Based On The New Resonant Soft Switching DC/AC Photovoltaic Control Research And Application

With the rapid development of technology and the explosive growth of population, human beings are facing the great challenges of environment and resources. Thus the development of new clean energy is imminent. In this paper, a new type of complementary power supply system based on resonant soft switching DC/AC is proposed, which can effectively alleviate the pressure above.First, on the research of soft switching, a resonant soft switching DC/AC converter which based on half bridge model is proposed. Analysis the principle of circuit and choose LC filter. In order to ensure the soft switching last working under the environment of ZCS(Zero Current Switch), changing the voltage amplitude and the current phase by PWM and PFM modulation. Converter using the double closed loop of voltage and current as control strategy to achieve DC/AC.Secondly, put the soft switching into the full-time complementary power supply system of photovoltaic and grid. Put forward the photoelectric complementary system topology structure, which is composed of the DC side of the photovoltaic, new resonant soft switching, rectifier inverter and grid complementary side. Design the strategy of energy management. Analysis four working modes of the system and discuss the strategy of mode switching in details. When the solar energy is larger than the demand, the photovoltaic work on the maximum power point and connect excess energy to the grid; When the solar energy is less than the demand, the photovoltaic also work on the maximum power point and operate in the current socurce mode. The shortage of power is supplemented by the grid. Use phase-locked control to ensure that the PV work on the same frequency and phase with grid. The complementary power supply system can reduce the impact of photovoltaic instability and improve the reliability of the system.Then, in terms of hardware, this paper calculates the parameters of the main circuit, including the resonant capacitance and inductance, high frequency transformer, BOOST circuit, filter circuit and power device. In terms of software, this paper introduces the design of the main program, Resonant soft switching control subroutine.Finally, Using Simulink to realize the simulation of the resonant soft switch and the rectifier inverter working together as DC/AC, and validate the dynamic response waveform of the soft switch when the load is reduced and removed. Make the simulation of optoelectronic hybrid system by Simulink and test the switching speed of system changing between each working mode, and then build a 3kW prototype, make the experiments under different light conditions, through different number of bulbs changing the load power size, and validate the feasibility and stability of the PV and grid complementary power supply.