Dual-active full-bridge converter-based hybrid energy storage system and control method therefor

Abstract

The invention discloses a dual-active full-bridge converter-based hybrid energy storage system and a control method therefor. The hybrid energy storage system comprises a supercapacitor, a lithium battery, a dual-active full-bridge converter, a Buck/Boost bidirectional converter and a direct current bus; and two kinds of energy storage equipment form a cascading type hybrid energy storage system. The supercapacitor is connected with the direct current bus through the dual-active full-bridge converter; by adoption of phase-shifting closed-loop control and by collecting the voltage information of the direct current bus, the output power of the hybrid energy storage system can be automatically regulated so as to stabilize the voltage of the direct current bus; the lithium battery is connected with the supercapacitor through the Buck/Boost bidirectional converter; and by adoption of voltage and current dual-closed-loop control, and by collecting the voltage of the supercapacitor, automatic charging and discharging of the lithium battery can be controlled, so that the voltage of the supercapacitor can be maintained within a working voltage range, so as to perform indirect compensation to power fluctuation of a direct current microgrid, reduce action frequency of the lithium battery, and effectively prolong the service life.

Description

technical field [0001] The invention relates to the field of DC microgrid hybrid energy storage, in particular to a hybrid energy storage system based on dual active full-bridge converters and a control method thereof. Background technique [0002] With the severe aggravation of environmental pollution and the increasing demand for new energy sources, the development of DC microgrid technology has received more and more attention. Microgrid is a power generation and distribution system that organically integrates distributed power sources, loads, energy storage devices, power electronic converters, and monitoring and protection devices. In the DC microgrid, due to the intermittent and random nature of the distributed power output power, the energy storage system has become an important part of the DC microgrid, which is used to maintain the internal power balance of the DC microgrid and stabilize the DC bus voltage. The hybrid energy storage system takes advantage of the co...

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Problems solved by technology

[0003] In order to solve the problems of small transformation ratio, lack of electrical isolation performance, frequent charging and discharging of lithium batteries, and short service life in the existing hybrid energy storage system, the present invention provides a hybrid energy storage system based on dual active full-bridge converters and its control method

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