A Quasi-Noncascaded DC-Link Voltage Predictive Control of a PWM Converter

Abstract

The main function of pulse-width modulation (PWM) converters in many applications is to control the dc-link voltage with good dynamic performance and strong disturbance rejection capability. Finite-control-set model predictive control (FCS-MPC) is known for its merits in both the above aspects, especially the noncascaded FCS-MPC control structure. However, as to be discussed in this article, the noncascaded FCS-MPC cannot be used to directly control the dc-link voltage of PWM converters, due to the problem of multiequilibrium points caused by the essential nonlinear characteristic of PWM converters. Hence, a quasi-noncascaded dc-link voltage predictive control structure is proposed for the first time, which keeps the outstanding dynamic performance and strong disturbance rejection capability of noncascaded FCS-MPC while avoids overcurrent caused by the unexpected equilibrium points. In addition, the proposed method can inherently handle the parameter mismatch issue, which is an important merit for MPC. Experimental results validate the theoretical analysis and performance of the proposed control strategy.