A Hybrid Control Scheme for Three-Phase Vienna Rectifiers

Abstract

Vienna rectifier is a kind of power converter with complicated operating constraints. Thus, it is difficult to control with conventional control strategies, especially during transients or under low power factor operation. This study proposes a hybrid control scheme with dual loops for the three-phase Vienna rectifier. In the outer loop, proportional-integral controller is designed to regulate the dc-link voltage and input reactive power. And in the inner loop, finite set model predictive control is utilized to control the input currents and maintain the neutral point voltage balance. To reduce the costs, an extended state observer is introduced to estimate the load current. In view of the characteristics of the proposed control scheme, it has the following advantages: 1) good dynamic performance; 2) wide operating range and enhanced input reactive power capability; 3) lower computational burden; and 4) without the need of modulation method. The correctness and effectiveness of the proposed control scheme are verified by the simulation and experiment results.