Internal Model Control Of Three-phase Voltage Sourced PWM Rectifier

With the development of plug-in hybrid electric vehicle,as an usual kind of charging strategy,three-phase voltage sourced PWM rectifier that can realize the objectives of bi-directional power transfer,controllable output voltage,unity power factor operation and low input current harmonics has been used more and more widely.Nowadays,the dual closed loop control in dq synchronous rotating frame has been the most studied and utilized control strategy with relatively good performance.At first,the model in three different coordinates and the dual closed loop control strategy of three-phase voltage sourced PWM rectifier in dq synchronous rotating frame are detailed analysed.Then,a simplified action time calculation method of the basic voltage space vector has been proposed based on the fundamental principle analysis of SVPWM.Meanwhile,a creative combination connecting sector judgement to action time calculation has been proposed to reduce the calculation complexity.Subsequently,improvements have been applied to three parts: linearized control of voltage loop,simplification of parameter tuning of PI controllers and enhancement of disturbance rejection through two-degree-of-freedom internal model control which has been successedly applied to the dual closed loop control.Specifically,the decoupling control based on internal model control has been applied to inner current loop and the disturbance rejection linear control based on two-degree-of-freedom internal model control with the idea of power conservation has been applied to outer voltage loop.The proposed new control strategy is simple and easy to implement.Using this proposed strategy can not only realize the decoupling between active current and reactive current and simplify parameter tuning of PI controllers,but also achieve the linearized control of voltage loop and strengthen the disturbance rejection capability of the system.Finally,the simulation results demonstrate the validity and the feasibility of the proposed new control strategy.Simultaneously,simulation results of steady and dynamic state indicate that two-degree-of-freedom internal model control owns better stability and anti-disturbance characteristics when compared with traditional dual closed loop control.