A three-phase to DC converter combining controlled step-down of voltage and bi-directional power flow

A new configuration for a three-phase bi-directional power converter (AC-DC and DC-AC) is presented. The converter is operated as a step-down converter where the output voltage can be controlled in the range of 0 to 1.5 Vˆ_ph. The power switch configuration is simpler than the conventional anti-parallel bridge used for bi-directional step-down rectification. It has nine controllable switches and twelve diodes. In the rectifier and inverter mode, line current can be sinusoidally regulated with unity displacement factor. This complies with the EN standard on harmonic currents. Synchronous PWM is implemented in a field programmable gate array and regulation of the output is achieved with a PID controller. Simulation and experimental results are provided to demonstrate the effectiveness of the proposed converter system