AN2357 Freescale Semiconductor / Motorola, AN2357 Datasheet - Page 18

• Manufacturer Part Number: AN2357
• Description: Sine Voltage Powered 3-Phase Permanent Magnet Motor with Hall Sensor
• Manufacturer: Freescale Semiconductor / Motorola

AN2357/D
Sine Wave
Generation
Over-Voltage
Limitation
CPU Reset to
Turning Motor
PC Master Software (Remote) Operating Mode
18
Sine Voltage Powered 3-Phase Permanent Magnet Motor with Hall Sensor
The sine wave generation is calculated with each PWM reload interrupt, which
is every 64 µs. The function
gets the sinus of the actual phase for all three phases from the table, and
multiplies it by the phase amplitude. Resolution of the sinus is 1024 points per
period and 256 points per amplitude. The function is written in assembly
language to minimize execution time. The execution time is about 20 µs.
Over-voltage limitation protects the power stage during recuperation. If the
required speed is lower then the actual while over voltage occurs, the required
speed is increased to stabilize the dc-bus voltage. The required speed is
decreased so that the dc voltage keeps to the limiting value, until the actual
speed is higher than required.
If the CPU is reset while the motor is running, the initialization routine
recognizes the running motor from the Hall sensor signal. Then, the speed of
motor is calculated and PLL is synchronized with the Hall sensor signal. The
voltage amplitude is estimated from the measured speed, which helps to
switch-on PWM without torque surge. CPU reset always switches the
application to manual control, even if the application was controlled by PC
master software.
The drive is controlled remotely from a PC via an RS-232 physical interface.
The manual control is ignored and all required values are controlled from PC.
PC master software displays the following information on a control page:
The other variables can be viewed in the variables section.
Project files for the PC master are located in:
Start the PC master software window’s application, 3ph_pm_hs.pmp;
If the PC master project (.pmp file) is unable to control the application, it is
possible that the wrong load map (.elf file) has been selected. PC master uses
Freescale Semiconductor, Inc.
•
•
•
•
•
...\applications\3ph_pm_sin\sources\pcmaster\3ph_pm_sin.pmp
For More Information On This Product,
Required speed
Actual speed
RUN/STOP switch status
CLOSE LOOP/OPEN LOOP
Application status
(Abate u_phase_amplitude, SWord16 phase_actual);
Go to: www.freescale.com
sin3p3hPIxLUT
MOTOROLA