Research Of Photovoltaic Power Charging And Inverter Control

The development of social economy needs energy as a support. The growth of energy demand causes the oil, coal, natural gas and other nonrenewable energy is widely used on global scale, which directly threatens the sustainable development of the mankind. The development of alternative energy is imminent. As an inexhaustible, safe, reliable and natural resource, solar energy is becoming a hot spot of science research around the world. Photovoltaic maximum power tracking system responses slowly, anti-interference capacity of the external environment is not strong, low efficiency of the inverter output is insufficient. In order to overcome these disadvantages of traditionally independent photovoltaic system, the technology of high frequency and independently photovoltaic system is the research object in this paper, the charging and inverter control are the key technology through the research.First, the topology of independently photovoltaic power generation system and working principle of each part are introduced in detail. Based on the advantages and disadvantages of traditionally photovoltaic power generation system and other photovoltaic systems, the independently photovoltaic system structure about the technology of high frequency makes the system structure simple and easy to control, which reduces noise and conversion efficiency.Second, under the premise of the PV array mathematical model and battery performance, a new type of charging method is proposed which combines a three-stage charging method with the modified variable-step and incremental conductance method, thus effectively improves the work efficiency of the PV array maximum power point, and makes the tracking more accurate. It realizes high efficient conversion of energy and storage.Third, the control strategy of independently photovoltaic system, hardware designing, software implementation are analyzed in detail. The double closed loop control strategy and the single polarity pulse width modulation method are used to control the push-pull converter and full bridge inverter circuit in the links of high frequency. It reduces the inverter output harmonic and improves the efficiency of the inverter. In terms of hardware design, large numbers of parameter calculation and selection of related devices about the charging power circuit, power boost converter circuit, inverter circuit, sampling circuit and drive circuit are illustrated. The software design in the process of charging and inverter function realization is elaborated in detail.Finally, Matlab/simulink is as a simulation tool to verify the realization of each module in the independently photovoltaic system through a large amount of simulation test. Then, the system of on-line debugging experiment platform is set up. Through the oscilloscope waveform tests, the experimental results show that the system meets the design requirements, it can precisely control charging and inverter output of the independently photovoltaic system.