CN108281993B - Improved flying capacitor equalization circuit and equalization method thereof - Google Patents
Improved flying capacitor equalization circuit and equalization method thereof Download PDFInfo
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- CN108281993B CN108281993B CN201711298804.4A CN201711298804A CN108281993B CN 108281993 B CN108281993 B CN 108281993B CN 201711298804 A CN201711298804 A CN 201711298804A CN 108281993 B CN108281993 B CN 108281993B
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
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Abstract
The invention discloses an improved flying capacitor equalization circuit and an equalization method thereof, wherein the improved flying capacitor equalization circuit comprises a series battery pack, a single-pole double-throw switch group, a plurality of LC series energy storage circuits, 1 switch controller and a plurality of switch driving circuits; the series battery pack is formed by connecting a plurality of batteries in series, and the batteries in the series battery pack can be secondary batteries, including any one of lithium ion batteries, lead-acid batteries, super capacitors or nickel-hydrogen batteries, and are the main body for receiving balance. According to the invention, the LC series circuit is adopted, the switching frequency of the equalizing circuit is controlled according to the actual situation, the circuit current is zero at the moment of switching on and switching off the switch, the switching loss is greatly reduced, the equalizing efficiency is improved, the series battery is placed under the charging voltage, the single-pole double-throw switch is controlled by the main control switch, the battery is equalized in the charging and discharging process of the LC series circuit, and the equalizing circuit is suitable for the field of lithium batteries, safe and high in efficiency.
Description
Technical Field
The invention relates to the field of lithium batteries, in particular to an improved flying capacitor equalization circuit and an equalization method thereof.
Background
The lithium battery is used as an energy source widely used in daily life, but the energy storage of a single battery is limited, or the charging time is too long, so that a plurality of batteries are combined into a battery pack for use, the replacement is convenient, the reliability is high, the charging time is greatly saved, and the service life of the battery is prolonged. However, the problem is also obvious, after a plurality of charging and discharging cycles, the distribution of the residual capacity of each battery monomer will be approximately different, if the battery pack is not equalized, due to reasons such as different internal resistances, the problem of uneven charging will occur during use, and the phenomena of overcharge and overdischarge will easily occur, which will cause the battery to heat, energy loss, affect the service life and even cause fire, in order to improve the inconsistency of the battery pack and improve the overall performance of the battery pack, the equalization control is needed,
in the existing equalizing charge method, energy is transferred by adopting a capacitor, but in the flying capacitor equalizing topology, the problems of larger current and higher switch loss at the moment of switching on and switching off a switch in the equalizing process exist, the capacitor can transfer less energy in a single pulse width modulation period, and the capacitor equalizing topology generally has the defect of longer equalizing time.
Disclosure of Invention
Aiming at the defects of the prior art, the equalizing circuit and the equalizing mode are provided, which can realize zero current at the moment of switching on and switching off the switch, greatly reduce the switch loss and improve the equalizing efficiency.
An improved flying capacitor equalization circuit comprises a series battery pack, a single-pole double-throw switch pack, a plurality of LC series energy storage circuits, 1 switch controller (a main control unit and a main controller) and a plurality of switch driving circuits; the series battery pack is formed by connecting a plurality of batteries Bi (i ═ 1,2,3, … …, n) in series, and the batteries Bi (i ═ 1,2,3, … …, n) in the series battery pack can be secondary batteries, including any one of lithium ion batteries, lead acid batteries, super capacitors or nickel-metal hydride batteries, and are the main bodies for receiving equalization;
the single-pole double-throw switch group is formed by connecting a plurality of single-pole double-throw switches Si in series; the single-pole double-throw switch Si is formed by connecting two N-channel MOSFET tubes in series in the same direction, the drain D of the first MOSFET tube is a first static contact terminal Sia of the single-pole double-throw switch Si, the source S of the second MOSFET tube is a second static contact terminal Sib of the Si, and the connection point of the two MOSFET tubes is a selection terminal Sic of the Si;
the single-pole double-throw switch Si is formed by connecting two N-channel MOSFET tubes in series in the same direction, and is provided with three contact terminals including a first static contact terminal Sia, a second static contact terminal Sib and a selection terminal Sic.
The LC series energy storage circuit works in a quasi-resonance state, the switching frequency fs of the equalizing circuit is determined according to the lumped parameter R, L, C in the equalizing circuit, the LC series circuit is guaranteed to work in the quasi-resonance state, and the current of the LC series circuit is reduced to zero at each switching moment.
