Total harmonic current distortion control circuit and method thereof

摘要

A total harmonic current distortion (THDi) control circuit includes a power factor correction circuit and a control circuit. The power factor correction circuit includes a boost unit, an inverter unit, and a feedback unit. The boost unit includes a switch element and a current detection element series-coupled to the switch element. The feedback unit operatively detects an output voltage and an output current of the power factor correction circuit. The control circuit calculates an output power according to the output voltage and the output current, and calculates an input voltage and an input current according to the output power. The control circuit outputs a pulse width modulation signal and controls a conduction current generated by the switch element according to the input current. The control circuit adjusts the duty cycle of the pulse width modulation signal according to the conduction current detected by the current detection element.

主权项

1. A total harmonic current distortion (THDi) control circuit, comprising:
a power factor correction circuit, comprising:
a boost unit, comprising a switch element and a current detection element, wherein the switch element is coupled to the current detection element in series;an inverter unit coupled to the boost unit; anda feedback unit coupled to the inverter unit, configured for operatively detecting an output voltage and an output current of the power factor correction circuit; anda control circuit coupled to the boost unit and the feedback unit;wherein the control circuit operatively calculates an output power according to the output voltage and the output current, and thereafter the control circuit calculates an input voltage and an input current supplied to the power factor correction circuit according to the output power calculated for generating a pulse width modulation signal to control a conduction current of the switch element of the boost unit; wherein the current detection element operatively outputs a sensing current to the control circuit responsive to the conduction current and the control circuit adjusts a duty cycle of the pulse width modulation signal according to the sensing current received; wherein the sensing current is proportional to the duty cycle of the pulse width modulation signal.