The Research of Photovoltaic Grid-Connected Inverter Based on Adaptive Current Hysteresis Band Control Scheme

Based on conventional current hysteresis band control, an adaptive hysteresis band control algorithm featuring dynamically modulate hysteresis band width was presented in this paper, and will be used in the application of photovoltaic grid-connected inverter. In the platform environment of Matlab/Simulink, the simulation modules of photovoltaic array, hysteresis band calculator, adaptive hysteresis band controller and reference current generator specially for non-linear load were built based on the new mathematical models and novel algorithms, finally, A single-phase photovoltaic grid-connected inverter system composed of photovoltaic array, DC link capacitor, single phase full-bridge PWM inverter, filter inductor, power grid and non-linear load modeled as a rectifier was created, the adaptive hysteresis band controller was integrated into the inverter system to control switching frequency, while the reference current generator to control the current injected into power grid with good power quality. The simulation result indicated that the switching frequency could be fixed constant while dynamically and instantaneously modulating current hysteresis band width and should be adequate high, which will result in the synchronization of power grid voltage and inverter current and near unity of power factor.