Model Predictive Control Method With Reduced Switching States for Single-Stage Buck-Boost Rectifier

This article proposes a control strategy based on the finite control set model predictive control (FCS-MPC) for a single-stage buck-boost (SSBB) rectifier. The proposed FCS-MPC requires the reference of parallel inductor current in the SSBB, which can be generated by two steps. First, the dc output voltage error is applied to a proportional-integral (PI) controller, which generates the grid current reference. Then, the grid current error is applied to a proportional-resonant (PR) regulator, which generates the reference of the parallel inductor current. Finally, the control of parallel inductor current is achieved by the proposed method, which evaluates possible switching states. Considering the charging and discharging states of the parallel inductor, the number of switching states is reduced from six to three by eliminating the redundant options. The effectiveness of the proposed controller is investigated experimentally on the built prototype. The results are obtained to prove that the proposed control of the dc output voltage and grid current together with unity input power factor are achieved in steady-state and transients under load and grid voltage variations. Furthermore, the performance of the proposed controller is tested under parameter mismatch. The execution times of the proposed controller with six and reduced (three) switching states are compared in this article to further demonstrate the correctness of the proposed approach.