Electronically commutated motor control device for electric power assisted steering system, comprises fixed sensor disposed opposite at air gap distance from multi-pole encoder and control circuit for commutation circuit

摘要

The device comprises a circular multi-pole encoder (17) having main multi-pole and multi-pole commutation track. A fixed sensor (19) disposed opposite at a air gap distance from the encoder delivers square digital signals A, B in quadrature and a signal C in the form of 2 asterisk P asterisk N pulses per revolution of the rotor. A control circuit (21) is also provided for the commutation circuit. A control circuit supplies commutation signals from the signal C for the switches (T1-T6). The control circuit defines a current set point (I ref) according to a torque set point (I), which controls the current (Im) supplying the phase windings of the motor.