The Design Of Photovoltaic DC/DC Converter For Integrated Power Supply In Intelligent Substation

The energy crisis,environmental pollution and other defects caused by traditional energy have attracted the attention of the major countries in the world.Renewable energy has become the focus of research.As a typical representative of renewable energy,the photovoltaic power industry has been rapid progress.On the other hand,with the development of smart grid,in order to reduce the size of equipment and to achieve digital and network,the station power supply of substation gradually turned to integration.AC-DC integrated power supply has been designed,which integrates the DC power supply,AC uninterruptible power supply,power inverter power supply and communication power supply.Multiple outputs use the same set of DC system batteries and are subject to the same monitoring.Storage battery is the core of the integrated power supply equipment,of which the traditional way of charging is directly connected with the battery through the rectification device.Considering the diversification of power supply for substation stations,and in order to explore the development of power application technology of solar photovoltaic power generation,this paper adds the charging method of the integrated power supply of PV access substation based on the traditional charging method,and designs DC/DC converter system to realize the charging of the storage battery in the integrated power supply by the solar power generation.Aiming at the output control of PV and the charging control of the battery,this paper designs a two-stage DC/DC converter system and put forward a control strategy of PV output and battery charging.The PV-side DC/DC converter selects the traditional Boost structure to complete the photovoltaic maximum power tracking and constant voltage control switching,and the improved fuzzy PID algorithm is designed to achieve photovoltaic maximum power tracking.Based on the problems existing in the typical phase-shifted full-bridge bridge rectifier circuit,the battery-side DC/DC converter is designed to improve the phase-shifted full-bridge rectified DC/DC structure,so as to complete the battery fixed DC bus voltage mode and the two-stage charging mode switching..Through the parameter design and the model selection of the main circuit and control circuit,this paper uses Matlab/Simulink to build a simulation model for simulation test.The simulation results show that the system will quickly reach the maximum output power point of the PV by the improved fuzzy PID algorithm when the environment,such as the light intensity,is changed,and charge the battery with the maximum energy.When the battery overvoltage is monitored,the system will reduce the power to run and the battery enters the two-stage charging mode.The battery-side improved phase-shifted full-bridge DC/DC circuit structure completes the zero-voltage switch of the power transistor,reducing switching losses and improving system efficiency.Then the experimental prototype is also set up.The experimental test also verifies the rationality of the design of the photovoltaic DC/DC converter system.