56F8300
3-Phase AC Induction Motor V/Hz Control
using Processor Expert
TM
Targeting Document
56F8300
16-bit Digital Signal Controllers
8300ACIMTD
Rev. 1
08/2005
freescale.com
Document Revision History
Version History
Rev 0
Rev 1
Initial release
Updating format; adding references to 56F8100 family and 56F8367EVM
Description of Change
3-Phase AC Induction Motor V/Hz Control, Rev. 1
2
Freescale Semiconductor
3-Phase AC Induction Motor Control V/Hz
Application - Closed Loop
This application demonstrates a principal of the Volts per Hertz (V/Hz) control of the 3-Phase
AC Induction motor in closed-loop using the 56F8346, 56F8357 or 56F8367 EVM board,
Optoisolation board, and 3-phase AC BLDC high-voltage power stage.
Applications developed for this demonstration board were not designed for the 56F8100
devices. The 56F8300 demonstration board does, however, fully support 56F8100 software
development.
1. Specifications
This application performs principal control of the 3-phase AC induction motor using a 56F8300
processor. The control technique sets the speed (rpm or Hz) of the magnetic field and calculates
the phase voltage amplitude according to a V/Hz table. This table is private to the application and
reflects AC induction motor parameters (Base Voltage/frequency; Boost Voltage/frequency; DC
Boost Voltage). The incremental encoder is used to derive the actual rotor speed.
The closed-loop system is characterized by a feedback signal (Actual speed), derived from a
quadrature decoder in the controlled system. This signal monitors the actual behavior of the
system, and is compared with the reference signal (Required Speed). The magnitude and
polarity of the resulting error signal are directly related to the difference between the required and
actual values of the controlled variable, which may be the speed of a motor. The error signal is
amplified by the controller, and the controller output makes a correction to the controlled system,
reducing the error signal.
Protection is provided against drive faults Overcurrent, Overvoltage, Undervoltage, and
Overheating.
System Outline
The system is designed to drive a 3-phase AC Induction Motor (ACIM). The application has the
following specifications:
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Volt per Hertz control technique used for ACIM control
Closed-loop control
Targeted for 56F8346, 56F8357 or 56F8367 EVM
Running on 3-phase AC induction motor control development platform at variable line voltage
115V AC and 230V AC (range -15% to +10%)
Motor mode
Generator mode
DCBus brake
Minimum speed 50rpm
Maximum speed 2250rpm at input power line 230V AC
3-Phase AC Induction Motor V/Hz Control, Rev. 1
Freescale Semiconductor
3
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Maximum speed 1200rpm at input power line 115V AC
Power stage and optoisolation board identification
Fault protection
Manual interface (RUN/STOP switch; UP/DOWN push buttons control; LED indication)
PC master software remote control interface (speed set-up)
PC master software remote monitor — PC master software monitor interface (required speed;
actual motor speed; drive fault status; DCBus voltage level; identified power stage boards)
Application Description
The Volt per Hertz control algorithm is calculated on the Freescale 56F8300 devices. The
algorithm generates the 3-phase PWM signals for AC induction motor inverter according to the
user-required inputs, measured and calculated signals.
The concept of the ACIM drive incorporates the following hardware components:
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AC induction motor-brake set
3-phase AC/BLDC high voltage power stage
56F8346, 56F8357 or 56F8367 EVM board
Optoisolation box, which is connected between the power stage board and the EVM
The AC induction motor-brake set incorporates a 3-phase AC induction motor and attached
BLDC motor brake. The AC induction motor has four poles. The incremental position sensor
(encoder) is coupled on the motor shaft. The detailed motor-brake specifications are listed in
Table 1-1.
3-Phase AC Induction Motor V/Hz Control, Rev. 1
4
Freescale Semiconductor
Table 1-1 Motor-Brake Specifications
Set Manufactured
Motor Specification
Motor Type
Pole-Number
Nominal Speed
Nominal Voltage
Nominal Current
Brake Specification
Brake Type
Pole-Number
Nominal Speed
Nominal Voltage
Nominal Current
Position Sensor (Encoder)
Type
Pulses per revolution
EM Brno, Czech Republic
AM40V
3-Phase AC Induction Motor
4
1300rpm
3 x 200V
0.88A
SG40N
3-Phase BLDC Motor
6
1500rpm
3 x 27V
2.6A
Baumer Electric
BHK 16.05A 1024-12.5
1024
The following software tools are needed for compiling, debugging, loading to the EVM, remote
control and monitoring, RUN/STOP Switch and UP/DOWN Buttons:
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Metrowerks CodeWarrior 6.0
PC master software
Processor Expert v. 2.92
DCBus voltage
Power module temperature
Rotor speed
Overvoltage (PC master software error message = “Overvoltage fault”)
Undervoltage (PC master software error message = “Undervoltage fault”)
Overcurrent (PC master software error message = “Overcurrent fault”)
Overheating (PC master software error message = “Overheating fault”)
Wrong hardware (PC master software error message = “Wrong HW used”)
Measured quantities include:
The faults used for drive protection:
The 3-phase AC Induction Motor V/Hz application can operate in two modes:
1.
Manual Operating Mode
The drive is controlled by the RUN/STOP switch (S3). The motor speed is set by the UP (S2) and
DOWN (S1) push buttons (Figure
1-1).
If the application runs and motor spinning is disabled
(i.e., the system is ready), the green user LED (LED2; see
Figure 1-2
) will blink. When motor
3-Phase AC Induction Motor V/Hz Control, Rev. 1
Freescale Semiconductor
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实时操作系统RTOS
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