Linear Hall Effect Sensors For Multi-Phase Permanent Magnet Motors with PWM Drive

摘要

Low cost linear Hall Effect sensors are used for determining motor shaft positions and generating voltages proportional to the motor shaft positions. The voltages from the linear Hall Effect sensors are compared to a triangle waveform and PWM signals are generated therefrom. A constant current source and constant current sink are used in the triangle waveform generator. The voltages from the linear Hall Effect sensors are adjusted to change the PWM duty cycles used to startup and vary the speed of the motor. Comparators compare the voltages from the Hall Effect sensors and product the PWM signals having duty cycles proportional to the voltage drive requirements of the motor.