Energy management of hybrid energy storage system (HESS) based on sliding mode control

The renewable energy has become the research focus in recent years with the environment-friendly characteristic. Integrating energy storage system to the renewable energy system can enhance the stability and reliability of the whole power system. As one of the core technologies, energy management of the hybrid energy storage system attracts more and more attention. Hybrid energy storage system can improve the performance of the storage device with the battery as the main power source and the super capacitor as the auxiliary power source. This paper presents a control strategy based on the DC voltage regulation via sliding mode control that changes the working conditions of battery and super capacitor. When the supercapacitor voltage stays in the working range as designed, it will work as the auxiliary power source to maintain the DC voltage. When the supercapacitor voltage reaches the upper limit or the lower limit, the battery will be controlled to maintain the DC bus voltage, making the super capacitor voltage remain in a proper range. The simulation model is established in MATLAB and simulation results verify the validity of the proposed control method.