Real-time and grid-connected control of PV power system

This paper analyzes the equivalent model of photovoltaic cells and then discusses the output characteristics of photovoltaic cells. Using the RTDS (Real Time Digital Simulator) to build a real-time simulation system of grid-connected photovoltaic power generation that includes three-phase grid-connected PV systems, maximum power point tracking (MPPT) methods for PV arrays, grid-connected control of PV system, inverter control and filter design methods. This model achieves the maximum power tracking by the method of the photovoltaic cells self-optimization perturbation and observation based on the buck circuit. According to the control target of three-phase PWM inverter designing a amplitude and phase control system which makes the network systems realize separately control the active power output and reactive power output, in the meanwhile the DC bus voltage can be limited at the reference value. The simulation results show that the system cannot only track the maximum power point of photovoltaic cells quickly, accurately and effectively, it can realize the stability control of the DC bus voltage. Further, fit out the maximum power curves at different environmental changes (include the Ambient temperature and Illumination intensity) to verify the output characteristics of photovoltaic cells; enhance the grid-connected PV system applications generally.