Inverter nonlinearity effects in high frequency signal injection-based, sensorless control methods

An analysis of PWM inverter nonlinearities influencing high frequency carrier signal voltage injection for saliency-tracking-based rotor/flux position estimation is presented in this paper. Distortion of the injected carrier voltage caused by the nonlinear behavior of the inverter has been reported to cause errors in the estimated rotor/flux position. Though a number of techniques have been developed to compensate for inverter nonlinearities, they have not been proven to be effective when a high frequency, low magnitude voltage needs to be generated. Both the origins of the distortion as well as the requirements for compensation methods to be effective when producing such high frequency voltages is established in this paper.