The Application Of The Electronic Power Transformer In The Photovoltaic Systems

With the continuous economic development and population growth, the demand forenergy is growing. Because traditional fossil energy is limited and will pollute theenvironment so development and utilization of new energy source is imperative. In thiscase, many countries develop new energy. As a renewable clean energy, PV is valued bylots of countries.Generally we use a traditional transformer connecting with the grid. As the traditionaltransformer is larger and heavier, so researchers hope to find a new method for Photovoltaicconnecting with the grid. At the same time, the study of the electronic power transformer isbecoming mature, and it’s excellent features to better adapt to the modern power systemrequirements. So in this paper we research the PV system connecting to the grid using theelectronic power transformer, research the steady-state characteristics and the transientcharacteristics.In this paper, we first build the model of the Photovoltaic cells in PSCAD, then studythe output characteristics in steady state. Because the output of the PV is a DC in theMPPT control, so the PV can be equivalent to the voltage source. On this basis, we built themodels of the electronic power transformer, the micro-grid and the distribution network inPSCAD.Then, the Photovoltaic is connected with the micro-grid and the distribution networkthrough the electronic power transformer. We research the steady-state characteristics of theaccess, including the characteristics of the voltage, the current, the power and the frequency.Meanwhile, when the micro-grid/distribution network is failure, we study the transientcharacteristics of the Photovoltaic systems, including the characteristics of the voltage, thecurrent and the power.Through the research, we know the steady-state characteristics of the Photovoltaicaccessing to the micro-gird/distribution network is good, along with the ability to run acertain accident, in the accident, the Photovoltaic can continue running connected with thegrid for some time and transmit the energy to the grid. Through the above research, we finda new method for the Photovoltaic connecting with the grid, and it lies a foundation for thesubsequent research work.