Motorola M68HC08 manual Application Control, Speed Control, PC Master Software

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

BLDC Motor Control

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 Microsoft1 Internet Explorer as a user interface on the PC.

Designer Reference Manual		DRM028 — Rev 0
50	BLDC Motor Control	MOTOROLA
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