The series battery pack is formed by connecting a plurality of batteries Bi in series.
The single-pole double-throw switch group comprises a plurality of single-pole double-throw switches Si, wherein the single-pole double-throw switches Si comprise three contact terminal switches, namely a first static contact terminal Sia, a second static contact terminal Sib and a selection terminal Sic. The single-pole double-throw switch Si is formed by connecting two N-channel MOSFET tubes in series in the same direction, a source S of a first MOSFET tube is connected with a drain D of a second MOSFET tube, a first static contact terminal Sia of the single-pole double-throw switch Si is connected with the drain D of the first MOSFET tube, a second static contact terminal Sib of the single-pole double-throw switch Si is connected with the source S of the second MOSFET tube, and a selection terminal Sic of the single-pole double-throw switch Si is a connection point of the two MOSFET tubes (the connection position of the source S of the first MOSFET tube and the drain D of the second MOSFET tube). The switch has a first static contact terminal Sia connected to the positive pole of the battery Bi and a second static contact terminal Sib connected to the negative pole of the battery Bi. The selection terminal Sic is connected to the LC series tank circuit. The selection terminal Sic is connected to the capacitor Ci and the inductor Li-1.
The LC series tank circuit is formed by connecting a capacitor Ci and an inductor Li in series. One end of the capacitor Ci is connected with the selection terminal Sic and the inductor Li-1, and the other end of the capacitor Ci is connected with the inductor Li.
The grid G of the first MOSFET and the grid G of the second MOSFET are respectively connected with a switch controller (a main control unit and a main controller) through a switch driving circuit.
Further, in some embodiments, the series battery pack is composed of 4 batteries B1, B2, B3 and B4 connected in series, the single-pole double-throw switch group is composed of 4 single-pole double-throw switches S1, S2, S3 and S4 connected in series, the LC series energy storage circuit is composed of 3 series LC circuits C1+ L1, C2+ L2 and C3+ L3 connected in series (a capacitor C is connected with an inductor L in series), 1 switch controller, and 4 switch driving circuits;
the first unit of the LC series energy storage circuit is formed by connecting a capacitor C1 and an inductor L1(C1+ L1) in series, one end of the capacitor C1 is connected with a selection terminal S1C of a single-pole double-throw switch S1, and the other end of the capacitor C1 is connected with the inductor L1; the other end of the inductor L1, which is far away from the capacitor C1, is connected with the capacitor C2 and the selection terminal S2C of the single-pole double-throw switch S2; the second static contact terminal S1B of the single-pole double-throw switch S1 is connected with the negative electrode of the battery B1, and the first static contact terminal S1a of the single-pole double-throw switch S1 is connected with the positive electrode of the battery B1 and the second static contact terminal S2B of the single-pole double-throw switch S2;
the second unit of the LC series energy storage circuit is formed by connecting a capacitor C2 and an inductor L2(C2+ L2) in series, one end of the capacitor C2 is connected with a selection terminal S2C and an inductor L1, and the other end of the capacitor C2 is connected with the inductor L2; the other end of the inductor L2, which is far away from the capacitor C2, is connected with the selection terminal S3C and the capacitor C3; the second static contact terminal S2B of the single-pole double-throw switch S2 is connected with the negative electrode of the battery B2, and the first static contact terminal S2a of the single-pole double-throw switch S2 is connected with the positive electrode of the battery B2 and the second static contact terminal S3B of the single-pole double-throw switch S3;
the third unit of the LC series energy storage circuit is formed by connecting a capacitor C3 and an inductor L3 in series, one end of a capacitor C3 is connected with a selection terminal S3C and the inductor L2, and the other end of a capacitor C3 is connected with an inductor L3; the other end of the inductor L3 far away from the capacitor C3 is connected with a selection terminal S4C; the second static contact terminal S4B of the single-pole double-throw switch S4 is connected with the negative electrode of the battery B4, and the first static contact terminal S4a is connected with the positive electrode of the battery B4; the second static contact terminal S3B is connected with the negative pole of the battery B3, and the first static contact terminal S3a is connected with the positive pole of the battery B3;
the grids G of all the single-pole double-throw switches Si are respectively connected with a switch controller through a switch driving circuit, and the switch controller is provided with independent control modules 104-a, 104-b and the like.
