| The voltage and power of wind generator output are not stable, so that the energy storage devices are needed generally in order to provide stable power to the load. The power pulsating load is increasing, which is harm to the life of the energy storage device and stable operation of wind power system. To prolong the life of the energy storage device and improve the output power of wind power system, this paper applied hybrid energy storage system which consisted of battery and super capacitor to the small wind power generation system, and the energy management control strategy and hybrid energy storage capacity optimization of system were studied.Firstly, a small wind power generation system with the battery and super capacitor hybrid energy storage was designed. The power management control strategy of small wind power system was studied based on the analysis of the system energy flow, which made the wind generator, battery, super capacitor, damp load, city electricity switch unit etc work in optimal state.Secondly, in order to give full play to the complementary advantages of high energy density of battery and high power density, fast response and long circle life of super capacitor, the power allocation of hybrid energy storage system was studied. First of all, low-pass filter was utilized to divide the power of hybrid energy storage system into low frequency part and high frequency part, which shall be borne respectively by the battery and super capacitor, and then fuzzy controller was utilized to adjust the distribution power according to the state of charge of battery and super capacitor, and finally, the redistribution of power was limited, outputting the battery’s and super capacitor’s given charging and discharging reference power reference value, realizing the reasonable charge and discharge of hybrid energy storage system.Thirdly, capacity optimization of hybrid energy storage system was studied. Based on analyzing the necessity of capacity optimization of hybrid energy storage system and establishing the capacity of the hybrid energy storage system optimization model, considering the lowest cost of investment in hybrid energy storage system as the optimization goal and with the technical indicators of system capacity requirement and power demand as constraint conditions, simplex method was utilized to realize the capacity optimization of hybrid energy storage system, and it is realized by programming and proved by the example verification.Fourthly, based on completion of the design parameters, small wind power system simulation model was established for simulation. The simulation experimental results showed that the addition of the super capacitor to response mutation and peak power improved the the power output capacity and energy efficiency of the system and avoided large current of battery, so that it is beneficial to extend the service life of battery. The energy management control strategy adjusted the state of charge of battery and super capacitor and stabilized the DC bus voltage, furthermore, it realized the system energy balance and avoided the energy storage equipment early removal affecting the performance of the energy storage system due to the state of charge saturated or dried up. |
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