Series battery equalization circuit based on symmetrical multi-winding transformer structure and control method applied to same

Abstract

The invention belongs to the technical field of battery application, and in particular to a series battery active equalization circuit based on a symmetrical multi-winding transformer structure and a control method applied to the same. The circuit comprises two groups of battery units which are arranged serially and a multi-winding transformer T which is arranged corresponding to each battery unit, wherein the battery unit comprises a battery B, a filter, a high-frequency switch M, a current-limit resistor R, a magnetic-reset and soft-switch resonance circuit and a driving circuit G which drives the high-frequency switch M to turn on / off; and the circuit is low in cost, simple in structure and control and quite high in energy transfer efficiency. Moreover, a path of duty ratio signal Vg which has two loading states also can be loaded on the driving circuit G to control the equalization circuit; if the value of the duty ratio signal Vg is increased, an equalization current is increased, and if the value of the duty ratio signal Vg is reduced, the equalization current is reduced, so that the equalization circuit current is controlled reliably, and the working efficiency is high.

Description

technical field [0001] The invention belongs to the technical field of battery application, and in particular relates to a balance circuit of series battery packs based on a symmetrical multi-winding transformer structure and a control method applied to the circuit. Background technique [0002] With the rapid development of new energy technologies, batteries have been widely used as an important energy storage unit. Due to the limitations of current battery technology, the voltage of battery cells is low. In order to increase energy storage capacity and output power, in high-capacity and high-power applications, batteries are usually combined in parallel and in series. However, due to differences in manufacturing process, initial capacity, ambient temperature, etc., the parameter characteristics between batteries are not completely consistent. In the process of using in series, these inconsistencies will gradually accumulate, causing the battery voltage of different series...

AI Technical Summary

Problems solved by technology

The method of resisting energy consumption is simple and reliable, and is often used in practical applications; however, due to resistance loss, increasing the equalization current will cause a lot of heat, which greatly increases the heat dissipation volume of the equalization system, and brings energy waste, and the resistance loss The effective method only works before the end of the charging process, and cannot solve the over-discharge of some batteries caused by imbalance. When the capacity of the battery cells is different, the energy storage of all the battery cells cannot be fully utilized.

Due to the many limitations of the resistance energy consumption equalization method, the equalization circuit based on the principle of active energy transfer has become a research hotspot; theoretically, the equalization method based on active energy transfer can make full use of the energy of all battery cells without loss; but due to In practical applications, there are usually a large number of series-connected batteries. For example, the power battery pack of an electric vehicle is composed of nearly hundreds of battery cells in series, resulting in a complex structure of this type of equalization system, high cost, excessive control, reduced reliability, and low energy transfer efficiency. Low, the actual application value is not significantly improved compared with the resistance energy consumption equalization method

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