Equalization circuit based on bipolar T-type double-resonance switched capacitor converter and control method

A technology of switching capacitors and balancing circuits, applied in charge balancing circuits, battery circuit devices, current collectors, etc., can solve problems such as slow balancing speed, reduce switching loss, increase switching frequency, and reduce circuit volume.

Active Publication Date: 2021-01-08
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Chinese invention patent (application number CN201710017754.1) discloses a battery pack equalization circuit and method based on external energy storage unit and LC quasi-resonance, using external energy storage unit and LC resonance module to achieve energy balance, but the equalization speed is still slow

Method used

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  • Equalization circuit based on bipolar T-type double-resonance switched capacitor converter and control method
  • Equalization circuit based on bipolar T-type double-resonance switched capacitor converter and control method
  • Equalization circuit based on bipolar T-type double-resonance switched capacitor converter and control method

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Experimental program
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Effect test

Embodiment 1

[0046]figure 1 It is an equalizing circuit based on a bipolar T-type dual resonant switched capacitor converter suitable for 2*N batteries, including two series battery packs, a switch network, a balanced bus, a bipolar T-type dual resonant switched capacitor converter, Switch drive circuit, voltage sampling circuit and controller. Among them, the voltage sampling circuit collects the voltage signal of each battery cell and transmits it to the controller. The controller outputs the switch signal, which is amplified by the switch drive circuit to control the on and off of the switch network.

[0047]Two series battery packs share a bipolar T-type dual resonant switched capacitor converter for equalization. The series battery group A is connected to the equalizing bus a through the switch network A1And a2Connect to the bipolar T-type dual resonant switched capacitor converter; the series battery pack B is connected to the balanced bus b through the switch network B1And b2Connect to the b...

Embodiment 2

[0059]figure 2 It is an equalizing circuit based on bipolar T-type dual resonant switched capacitor converter suitable for 2*2 batteries. Switch SA1, SA2, SA5, SA6And SB1, SB2, SB5, SB6Consists of an N-channel MOSFET. SA1(SB1) And SA5(SB5) The D pole of the battery A1(B1) Of the positive pole and A2(B2) Is connected to the negative pole, SA1(SB1) And SA5(SB5) S pole and balanced bus a1(b1) Connection; SA2(SB2) And SA6(SB6) The D pole of the battery A1(B1) Of the positive pole and A2(B2) Is connected to the negative pole, SA2(SB2) And SA6(SB6) S pole and balanced bus a2(b2)connection. Switch SA3(SB3) And SA4(SB4) Consists of two N-channel MOSFETs connected in series with S poles, and both ends are connected to battery A1(B1)'S negative pole, balanced bus a1(b1) And battery A1(B1)'S negative pole, balanced bus a2(b2) Connected.

[0060]The bipolar T-type dual resonant switched capacitor converter consists of two inductors L1, L2It is composed of a capacitor C. Among them, one end of the ...

Embodiment 3

[0071]Assuming that in the equalization circuit of the second embodiment, the battery voltage is VA1>VB1>VB2>VA2, After the voltage sampling circuit collects the voltage information of each battery cell, it is sent to the controller, and the controller judges Amax -Amin The value of is the largest, then enters the balance mode two, the energy is from battery A1Pass to battery A2.

[0072]Figure 5 Is the direction of current flow in the equalization process,Figure 6 It is the corresponding theoretical waveform.

[0073]The positive charge state of the capacitor, such asFigure 5 As shown in (a), the duration is t0'To t1'. At t0'Moment, switch SA1And SA4Conduction. Battery A1After the inductor L1Charge the positive polarity of the capacitor C, the positive polarity of the capacitor voltage VC' rises, and the inductor current iL1'The positive polarity rises and then drops to 0. At t1'Moment, switch SA1And SA4Zero current shutdown.

[0074]The positive discharge state of the capacitor, such asFig...

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Abstract

The invention discloses an equalization circuit based on a bipolar T-shaped double-resonance switched capacitor converter and a control method. The equalization circuit comprises two series battery packs, a switch network, an equalization bus, the bipolar T-shaped double-resonance switched capacitor converter, a switch driving circuit, a voltage sampling circuit and a controller. Energy balance ofthe battery pack is achieved through the bipolar T-shaped double-resonance switched capacitor converter, the method has the advantages of being high in balance speed and flexible in balance path, andthe available capacity of the battery pack can be effectively improved. Zero-current switching is achieved through resonance of the inductor and the capacitor, switching loss is greatly reduced, theswitching frequency can be improved, and the circuit size is reduced. The equalization circuit control method not only can realize equalization in the series battery packs, but also can realize energytransmission of the battery monomers among different series battery packs, and the equalization path is more flexible.

Description

Technical field[0001]The invention relates to the technical field of lithium-ion battery pack equalization, in particular to an equalization circuit and a control method based on a bipolar T-type dual resonant switched capacitor converter.Background technique[0002]Due to the advantages of small size, light weight, high energy density, low self-discharge rate, long cycle life, and no memory effect, lithium batteries are widely used in electric vehicles and energy storage power stations. However, the voltage and capacity of a single-cell lithium battery are usually very low and cannot meet the requirements of electric vehicles and energy storage power stations. In order to improve the storage capacity and voltage level of lithium batteries, it is usually necessary to connect multiple lithium batteries in series and parallel. Different from electric vehicle battery packs, energy storage power stations have large capacity requirements and a large number of battery cells. In order to sav...

Claims

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Application Information

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IPC IPC(8): H02J7/00H02M3/335
CPCH02J7/0014H02M3/33584H02M3/33507H02M1/0058Y02B70/10
Inventor 康龙云林鸿业罗璇卢楚生于玮
Owner SOUTH CHINA UNIV OF TECH
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