Improving the performance of PV grid interface inverter using the adaptive hysteresis band current controller

In this paper, an adaptive-hysteresis band current controller is compared with a fixed-hysteresis band controller for a photovoltaic systems (PV) grid interface inverter. The inverter utilization is maximized by adding the task of an active power filter (APF) to it with a specific control method so that the inverter can be used whether or not the PV generates power. The inverter is able to perform: 1) transferring the harvested power from PV to the grid; and 2) active filtering (load harmonic elimination, reactive power compensation and load balancing) individually or simultaneously. Both controllers do not let the THD of the grid currents to surpass the limit that is set by the IEEE-519 standard. The simulation results show that not only does the adaptive controller have all the benefits of the fixed controller, but it also alleviates the drawbacks of the adaptive controller. Maximizing the inverter utilization and applying the adaptive-hysteresis band current controller come at no additional hardware cost. All studies are carried out using MATLAB/Simulink. Simulations suggest that the adaptive controller leads to a more efficient performance of the inverter compared to the traditional method.