The switch controller can collect the voltage of each battery, send out PWM signal, drive the switch-on and switch-off of the single-pole double-throw switch, control the contact of the first static contact terminal Sia, second static contact terminal Sib of the selection terminal Sic and switch.
Energy exchange between any two batteries can be realized by controlling the conduction and the disconnection of different switches of the single-pole double-throw switch group.
An improved flying capacitor equalization circuit equalization method comprises the following steps:
measuring the voltage of the battery, and in the N batteries, when the voltage of Bj is highest and the energy of battery Bi is lowest (assuming that N > -j > i > -1), the single-pole double-throw switch Sj and Si (control switch) throw the high contact terminals (i.e. Sjc and Sja are closed, and the selection terminal Sic and the first static contact terminal Sia of the switch are closed), a circuit (Ci + Li, … … Cj-1+ Lj-1) in the LC series energy storage circuit is connected in parallel with the batteries (Bi +1,. Bj) in the series battery pack, and the LC series energy storage circuit stores energy;
after half a PWM cycle, switching Sj and Si to low contact terminals (i.e. Sjc and Sjb are closed, and a selection terminal Sic and a second static contact terminal Sib are closed), connecting a circuit (Ci + Li, … … Cj-1+ Lj-1) in an LC series energy storage circuit in parallel with a battery (Bi, … Bj-1) in a series battery pack, and discharging energy by the LC series energy storage circuit; in the PWM period, the battery Bj transfers energy to the LC series energy storage circuit, and then the LC series energy storage circuit transfers the energy to the battery Bi, so that the energy is transferred from the Bj with the highest voltage to the battery Bi with the lowest voltage.
The steps are repeated repeatedly to achieve the effect of battery equalization.
Marks Bi (i ═ 1,2,3, … …, n) and Si (i ═ 1,2,3, … …, n) denote a plurality of batteries and single-pole double-throw switches, marks Bi and Si denote the ith battery and the single-pole double-throw switch, and marks Bj and Sj denote the jth battery and the single-pole double-throw switch;
the marks i +1 and j-1 are numbers respectively, i +1 represents the numerical value i plus 1, and j-1 represents the numerical value j minus 1.
According to the invention, the LC series circuit is adopted, and the switching frequency of the equalizing circuit is controlled according to the actual situation, so that the circuit current is zero at the moment of switching on and switching off the switch, the switching loss is greatly reduced, and the equalizing efficiency is improved. The series battery is placed under the charging voltage, the single-pole double-throw switch is controlled by the main control switch, and the battery is balanced in the charging and discharging process of the LC series circuit. The lithium battery is suitable for the field of lithium batteries, and is safe and efficient.
Drawings
FIG. 1 is a schematic diagram of a conventional flying capacitor circuit;
FIG. 2 is a circuit schematic of the present invention;
FIG. 3 is a schematic diagram of a single pole double throw switch configuration of the circuit of the present invention;
FIG. 4 is a schematic diagram of the LC circuit configuration of the circuit of the present invention;
FIG. 5 is a current path diagram for charging the circuit of the present invention;
FIG. 6 is a current schematic of the LC tank equalization process of the circuit of the present invention;
FIG. 7 is a graph of voltage current change for a conventional flying capacitor circuit;
FIG. 8 is a graph of the voltage current variation of the circuit of the present invention;
FIG. 9 is a graph of the voltage change of a conventional flying capacitor circuit battery;
fig. 10 is a voltage variation diagram of the battery of the circuit of the present invention.
Detailed Description
For further understanding of the features and technical means of the present invention, as well as the specific objects and functions attained by the present invention, the present invention will be described in further detail with reference to the accompanying drawings and detailed description.
Referring to fig. 1,2,3, and 4, the present embodiment includes a series battery pack 101, a single-pole double-throw switch set 102, a plurality of LC series energy storage circuits 103, 1 switch controller 104 (main control unit), and a plurality of switch driving circuits 105.
The battery Bi (i ═ 1,2,3, … …, n) in the series assembled battery 101 may be a secondary battery including any one of a lithium ion battery, a lead acid battery, a super capacitor, or a nickel metal hydride battery.
