Motorola M68HC08 - Manual (Page 50)

BLDC Motor Control
Designer Reference Manual DRM028 — Rev 0
50 BLDC Motor Control MOTOROLA
Coef_Toff = 0.5 at Running state, Per_Dis = 150 with default s/w
setting
3.3.2 Speed Control
The speed close loop control is provided by a well known PI regulator.
The required speed is calculated from speed input variable, as explained
in
Process Desired Speed Setting . The actual speed is calculated from
the average of two back-EMF zero crossing periods (time intervals),
received from the sensorless commutation control block. The speed
regulator output is a PWM duty cycle.
The speed controller works with the constant execution (sampling)
period PER_T3_RUN_US. A detailed explanation is provided in
Processs Speed Control .
3.4 Application Control
The application can be controlled in two basic modes:
• Manual mode
• PC master software mode
In manual mode, it is controlled by an on-board start/stop switch and
speed potentiometer. In PC master mode, it is controlled from a
computer using PC master software. In both modes, the individual
variables can be observed using the PC master software.
3.4.1 PC Master Software
PC master software was designed to provide the debugging, diagnostic,
and demonstration tools for developing algorithms and applications. It
consists of components running on PCs and parts running on the target
MCU, connected by an RS232 serial port. A small program is resident in
the MCU that communicates with the PC master software to parse
commands, return status information, and process control information
from the PC. The PC master software uses Microsoft
1
Internet Explorer
as a user interface on the PC.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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