Research On MH-Ni Battery Storage System Simulation Modeling And Its Applications

In recent years, with the development and utilization of renewable energy,more and more renewable energy distributed generation connected to the grid.However, the renewable energy, represented by wind, photovoltaic, is unstable andcontinuous, changes with time, season, weather, the output power is random andintermittent. With the proportion of these energy power generation equipmentbecoming larger, the synchronization system will have some impact. If you configurea volume of energy storage devices in wind and solar and other renewable energypower generation equipment, the negative impact will greatly contribute to solve. So,this paper studies the modeling and control strategy of Ni MH battery energy storagesystem.Firstly, the working principle and charge-discharge characteristics of Ni MHbatteries were described in detail, The classical battery equivalent circuit modelcannot reflect the effects caused by electrochemical polarization and concentrationpolarization to battery terminal voltage well, in this study, a piecewise mathematicalmodel with decay factor was proposed. On this basis, by analyzing the temperature,rate of charge and discharge, self-discharge, cycle times, hysteresis characteristics,polarization phenomenon and other factors, the paper proposes a Ni MH batteryequivalent circuit model considering the comprehensive factors, identification methodof battery parameters were given.Then, the sensitive analysis has been done to extractthe main parameters that affect the performance of the model, provide the basis for theoptimization model.For Ni MH battery pack inconsistency problem, the expressive form andgeneration causes of the battery pack inconsistency were analyzed, considering thepossible factors affecting the battery pack inconsistency. Based on the theoreticalanalysis, a mathematical model about life and inconsistency was established,describing the relationship between the battery voltage and the SOC by introducingthe relevant knowledge of mathematical statistics.Described the structural framework of the storage system, On this basis, thetopology and working principle of bidirectional DC/DC converter and bidirectionalDC/AC inverter were described in detail. According to the actual application of NiMH battery energy storage system, Bi-directional DC/DC converter took current inner and outer voltage control mode; bidirectional DC/AC inverter took PQ control.Established a Ni MH battery energy storage system model in the Matlab/Simulinkplatform. Control theory used a first-order RC low-pass filter, the model was appliedto stabilize the output power fluctuation of wind power, wind turbine data based onwind/photovoltaic/energy storage base, considered separately from the stabilizingeffect and economic point, deployed power and capacity to the energy storage system.Finally, tested in Matlab/Simulink simulation platform, and had a good effect.