The single-pole double-throw switch group 102 is composed of a plurality of single-pole double-throw switches Si (i is 1,2,3, … …, n), the single-pole double-throw switches Si are composed of two MOSFET tubes which are connected in series in the same direction, and there are three contact terminals including a first static contact terminal Sia, a second static contact terminal Sib, and a selection terminal Sic. The drain D of the first MOSFET is a first static contact terminal Sia of a single-pole double-throw switch Si, the source S of the second MOSFET is a second static contact terminal Sib of Si, and the connection point of the two MOSFETs is a selection terminal Sic of Si. The switch controller 104 is provided with independent control modules 104-a, 104-b, etc., the gate G of the first MOSFET is connected with the control module 104-a, and the gate G of the second MOSFET is connected with the control module 104-b.
The LC series tank 103 works in a quasi-resonant state, and the switching frequency fs of the equalizer circuit is determined according to the lumped parameter R, L, C in the equalizer circuit, so that the LC series tank 103 works in the quasi-resonant state, and the current of the LC series tank 103 is reduced to zero at each switching moment.
The series battery pack 101 is formed by connecting a plurality of batteries in series.
The spdt switch set 102 has a number of switches in common. The single-pole double-throw switch Si has three contact terminals: a first stationary contact terminal Sia, a second stationary contact terminal Sib, and a selection terminal Sic. The single-pole double-throw switch Si is formed by connecting two N-channel MOSFET tubes in series, a source S of a first MOSFET tube is connected with a drain D of a second MOSFET tube, a first static contact terminal Sia of the switch is connected with the drain D of the first MOSFET tube, a second static contact terminal Sib is connected with the source S of the second MOSFET tube, and a selection terminal Sic is a link point of the two MOSFET tubes. The first static contact terminal Sia of the switch is connected with the positive pole of the battery Bi, and the second static contact terminal Sib is connected with the negative pole of the battery Bi. The selection terminal Sic is connected to the LC series tank 103.
The selection terminal Sic is connected to the capacitor Ci and the inductor Li-1.
The LC series tank 103 is formed by a capacitor Ci connected in series with an inductor Li. One end of the capacitor Ci is connected with the selection terminal Sic and the inductor Li-1, and the other end of the capacitor Ci is connected with the inductor Li.
The switch controller 104 includes a battery voltage collecting device, and a PWM signal generator for controlling the contact of the selection terminal Sic with the first static contact terminal Sia and the second static contact terminal Sib of the switch, so as to drive the single-pole double-throw switch Si to be turned on and off.
By controlling the on and off of the different switches of the single-pole double-throw switch set 102, energy exchange between any two batteries can be realized.
To understand the equalization method of the present invention, please refer to fig. 5 and fig. 6:
firstly, measuring the battery voltage, and when the Bj voltage is the highest and the battery Bi energy is the lowest in the N batteries (assuming that N > -j > i > -1), the single-pole double-throw switch Sj and Si (control switch) throw their high contact terminals (i.e. Sjc and Sja are closed, and the selection terminal Sic and the switch first static contact terminal Sia are closed), and the circuit (Ci + Li, … … Cj-1+ Lj-1) in the LC series energy storage circuit 103 is connected in parallel with the batteries (Bi +1,. Bj) in the series battery pack 101, and the LC series energy storage circuit 103 stores energy.
Second, after half a PWM cycle, Sj is thrown against Si to throw the low contact terminals (i.e., Sjc and Sjb closed, select terminal Sic is closed against second static contact terminal Sib). The circuit (Ci + Li, … … Cj-1+ Lj-1) in the LC series tank circuit 103 is connected in parallel with the battery (Bi, … Bj-1) in the series battery pack 101, and the LC series tank circuit 103 releases energy. In the PWM period, the battery Bj transfers energy to the LC series energy storage circuit 103, and then the LC series energy storage circuit 103 transfers energy to the battery Bi, so that the energy is transferred from the Bj with the highest voltage to the battery Bi with the lowest voltage.
The steps are repeated repeatedly to achieve the effect of battery equalization.
To show the specific effects of the present invention, please refer to fig. 7, fig. 8, fig. 9, and fig. 10:
when the circuit of the original flying capacitor circuit is switched on and switched off, the current of the circuit changes suddenly, and as can be seen from fig. 7, the current of the circuit directly reaches 0.15 ampere, and then the current of the circuit is rapidly reduced; in fig. 8, under the same equilibrium condition, the current magnitude is 0 when the circuit is switched on and off, the power generation curve is relatively smooth, and the current magnitude change of the circuit is small by adopting the circuit of the invention.
