An asymmetric chain hybrid energy storage system and its control method

Abstract

The invention discloses an asymmetric chain type hybrid energy storage system and a control method thereof. The asymmetric chain type hybrid energy storage system mainly comprises a chain type hybrid energy storage structure and an LC tuned filter, wherein the chain type hybrid energy storage structure is composed of a super-capacitor energy storage unit and a rechargeable battery energy storage unit, and the LC tuned filter is connected with the chain type hybrid energy storage structure to form an assistant power loop. When charging and discharging, the alternating voltage output from the rechargeable battery energy storage unit comprises a high-frequency component through controlling PWM switching signals in a cascade converter of the rechargeable battery energy storage unit, and the power flow size and direction between different units can be changed through regulating the amplitude and phase of the high-frequency voltage component. Through power exchange, when the current output from the rechargeable battery energy storage unit is insufficient, the super-capacitor energy storage unit is capable of providing power for the rechargeable battery energy storage unit through the assistant power loop so as to improve the current output ability thereof; when the surplus energy of the super-capacitor is insufficient, the rechargeable battery charges the super-capacitor through the assistant power loop.

Description

technical field [0001] The invention relates to the technical field of energy storage, in particular to a chain hybrid energy storage system and a control method thereof. Background technique [0002] Existing energy storage elements can be divided into two types: energy type (lead-acid battery, lithium battery and sodium-sulfur battery, etc.) and power type (supercapacitor, superconducting magnetic energy storage, flywheel energy storage, etc.). Certain requirements in practical applications, such as smoothing intermittent power fluctuations, require the energy storage system to have both a fast response part and a certain energy storage capacity, so it is difficult to meet only one type of energy storage technology. The hybrid energy storage system (Hybrid Energy Storage System, HESS) can complement the characteristics of different energy storage technologies by directly connecting different types of energy storage components in parallel or through power electronic convert...

AI Technical Summary

Problems solved by technology

However, due to the series structure between the converters, the energy storage unit of the battery and the energy storage unit of the supercapacitor need to have the same current output capability, which is contradictory to the characteristics that the supercapacitor has a strong current output capability and the battery power output capability is weak

At the same time, in the series structure, the energy in the supercapacitor is difficult to replenish from the battery

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