optical encoder you can have the phenomena of edge jitter, when and encoder line is on the edge of the optical pick-up and the motor is at stand still, and movement in the motor can cause fast edges that can be interpreted as

Figure 15. PWM Space Vector Modulation (Neutral Reference)


25


sensing high speed. This is filtered out by not allowing a jump in speed. The Tachometer update function is divided into three subfunction calls to limit the execution time for each call.

Field WeakeningCurrently not developed for this application.

Slip Update (Current Model)Currently not developed for this application

Speed RegulatorThe speed regulator is a standard Proportional Integral (PI) regulator. The command comes from the UART and the speed feedback comes from the Tachometer.

UART CommunicationThe UART communicates with the Z8 Encore! XP® module that simulates a washing machine control panel. The control module has a potentiometer and two momentary switches. The potentiometer setting determines the transmitted speed command. Switch 1 stops/starts communication (stopping the communication stops motor).

The control module sends a single command byte that is read at each UART update. Bits 7:1 of the command byte are the speed command (MSB of the control module’s ADC sample). Bit 0 reflects the controller module Switch 2 status, which is used to control the motor direction.

Acknowledge byte from motor controller: AAh

The UART baud rate is 9600 Baud.

Software MetricsTable 3 illustrates the execution time for each program initialization routine, executed once at startup.

Table 3. Initialization Execution Times

Routine Time

init_osc 50 ms

init_out 1 µs

init_comp 1 µs

init_amp 2 µs


26


Table 4 illustrates the execution time for each routine in the PWM ISR, executed every 250 μs (4 kHz loop).

init_adc 2 µs

init_relay 4 s

init_current 32 µs

init_uart 2 µs

init_i2c 3 µs

init_timer0 3 µs

init_pwm 5 µs

init_pwmint 1 µs

Table 4. Main Loop (ISR) Execution Times

Routine Time (µs)

Current Sample 5

I2C Send Address and Start Bit 1

Current Reconstruction 14

Clarke Transform (3=>2 Conversion) 18

PWM Period Test 1

Theta Update 6

Sine and Cosine Lookup 3

I2C Send Control Byte 1

Park Transform (Vector Rotation) 28

PWM Period Test 1

I2C Send MSB 1

I_d Regulator 13

I_q Regulator 13

Quadrant Test 5

I2C Send LSB 1

Bus Voltage Sample 1

Table 3. Initialization Execution Times (Continued)

Routine Time


27


Table 5 illustrates the execution time for each subfunction routine, executed every 2 ms.

Bus Ripple Compensation 3

PWM Period Test 1

Inverse Park Transform (Vector Rotation)

28

PWM Period Test 1

I2C Send Stop Bit 1

Inverse Clarke Transform (2=>3 Conversion)

18

PWM Period Test 1

PWM Space Vector Modulation 33

PWM Period Test 1

WDT refresh 1

Sub Function (stepped through list) 26

Subtotal 224

End of PWM Period Test Variable

Total 250

Table 5. Subfunction Execution Times

Subroutine Time (µs)

Tachometer Update 1 of 3 7



Field Weakening Unused

Slip Update Unused

Speed Regulator 26

UART Communication 4

Table 4. Main Loop (ISR) Execution Times (Continued)

Routine Time (µs)


28


SummaryThe purpose of this application is to demonstrate how a Z8 Encore!® MC microcontroller is used for efficient rotor flux field oriented vector control of a 3-phase AC induction motor. The following microcontroller features make this part particularly suited to motor control applications:

• The eZ8 processor core runs at up to 10 MIPS with a 20 MHz clock.

• The integrated PWM interface module provides the necessary timing and logic outputs for synthesizing 3-phase voltage in motor control applications.

• The 2.5 μs successive approximation register (SAR) ADC can be triggered by PWM events for sampling and reconstructing phase currents. The integrated Op Amp amplifies and provides offset adjustment of a single ground-referenced sense resistor, centered to one-half of the built-in ADC reference. The integrated comparator provides for fast overcurrent shutdown.

• The integrated communication peripherals (UART, I2C, and SPI) provide for system level communication. For example, the UART in this application provides a highly capable user command interface, yet simple enough to be optically coupled for electrical isolation.