According to the invention, the LC energy storage circuit is adopted, and the switching frequency of the equalization circuit is controlled according to the actual situation, so that the circuit current is zero at the moment of switching on and switching off the switch, the switching loss is greatly reduced, and the equalization efficiency is improved. The invention obtains the project subsidy of the introduced innovation Research team in Dongguan city (project number: 2014607119) Supported by Dongguan Innovative Research team (NO. 2014607119).
In one specific embodiment, the series battery pack 101 comprises 4 batteries B1, B2, B3 and B4 connected in series, the single-pole double-throw switch group 102 comprises 4 single-pole double-throw switches S1, S2, S3 and S4 connected in series, the LC series energy storage circuit 103 comprises 3 series LC circuits C1+ L1, C2+ L2 and C3+ L3 connected in series (a capacitor C is connected with an inductor L in series), and 1 switch controller 104 and 4 switch driving circuits 105 are connected in series;
the first unit of the LC series energy storage circuit 103 is formed by connecting a capacitor C1 and an inductor L1(C1+ L1) in series, one end of the capacitor C1 is connected with a selection terminal S1C of the single-pole double-throw switch S1, and the other end of the capacitor C1 is connected with the inductor L1; the other end of the inductor L1, which is far away from the capacitor C1, is connected with the capacitor C2 and the selection terminal S2C of the single-pole double-throw switch S2; the second static contact terminal S1B of the single-pole double-throw switch S1 is connected with the negative electrode of the battery B1, and the first static contact terminal S1a of the single-pole double-throw switch S1 is connected with the positive electrode of the battery B1 and the second static contact terminal S2B of the single-pole double-throw switch S2;
the second unit of the LC series tank 103 is formed by connecting a capacitor C2 and an inductor L2(C2+ L2) in series, one end of the capacitor C2 is connected with the selection terminal S2C and the inductor L1, and the other end of the capacitor C2 is connected with the inductor L2; the other end of the inductor L2, which is far away from the capacitor C2, is connected with the selection terminal S3C and the capacitor C3; the second static contact terminal S2B of the single-pole double-throw switch S2 is connected with the negative electrode of the battery B2, and the first static contact terminal S2a of the single-pole double-throw switch S2 is connected with the positive electrode of the battery B2 and the second static contact terminal S3B of the single-pole double-throw switch S3;
the third unit of the LC series tank 103 is formed by connecting a capacitor C3 and an inductor L3 in series, one end of a capacitor C3 is connected with a selection terminal S3C and an inductor L2, and the other end of a capacitor C3 is connected with an inductor L3; the other end of the inductor L3 far away from the capacitor C3 is connected with a selection terminal S4C; the second static contact terminal S4B of the single-pole double-throw switch S4 is connected with the negative electrode of the battery B4, and the first static contact terminal S4a is connected with the positive electrode of the battery B4; the second static contact terminal S3B is connected with the negative pole of the battery B3, and the first static contact terminal S3a is connected with the positive pole of the battery B3;
the gates G of all the single-pole double-throw switches Si are connected to the switch controller 104 through the switch driving circuit 105, respectively.
In addition, in fig. 9, the equalization time of the two batteries is 0.995s by adopting the conventional flying capacitor circuit, and in fig. 10, the same conditions are adopted, but the equalization time is reduced to 0.735s by adopting the equalization circuit and the equalization method of the present invention, so that the efficiency is improved by 26% compared with the original efficiency.
According to the invention, the LC series circuit is adopted, and the switching frequency of the equalizing circuit is controlled according to the actual situation, so that the circuit current is zero at the moment of switching on and switching off the switch, the switching loss is greatly reduced, and the equalizing efficiency is improved. The battery balancing system comprises a series battery pack, a single-pole double-throw switch group, a plurality of LC series circuits, 1 switch controller and a plurality of switch driving circuits, wherein the series batteries are placed under a charging voltage, the single-pole double-throw switch is controlled by a main control switch, and the balance of the batteries is realized in the charging and discharging processes of the LC series circuits.
Therefore, the invention is safer and has high equalization efficiency.
