Sliding mode and predictive current control strategy of the three-phase Vienna rectifier

Abstract

This study involves the design and implementation of a novel double closed-loop control of the three-phase Vienna rectifier. To achieve the unit power factor operation of the rectifier and reduce the harmonic content of the grid side, the double closed-loop control strategy is proposed on the basis of the voltage control of the outer loop and the current control of the inner loop. The voltage outer loop adopts the sliding-mode variable structure control strategy based on the improved reaching law; this strategy can effectively suppress switching jitter. The current inner loop adopts an improved predictive current control strategy that combines the traditional finite control set model predictive control (FCS-MPC) with the space vector modulation method (SVPWM), such that the optimal switching state obtained by the predictive controller is modulated to generate a switching signal. Moreover, the switching frequency can be controlled by adjusting the frequency of the carrier, and the switching frequency is fixed while preserving the advantages of model prediction control. The primary advantages of the proposed double closed-loop control strategy are as follows: (1) it does not require proportional–integral controllers in the current control loops, and (2) it keeps the output voltage stable. The Vienna rectifier simulation is performed on MATLAB. Then an experimental prototype based on SiC devices is developed to verify the excellent performance of the proposed strategy in steady and transient states.