Model Predictive Current Control of Multilevel Smart Load Based on MPUC7 Converter

Abstract

Considering the poor power quality performance of a two-level capacitor-based electric spring (ES1), this article presents a high-power density multilevel ES1 configuration based on a seven-level modified packed U-cell converter (MPUC7-ES1). A novel control strategy based on finite control-set model predictive current control (FCS-MPCC) is also proposed for MPUC7-ES1 application. This algorithm is designed to predict the system behavior for all the conceivable switching vectors based on the discrete models of MPUC7-ES1 that is developed for the first time. To guarantee a desirable operation, the main control objectives are the MPUC7-ES1 current, auxiliary capacitors’ voltages, and switching frequency reduction. Compared with the conventional ES1 control methods, the proposed strategy has key merits including considering the dynamic models of ES1 converter, not requiring a modulator, and lower switching frequency. The operation and robustness of MPUC7-ES1 and the introduced nonlinear FCS-MPCC technique are also illustrated through extensive simulation and experimental results.

Keywords

• Electric spring
• modified packed u-cell
• MPUC7
• multilevel converter
• MPUC7-ES1
• model predictive current control