Sliding Mode Sensorless Control of PM Synchronous Motor for Direct-Driven Washing Machines

The rotor position of PMSM is estimated by a novel sliding mode observer (SMO) operating over a wide speed range including deep flux-weakening region. By properly selecting equivalent control feedback gains, the estimation error of rotor position is reduced in low speeds and fast convergence of SMO guaranteed in high speeds. Compared to other PMSM systems for direct-driven washers using Hall effect sensors, the control scheme features high torque production and fast dynamic response, especially in the deep flux weakening high-speed range. The sensorless control algorithm is robust to the armature reaction that seriously affects Hall effect sensor signals and degrades torque production. The proposed sensorless control algorithm is verified by both computer simulation and experimental testing with a dynamometer as well as a direct-driven washer