Current observer based position estimation using the stationary frame equivalent of a synchronous frame PI regulator for PMSM sensorless drives

This paper introduces a new current observer-based position estimation method using the stationary frame equivalent of a synchronous frame PI regulator for a 3-phase PMSM. The introduced method eliminates a positive feedback type of interdependency between the performance of the position estimation and the synchronous reference frame transformation by implementing the position estimation method in the stationary frame. In the proposed method, the major drawbacks of steady-state error caused by regulating ac signals with conventional PI control and high frequency ripple in a state variable caused by sliding mode control of the current observer based estimation approach in the stationary frame, are overcome by using the stationary frame equivalent of a synchronous frame PI regulator. The concept and implementation are simple, straightforward, and intuitive. Simulated and experimental results are provided to confirm the attractive performance characteristics of the resulting position estimation using the proposed method.