The above-mentioned embodiments only express one embodiment of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (2)
1. An improved flying capacitor equalization circuit is characterized by comprising a series battery pack (101), a single-pole double-throw switch group (102), a plurality of LC series energy storage circuits (103), 1 switch controller (104) and a plurality of switch driving circuits (105), wherein the series battery pack (101) is formed by connecting a plurality of batteries Bi in series;
the LC series energy storage circuit (103) is connected with the series battery pack (101) in parallel;
the battery in the series battery pack (101) can be a secondary battery, and comprises any one of a lithium ion battery, a lead-acid battery, a super capacitor or a nickel-metal hydride battery;
the single-pole double-throw switch group (102) is formed by connecting a plurality of single-pole double-throw switches Si in series; the single-pole double-throw switch Si is composed of two N-channel MOSFET tubes which are connected in series in the same direction, i in Si is 1,2,3, … … and N, and the single-pole double-throw switch Si has three contact terminals: the static contact terminal comprises a first static contact terminal Sia, a second static contact terminal Sib and a selection terminal Sic; the drain D of the first MOSFET is a first static contact terminal Sia of a single-pole double-throw switch Si, the source S of the second MOSFET is a second static contact terminal Sib of Si, and the connection point of the two MOSFETs is a selection terminal Sic of Si;
the switch controller (104) is provided with independent control modules 104-a and 104-b, the grid G of the first MOSFET is connected with the control module 104-a, and the grid G of the second MOSFET is connected with the control module 104-b;
the source S of the first MOSFET is connected with the drain D of the second MOSFET, the first static contact terminal Sia of the single-pole double-throw switch Si is connected with the drain D of the first MOSFET, i in the Sia is 1,2,3, … …, n, the second static contact terminal Sib of the single-pole double-throw switch Si is connected with the source S of the second MOSFET, the selection terminal Sic of the single-pole double-throw switch Si is a connection point of the two MOSFETs, and the connection point is the connection position of the source S of the first MOSFET and the drain D of the second MOSFET; the first static contact terminal Sia is connected with the positive pole of the battery Bi, and the second static contact terminal Sib is connected with the negative pole of the battery Bi; the selection terminal Sic is connected with an LC series energy storage circuit (103), and is connected with a capacitor Ci and an inductor Li-1;
the grid G of the first MOSFET and the grid G of the second MOSFET are respectively connected with the switch controller (104) through a switch driving circuit (105);
the LC series energy storage circuit (103) is formed by connecting a capacitor Ci and an inductor Li in series, one end of the capacitor Ci is connected with the selection terminal Sic and the inductor Li-1, and the other end of the capacitor Ci is connected with the inductor Li;
the LC series energy storage circuit (103) works in a quasi-resonance state, the switching frequency fs of the equalizing circuit is determined according to the lumped parameter R, L, C in the equalizing circuit, the LC series energy storage circuit (103) is ensured to work in the quasi-resonance state, and the current of the LC series energy storage circuit (103) is reduced to zero at each switching moment;
the switch controller (104) comprises a battery voltage acquisition device and a PWM signal generator, drives the conduction and the closing of the single-pole double-throw switch Si, and is used for controlling the contact of a selection terminal Sic with a first static contact terminal Sia and a second static contact terminal Sib of the single-pole double-throw switch Si so as to drive the conduction and the closing of the single-pole double-throw switch Si;
energy exchange between any two batteries can be realized by controlling the conduction and the disconnection of different switches of the single-pole double-throw switch group (102);
the series battery pack (101) consists of 4 batteries B1, B2, B3 and B4 which are connected in series, the single-pole double-throw switch group (102) consists of 4 single-pole double-throw switches S1, S2, S3 and S4 which are connected in series, the LC series energy storage circuit (103) consists of 3 LC circuits C1+ L1, C2+ L2 and C3+ L3 which are connected in series, and 1 switch controller (104) and a 4-way switch driving circuit (105) are connected in series;
the first unit of the LC series energy storage circuit (103) is formed by connecting a capacitor C1 and an inductor L1 in series, one end of a capacitor C1 is connected with a selection terminal S1C of a single-pole double-throw switch S1, and the other end of a capacitor C1 is connected with an inductor L1; the other end of the inductor L1, which is far away from the capacitor C1, is connected with the capacitor C2 and the selection terminal S2C of the single-pole double-throw switch S2; the second static contact terminal S1B of the single-pole double-throw switch S1 is connected with the negative electrode of the battery B1, and the first static contact terminal S1a of the single-pole double-throw switch S1 is connected with the positive electrode of the battery B1 and the second static contact terminal S2B of the single-pole double-throw switch S2;
