Active power filter (APF) for mitigation of power quality issues in grid integration of wind and photovoltaic energy conversion system

The deep integration of renewable energy resources, including solar photovoltaic (PV) and wind turbine (WT) energy, mainly depend on the inexpensive technological improvement of global emissions and the precise techniques for power quality. Grid-connected inverters act as key components in distributed generation systems for cutting-edge technology. The inverter connects the renewable energy sources and power distribution network systems for the conversion of power. In grid-connected systems, several current and voltage harmonics affect the system performances. Likewise, highly unstable devices coupled with the growing demand for nonlinear loads and renewable energy resources influence the power networks and systems performance in terms of power quality. The effective solutions to these problems are passive filters (PFs), static var generators, and active power filters (APFs). However, the use of PFs in a high-power system increases its cost, size, and weight. This study aims to assess the most advanced APFs by reducing the number of power switches and focus on the reduction of cost, size, and weight of grid-connected inverters. Several studies compared and evaluated reduced-switch-count APF inverter topologies, such as AC–AC, back-to-back, and common leg, under the single-phase and three-phase systems. Recently, cost-effective solutions to reduce the number of components, transformerless inverters, multilevel and multifunctional inverters based on the APF in PV, and wind energy conversion systems have been greatly explored. The current techniques and their limitations for developing advanced inverter-based devices for renewable energy systems are discussed with justifications. Therefore, this review would potentially help industrial researchers improve power quality in PV and WT energies and power distribution network systems.