Majority of loads in use today are power electronics based non-linear devices. Despite being compact and providing low energy consumption these loads generate inherent harmonics. Harmonics have several adverse effects such as interference with the communication lines, incorrect meter readings, increased losses, increased heating of electrical and sensitive electronic equipment. Sophisticated power electronic converter based filters named as Shunt Active Power Filters (SAPF) are widely being employed that provide superior harmonic filtering capabilities. Basic objective of SAPF is to generate or absorb currents that compensate harmonic currents produced by non- linear loads. These currents should be opposite in phase but have equivalent magnitude as that of harmonic currents. As compared to Diode-Clamped and Flying capacitor multilevel inverters, Cascaded multilevel configuration is employed for many applications due to ease of control and simple structure. In this research paper, power quality in a three-phase threewire system is improved by reducing source side current harmonics produced by a non-linear load. Initially a three-level Cascaded multilevel inverter based SAPF is developed and its performance is analyzed by using advanced Adaptive Neuro Fuzzy Inference System (ANFIS) controller. DC link capacitor voltage and percentage Total Harmonic Distortion (%THD) in source currents is measured at PCC for balanced loading conditions and results are compared. In this paper, it is also proposed to incorporate multilevel inverter topology concepts by employing Five-Level and Seven-Level Cascaded Multilevel Inverters as VSI circuit for SAPF. Performance of these multilevel Shunt Active power filters is analyzed by ANFIS controller. Instantaneous Active-Reactive power theory is implemented to compute reference compensating currents for all Shunt Active power filter models. Phase Disposition type Pulse Width modulation is chosen for generating gate pulses for VSI circuits of all Cascaded multilevel inverter configurations. Three-level, Five-level and Seven-level Shunt active power filter models are developed and simulated using MATLAB/ Simulink and results are presented.
A Modular Cascaded Multilevel Inverter Based Shunt Hybrid Active Power Filter for Selective Harmonic and Reactive Power Compensation Under Distorted/Unbalanced Grid Voltage Conditions
