Research On Voltage Stabilizing Control Strategy Of Microgrid Based On Electric Springs

There are more and moer environmental and energy problems in today’s society.The development and utilization of new energy is the primary goal of sustainable development.Therefore,people have payed more attention to distributed generation.Distributed generation is mainly a technology that converts solar energy,wind energy and other energy into electric energy for power supply.Due to the randomness and instability of natural factors such as wind and light,the output power of distributed generation will fluctuate greatly.If it is not controlled in time,it will have a bad impact on the stability of the system.Electric spring technology is a new method proposed in view of the current situation that microgrid is becoming more and more regional and intelligent.As a new generation of voltage stabilizing device,it represents a new idea for the voltage stabilizing control of microgrid,and provides convenience for the large-scale access of subsequent distributed power generation.Therefore,this paper will use the electric spring technology to control of voltage stability in the micronet,and design different application modes of electric spring for different working environments of microgrid,so as to realize the voltage stability control in microgrid and ensure the power supply reliability of critical loads in microgrid system.The main work of this paper is as follows:(1)The structure and operation mode of microgrid are analyzed,the mathematical model and engineering model of microgrid are established,and the MPPT control strategy is selected.Analyze the battery and establish the current output model and the energy model of the battery pack.(2)The concept and principle of electric spring are described,the operation modes under different working states are distinguished,the two topological structures of electric spring are compared and analyzed,and the role of electric spring in reducing the energy storage demand of microgrid is deduced and proved.(3)The design of DC voltage stabilizing strategy based on electric spring.Aiming at the problem that the bus voltage in the optical storage DC microgrid is easily affected by the output power of photovoltaic cells,the DC electric spring is designed to control the bus voltage of the microgrid,and the PI control is combined with the improved universal gravitation algorithm to optimize the control strategy of the electric spring and improve the control accuracy of the electric spring.(4)The parallel/off grid switching control strategy of microgrid is designed to ensure its smooth and stable switching.Expand DC microgrid,establish AC / DC hybrid microgrid,establish microgrid parallel / off grid model through grid connected inverter,and design grid connected inverter to ensure seamless switching of microgrid.(5)Based on the previous research,the voltage stabilizing control strategy of unplanned Island critical load based on electric spring is proposed.The electric spring control is introduced into the unplanned Island control for the first time,the three-phase three wire electric spring is designed,and a decoupling control strategy based on double closed loop is adopted to realize the voltage stabilizing control of critical loads.Finally,the simulation experiment is carried out.