Quasi-resonant staggered switched capacitor battery equalization circuit and control method thereof

A switching capacitor and battery equalization technology, applied in charge equalization circuits, battery circuit devices, secondary battery charging/discharging, etc., can solve the problems of slow equalization circuit equalization speed, etc., to improve equalization efficiency, small size, and reduce voltage effect of stress

Active Publication Date: 2019-04-12
SOUTHWEST JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem of slow equalization speed of the traditional switched capacitor battery equalization circuit and improve the efficiency of the equalization circuit, the present invention provides a quasi-resonant interleaved switched capacitor battery equalization circuit and its control method

Method used

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  • Quasi-resonant staggered switched capacitor battery equalization circuit and control method thereof
  • Quasi-resonant staggered switched capacitor battery equalization circuit and control method thereof
  • Quasi-resonant staggered switched capacitor battery equalization circuit and control method thereof

Examples

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Embodiment 1

[0035] Taking the balancing circuit of 4 batteries as an example, its structure is as follows figure 2 shown. Without considering the dead time of the driving signal, the circuit equalization process has two working states, when the battery voltage V B1 >V B2 >V B3 >V B4 When , the circuit diagrams of the two working states of the circuit are as follows Figure 3a and 3b shown.

[0036] State A: drive signal V GSa When the level is high, the lower switching tube S corresponding to each battery inside the equalization sub-circuit 1 and equalization sub-circuit 2 1a , S 2a , S 3a , S 4a conduction, battery B 1 , B 3 to the balancing capacitor C 11 、C 21 Charging; the right switch tube S inside the equalization sub-circuit 3 a1 , S a2 , S a3 conduction, battery B 1 , B 2 to the balancing capacitor C 31 、C 32 Charge. At the same time, each balancing capacitor and the corresponding resonant inductor resonate, and when the inductor current resonates to zero, t...

Embodiment 2

[0041] Figure 8 It is the circuit structure diagram of the embodiment of the present invention with the balancing circuit of 8 batteries, Figure 9 for Figure 8 The simulation waveform of embodiment, simulation parameter is identical with embodiment 1, and initial voltage is V B1 =3.7V, V B2 =3.6V, V B3 =3.5V, V B4 =3.4V, V B5 =3.35V, V B6 =3.45V, V B7 =3.55V, V B6 = 3.65V. Depend on Figure 9It can be seen that with the increase of the equalization time, the voltages of the eight batteries in the battery pack are gradually approaching, and finally reach the equilibrium state, and the equalization time is 0.046s. Compared Figure 7 and Figure 8 It can be seen that the equalization time of 8 batteries and 4 batteries is basically the same, and the equalization speed has nothing to do with the number of batteries.

[0042] In summary, the quasi-resonant interleaved switched capacitor battery equalization circuit proposed by the present invention has simple struct...

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Abstract

The invention discloses a quasi-resonant staggered switched capacitor battery equalization circuit and a control method thereof. The equalization circuit comprises a battery pack 1, a battery pack 2,an equalization subcircuit 1, an equalization subcircuit 2 and an equalization subcircuit 3; the battery packs composed of 2n batteries in series connection are divided into the battery pack 1 and thebattery pack 3; the equalization subcircuit 1 is connected with the battery pack 1, the equalization subcircuit 2 is connected with the battery pack 2, and the equalization subcircuit 3 is connectedwith the battery pack 1 and the battery pack 2. A pair of drive signals with fixed frequency, supplementary duty ratio and dead time are used for controlling the connection and disconnection of switchtubes inside the equalization subcircuit 2 and the equalization subcircuit 3 in the equalization subcircuit 1, the energy of high-voltage batteries is transmitted to low-voltage batteries through equalization capacitors, and automatic equalization for the voltage of each battery is realized. The equalization path between any two batteries is shortened, and two equalization passages are provided for any two batteries incapable of direct equalization, so that the influence of battery quantity on equalization speed is eliminated.

Description

technical field [0001] The invention relates to the technical field of lithium battery voltage equalization, in particular to a quasi-resonant interleaved switched capacitor battery equalization circuit and a control method thereof. Background technique [0002] Due to the advantages of high energy density, low self-discharge rate, and no memory effect, lithium batteries, as energy storage devices, are widely used in high-voltage applications such as electric vehicles, distributed power generation, and smart microgrids. However, the voltage of a single lithium battery is very low, and a large number of lithium batteries need to be connected in series or in parallel to form a battery pack to meet the voltage and power requirements of the load. However, due to manufacturing reasons, the battery has inconsistencies in internal resistance, voltage, capacity, etc., and with the use of the battery and the difference in operating temperature, this inconsistency will gradually incre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J7/00H01M10/42H01M10/44
CPCH01M10/4207H01M10/441H02J7/0019Y02E60/10
Inventor 张小兵周国华冷敏瑞田庆新
Owner SOUTHWEST JIAOTONG UNIV
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