A TD-Based Speed Sensorless Composite Controller for a PMSM with Disturbances: Design and Verifications

To deal with the modeling error, dynamical uncertainties and disturbances caused by actual operating conditions, i.e., total disturbance, a speed composite sensorless controller based on tracking differentiator (TD) for a permanent magnet synchronous motor system (PMSMs) is proposed in the paper. Aiming to obtain precise electric angular velocity and the rotor position without mechanical sensors, a sliding mode observer (SMO) is established, which can estimate above signals from the back electromotive force (EMF). A time-optimal tracking differentiator (TD), attenuating the chattering phenomenon with a low-pass filter, is designed to optimize the performance of SMO. In addition, an extended state observer (ESO) is introduced to obtain the estimation value of the total disturbance, and can achieve satisfactory control performance via a feedforward compensation channel. Simulation and experimental results validate that the proposed speed sensorless composite control algorithm has excellent anti-disturbance ability and satisfactory speed regulation performance.