In addition to the Z8 Encore!® MC microcontroller’s native advantages, the software design uses the following techniques to manage the processing task:

• To make time for the waveform calculations, the main loop operates at one fifth of the 20 kHz PWM chop rate (five 50 μs cycles, 250 μs per loop). This preserves most of the advantages of a high-frequency PWM rate, while still producing a good approximation of the appropriate output waveform.

• To free up additional time for main loop calculations, low-priority subfunctions are called in a 10-position round-robin schedule, so that each subfunction is executed only once every 2.5 ms. The lengthy tachometer update operation is further divided into three subfunction calls to limit execution time per call.

• Converting current measurements to a 2-phase vector for the rotation transform reduces calculation time compared to rotating a 3-phase vector.

• All signed values are expressed as pairs of unsigned variables. This requires extra code to perform an if-then-else for each calculation, but the eZ8 processor’s short-range branch instructions are efficient enough so the unsigned calculations can execute faster than the equivalent library routines, which are written for general-case signed arithmetic.

The example application and techniques described in this document should prove helpful for anyone who intend to develop motor control applications based on the Z8 Encore!® MC family of microcontrollers.

AN024702-1006 Summary

AN024702-1006 Appendix A—References

29


Appendix A—ReferencesFurther details on this topic and the eZ80® family of products is available in the references listed in Table 6.

Table 6. List of References

Topic Document Name

Z8 Encore!® CPU eZ8 CPU User Manual (UM0128)

Z8FMC16100 MCU Z8FMC16100 Series Product Specification (PS0246)

Motor Control Hsu, P.,. “A Short Course on Vector Control”. San Jose State University, pp. 49-54, 1996.

Garcia, G., Stephan R. & Watanabe E. “Comparing the Indirect Field-Oriented Control with a Scalar Method”. IEEE Trans. Ind. Electronics, vol. 41 Nº2, pp. 201-207, April 1994.

Trzynadlowski, M., Andrzej “Control of Induction Motors”. Academic Press, pp. 102-105, 2001.

Ned Mohan, “Short Course on Electric Drives: Understanding Basics to Advanced Control & Encoder-Less Operation.” University of Minnesota, 2005 (A recording of the internet-based short course presented on May 12, 2005 by Professor Ned Mohan, edited to fit on one Video DVD.)

AN024702-1006 Appendix B—Glossary

30


Appendix B—GlossaryDefinitions for terms and abbreviations used in this application note that are not commonly known are listed in Table 7.

Table 7. Glossary

Term/Abbreviation Definition

ADC Analog-to-Digital Converter

DAC Digital-to-Analog Converter

IGBT Insulated-gate bipolar transistor

ISR Interrupt Service Routine

PI Proportional plus Integral

PWM Pulse Width Modulation

Rotor Rotating cage and windings of AC motor

Stator Stationary windings of AC motor

Application Noteing FMC16100 MCU

31

AN024 Appendix C—Schematic Diagrams

Apples.

6

A

B

C

D

6

Number Revision

26-Jun-2006 Sheet of C:\Program Files\Design Explorer 99 SE\PROJECTS\APPLICATIONS\Rex\HiVoltRefDes\Drawn By:

M_TEMP

M_FGND

M_FGND

M_T2

M_ISO_VCCM_ISO_DATAM_ISO_GND

M_1_ACM_2_AC

M_7_PH_BM_8_PH_C

M_3_CENTER_TAP

M_6_PH_A

M_GND

123

M_P3

EDGE3

60RUFD

123456

M_P2

EDGE 6 HV

M_R1710k NTC

12

MW_J4

pad 2 HV

60RUFD

1234

M_P1

EDGE 4 HV

123

MW_J5

pad 3

HEATSINK

AC POWER

MOTOR

OPTO UART

2322 640 66103

96C1024-001 A

HV MAIN BOARD

MTHOLE1

MTHOLE

MTHOLE2

MTHOLE

MTHOLE3

MTHOLE

MTHOLE4

MTHOLE

12

M_P4

EDGE2

M_12VM_GND

TEMP SENSOR

1

2

3

M_D2BAS16

M_Q7MMBT2N2222A

M_R18

2K

M_12V

M_GND

M_ENABLE M_BASE

M_RELAY

AUX POWER

M_T1SHINGCHINERFACEDULE

Vector Control of a 3-Phase AC Induction Motor Us

702-1006

endix C—Schematic DiagramsFigure 16 through Figure 22 are the schematic diagrams for the Vector Control application modu

