Post-fault performance enhancement of the PMSM drive by employing the predictive torque control

Abstract

Several inverter faults such as open-phase or loss of the driving signals could terminate the operation of a PMSM drive. By reconfiguring the two-level three-phase six-switch inverter and employing the four-switch (B4) topology during the post-fault condition, unceasing operation of the drive is attainable. In this paper a predictive torque control (PTC) scheme is proposed to control the B4 inverter-fed permanent magnet synchronous motor (PMSM). An extended cost function of the predictive scheme not only reduces the fluctuation of electromagnetic torque and stator flux, but also it reduces the voltage offset between the DC bus capacitors. The B4 inverter controlled by the proposed method reduces the switching losses and helps to tolerate several inverter faults. Proposed PTC method alleviates the unbalanced phase currents induced by fluctuation of DC bus center tap voltage. It provides an effective approach to reduce the harmonic distortions of the motor currents and relevant stator vibrations. It also suggests a systematic, automated approach for the tuning of applied Proportional-Integral controller in the speed control loop, which utilizes the fuzzy logic algorithm. Simulation results demonstrate the effectiveness and potentials of the proposed PTC method to control the post-fault B4 inverter-fed PMSM drive.