Current-fed three-phase converter with optimum PWM scheme and its practical input line filter design

A method is described of selecting the optimum sine wave PWM patterns of a large-capacity current source-fed three-phase active PWM converter. Its performance evaluations are also described. A practical procedure is presented of designing a low-pass filter connected to suppress higher line current harmonics flowing into the utility-grid power source. A feasibility test is performed by using a 500kVA three-phase active current-fed PWM converter, which has been modified. It is verified, from a practical point of view, that such conceptual considerations are more effective and acceptable in minimising higher harmonic current components flowing into the utility-grid AC power line. Furthermore, this experimental set-up provides highly efficient AC/DC PWM-PFC converter characteristics, under the operating condition of a unity power factor correction and sine wave line current shaping schemes.