New control method of injection-type hybrid active power filter

Injection-type hybrid active power filter (IHAPF) shows great promise in reducing harmonics and improving power factor with a relatively low-capacity active power filter (APF). This study analysed the topology characteristics of IHAPF and established the electrical model. To improve the performance of IHAPF, generalised integral proportional-integral (PI) control is proposed. The control method is generally useful and applicable to any other active filters. Compared with other control methods, the proposed control shows the advantages of higher control precision. It is implemented in an IHAPF with a 50 kVA APF in the laboratory. Both simulation and experimental results show that the new control method is not only easy to be calculated and implemented, but is also very effective in reducing harmonics.