Current-fed three phase PWM converter with sinewave line current shaping scheme and its practical input filter design procedure

Abstract

This paper describes a new method to select the optimum PWM patterns and a procedure to design a low-pass filter in a large-capacity current-source-fed active PWM power converter which is used to suppress higher harmonics flowing into the utility-grid power source. A feasible test is carried out using a 500 kVA active PWM power converter designed for the unique considerations mentioned above. It is verified that these new considerations are effective to minimize higher harmonic current components flowing into the utility-grid AC line. Furthermore, this experimental work provides highly efficient AC/DC power converter characteristics under unity power factor correction and sinewave line current shaping schemes. Finally, this paper indicates that the optimum PWM pattern can be applied to the voltage source converter and has an excellent switching performance as compared with conventional PWM modulation.