Research On The Key Technology At Energy Transformation Of Photovoltaic And Commercial Power Parallel In DC Power Supply System

In response to the increasingly serious environmental pollution and resource shortages and other problems, photovoltaic(PV) energy as a hugely renewable and clean energy resource is developed constantly. With the development trend of distributed PV and building integrated photovoltaic, solar direct current(DC) power supply system would be widely used.This paper mainly researches the DC power supply system of PV, for a comprehensive theoretical analysis and research on photoelectric complementary power supply system. The topological structure of the system, the energy management control strategy, the main circuit parameters and control loop are studied and designed in detail. The main contents are:Firstly, by analyzing the different circuit topologies and their respective applications in photovoltaic systems, the high‐frequency phase‐shifted full‐bridge eventually chose as photovoltaic energy converters for the realization of PV maximum power point tracking or stable the output voltage, and phase‐shifted full‐bridge circuit conducted a small‐ signal modeling, analysis and design. At the same time, in order to ensure the stability of the load energy, it introduces commercial power to make back‐up power. Taking into account the commercial power factor and energy whether reversible, select the PWM rectifier compensation as photovoltaic energy converters.Secondly, the energy of the system is managed by designing feasible control strategy to achieve the PV array always maximum power output, while providing a stable DC power for the load. Power supply system is a two‐stage system consists of two subsystems. Through the subsystem analysis and research, combined with the core system control, maximum power point tracking and stable voltage, it proposed two possible control strategies and made energy decoupling design.Thirdly, the main circuit parameters’ selecting is decides whether the system can work normally and plays an important role in the level of commercial power factor, for which the main circuit parameters were studied and design. Filter design is reasonable will affect the stability of the whole system, so it discuss the design idea and process analysis of DC and AC side filter. To achieve fast load regulation, the voltage loop uses a fuzzy PID control, for increased speed and robustness of the system. It also studies the digital controller in system control and how to achieve control objectives.Finally, according to the energy control strategy proposed in this paper, using Simulink build the system’s simulation model and does the corresponding simulation. According to the technical parameters of 4kW power supply system, using DSP chip TMS320F2812 as the main control chip, an experimental platform is built and does some related experiments.