CN111555408A - Single-inductor-based active equalization method for series-parallel battery pack - Google Patents

Single-inductor-based active equalization method for series-parallel battery pack Download PDF

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CN111555408A
CN111555408A CN202010474800.2A CN202010474800A CN111555408A CN 111555408 A CN111555408 A CN 111555408A CN 202010474800 A CN202010474800 A CN 202010474800A CN 111555408 A CN111555408 A CN 111555408A
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series
soc
monomer
battery pack
parallel
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CN111555408B (en
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郭向伟
刘震
朱军
刘鹏辉
杜少通
谢东垒
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Henan University of Technology
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    • H—ELECTRICITY
    • 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
    • H02J7/0014—Circuits for equalisation of charge between batteries
    • H02J7/0016—Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/22—Balancing the charge of battery modules
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
    • H—ELECTRICITY
    • 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
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/342—The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Abstract

The invention discloses a series-parallel battery pack active equalization method based on a single inductor, wherein the series-parallel battery pack is formed by connecting m series-parallel battery packs in parallel, and each series-parallel battery pack comprises n monomers; the balanced topology comprises (2m × n +2m) MOS tubes, (2m × n +2m) diodes and an inductor; the active balancing method is that the SOC of all the monomers in the series-parallel battery pack tends to be consistent through a balancing topology. The invention is characterized in that: based on inductive energy storage, balance energy can be directly transferred among any single bodies in the series-parallel battery pack, and balance of all the single bodies in the series-parallel battery pack is achieved. Secondly, the balanced topology energy storage unit has simple structure, small volume and simple control. And balanced topology is easy to expand, and when the number of monomers in the series battery pack or the number of the series battery packs changes, the number of corresponding MOS (metal oxide semiconductor) tubes and diodes is increased or decreased.

