Control Strategy of a Hybrid Energy Storage System to Smooth Photovoltaic Power Fluctuations Considering Photovoltaic Output Power Curtailment

Abstract

The power fluctuations of grid-connected photovoltaic (PV) systems have negative impacts on the power quality and stability of the utility grid. In this study, the combinations of a battery/supercapacitor hybrid energy storage system (HESS) and the PV power curtailment are used to smooth PV power fluctuations. A PV power curtailment algorithm is developed to limit PV power when power fluctuation exceeds the power capacity of the HESS. A multi-objective optimization model is established to dispatch the HESS power, considering energy losses and the state of charge (SOC) of the supercapacitor. To prevent the SOCs of the HESS from approaching their lower limits, a SOC correction strategy is proposed to correct the SOCs of the HESS. Moreover, this paper also investigates the performances (such as the smoothing effects, losses and lifetime of energy storage, and system net profits) of two different smoothing strategies, including the method of using the HESS and the proposed strategy. Finally, numerous simulations are carried out based on data obtained from a 750 kWp PV plant. Simulation results indicate that the proposed method is more economical and can effectively smooth power fluctuations compared with the method of using the HESS.

Multi-Objective Sizing of Hybrid Energy Storage System for Large-Scale Photovoltaic Power Generation System

“…As such, numerous excessive fluctuations that exceed the rated power of the VRB, which is due to the high power and high fluctuation frequency of PV output can be observed during cloudy days. As a remedy, two methods can be used to alleviate the effects of these excessive fluctuations: one is to limit the power exceeding the rated power by power curtailment [35], but this method cannot solve the power shortage of the fluctuation; the other method is to increase the power capacity of the energy storage device, which will significantly increase the cost. In the future, the improvement of energy storage technology and the further reduction of costs will alleviate this problem.…”

Research on Energy Storage Optimization for Large-Scale PV Power Stations under Given Long-Distance Delivery Mode

“…Recently, the complementary operation patterns of energy storage and PV power stations have been researched, which are generally classified into two categories: smoothening the output of PV power stations and achieving electrical energy transfer. Ma et al [27] proposed that because an energy storage system can absorb and release electricity instantly, it could be used for Complementing PV power stations with energy storage can realize energy transfer on the time axis, control power effectively, improve the quality of electric energy, and enhance the planning tracking ability [26]. Recently, the complementary operation patterns of energy storage and PV power stations have been researched, which are generally classified into two categories: smoothening the output of PV power stations and achieving electrical energy transfer.…”

Design and Sizing of Mobile Solar Photovoltaic Power Plant to Support Rapid Charging for Electric Vehicles

“…Due to the utilization of renewables and storage, the system reduces the impact on the electrical grid. Ma et al [35] propose a methodology for smooth PV power fluctuations at the point of common coupling and also investigate about smoothing effects, losses, and lifetime of energy storage for hybrid energy storage systems (HESS). They contribute to the development of a control strategy for HESS and PV.…”