Torque ripple compensation system for permanent magnet electric motor - uses stored tables of values to modify input current command signal to obtain ripple-free torque characteristic

摘要

The torque ripple compensation system includes an input current signal, representing the motor current for the desired torque output, multiplied with a modification value defined by a stored compensation factor for each angular shaft position of the motor, held in a table of values. A second table of values holds current amplitude factors for the angular shaft positions of the motor, combined with the modified current signal to provide a current regulation control signal. The control signal is used to provide a driving current for each phase of the motor, to obtain a required output torque with a ripple-free characteristic. The stored values are determined in dependence on the torque ripple source, e.g. vibration, load operation and variations resulting from the motor construction.