Latest development of current-fed three phase converter with ROM table-based optimum PWM control scheme and its input line filter design

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 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 converter designed for 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 converter characteristics under a unity power factor correction and sinewave line current shaping schemes. Finally, the application for voltage source inverter is described. It is verified that this optimum PWM pattern has an excellent switching performance as compared with conventional PWM modulation.