Patent ID: 8004119

Claim:
An analog three-phase active power filter with power factor correction, harmonic load reduction, and load balancing, comprising: a voltage control loop configured to receive a reference voltage and a direct current busbar voltage and two line voltages V 1N (t) and V 2N (t), and generate a first and second reference line currents based on the two line voltages; a first current control loop is configured to receive a load current i L1 (t), the first reference line current and a filter current i F1 (t), and output a duty ratio U 1 (t), or receive the first reference line current and a first line current, and output a duty ratio U 1 (t); a second current control loop is configured to receive a load current i L2 (t), the second reference line current and a filter current i F2 (t), and output a duty ratio U 2 (t), or receive the second reference line current and a second line current, and output a duty ratio U 2 (t), wherein the first and second current control loops are inside of the voltage control loop, and the first and second current control loops having two PI controllers, the two PI controllers are configured to receive the first and second reference line currents from the voltage control loop and generate two PI controller outputs U 1 (t) and U 2 (t); and a pseudo inverse decoupling circuit, within the first and second current control loops, configured to receive the PI controller outputs U 1 (t) and U 2 (t) from the two PI controllers, and outputs a third duty ratio U 3 (t).