Patent ID: 7848120

Claim:
A voltage-sourced High-Voltage Direct Current (HVDC) apparatus that converts a 3-phase AC voltage generated by a 3-phase AC power source into high voltage DC through a rectifier including switching elements, the apparatus comprising: a sensor unit that detects 3-phase currents, apparent power, and active power from the 3-phase AC voltage generated by a 3-phase AC power source; a rectifier controller that receives the detected 3-phase currents, apparent power, and active power and generates a D-axis signal and a Q-axis signal; a D/Q controller that receives the D-axis signal and the Q-axis signal from the rectifier controller and generates active power D-axis signal and apparent power Q-axis signal; and a PWM unit that generates a PWM on/off control signal for turning on/off the switching elements based on output signals from the D/Q controller, wherein the D/Q controller includes a rotary converter to convert the D-axis and Q-axis signals into an AC signal and a D-axis order unit and Q-axis order unit coupled to the rotary converter, and the D/Q controller generates the active power D-axis signal and the apparent power Q-axis signal through the D-axis order unit and the Q-axis order unit, and the PWM unit converts the active power D-axis signal and the apparent power Q-axis signal into 3-phase AC signals through a 2/3-phase converter and compares the 3-phase AC signals with 3-phase triangular waves to generate an on/off control signal for turning on/off the switching elements.