Dynamic torque reference limiting in torque-controlled permanent magnet motor drives

摘要

A control system and method for use in controlling a torque-controlled permanent magnet synchronous motor drive. A slew-rate limiter processes an input torque command to produce a modified torque command that is input to the motor drive. A controller is coupled to the slew-rate limiter and the motor drive for dynamically limiting the input torque command applied to the motor drive and its rate of increase. The slew rate limiter processes an applied torque command to output a modified torque command that is applied to the motor drive. Current control error signals are output by the motor drive. The RMS value of the current control error signals is computed. The RMS value is compared to low and high thresholds. If the RMS value is greater than the high threshold, the modified torque command is reduced until the RMS value is less than the high threshold. If the current control error signal is greater than the low threshold and less than the high threshold, the modified torque command is not increased in absolute value even if the input torque command is increasing in absolute value. If the RMS value is less than the low threshold, no change is made to the input torque command.