Description

Single-inductor-based active equalization method for series-parallel battery pack
Technical Field
The invention belongs to the field of battery equalization, and relates to a series-parallel battery pack active equalization method based on a single inductor, which is suitable for a battery management system in a new energy automobile.
Background
In recent years, new energy automobiles are becoming more popular with more and more severe environmental pollution and increasingly scarce petroleum resources. The lithium battery has the advantages of high energy density and long cycle life, and is gradually the main power source of new energy automobiles. Due to the fact that the voltage and the capacity of the single battery are low, the battery is required to be connected in series and in parallel to form a battery pack in application. The monomer is influenced by factors such as production process and the like, and the phenomenon of inconsistency can occur after the battery pack is charged and discharged circularly for a period of time, so that the energy utilization rate and the cycle life of the battery pack are reduced, and the phenomena of overcharge and overdischarge are easily caused. Equalization is of great importance to improve the inconsistency of the battery pack.
Currently, equalization methods are mainly divided into two categories: passive equalization and active equalization. The passive equalization mainly adopts a resistor as a shunt of each battery, and converts redundant energy of a high-energy monomer into heat energy to be consumed. The method has the advantages of small volume and low cost, but the problems of energy dissipation and heat dissipation are key disadvantages. Active equalization is a hotspot of equalization research in recent years, and energy is transferred from high-energy monomers to low-energy monomers through energy storage devices such as capacitors, inductors and converters, so that equalization of the battery pack is realized, and the equalization is also called non-energy-consumption equalization or lossless equalization. The balancing method based on the switched capacitor has the advantages of small balancing topology volume and easiness in control, but the balancing efficiency is low, the capacitor balancing time is long, and the problem is particularly obvious when the voltage difference between the battery monomers is not large. The equalization method based on the inductor has higher equalization efficiency, but the circuit structure is complex, the number of switching tubes and inductors is large, the control is complex, and the reduction of the volume of the equalization system is not facilitated. The single inductance resonance circuit is switched near the resonance frequency, so that the impedance in the equalizing loop is minimum, and the equalizing method based on the single inductance resonance circuit has the advantages of high equalizing efficiency, high equalizing speed and the like, but a plurality of switching devices are required, and the control is complex. The transformer-based equalization method has the advantages of high equalization efficiency, simplicity in control and easiness in isolation, but the transformer is complex in design and has the problem of magnetic saturation, so that the equalization topology is large in size, difficult to modularize, high in cost and difficult to expand. The balancing method based on the Buck, Boost and other converters can realize bidirectional flow of energy, has high balancing efficiency and high balancing speed, but still has the defects of large volume, complex control, high cost and the like.
Disclosure of Invention
The invention aims to overcome the defects and shortcomings of the existing balancing method, provides a series-parallel battery pack active balancing method based on a single inductor, simultaneously improves the unbalance phenomenon of a series battery pack and a series-parallel battery pack, and prolongs the service life of the battery pack.
To achieve the above object, the present invention is implemented according to the following embodiments:
a series-parallel battery pack active equalization method based on single inductance is characterized in that a series-parallel battery pack is formed by connecting m series-parallel battery packs in parallel, and each series-parallel battery pack comprises n monomers;
the balanced topology comprises (2m × n +2m) MOS tubes, (2m × n +2m) diodes and an inductor;
in each group of series-connected battery packs, the left and right bridge arms of the single anode are respectively connected with an MOS tube diode series circuit, and the left and right bridge arms of the single cathode are respectively connected with an MOS tube diode series circuit; the MOS tube diode series circuit comprises an MOS tube and a diode which are connected in series, and the conduction directions of the diode and a freewheeling diode in the MOS tube are opposite;
the tail ends of the left bridge arm and the right bridge arm of each group of series battery packs are respectively connected with the two ends of the inductor;
the active balancing method is that the SOC of all the monomers in the series-parallel battery pack tends to be consistent through a balancing topology.
Preferably, the series battery packs in the series-parallel battery packs are respectively marked as P1，P2…Pm；
In each group of series-connected battery packs, each monomer is marked as B in sequencex1，Bx2，…，BxnEach MOS tube is marked as S in sequencex0，Sx1，…，Sx(2n+1)Wherein x is the serial number of each series battery pack connected together in parallel; the inductance is marked L;
the aim of the balanced topology is to make the SOC of all monomers in the series-parallel battery pack tend to be consistent;
the above object is achieved by the steps of:
respectively setting starting working threshold values of balanced topologysAnd a shutdown thresholdeWhen the maximum difference value of the SOC of each monomer in the series-parallel battery pack is larger thansWhen the topology is balanced, the topology starts to work; when the maximum difference value of SOC of each monomer in the series-parallel battery pack is less thaneWhen the topology is in a normal state, the balancing topology stops working;
the specific working process of the balanced topology is as follows:
when the number of the maximum SOC monomer and the minimum SOC monomer is 1: discharging balance is carried out on the maximum SOC monomer and charging balance is carried out on the minimum SOC monomer through inductive energy storage, and the balance energy is directly transferred from the maximum SOC monomer to the minimum SOC monomer;
when the maximum SOC single number is not 1 and the minimum SOC single number is 1: if the number of the series battery packs with the highest average SOC is 1 in all the series battery packs containing the maximum SOC monomers, discharging and balancing the maximum SOC monomers in the series battery packs with the highest average SOC, and charging and balancing the minimum SOC monomers; if the number of the series battery packs with the highest average SOC in all the series battery packs containing the maximum SOC monomers is not 1, discharging and balancing the highest SOC monomer closest to the sequence number of the minimum SOC monomer, and charging and balancing the minimum SOC monomer;
when the maximum SOC single number is 1 and the minimum SOC single number is not 1: if the number of the series battery packs with the lowest average SOC is 1 in all the series battery packs containing the minimum SOC, the minimum SOC monomer in the series battery packs with the lowest average SOC is charged and balanced, and the maximum SOC monomer is discharged and balanced; if the number of the series battery packs with the lowest average SOC is not 1 in all the series battery packs containing the minimum SOC monomers, the minimum SOC monomers with the lowest average SOC are charged and balanced, and the maximum SOC monomers are discharged and balanced;
