Research On Modeling And Power Allocation Strategy Of Distributed Wind-hydrogen Hybrid Energy System

With the overall revival of the national livelihood economy,the contradiction between supply and demand with coal,oil and natural gas as the main energy resources has further intensified.After the national "Thirteenth Five" plan put forward a strategy for vigorously developing green energy,the scientific and technological development of wind and hydrogen power generation rise rapidly.However,the characteristics of reverse peak regulation and wind abandonment of wind turbines have become one of the main factors affecting wind energy utilization.Therefore,the efficient and controllable grid connection of renewable wind power systems has attracted the attention of scholars at home and abroad.This paper takes the distributed wind-hydrogen hybrid energy system as the research object,and analyzes the working principles of direct-drive permanent magnet wind turbines,electrolytic cells,fuel cells and energy storage batteries to construct a grid-connected common DC bus system structure.Relevant mathematical models are established,and the control equations of each subsystem are deduced.Based on the analysis of the operating characteristics of fuel cells and electrolytic cells,the effects of factors such as temperature and pressure are studied.A multi-factor dynamic simulation model considering the rate and temperature is established based on the performance test experiments of individual batteries.An optimal mode of multi-stage pulse charging is proposed for battery charging,and experimentation verification is performed.Based on this,an adaptive unscented Kalman filter(UKF)power allocation strategy is proposed to achieve controllable grid connection of wind power and optimize the operating range of battery state of charge(SOC).Among them,the battery bears the fluctuating wind power after filtering,and the hydrogen energy bears the difference between the grid load demand and the smooth wind power.Due to the characteristics of delayed response of hydrogen energy storage,it will generate unbalanced power of the system,which cannot fully meet the load demand of the grid.Therefore,in addition to fluctuating wind power,the reference power of the battery needs to compensate for the unbalanced power of the system caused by hydrogen energy storage.The adaptive UKF adjustment is mainly reflected when the battery is in the overcharge and overdischarge state.And the filter effect is adjusted by the feedback of the SOC and the change amountof DC bus voltage,thereby changing the reference power of the battery and slowing down the deep charge and discharge of the battery.In order to accurately track the battery operation status,the SOC is estimated based on the battery dynamic model.The simulation results show that when the SOC of the battery is at its limit,the power allocation strategy proposed can timely adjust the power allocation between the battery and the hydrogen energy storage,slow down the battery's overcharge and overdischarge behavior,and meet the grid load requirements in this paper.