Linear Quadratic Extended State Observer Based Load Torque Compensation for PMSM in a Single Rotor Compressor

Abstract

Permanent magnetic synchronous motor (PMSM) has been widely used in the compressor system. The single rotor compressor with variable speed drives has serious mechanical vibration caused by large load torque pulsation during each mechanical period at low speeds. To solve this problem, a linear extended state observer (LESO) based load torque compensation is studied in this paper. The load torque is treated as a state, namely, the extended state, which is estimated by the LESO, and is subsequently cancelled by a feedforward compensation of load torque current. The linear quadratic (LQ) approach is used to design the LESO, and the relationship between the LQ performance index and the LESO bandwidth is revealed. Simulation results prove the effectiveness of the proposed method.