Research on Control Technology of Buck-Type PWM Rectifier System Based on Active Damping

The three-phase six-switch current-source type rectifier has a simple structure, can achieve single-stage step-down rectification and has the advantages of wide-range output voltage regulation capability, easy parallel operation, high reliability during DC short circuit, etc. This paper conducts research on the control strategy of the three-phase six-switch current-source type rectifier. Firstly, the circuit topology is linearized by small-signal modeling and the open-loop transfer functions of the system with and without active damping are established. Secondly, the design method of the active damping coefficient is studied. On this basis, a new control strategy combining the Switching Loss Optimized (SLO) modulation strategy and active damping control is proposed. The parameter design method of the controller is given and verified through simulation. Finally, a 2.5 kW experimental prototype is built. The experimental results show that the proposed control strategy has good tracking performance, dynamic response speed and operational stability, and also possesses excellent characteristics such as high power factor and low input current harmonics.