SOC Optimization Based Energy Management Strategy for Hybrid Energy Storage System in Vessel Integrated Power System

Hybrid energy storage system (HESS) consisted of battery and supercapacitor plays an essential role in supporting the normal operation of pulse load in vessel integrated power system (IPS) as well as improving power quality. However, due to the unique properties of the pulse load and diversified operations of the vessel, such advanced power system architectures tend to face greater challenges in optimal power allocation. In order to address the power allocation challenges, a novel optimized state-of-charge (SOC) feedback based energy management strategy is proposed for HESS in IPS to restrain the DC bus voltage fluctuation in this paper. Firstly, considering the operating characteristics of the pulse load in IPS, the optimized SOC of the HESS is introduced to the low-pass filter (LPF) with variable time constant to split the power in the HESS. Secondly, SOC recovery control of the supercapacitor is introduced to the LPF to optimize the size of the HESS as well as prolong the lifetime of the battery. Also, the enforced intervention is introduced to avoid the opposite state of the HESS. The proposed strategy can make full use of the HESS complementary characteristics to compensate the pulse load and optimize the HESS. Finally, the simulation conducted in PSCAD demonstrates the effectiveness of the strategy proposed in pulse load compensation as well as HESS optimization.