Lithium battery management system based on half-bridge series and control strategy thereof

Abstract

The invention relates to a lithium battery management system based on half-bridge series and control strategy thereof. The lithium battery management system is composed of N - half - bridge modules in series successively. The battery current flow and the busbar voltage are controlled by controlling the opening and closing of the half-bridge switching devices of each module. The lithium battery balance control strategy comprises: getting the duty ratio of basic control by utilizing closed-loop control; bypassing or locking modules with excessive low or high access electric quantity and recalculating and redistributing the duty ratio of the control of other modules after getting the duty ratio of basic control according to the battery condition of each battery; achieving the rapid balance control of battery power under the premise of guarantying two equivalent level output.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a lithium battery management system based on a half-bridge series connection and a control strategy thereof. Background technique [0002] Lithium batteries have the advantages of high energy density, long service life, no pollution, no memory effect, wide operating temperature range, and small self-discharge. They play a huge role in aerospace, micro-grid energy storage, electric vehicles, and energy Internet. effect. Due to the limitation of the voltage and capacity of lithium battery cells, it is often necessary to use series and parallel connections to meet the voltage and current requirements of the usage scenario. The inconsistency of the battery pack will lead to a rapid decline in the energy of the battery pack. Therefore, the equalization method of the battery pack has always been a research hotspot. The method is to ensure the power balance of the series bat...

AI Technical Summary

Problems solved by technology

Due to the limitation of the voltage and capacity of lithium battery cells, it is often necessary to use series and parallel connections to meet the voltage and current requirements of the usage scenario. The inconsistency of the battery pack will cause the energy of the battery pack to drop rapidly, so the equalization method of the battery pack has always been a research hotspot. The method is to ensure the power balance of the series batteries, transfer or directly consume the unbalanced power, but these methods have their corresponding shortcomings

However, this kind of method has the disadvantages of limited equalization ability or complicated equalization circuit. A simple battery equalization method disclosed in Chinese patent application No. 201510653845.5 proposes an equalization method of overall discharge and then individual equalization, but this This method needs to maintain the battery separately, the process is cumbersome and cannot be performed dynamically during operation; in addition, Chinese patent application number 201210142426.1 discloses a battery balancing system and method, and proposes a battery balancing system that transfers excess battery power through a transformer , the control is relatively simple, but the topology of this system is complex and the cost is high

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