Figure 16. High-Voltage Main Board Schematic

1 2 3 4 5

54321

D

C

B

A

Title

Size

B

Date:File:

M_7_BH

M_GATE_BL

M_8_CH

M_GATE_CL

M_CS+

M_CS-

M_6_AH

M_7_PH_B

M_VB M_VC

M_7_PH_B M_8_PH_C

M_9_DIV M_11_DIV

M_3_DIV

M_GATE_AL

M_8_PH_C

M_V+

M_6_PH_A

M_6_PH_A

M_VA

M_1_AC

M_2_AC M_1

2V

M_RELAY M_3_CENTER_TAP

M_GND

M_CL

M_GND

M_CH

M_GND

M_BL

M_GND

M_BH

M_GND

M_AL

M_GND

M_AH

M_GNDM_3_3V

M_GNDM_12V

M_GND

M_4_DC_IN

M_GND

M_GND

M_4_DC_IN

M_RSENSE

M_6_AH

M_6_PH_A

M_GATE_AL

M_GND

M_7_BH

M_7_PH_B

M_GATE_BL

M_GND

M_8_CH

M_8_PH_C

M_GATE_CL

M_GND

M_V+

M_GND

M_VA

M_GND

M_VB

M_GND

M_VC

M_GND

M_TEMP

M_GND

M_CS+

M_CS-

M_GNDM_ENABLE

M_5_VBUS

M_10_DIV

M_3_3VM_SCL

M_SDAM_GND

1 2

MC_J8pad 2

M_R510.0k

1 2

MP_J2pad 2

1 2

MG_J11pad 2

1 2MC_J4pad 2

M_Q5SGS5N

1 2

MC_J3pad 2

1 2

MG_J3pad 2

M_Q3SGS5N60RUFD

12 MC_J2

pad 2

M_R71.00M

M_R14UNUSED

1234

ME_J1

+

M_C11000uF 200V

M_R8UNUSED

1 2

MC_J7pad 2

M_R4

CL-140

1 2

MC_J6pad 2

1 2

MG_J2pad 2

M_R15UNUSED

1 2

MG_J5pad 2

1 2

MG_J10pad 2

1 2

MP_J3pad 2

1 2

MC_J13pad 2

M_Q4SGS5N60RUFD

1 2

MG_J4pad 2

M_R9UNUSED

1 2

MG_J7pad 2

1 2

MG_J9pad 2

12 MG_J1

pad 2

1 2

MC_J14pad 2

1 2

MC_J15pad 2

M_R16UNUSED

M_Q1SGS5N60RUFD

1 2

MG_J8pad 2

M_R10UNUSED

1 2

MP_J1pad 2 HV

1 2

MG_J13pad 2

1 2

MC_J16pad 2

M_R61.00M

M_R3 10.0k

M_R11UNUSED

1 2

MG_J12pad 2

M_C422nF 400V

M_R13UNUSED

1234

MC_J17pad 4

12 MC_J1

pad 2

+ M_C2

1000uF 200V

1 2

MC_J5pad 2

M_Q6SGS5N

M_R12UNUSED

M_Q2SGS5N60RUFD

M_R2 10.0k

1 2

MG_J6pad 2

1 2MC_11pad 2

2

1

3

4

M_D1

Rectifier

M_C322nF 400V

M_R1

0.020 OHM

1 2

MC_J12pad 2

A B C

BEMF DIVIDERS

HIGH VOLTAGE POWER STAGE

HV POWER SUPPLY MODULE

FMC16 CONTROL MODULE

HV GATE DRIVE MODULE

DAC MODULE

ERJ-M1WSF20MU

GBU6J

ESMQ201VSN102MR30S

ESMQ201VSN102MR30S

B32529B6223J B32529B6223J

123

MW_J3

Pad3

12

MW_J2

Pad2

12

MW_J1

Pad2

123

MC_J10

Pad3

M_3_3VM_GND

M_GND

M_GND

M_VC

M_RXDM_TXD

1

2

3

5

M_K1RELAY_JS1A-12V

M_C54700pF

M_C64700pF

M_FGND

M_GND

M_5_VBUS

TP1GND M_GND

WAMA

INTEMO


32


6

A

B

C

D

6

D

C

B

A

itle

Number Revisionize

B

ate: 12-Jul-2006 Sheet of ile: C:\Program Files\Design Explorer 99 SE\PROJECTS\APPLICATIONS\Rex\HiVoltRefDes\Drawn By:

