Abstract:  ABSTRACT：  Due to the strong randomness and volatility of the photovoltaic power generation, the energy storage system can be used to effectively stabilize the fluctuation of the photovoltaic output power. This paper proposes a coordinated optimization control method of hybrid energy storage system （HESS） bases on ensemble empirical mode decomposition （EEMD）. The photovoltaic output power is decomposed into the high frequency component and low frequency component by adjusting the filter order k1 of the EEMD according to the fluctuation rate limit of the photovoltaic output power, and the low frequency component is regarded as the connected grid power to achieve a smoothing control of the photovoltaic output power. In order to improve the service life of hybrid energy storage system, according to the SOC （state of charge） of batteries and super capacitors, the filter order k2 of the EEMD is adjusted to realize the energy distribution between batteries and super capacitors. According to the priority rule of charge and discharge of batteries and super capacitors, the optimal control between super capacitors and batteries is realized. The effectiveness and correctness of the proposed method are verified by a simulation example.

Key words:  KEYWORDS： ensemble empirical mode decomposition （EEMD）, hybrid energy storage system （HESS）, filter order, volatility, state of charge （SOC）, photovoltaic power generation