A cascaded inverter based hybrid shunt active filter to improve the power quality of 415V 50Hz four wire distribution systems

There are two approaches to the mitigation of power quality problems. The first approach is called load conditioning, which ensures that the equipment is less sensitive to power disturbances, allowing the operation even under significant voltage distortion. The other solution is to install line conditioning systems that suppress or counteracts the power system disturbances. A flexible and versatile solution to voltage quality problems is offered by active power filters AF. Currently they are based on PWM converters and connect to low and medium voltage distribution system in shunt or in series. Shunt Active Power Filters (SAPF) operate as a controllable current source. The Shunt AF filters can be used in multilevel mode to enhance the power quality. Cascaded multilevel Inverter is used as Shunt Active Power Filter to compensate the voltage sag during the presence of non-linear loads with reduced harmonics. Five level and seven level cascaded H-bridge multilevel inverter are used as SAPF. The number of levels in cascaded multilevel inverter is increased to reduce THD. The simulation is carried out in MATLAB/Simulink platform and the simulation results are presented in this paper.