Rectifier circuit with increased power factor - has LC filter in primary transformer circuit tuned to harmonics of mains frequency

摘要

Rectifier circuitry to provide dc from incoming mains and to improve the power factor of the unit. An LC filter circuit is connected into the primary, mains, circuit of the unit to improve the waveform through the transformer circuit. The resonant frequency of the LC circuit is chosen to reduce overvoltage peaks and improve the current phase angle. Usually the frequency is the fifth but maybe the ninth or thirteenth harmonic of the mains frequency. The LC filter may be connected in the transformer (T) primary or secondary but must be followed by the bridge rectifier (G) and a reservoir capacitor (Co). The LC circuit is tuned to the fifth, ninth or thirteenth harmonic of the supply frequency.