Patent ID: 6388900
Filing Date: 2002-05-14
Classification: H02M,Y02B,Y02P

Abstract:
A constant-frequency active filter controlled by a peak current control mode, the constant-frequency active filter comprising:a voltage step-up unit comprising a transistor used as an active switch to adjust a waveform of an input current to form a sine wave, wherein the voltage step-up unit comprises: a power supply arranged to provide an input voltage and the input current; a voltage step-up inductor connected to the power supply; a bridge rectifier connected to the voltage step-up inductor and to a first diode; a current transformer having a primary coil connected to the bridge rectifier and to the transistor; two series-connected capacitors connected to the first diode; and a second diode connected to the two series-connected capacitors and to the first diode; a current control unit connected to the voltage step-up unit, wherein the current control unit comprises a PWM controller that outputs a clock signal to control a photocoupler connected to an output of the PWM controller so as to control the transistor connected to the photocoupler to be selectively activated and deactivated; and a voltage control unit connected to the current control unit, wherein the voltage control unit comprises a microprocessor for providing a current command to control the clock signal outputted by the PWM controller.