A Finite Control Set Model Predictive Control for Five-Phase PMSMs With Improved DC-Link Utilization

Abstract

Finite control set model predictive control (FCS-MPC) based on virtual voltage vectors (V3s) is widely studied and applied in five-phase permanent magnet synchronous motor (PMSM) drives. The synthesized V3s can inherently eliminate <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xy</i> -axes voltages and reduce the number of candidate vectors, which can significantly reduce the computation burden. However, the dc-link utilization is reduced due to the usage of V3s. To address this issue, an FCS-MPC method with improved dc-link utilization is proposed in this article. First, only large vectors are selected to predict the system evolution. The large vector that minimizes cost function is selected, and rescaled using the duty ratio estimation. Then, in order to control the third harmonic currents, three adjacent large vectors are applied to replace the selected vector, and the duty ratios are reassigned. Additionally, zero vectors are replaced with two opposite large vectors to reduce common-mode voltage (CMV). Finally, the proposed FCS-MPC is compared with conventional methods in experiments. Experimental results have verified that the proposed method can improve the dc-link utilization, and keep the superiorities of low CMV and low computation burden.