Patent ID: 8228016

Claim:
A control system for an electric machine, the control system comprising: a current regulator module designed to generate a first voltage command signal, and a second voltage command signal; a field weakening module designed to generate a first adjusting current command signal based on the first voltage command signal and the second voltage command signal; and a torque linearity module designed to generate a second adjusting current command signal based on the first adjusting current command signal, a torque command signal and a first limited current command signal, wherein the torque linearity module further comprises: a derivative gain module having a derivative gain that is computed based on the torque command signal and the first limited current command signal, wherein the first adjusting current command signal is multiplied by the derivative gain to generate a raw second adjusting current command signal; and a limiter module, coupled to the gain module, and designed to generate the second adjusting current command signal by limiting the raw second adjusting current command signal within limits set by the limiter module.