The harmonic compensation currents generated by the shunt active power filter (SAPF) employing inverterside current feedback (ICF) control are distorted by the LCL filter. In the case of a large-capacity SAPF with a low resonance frequency of the LCL filter, the distortion of the LCL filter's inverter-side current and grid-side current becomes more severe. Grid-side current can be used as feedback current for harmonic current control of SAPF, however overcurrent protection sensor additionally and current controller stability issues. This paper proposes the inverter-side harmonic current reference compensation method to indirectly control the grid-side harmonic currents. Since the proposed method controls the inverter-side current, it can stably control the harmonic current, and at the same time, it can improve the harmonic current quality of the AC grid by accurately supplying the harmonic current required for the system.
.jpg "Deokyong Woo, MS photo")