*Review* **Critical Review of PV Grid-Tied Inverters**

#### **B. Kavya Santhoshi 1, K. Mohana Sundaram 1,\*, Sanjeevikumar Padmanaban 2, Jens Bo Holm-Nielsen 2 and Prabhakaran K. K. 3**


Received: 12 March 2019; Accepted: 15 May 2019; Published: 20 May 2019

**Abstract:** Solar Photovoltaic (PV) systems have been in use predominantly since the last decade. Inverter fed PV grid topologies are being used prominently to meet power requirements and to insert renewable forms of energy into power grids. At present, coping with growing electricity demands is a major challenge. This paper presents a detailed review of topological advancements in PV-Grid Tied Inverters along with the advantages, disadvantages and main features of each. The different types of inverters used in the literature in this context are presented. Reactive power is one of the ancillary services provided by PV. It is recommended that reactive power from the inverter to grid be injected for reactive power compensation in localized networks. This practice is being implemented in many countries, and researchers have been trying to find an optimal way of injecting reactive power into grids considering grid codes and requirements. Keeping in mind the importance of grid codes and standards, a review of grid integration, the popular configurations available in literature, Synchronization methods and standards is presented, citing the key features of each kind. For successful integration with a grid, coordination between the support devices used for reactive power compensation and their optimal reactive power capacity is important for stability in grid power. Hence, the most important and recommended intelligent algorithms for the optimization and proper coordination are peer reviewed and presented. Thus, an overview of Solar PV energy-fed inverters connected to the grid is presented in this paper, which can serve as a guide for researchers and policymakers.

**Keywords:** ancillary services; grid; inverter; PV; reactive power; solar; Quasi-Z source inverter (QZSI); Y source inverter (YSI)
