Research On The Control Strategy Of Off Grid Wind/Solar/Battery Hybrid Power System And Design Of Inverter

With the consumption of fossil energy,the countries are competing to develop new energy industry to deal with the continuous oil crisis and energy crisis.Among them,the fastest growing new energy was wind power and solar power.China is developing particularly rapidly in this regard and has becoming the country with the highest capacity of the wind power generation capacity.Even in photovoltaic power generation installed capacity,China is also among the best.But due to intermittent and volatility of wind and solar,the reliability and stability of single PV or wind generation system are pretty low,not suitable for grid connected power generation.The emergence of Wind/Solar/Battery hybrid power system gives us a way to solve this problem.It well uses the complementarities of wind and solar,greatly strengthened the stability and reliability of the power generation system.Off Grid Wind/Solar/Battery hybrid power system has been taken as the research object in this paper,the working principle of each part of the system was deeply analyzed,the mathematical model of the system was established,and a comprehensive study on integrated energy control strategy and stand alone inverter were made.The main research contents are as follows:First,an overall design of Wind/Solar/Battery hybrid power system has been made in this paper.The main circuits of each part of the system and assistant circuit that includes AC/DC detection circuit,drive circuit,protection circuit were designed,and electrical structure of the system was also designed.Second,the control strategy of Wind/Solar/Battery hybrid power system was studied.The maximum power point tracking algorithm of wind power generation and photovoltaic power generation was analyzed,and the maximum power point tracking method for the wind power generation based on fuzzy PID was proposed.The charging and discharging characteristics of lead-acid battery and the common charging technology were introduced,and the method of the variable current charge and the back difference voltage method were adopted as storage system strategy.Finally,the energy integration management strategy of the Wind/Solar/Battery hybrid power system is proposed.Third,the control strategy for off grid inverter was studied.Based on mathematical model of off grid inverter and unipolar frequency doubled SPWM modulation,double closed loop PI control method was put forward,the parameters of the double closed-loop controller was optimized.For the waveform distortion problem of the inverter with the nonlinear load,the improved double closed-loop PI control method was proposed.Fourth,the simulation analysis of Wind/Solar/Battery hybrid power system was carried out to verify the rationality of the structure and the feasibility of the control strategy.