Study of control strategy for hybrid energy storage in wind- photovoltaic hybrid streetlight system

A hybrid energy storage with super capacitor and batteries for energy storage unit in wind-pv hybrid streetlight system has been presented. Hybrid energy storage system with super capacitor is given priority to, supplemented by the batter provide adequate, stable and reliable energy guarantee for wind-pv hybrid streetlight system. With this technique a lighter and smaller energy storage system can be achieved which enhances the performance of wind-pv hybrid streetlight system. Super capacitor has drawn more and more attention on energy storage systems because of its advantages of high power density, high charging speed, long service life and small size, light weight and extremely high cycling capability. In this way the batteries can ensure only the average power and the super capacitors can ensure the power variations. When power is greatly change, super capacitors have energy storage buffer action. Storing capacity of super capacitor and variable current control function of parallel controller can reduce times of tiny battery charging and discharging, reduce the discharge depth, prolong the service life of the battery, which basiciy solved the problem of wind-pv hybrid streetlight system. The lifetime of the batteries, weight and volume of the HESS in wind-pv hybrid streetlight can thus been improved. The simulation results verified the validity of proposed control strategy.