MODELING OF GRID TIED PV INVERTER TO IMPROVE ITS PERFORMANCE DURING UNBALANCE LOAD AND UNBALANCE FAULT

Abstract

With the demand of alternative source of energy, there is an increasing trend in solar power plants, as it is abundant, clean and has significantly reduced the reliance on conventional energy sources. Integrating solar through inverter brings about various challenges in the microgrids and the inverter itself. This project aims the study of problems in the operation of inverter during unbalance load and unbalance fault condition along with the possible control measures to mitigate those problems to ensure the safe and reliable operation of the inverter. A grid connected PV inverter is modeled using hysteresis band controller and implementing the MPPT of the PV system with the buck boost converter. During unbalance load and unbalance fault condition, the negative and zero sequence components of current exists. All the zero-sequence component of current is delivered by the grid. The negative sequence component of current also flows through the inverter resulting in high value of current and loss of stability. Also, the voltage across the dc link capacitor increases during voltage dip. The high value of current flowing through the inverter and high voltage across dc link capacitor may damages the inverter and capacitor respectively.