Research On Coordinated Control Technology Of Stand-Alone PV Syetem

Solar energy has become the research hotspot of the domestic and foreign scholars in industrial fields because of the crisis of conventional energy growing depletion and the increasingly serious environmental pollution, at the same time, photovoltaic generation is one of the main forms in solar energy utilization. This paper did some researches on some key technologies of stand-alone PV power system.Firstly, the paper focuses on the PV power generation system,summarizes the system architecture, points out the significance of the subject and research content. In PV system, solar cells and batteries are two main components, the paper describes in detail. The MPPT technology is one of the principal means of improving the system's efficiency. According to the advantages and disadv- antages of the traditional maximum power tracking control in PV system, the paper introduces a novel MPPT algorithm——Equivalent Impedance Matching (EIM), the MPPT circuit is simulated , and the overall comparison of performance is given between new algorithm and traditional algorithm.Secondly, the paper proposes a kind of PV system that the solar cells as energy, battery as energy storage unit. The inverters should work in different mode when the PV system is in different working conditions, in order to maintain DC Bus voltage stability. Regarding the problem of DC Bus voltage and converters' working mode, this paper presents a kind of photovoltaic system coordinated control scheme, manages energy of the system, makes the photovoltaic cells and batteries collaborative work, keeps DC Bus voltage stability.Finally, the hardware circuit of PV system is designed, the experiment platform based on TMS320LF2407 A is built up, the program is written, and conduct the MPPT experiment and PV system experiment. The MPPT experiment result shows the validity of the equivalent impedance matching method in application of the PV MPPT. The PV system experiment result verifies the effectiveness of the proposed strategy, that makes the inverters work at equitable mode along with the different work conditions, and harmonizes the work of solar cells and batteries, holds the DC bus voltage stability, makes the PV system operate in normal.