Research On Intelligent PV Grid - Connected System And PLC Channel Characteristics Of Micro Inverters Based On

Solar photovoltaic power generation is the important developing direction of renewable energy for its advantages, such as environmental, small covering area,simple installation, etc. And the photovoltaic grid-connected system based on micro-inverter is the main trend of the future solar photovoltaic utilization. As the development of smart grid, the micro-inverter smart grid-connected system is the important way to ensure grid-connected friendliness of the solar photovoltaic and guarantee the quality and stability of power grid. And power line communication(PLC) will be the most ideal way to realize the intelligent of photovoltaic grid-connected system because of its incomparable advantages: no need to deploy communication lines, plug and play, flexible networking low cost, etc.In this paper, all researches are around the PLC technology and photovoltaic gird-connected system. Firstly, the feasibility of the application of PLC technology is discussed. Secondly, the PLC channel characteristic measurement circuit is designed and the PLC channel characteristic of micro-inverter photovoltaic grid-connected system is measured and studied. Thirdly, the intelligent photovoltaic grid-connected system based on micro-inverter is provided. Lastly, the data acquisition circuit in the grid-monitoring system and the communication protocol between PLC modem and master MCU chip are designed.The results of the research of PLC channel characteristics are as follows: the change between the impedance before grid-connecting and after grid-connecting is different in different band.When the grid-power is 2kW, The change is very small in CA band from 30KHz~150KHz. In CB and CC band from 150KHz~400KHz, the magnitude of impedance is reduced by about 10?.The change is more obvious in CD band from 400KHz~500KHz. The channel noises in terms of pattern and amplitude are more complicated and disorder during the micro-inverter starting-up phase,periodic impulse noises in the band of 50 KHz and 100 KHz are added and themagnitude of noises in the whole band from 30 KHz to 500 KHz are increased when the system working steadily. In conclusion, it’s important to consider the PLC channel characteristic for designing the impedance matching circuit and optimizing the communication protocol in order to improving the efficiency of communication and realizing intelligent of photovoltaic grid-connected system.The researches in this paper provide important reference for the PLC technology being widely applied to the future solar photovoltaic power generation and the future development of intelligent photovoltaic grid-connected system.