AN1910 Freescale Semiconductor / Motorola, AN1910 Datasheet - Page 9

• Manufacturer Part Number: AN1910
• Description: 3-Phase AC Motor Control with V/Hz Speed Closed Loop Using the DSP56F80X
• Manufacturer: Freescale Semiconductor / Motorola

5.
5.1 System Outline
5.2 High Voltage Hardware Set
The Control Process:
When the start command is accepted, using the Start/Stop switch, the state of the inputs is periodically
scanned. According to the state of the control signals (Start/Stop switch, speed up/down buttons or
PC Master set speed) the speed command is calculated using an acceleration/deceleration ramp.
The comparison between the actual speed command and the measured speed generates a speed error E.
The speed error is brought to the speed PI controller that generates a new corrected motor stator
frequency. With the use of the V/Hz ramp the corresponding voltage is calculated and then DC-bus
ripple cancellation function eliminates the influence of the DC-bus voltage ripples to the generated
phase voltage amplitude. The PWM generation process calculates a 3-phase voltage system at the
required amplitude and frequency, includes dead time. Finally the 3-phase PWM motor control signals
are generated.
The DC-bus voltage and power stage temperature are measured during the control process. They are
overvoltage, undervoltage, and overheating protection of the drive. Both undervoltage protection and
overheating are performed by ADC and software while the DC-bus overcurrent and overvoltage fault
signals are connected to PWM fault inputs.
If any of the above mentioned faults occurs, the motor control PWM outputs are disabled in order to
protect the drive and the fault state of the system is displayed in PC Master control page.
The motor control system is designed to drive the 3-phase AC motor in a speed close loop.
There are more SW versions targeted for a real DSP and evaluation module (DSP/EVM):
The HW setup for a real DSP/EVM differs only by evaluation module (EVM) module used.
The designed software is capable to run only on high voltage HW set described below.
Other power module boardswill be denied due to board identification build in SW. This feature
protects misuse of HW module.
The HW setup is shown in
Targetting_DSP5680X_Platform, according to targeted DSP/EVM. That documents also describes
EVM jumper settings.
The system configuration is shown in
•
Hardware
DSP56F80X
3-Phase AC Motor Control with V/Hz Speech Closed Loop
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
Figure
Figure
4-1, but it can also be found in the documents
5-1.
Hardware
9