Performance evaluation of PMSM based on model predictive control with field weakening operation and bidirectional quasi Z-source inverter

Abstract

This paper presents a comparative study between the performance of Permanent Magnet Synchronous Machines (PMSM) fed by two types of inverters when the speed exceeds the base value. The first one is the Voltage Source Inverter (VSI), at this case the Field Weakening Control (FWC) is adopted to drive the motor. The second type is a Bidirectional quasi Z-Source Inverter (BqZSI) that has both the bucking and boosting capability within a single stage. Consequently, if the motor has to operate above the rated speed, BqZSI will boost the dc link voltage to avoid applying the field weakening technique. With FWC, the direct current of the PMSM has a negative value to reduce the total field inside the motor to increase the speed, so the drawn current from the supply is increased and the efficiency of the drive system will be decreased. Unlike VSI, BqZSI boosts the voltage across the PMSM utilizing the shoot-through periods and keeps the direct motor current equal to zero value. The comparative study is done with the same parameters with the two inverters based on MATLAB software. The results show that PMSM driven by BqZSI has high efficiency compared to that driven by VSI with FWC.