Zero-voltage soft-switched PDM three phase AC-DC active power converter operating at unity power factor and sinewave line current

This paper is concerned with a newly improved version of the pulse density modulation (PDM) three-phase AC-DC converter including an active clamped resonant DC link (ACRDCL) and its digital signal processor (DSP) control strategy to achieve a unity power factor correction and sinewave line current shaping. The operating principle of the zero-voltage soft-switched three-phase AC-DC converter using ACRDCL under the control scheme of an instantaneous space voltage vector-based clamping-voltage distributed PDM (modified-PDM) scheme to improve its control response and operating performances is illustrated. Performance evaluations are discussed using simulation and experimental results, and a comparison with the conventional PDM converter is given. The experimental results of this active converter are shown from a practical point of view. Finally, the utility-interfaced ACRDCL double-converter system operating under the DSP controlled modified-PDM strategy is illustrated and evaluated by using simulation results under inductive load conditions