Polyphase collectorless d.c. motor compares sensor signals with periodic sawtooth signal to produce PWM comparison signals with information used to drive FETs to enable multi-quadrant motor operation

摘要

The motor has a permanent magnetic rotor, a polyphase stator, a polyphase bridge circuit associated with the stator with bridge arms, each with two power FETs, and a rotor position sensor arrangement whose signals are compared with a periodic sawtooth signal to produce PWM comparison signals with duty cycles dependent on the sensor signals and with information used to drive the FETs in hard chopping mode to enable multi-quadrant motor operation. The motor (20) has a permanent magnetic rotor (28), a polyphase stator (22,24,26), a polyphase bridge circuit associated with the stator with a number of bridge arms, each with two power FETs (90,108,120;96,112,124) and a rotor position sensor arrangement (30,32,34) that outputs phase shifted signals with analog values dependent on a rotor position-dependent physical parameter acting on the rotor. The signals from the sensor arrangement are compared with a periodic sawtooth signal to produce PWM comparison signals with duty cycles dependent on the sensor signals and containing information used to drive the FETs in a hard chopping mode to enable multi-quadrant motor operation.