Research On Magnetic Integrated High Frequency Transformer For Photovoltaic Power Plant DC Voltage Boost

Photovoltaic power generation uses green,pollution-free solar energy resources,and photovoltaic power plants are rapidly developing in sparsely populated areas such as northwest and southwest China.it is difficult to eliminate so much power generation.The excess power must be sent to the large load area through the long-distance transmission line.The high voltage direct current technology is adopted by the photovoltaic power station for long-distance transmission due to its large transmission capacity,low loss,and no need for reactive power compensation.As a result of the limited voltage resistance of PV modules,the output is difficult to meet the voltage level requirements of DC grid connection.Therefore,It's a key issue for DC grid connection of PV power plants to greatly increase the PV output voltage level.In this paper,a magnetic integrated high-frequency transformer with high boost ratio is designed,and two DC grid-connected topology schemes of photovoltaic power plants are established based on magnetic integrated high-frequency transformers.In this paper,the maximum power tracking of photovoltaic cells is studied firstly,and the more accurate photovoltaic model and control strategy are established.Then the working principle and structure of the magnetic integrated high-frequency transformer are introduced,and the equivalent magnetic circuit and circuit equation are also analyzed.Then the optimization design method of medium and high frequency transformers are introduced,and the magnetic integrated high-frequency transformer is optimized with the smallest volume as the target.The winding number and insulation arrangement of the transformer are designed.The finite element simulation software is used to verify and calculate the winding parameters,excitation parameters and core losses.Finally,the DC-DC converter based on magnetic integrated high-frequency transformer isolation is introduced.According to different application scenarios,bidirectional and unidirectional topologies are proposed,and the working principle,control strategy and soft switching technology are also studied.The simulation demonstrates the feasibility and effectiveness of the topology and control strategy.