the second unit of the LC series energy storage circuit (103) is formed by connecting a capacitor C2 and an inductor L2 in series, one end of a capacitor C2 is connected with a selection terminal S2C and the inductor L1, and the other end of a capacitor C2 is connected with an inductor L2; the other end of the inductor L2, which is far away from the capacitor C2, is connected with the selection terminal S3C and the capacitor C3; the second static contact terminal S2B of the single-pole double-throw switch S2 is connected with the negative electrode of the battery B2, and the first static contact terminal S2a of the single-pole double-throw switch S2 is connected with the positive electrode of the battery B2 and the second static contact terminal S3B of the single-pole double-throw switch S3;
the third unit of the LC series energy storage circuit (103) is formed by connecting a capacitor C3 and an inductor L3 in series, one end of a capacitor C3 is connected with a selection terminal S3C and the inductor L2, and the other end of a capacitor C3 is connected with an inductor L3; the other end of the inductor L3 far away from the capacitor C3 is connected with a selection terminal S4C; the second static contact terminal S4B of the single-pole double-throw switch S4 is connected with the negative electrode of the battery B4, and the first static contact terminal S4a is connected with the positive electrode of the battery B4; the second static contact terminal S3B is connected with the negative pole of the battery B3, and the first static contact terminal S3a is connected with the positive pole of the battery B3;
the selection terminals Sic of the single-pole double-throw switch Si are respectively connected with a switch controller (104) through a switch driving circuit (105);
the switch controller (104) can collect the voltage of each battery, send out PWM signal, drive the switch-on and switch-off of the single-pole double-throw switch Si, control the contact of the selective terminal Sic with the first static contact terminal Sia, the second static contact terminal Sib of the single-pole double-throw switch Si.
2. A method of equalization using the improved flying capacitor equalization circuit of claim 1, the method comprising:
measuring the voltage of the battery, and in the N batteries, when the voltage of the Bj is the highest and the energy of the battery Bi is the lowest, closing the single-pole double-throw switches Sj and Si through the high contact terminals of the single-pole double-throw switches, namely Sjc and Sja, and closing the selection terminal Sic and the first static contact terminal Sia; the LC series energy storage circuit (103) is connected with the series battery pack (101) in parallel, namely a circuit Ci + Li, … … Cj-1+ Lj-1 in the LC series energy storage circuit (103) is connected with batteries Bi +1, … … Bj in the series battery pack (101) in parallel, and the LC series energy storage circuit (103) stores energy;
after half a PWM period, the single pole double throw switch Sj is closed with the Si throw low contact terminal, i.e., Sjc and Sjb, and the select terminal Sic is closed with the second static contact terminal Sib; the LC series energy storage circuit (103) is connected with the series battery pack (101) in parallel, namely a circuit Ci + Li, … … Cj-1+ Lj-1 in the LC series energy storage circuit (103) is connected with batteries Bi, … … Bj-1 in the series battery pack 101 in parallel, the LC series energy storage circuit (103) releases energy, in the PWM period, the batteries Bj transmit the energy to the LC series energy storage circuit (103), then the LC series energy storage circuit (103) transmits the energy to the batteries Bi, and the energy is transmitted from the Bj with the highest voltage to the batteries Bi with the lowest voltage;
the LC series energy storage circuit (103) controls the switching frequency of the equalization circuit according to the actual situation, so that the circuit current is zero at the moment of switching on and switching off the switch, the power generation curve is relatively smooth, the change of the circuit current is small, the switching loss is reduced, and the equalization efficiency is improved;
and repeating the first step and the second step repeatedly to achieve the effect of battery equalization.
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| CN110649337B (en) * | 2019-10-25 | 2024-07-26 | 华南理工大学 | Novel lithium ion battery Cell-to-Cell modularized equalizing circuit based on single inductor and control method |
| CN112838624B (en) * | 2019-11-22 | 2024-02-06 | 圣邦微电子（北京）股份有限公司 | Power supply circuit |
| US11515789B2 (en) * | 2021-01-30 | 2022-11-29 | Ernest Henry Wittenbreder, Jr. | Zero voltage switching flying capacitor power converters |
| CN114643869A (en) * | 2022-02-16 | 2022-06-21 | 清华大学 | Battery pack and management method of battery pack |
| CN117791806B (en) * | 2023-12-27 | 2024-09-13 | 杭州华塑科技股份有限公司 | Method and device for balancing battery voltage and computer storage medium |
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| CN105576719A (en) * | 2014-10-08 | 2016-05-11 | 香港理工大学 | Voltage balancing circuit |
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