A Single Phase Active Power Filter Restraining High Frequency Harmonics in AC Electric Motor Vehicle

This paper deals in an Active Power Filter to reduce harmonics generated by PWM converters with GTO thyristors of electric railway vehicles. Parallel oscillation frequency components of electric motor vehicle affect substation equipment due to enlarged harmonics. This paper reports an on-board single phase Active Power Filter with compensating power of 200kVA for the purpose of restraining parallel oscillation and test results on its effectiveness.The Active Power Filter has following features. (1) Harmonics voltage detection from a summation of second winding voltages instead of harmonics current detection. (2) Serially connected capacitor charged by the fundamental frequency voltage that realizes a convertor of the Active Power Filter with smaller output.Test results with a Star 21 Shinkansen train showed a harmonics current reduction of 1.5_??_2.0kHz, 3/10 of the level that can be attained without Active Power Filter. Furthermore, we expect that the output power of Active Power Filter can be reduced when the design of main transformer is opetimized.