An Effective Method to Suppress Resonance in Input LC Filter of a PWM Current-Source Rectifier

The PWM Current-Source Rectifier (CSR) is becoming a preferred choice to provide a DC current source for DC loads or current source fed drives. However the control of the resonance of the input LC filter is one of the main challenges. To dampen the LC resonance with minimum control and implementation efforts, a two-step Posicast controller for modulation signal shaping is first examined, which can be easily inserted into the existing CSR control loop. The parameters of the two-step Posicast controller are fixed by the lightly damped plant, which makes it unsuitable at high power levels due to the inaccurate compensation associated with the low switching frequency. A three-step compensator is then designed in this work. By selecting its parameters according to the existing control algorithm, the three-step compensator is very effective for the low switching frequency CSR with precise resonance compensation and easy implementation. Detailed design and analysis are presented. Simulation and experimental results are provided to verify the effectiveness of the proposed damping approach.