C_VREF

C_CS-

C_GND

C_GND

C_GND

C_GND

C_VA

C_VB

C_VC

C_TEMP

C_V+C_GND

C_CS+

12

C_P16

con 2

12

C_P11

con 2

12

C_P13

con 2

12

C_P12

con 2

12

C_P15

con 2

C_R10

10.0K

12

C_P14

con 2

C_R1210.0K

DBGINTERFACE

96C1020-001

FMC16 CONTROL MODULE

1 23 45 6

C_P18

HEADER 3X2

A

C_R14

UNUSED

C_R15

UNUSED

C_R13

10K

C_3_3V

C_3_3V

C_3_3V


702-1006

Figure 17. FMC16 Control Module Schematic

1 2 3 4 5

54321

T

S

DF

C_CS-

C_T

EM

P

C_XOUT

C_AL

C_N

RE

SE

T

C_CS+

C_VREFC_AH

C_C

HC_XIN

C_C

UR

RE

NT

C_D

BG

C_C

INP

C_TXD

C_B

L

C_BH

C_C

L

C_3_3V

C_V

+

C_VBC_VA

C_VREF

C_GND

C_GND C_GND

C_3_3VC_VC

C_DBG

C_NRESET

C_GND

C_GND

C_GND

C_GND

C_GND

C_GND

C_CMD

C_ENABLE

C_SCL

C_GND

C_3_3VC_SCLC_SDAC_GND

C_GNDC_GND

C_GND

C_GND

C_GND

C_3_3V

C_GND

C_3_3VC_GND

C_C6

0.01uF

C_R310.0K

C_C8

UNUSED

C_C14

UNUSED

C_R212.4K

12

C_P4

con 2

C_R110.0K

C_C10

0.01uF

12

C_P8

con 2

12

C_P7

con 2

C_R1110.0K

12

C_P3

con 2

C_C7

2200pF

C_C2

100pF

C_C11

0.1uF

C_C19

2200pF

PB2/ANA2/T0IN0 1PB1/ANA1/T0IN1 2PB0/ANA0/T0IN0 3AVDD 4AGND 5VREF 6PA0/OPINN 7PA1/OPINP/CINN 8

PA2/

CIN

P9

PB7/

AN

A7

28

RE

SE

T/F

AU

LT

011

DB

G12

PC0/

T0O

UT

13PW

M2L

14PW

M2H

15PW

M1L

16

PWM1H17

PWM0L18

PWM0H19

GND20

XOUT21

XIN22

VDD23

PA3/TXDE/SCK/SCL24

PA4/

RX

D/M

ISO

25

PA5/

TX

D/M

OSI

26

PA6/

CT

S/SS

/SD

A27

PB6/

AN

A6

29

PB5/

AN

A5

30

PB4/

AN

A4/

CIN

N31

PB3/

AN

A3/

OPO

UT

32PA

7/FA

UL

T1/

T0O

UT

/CO

UT

10

C_U1Z8FMC16_32LQFP

12

C_P6

con 2

11

22

3 3

C_Y1

20MHz

1234

C_P17

con 4

C_C5

0.1uFC_C9

UNUSED

C_C18

UNUSEDC_C17

UNUSED

C_R9

49.9K

C_C1

0.1uF

C_C12

0.1uF

C_C13

10uF 6.3V

12

C_P5

con 2

C_R410.0K

12

C_P1

con 2

0805CCR20.0MXC7T

12

C_P2

CON2

123

CP10

CON3

C_RXD

C_ENABLEC_GND

TP1CURRENT

TP2

TEMP


33


6

A

B

C

D

6

D

C

B

A

Title

Number RevisionSize

Orcad B

Date: 26-Jun-2006 Sheet of File: C:\Program Files\Design Explorer 99 SE\PROJECTS\APPLICATIONS\Rex\HiVoltRefDesDrawn By:

