Simplified Model and Control Strategy of Three-Phase PWM Current Source Rectifiers for DC Voltage Power Supply Applications

Three-phase pulsewidth modulation (PWM) current source rectifiers (CSRs) that applied as dc voltage power supply include capacitors in the dc bus to obtain dc output voltage, which increase the system complexity and complicate the control strategy. In this paper, a dynamic model of the three-phase PWM CSR is first established in the dq-rotating frame for capacitive load applications. By aligning the vector of the ac capacitor voltage to the d-axis, the model of the CSR can be simplified and decoupled into dc and ac side circuits, which can be controlled separately. Based on this model, a control strategy composed of a state-variable feedback control method for the dc side and an active-damping control method for the ac side is proposed. Moreover, a unity power factor of the CSR is achieved by regulating the q component of the bridge currents. Simulation and experimental results are presented to validate the dynamic and static performance of the proposed control strategy.