Dividing Frequency Control of Hybrid Active Power Filter With Multi-Injection Branches Using Improved $i_{p}$--$i_{q}$ Algorithm

A novel hybrid active power filter with multi-injection hybrid active power filter (MIHAPF) branches is proposed in this paper; harmonic current is injected into the grid through multi-branches, and steady dc-side voltage can be gained by controlling the inverter to absorb and release energy from the grid. Furthermore, dividing frequency control method is proposed to improve the performance of MIHAPF. It can compensate the phase and amplitude error of injection current, which is generated by the system delay, injection branches, and output filter. Control precision can also be improved profiting from the control method. Improved i p-i q algorithm is proposed to calculate the amplitude and phase of each integral-order harmonic for the control strategy. Simulation and application results have shown the validity of the proposed MIHAPF, and the proposed dividing frequency control method using improved i p -i q algorithm can improve the filtering performance and ensure the stability of the dc-side voltage.