Power Allocation Strategy of Multivariate Hybrid Energy Storage System Suitable for Microgrid

Considering that hybrid energy storage system is regarded as one of the important components of microgrid, it is of great significance to study its power allocation strategy. The power fluctuation of microgrid is decomposed into three different components: random component, pulse component and continuous component. Accordingly, a multivariate hybrid energy storage system composed of supercapacitor, lithium iron phosphate battery and all-vanadium redox flow battery was used to stabilize the power fluctuation in microgrid; Two frequency dividing points of power fluctuation were obtained by wavelet transform, which were decomposed into three frequency components by a low-pass filter and a high-pass filter. Combined with system constraints, the power allocation strategy of multivariate hybrid energy storage system was designed. Compared with the traditional energy storage system, the simulation results showed that the multivariate hybrid energy storage system could effectively reduce the charging and discharging power as well as charging and discharging times of supercapacitors and lithium batteries, maintain the SOC fluctuation between 30% and 70%, and possess a more reasonable working range, thus prolonging the service life of energy storage components.