The effect of grid operating conditions on the current controller performance of grid connected photovoltaic inverters

This paper investigates the interactions which arise between grid connected photovoltaic inverter systems and the electrical grid. In particular, it considers the effect of grid voltage harmonics and grid impedance on the current control performance of grid connected inverter systems. In these photovoltaic inverter systems it is usual to control unity power factor, sinusoidal, current into the grid with low levels of distortion. However, due to the time varying nature of the grid it can be difficult to design a system which will always meet power quality standards. To overcome this problem, a better understanding of the impact of the grid operating conditions on the performance of the inverter is required.