Hybrid energy storage power control method for stabilizing photovoltaic power fluctuation

Abstract

The invention relates to a hybrid energy storage power control method for stabilizing photovoltaic power fluctuation. The method comprises the following steps: wavelet packet decomposition is carriedout on photovoltaic power generation power signals in a set time to obtain a power generation power fluctuation component; according to the power generation power fluctuation component, a grid-connected point voltage fluctuation value is calculated; and according to energy storage characteristics of a battery and a super capacitor, each compensation frequency band is determined, the grid-connectedpoint voltage fluctuation value is used to determine the wavelet packet decomposition layer number, the secondary high frequency component and the highest frequency component in the photovoltaic power generation power signals are extracted as compensation power instruction values of the battery and the super capacitor, and power compensation is carried out. Compared with the prior art, the methodhas the advantages that the grid-connected point voltage fluctuation is reduced, the delay of stabilizing the target power is reduced, and the service life of the hybrid energy storage system is enhanced.

Description

technical field [0001] The invention relates to a hybrid energy storage power control method, in particular to a hybrid energy storage power control method for smoothing photovoltaic power fluctuations. Background technique [0002] Photovoltaic power generation has the characteristics of simple structure, low noise, and strong applicability, making it suitable for large-scale promotion of photovoltaic power generation in cities. Therefore, photovoltaic power generation has changed from large-scale centralized grid connection to large-scale distributed grid connection. However, a large number of photovoltaics connected to the grid will cause power flow distribution and voltage changes in the power system. At the same time, fluctuations in photovoltaic power generation will also cause voltage fluctuations at grid-connected points. This reduces the power quality on the user side, and at the same time adversely affects equipment such as relay protection and transformers. Power...

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Problems solved by technology

[0003] When the photovoltaic power generation system is actually running, the generated power signal is obtained by real-time sampling. The traditional wavelet packet decomposition algorithm can only process the current power signal and the historical power signal. There is a gap between the target power and the photovoltaic output power obtained by this method. Due to the obvious delay, the target power obtained by traditional wavelet packet decomposition cannot accurately reflect the overall situation of photovoltaic output power

[0004] At present, the research on the control method of hybrid energy storage to stabilize photovoltaic power fluctuations at home and abroad mainly has the following deficiencies: ① The impact of photovoltaic power fluctuations on the grid voltage is not considered; ② The traditional real-time wavelet packet decomposition method has a high delay in extracting low-frequency components ③ The detailed information contained in the photovoltaic power generation signal and the specific performance characteristics of energy storage are less considered when calculating the energy storage compensation power command value

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