Load torque estimation for sensorless PMSM drive with output filter fed by PWM converter

The paper describes an load torque observer for sensorless control of permanent magnet synchronous motor, when the output voltage of the PWM inverter is filtered by an sinusoidal filter. The dynamics of the output filter are taken into account in the design of Unscented Kalman Filter. The use of the output filter does not require additional motor currents or voltages measurements. The speed and position are based on the estimation and are used for speed sensorless control, load torque signal is treated arbitrary as master robot control input. In that case the focus was state estimation rather than at the control at all. Laboratory results performed on 1,3kW PMSM shows the functionality of the proposed estimation and control method with estimation load torque presence.