Reliable 3-phase PWM boost rectifiers employing a series-connected dual boost converter sub-topology

This paper describes circuit topologies for 3-phase PWM boost rectifiers that operate with a unity fundamental power factor and a low line-current distortion. Overlap delays between the switching of the upper and lower devices in a PWM rectifier leg are not critical and diodes eliminate the possibility of the DC-link capacitor discharging into short circuits and shoot-through fault conditions. The rectifiers are operated using a “series connected dual boost converter cell” sub-topology that rotates connections every 60° of the mains cycle and can be used in two current control modes. The dual current control mode shapes two line currents and can achieve current distortion levels below 5%. The single current control mode controls one line current and can achieve current distortion levels close to 5% with the output DC voltage operated at the standard rectified mains voltage level. The per-unit current ratings of the active 3-phase switching networks are around 15-20% of the input RMS line current as compared to 70% for a standard 3-phase PWM rectifier. Circuit simulations and experimental results are used to demonstrate the performance and feasibility of the rectifiers described