A Comparative Study on Multilevel Inverters for Shunt Active Power Filter

In recent decade, extensive applications of high power switching devices affecting the power quality significantly. In order to maintain a quality power mainly for sensitive loads, shunt Active Power Filter (APF) are often used, which improves the power factor and decreases the percentage of Total Harmonics Distortion (THD). The APF, when connected with the load generates an reference compensating current which is in phase opposition to the harmonics present in the system, thus the resultant supply current becomes sinusoid and in phase. The compensating reference current waveform is of complex in nature, and therefore a suitable inverter operated through high frequency switching is necessary for generation of such complex waveform. A multistage inverter could be more capable of generating such complex waveform as required for the compensating current. This work explores a three-Level and five-level Cascaded H-bridge (CHB) inverter for shunt Active Power Filter in Power System (PS) to compensate the reactive power and harmonics. The performance comparisons between three-level and five-level cascaded H-bridge (CHB) inverter for a shunt active power filter (APF) are presented.