A new control strategy for DC voltage regulation and VAr generation using PWM three-phase rectifier

The basic PWM boost converter with six bidirectional current switches has been used as a reactive power generator or as a controlled rectifier and many control strategies have been developed for these two applications. A closed loop control of the dual-mode operation combining the VAr generation and the DC link voltage regulation, using a single converter is considered in this paper. The details of such a closed loop control based on the state space model, using synchronous d-q frame variables, are presented in order to achieve stable operation with improved dynamic response. During the design, the input reactor and the carrier frequency are at first selected based on open loop simulations. In order to compensate for the known nonlinearity in the state space model and facilitate the computation of the operating point variables and the feedforward terms; a gain scheduling technique is applied on one of the state variables. The feedback control is applied on the small signal model about the operating point, using pole-placement technique. Simulation results validating the closed loop operation of the complete system are also presented.