Patent ID: 6611442
Filing Date: 2003-08-26
Classification: H02M,Y02B

Abstract:
A controlled rectifier equipment with sinusoidal waveform supply current comprising:a controlled rectifier circuit including semiconductor switching devices of which conducting angles can be controlled; and a conduction control signal generating circuit which gives conduction control signals to said semiconductor switching devices for controlling said conducting angles so that said controlled rectifier circuit converts AC power to DC power and yet so that a waveform of AC supply current supplied to said controlled rectifier circuit may be a sinusoidal waveform; said conduction control signal generating circuit comprising: an AC current detecting circuit detecting said AC supply current by an AC current detector and generating an AC current detecting signal, the AC current detector being an AC current transformer; an AC voltage detecting circuit detecting an AC voltage supplied to said controlled rectifier circuit and generating an AC voltage detecting signal; a DC voltage detecting circuit detecting a DC voltage outputted from said controlled rectifier circuit and generating a DC voltage detecting signal; and a current control signal generating circuit generating a current control signal based on said AC current detecting signal, said AC voltage detecting signal, said DC voltage detecting signal and a voltage command signal commanding a DC voltage value to be outputted from said controlled rectifier circuit, so that said current control signal is used to make the waveform of said AC supply current a sinusoidal waveform and make the DC voltage from said controlled rectifier circuit such the DC voltage value as commanded by said DC voltage command signal; and a driving circuit generating said conduction control signals based on the current control signal; wherein said current control signal generating circuit having a DC component eliminating circuit for eliminating a DC component which causes an offset of said AC supply current from said current control signal.