Sensorless Control of Permanent Magnet Synchronous Motor Based on New Sliding Mode Observer with Single Resistor Current Reconstruction

To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer, a piecewise square root switching function with continuously varying characteristics is designed, and its stability is analyzed by using Lyapunov stability criterion. Secondly, according to the relationship among bus current, switching state and phase current, a single bus resistance sampling current reconstruction scheme without current sensors is adopted, which effectively reduces the cost of motor system. Finally, the feasibility and effectiveness of the proposed scheme are verified by simulation.