HV GATE DRIVE MODULE

96C1017-001 A


702-1006

Figure 18. HV Gate Drive Module Schematic

1 2 3 4 5

54321

G_6_AH

G_12VG_12V

G_AH

G_GATE_ALG_LO_A

G_6_VB

G_AL G_6_HO

G_12V

G_GND

G_GNDG_GNDG_GND

G_6_PH_A

G_7_PH_B

G_7_BH

G_12VG_12V

G_BH

G_GATE_BLG_LO_B

G_7_VB

G_BL G_7_HO

G_GNDG_GNDG_GND

G_8_PH_C

G_8_CH

G_12VG_12V

G_CH

G_GATE_CLG_LO_C

G_8_VB

G_CL G_8_HO

G_GNDG_GNDG_GND

G_GND

G_GND

G_GND

G_GND

G_GND

G_GND

G_C2

0.1uF

VCC1

HIN2

LIN3

COM6

LO7

VS 11

HO 12

VB 13

VSS5

G_U1

IR21064S

VCC1

HIN2

LIN3

COM6

LO7

VS 11

HO 12

VB 13

VSS5

G_U2

IR21064S

12

G_P3

con 2

G_C10

0.1uF

2 1G_D3 US1J

G_C6

0.1uF

2 1G_D2 US1J

+ G_C12

10uF 16V

12

G_P1

con 2

G_C3

0.1uF

G_R2 49.9

G_R6 49.9

12

G_P11

con 2

+ G_C8

10uF 16V

G_R4 49.9

12

G_P2

con 2

G_R5 49.9

G_R3 49.9

2 1G_D1 US1J

12

G_P5

con 2

12

G_P12

con 2

+ G_C4

10uF 16V

12

G_P13

con 2

12

G_P8

con 2

12

G_P9

con 2

12

G_P4

con 2

12

G_P10

con 2

12

G_P6

con 2

G_R1 49.9

+ G_C1

10uF 16V

G_C11

0.1uF

12

G_P7

con 2

+ G_C9

10uF 16V

G_C7

0.1uF

VCC1

HIN2

LIN3

COM6

LO7

VS 11

HO 12

VB 13

VSS5

G_U3

IR21064S

+ G_C5

10uF 16V

GATE DRIVE MODULE

UWX1C100MCL2GB UWX1C100MCL2GB




34


6

A

B

C

D

6

D

C

B

A

Title

Number RevisionSize

Orcad B

Date: 26-Jun-2006 Sheet of File: C:\Program Files\Design Explorer 99 SE\PROJECTS\APPLICATIONS\Rex\HiVoltRefDesDrawn By:

12

P_P3

con 2

16V01MCL1GB

0.1" Spacing

HV POWER MODULE

A96C1016-001


702-1006

Figure 19. HV Power Module Schematic

1 2 3 4 5

54321

P_2_BP

P_2_OUT

P_2_S

P_2_FB

P_3_3V

P_GND

P_12V

P_1_VBUS

21

P_D2

US1J

12

P_P1

con 2 HV

P_C1

0.01uF

+ P_C3

100uF 16V

+ P_C2

10uF

21

P_D1

US1J

+ P_C6

100uF

P_R12.00k

P_C4

0.1uF

P_R2 16.5k

P_C5

0.1uF12

P_P2

con 2

P_L1

1mHS1 1

S2 2

BP 3

FB 4D5

S77

S88

P_U1

LNK304G

VI1

GN

D2

VO 3

P_U2

UA78M33CSCYR

15V POWER SUPPLY

3.3V POWER SUPPLY

UWX1C101MCL1GB

UWX1C100MCL2GB

B82477G4105M

UWX1C1

0.2" Spacing

0.1" Spacing

REFERENCE DESIGNATORS AND NET NAMES: "P_" FOR POWER SUPPLY MODULE


35


6

A

B

C

D

6

D

C

B

A

Title

Number RevisionSize

B

Date: 26-Jun-2006 Sheet of File: C:\Program Files\Design Explorer 99 SE\PROJECTS\APPLICATIONS\Rex\HiVoltRefDes\Drawn By:

