A Novel Method for Compensating Inverter Nonlinearity Effects in Carrier Signal Injection-Based Sensorless Control From Positive-Sequence Carrier Current Distortion

In conventional rotating carrier signal injection-based sensorless method, a positive-sequence carrier current has no use, and only the negative-sequence carrier current is used to estimate the rotor position information. The inverter nonlinearity effects, however, distort the negative-sequence carrier current and result in inaccurate position estimation. With the aid of theoretical analysis and experimental measurement, it is proven in this paper that the positive-sequence carrier current distortion resulting from inverter nonlinearity effects can be used to compensate the influence of inverter nonlinearity on negative-sequence carrier current. Hence, a new online postcompensation scheme is developed in this paper by utilizing the distortion of positive-sequence carrier current due to inverter nonlinearity effects. The proposed method can be easily implemented on standard voltage source inverter without any offline commissioning process or hardware modification. Experimental results confirm the effectiveness of the proposed method in suppressing the influence of inverter nonlinearity on the rotor position estimation.