A Novel Voltage-Mode Control of Parallel Active Power Filter

Parallel active power filter is one of the most effective solutions to compensate the current harmonics and to enhance the power quality in industrial application. Regularly, the PAPF is controlled as a current source with the amplitude similar to the harmonics component of load current. This paper proposes a novel voltage-mode control in which the power inverter is controlled as a voltage source with a better and more general control algorithm than in regular current-mode control. Here, the APF acts as virtual transimpedance at harmonics frequency (virtual transinductor connected with resistor) to resist harmonic current flow through the source side. At low frequency, the APF act as an active impedance (virtual capacitor connected with resistor) to block the fundamental current, then all the active source current feeds to the load. Considering the algorithm with control diagram, this algorithm could be considered as two independent control loops. The fundamental loop controls the fundamental compensation current to follow zero, and the harmonic control loop restrict the harmonic source current tend to zero. If the loop gain is high enough, the harmonics of source current tends to zero, and less current flows through the shunt branch of APF. What's more, comparative study and discussion are also provided to thoroughly express the authors understanding. This shows that he proposed algorithm expands the horizon to improve the performance of PAPF with a better compensator. Simulation and experimental results are given at the end.