Washing Machine Interface Module

96C1021-001 A

SE

C_EMITTERW_C5

0.1uF

1

23

W_Q1MMBT2N2222A

W_R7100

SOR

12

W_P2

CON2

W_GNDW_VC


702-1006

Figure 20. Washing Machine Interface Module Schematic

1 2 3 4 5

54321

W_ISO_ANODE

W_GND

W_ANODE

W_3_3V

W_3_3V

W_ISO_GNDW_ISO_DATAW_ISO_5V

W_GND

W_C2

0.1uF

W_C1

0.1uF

W_R1220

1

2

3

4 5

6

7

8

W_U2

6N137

W_R3390

1

2

3

4 5

6

7

8

W_U1

6N137

123

W_P5

con 3

W_R44.99K

W_R24.99K

200mil spacing from rest of circuitryW_T1W_T2

W_BA

W_3_3V

W_GND

2

31

W_D2BAS16

W_R6 10.0K

2

31

W_D1BAS16

12

W_P4

con 2

W_R510.0K

W_C4

0.1uF

TACH/TURN SEN

OPTOISOLATED UART

12

W_P1

CON2

123

W_P3

CON3

W_C3

0.1uF

W_GNDW_GND

W_TXDW_RXD


36


4

A

B

C

D

4

Revision

Sheet of E\PROJECTS\APPLICATIONS\Rex\HiVoltRefDesDrawn By:

LE

001 A


702-1006

Figure 21. DAC Module Schematic

1 2 3

321

D

C

B

ATitle

NumberSize

A

Date: 26-Jun-2006File: C:\Program Files\Design Explorer 99 S

1 2 3 4

J7CON4

VOUTA1

VOUTB2

GND3

VOUTC4

VOUTD5 SCL 6SDA 7VDD 8A0 9A1 10U1

DAC5574IDGS

C1.1uF

3.3V

1

J1CON1

1

J6CON1

1

J2CON1

1

J3CON1

1

J4CON1

1

J5CON1

DAC MODU

96C1022-

R110K

R210K


37


le)

4

A

B

C

D

4

Revision

Sheet of \PROJECTS\APPLICATIONS\Rex\HiVoltRefDesDrawn By:

5678

1 2 3

J2CON3

3.3V

R3220

DA

TA

LED1GRN

AND MODULE

A-001


702-1006

Figure 22. XP Command Module Schematic (Connects to Washing Machine Modu

1 2 3

321

D

C

B

ATitle

NumberSize

A

Date: 26-Jun-2006File: C:\Program Files\Design Explorer 99 SE

VCC1

PA0/DBG2

PA1/VREF3

PA2/RESET4 PA3/CTS0PA4/RXD0PA5/TXD0

GND

U3

Z8F04XP_8PIN

1 2

J1CON2

IN2 V_OUT 1

GN

D3

U2

VREG_LM3480

GN

D2

V_OUT 3V_IN1

U1VREG_LM78M05CDT

1 23 45 6

JP1

HEADER 3X2

12V 5V

5V12V

3.3V

3.3V

C1.1uF

C2.1uF

C4.1uF

C3.1uF

C5.1uF

R210K

R110K

R42.49K

R52.49K

3.3V12V

3.3V

S2

DEBUG

S1

RESET

XP COMM

96C1023

R65K

38


Appendix D—FlowchartsFigure 23 illustrates the overall program flow. After main() initializes the application, it drops into an infinite loop. Meanwhile, the PWM timer generates an event every 50 μs. The PWM ISR is timed to execute on every fifth PWM event, once every 250 μs. The ISR calls one of ten low-priority subfunctions on every loop cycle, so each subfunction is called once every 2.5 ms.

Figure 23. Flowchart for the Application

Initialization

Infinite Loop

Calculate/UpdatePWM Values

Refresh WDT Timer

Tach Update 1

Tach Update 2

Tach Update 3

Field Weakening

Slip Update

Speed Regulator

UART

Unused

Unused

Communication

Unused

Wait for FifthPWM Period

(250 μs Loop)

PWM Interrupt

Return

main()

PWM TimerEvents (50 μs)

Service Routine

0–9 StepRound-Robin

AN024702-1006 Appendix D—Flowcharts

39


Figure 24 illustrates the PWM ISR main loop.

Figure 24. Flowchart for the PWM ISR

Refresh WDT Timer

Wait for 5th PWMPeriod (250 μs Loop)

PWM Interrupt

Return

Service Routine

Current Sample

I2C Send Address

CurrentReconstruction

Clark Transform(3 to 2 Phase)

Theta Update

I2C SendControl Byte

Park Transform(Rotation)

I2C Send MSB

PI Regulator

I2C Send LSB

Bus VoltageRipple Compensation

Inverse Park Transform(Rotation)

I2C SendStop Bit

Inverse ClarkeTransform

(3 to 2 Phase)

PWM SpaceVector Modulation

0–9 Step Call SubfunctionRound-Robin for Current Step

and Start Bit

AN024702-1006 Appendix D—Flowcharts

vector control of a 3-phase ac induction motor using

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