Multi-Level Current-Source PWM Rectifier Based on Direct Power Control

This paper describes a novel control strategy of a multi-level current-source PWM rectifier, which is based on relay control of instantaneous active and reactive power. The key of this strategy is direct selection of switching states on the basis of instantaneous control errors between the feedback values and the command values of the active and reactive power. Therefore, a theoretical analysis on relationship between the instantaneous power and the switching states of the PWM rectifier is investigated, which is essential to select current vectors. In addition, this paper discusses DC bus current control to balance the multiple PWM rectifiers. Several computer simulations are conducted and their results prove feasibility of the proposed technique of controlling the multi-level current-source PWM rectifier.