Research On Hybrid Energy Storage Capacity Configuration And Economy For Smoothing Photovoltaic Power Fluctuation

Renewable energy has emerged as the best option to accomplish sustainable energy development and a green and low-carbon transformation of the energy structure in light of the depletion of fossil fuels and the deterioration of the natural environment.One of the most developed and widely used sources of renewable energy is photovoltaic power generating.The vast size and high fraction of PV access,however,poses further difficulties for the planning and operation of the power system because to the stochastic and variable nature of PV power output.Energy storage’s bidirectional energy flow and quick reaction time allow it to be set in "sourcegrid-load" to enhance power quality.When energy storage is implemented on the PV power production side,its quick reaction capabilities can smooth out PV power output fluctuations,and its energy storage capabilities can absorb excess PV power and raise PV power generation’s utilization rate.Energy storage systems can be divided into power storage and energy storage systems based on the power density and energy density of the energy storage components.However,the current single-media energy storage systems are unable to meet the demands of large-scale storage and rapid response.By combining power and energy storage systems,PV power generation systems can satisfy these demands for high power and large capacity.An essential issue that has to be resolved is how to construct an acceptable design of a hybrid energy storage system(HESS)to satisfy the pertinent requirements of various application scenarios while also enhancing the economy.The mathematical model of solar power generation is initially built in this study,followed by an examination of the output properties of PV cells.Lithium batteries and supercapacitors are chosen as a hybrid energy storage system to reduce variations in solar power after the features of various energy storage technologies are introduced.The internal structure and operating principles of the Li-ion battery and supercapacitor are examined,and their respective capacity models are built.The architecture of the photovoltaic storage system under study in this research is provided,along with a comparison of the benefits and drawbacks of centralized and distributed energy storage arrangements.After that,the PV grid-connected power and hybrid energy storage reference power are obtained by smoothing the PV output using an algorithm consisting of recursive averaging and anti-pulse disturbance averaging weighted filtering with the PV grid-connected volatility and smoothness as indicators.The vibration components of different frequency bands of the hybrid energy storage reference power are extracted by using Complete Ensemble Empirical Modal Decomposition with Adaptive Noise(CEEMDAN)and Hilbert Transform(HT),so that the high-frequency components are borne by the supercapacitor and the low-frequency components,and the internal power of the hybrid energy storage is distributed once.In order to avoid the hybrid energy storage state of charge(SOC)from crossing the limit frequently and to ensure the sustainable operation of the hybrid energy storage system,a balanced management method of the hybrid energy storage power is proposed to correct the decay of the primary allocated power,and the corrected hybrid energy storage reference power is then used for capacity allocation.Finally,an economic evaluation model of the life cycle cost(LCC)of the lithium battery and the energy storage system is constructed to compare different energy storage capacity allocation strategies under two PV scenarios,and the effectiveness and economy of the proposed method is verified by using actual data simulation.