when the number of the maximum SOC monomer and the minimum SOC monomer is not 1, performing corresponding charge-discharge balance on a pair of the maximum SOC monomer and the minimum SOC monomer with the closest sequence numbers;
through the process, the quick equalization of the series-parallel battery packs is finally realized.
Preferably, the balancing topology is controlled by a control circuit, and the frequency of a control signal of the control circuit is determined according to parameters of the inductor, switching loss of the MOS transistor, the voltage of the battery of the whole series battery pack, and the voltage of the battery of the single battery.
Preferably, the duty cycle of the driving signal output by the control circuit resets the energy stored in the inductor in each signal period, that is, the current of the inductor first rises from zero and finally falls to zero.
Preferably, the single batteries of the series-parallel battery pack are secondary batteries; the secondary battery is one of a lead-acid battery, a lithium ion battery, a nickel-metal hydride battery and a super capacitor.
In order to implement the above stages smoothly, parameters of core components of the circuit need to be calculated and analyzed, and appropriate circuit parameters need to be set. Suppose a cell B in a series-parallel batteryxiHas a maximum voltage of UiMonomer ByjHas a minimum voltage of UjThe method comprises the steps of firstly determining the maximum equalizing current I to ensure equalizing speed and reliability, wherein x and y are serial numbers of series battery packs connected in parallel, I and j are serial numbers of monomers in the series battery packs, total conduction voltage drop of all switching devices in a loop is set to be delta U, time is represented as T, an equalizing period is represented as T, duty ratios of PWM waves for controlling charging and discharging of an inductor are α and α', the inductor is represented as L, and the maximum equalizing current I is determined firstly to ensure equalizing speed and reliabilityL。
In the first stage, when the MOS transistor Sx(2i-1)And Sx(2i)When conducting, the monomer BxiThe current flowing through the inductor rises linearly to store energy for charging the energy storage inductor L, the time T of the first stage is α T, and the impedance of the closed loop is ignoredMaximum equilibrium current, i.e. peak inductor current ILComprises the following steps:
Figure BDA0002515516170000041
the inductance L can be obtained from the required maximum equalization current and the selected intra-group switching frequency f:
Figure BDA0002515516170000042
inductor current iLThe expression of (a) is as follows:
Figure BDA0002515516170000051
when T ═ T, since T > (α + α') T, then:
Figure BDA0002515516170000052
further derivation yields:
Figure BDA0002515516170000053
at the beginning of the second phase, the MOS transistor Sy(2j-2)And Sy(2j+1)Open, the current through the inductor drops approximately linearly:
Figure BDA0002515516170000054
substituting the initial conditions above, we can obtain:
Figure BDA0002515516170000055
the above formula is combined with (1) to obtain:
Figure BDA0002515516170000056
in summary, the remaining parameters of the balanced topology can be obtained by the above formula according to the selection of the appropriate maximum balanced current and the corresponding balanced period.
The invention achieves the following beneficial effects:
compared with the prior art, the active equalization method for the series-parallel battery pack based on the single inductor has the first characteristic that the equalization of all monomers in the series-parallel battery pack can be realized simultaneously; the second characteristic is that the balanced topology energy storage unit has simple structure, small volume and simple control; the third characteristic is that the balanced topology is easy to expand, and when the number of monomers in the series battery pack or the number of the series battery packs changes, only the number of corresponding switch tubes needs to be increased or decreased.
Drawings
In order to more clearly illustrate the principle and technical solutions of the present invention in implementation, the technical solutions related to the present invention will be further described below by using the accompanying drawings, and the following drawings are only some implementation examples of the present invention, and it is obvious for those skilled in the art that other technical solutions can be obtained according to the following drawings without creative efforts.
FIG. 1 is a diagram of the equalization topology of the present invention;
fig. 2 is a first phase operation principle of the series-parallel battery pack equalization process;
FIG. 3 is a second phase operation principle of the series-parallel battery pack equalization process;
FIG. 4 is a timing diagram of the control signal duty cycle;
FIG. 5 is a series-parallel battery equalization control strategy of the present invention;
FIG. 6 is a four-string two-parallel-series-parallel battery pack simulation model built in MATLAB/Simulink;
FIG. 7 is a simulation model input condition current for a four-string two-parallel-series-parallel battery pack balancing topology;
FIG. 8 is a simulation curve of SOC balance for each cell in a four-string two-parallel-series-parallel battery pack;
FIG. 9 is a plot of the average SOC balance simulation for P1 and P2 for a four string two parallel-to-serial parallel battery pack;
FIG. 10 is a variation curve of the maximum difference of SOC of each cell in a four-string two-parallel-series-parallel battery pack;
Detailed Description
The invention will be further described with reference to the drawings and specific embodiments, which are illustrative and not limiting.
Example 1
A series-parallel battery pack active equalization method based on a single inductor is characterized in that the series-parallel battery pack is formed by connecting m series-parallel battery packs in parallel, and each series-parallel battery pack comprises n monomers.
The balanced topology comprises (2m × n +2m) MOS tubes, (2m × n +2m) diodes and an inductor;
in each group of series-connected battery packs, the left and right bridge arms of the single anode are respectively connected with an MOS tube diode series circuit, and the left and right bridge arms of the single cathode are respectively connected with an MOS tube diode series circuit; the MOS tube diode series circuit comprises an MOS tube and a diode which are connected in series, and the conduction directions of the diode and a freewheeling diode in the MOS tube are opposite;
the tail ends of the left and right bridge arms of each group of series battery packs are respectively connected with the two ends of the inductor.
The active balancing method is that the SOC of all the monomers in the series-parallel battery pack tends to be consistent through a balancing topology.
The series battery packs in the series-parallel battery packs are respectively marked as P1，P2…Pm；
In each group of series-connected battery packs, each monomer is marked as B in sequencex1，Bx2，…，BxnEach MOS tube is marked as S in sequencex0，Sx1，…，Sx(2n+1)Wherein x is the serial number of each series battery pack connected together in parallel; the inductance is marked L; the aim of the balanced topology is to make the SOC of all the single batteries in the series-parallel battery pack tend to be consistent.
The above object is achieved by the steps of:
respectively setting starting working threshold values of balanced topologysAnd a shutdown thresholdeWhen the maximum difference value of the SOC of each monomer in the series-parallel battery pack is larger thansWhen the topology is balanced, the topology starts to work; when the maximum difference value of SOC of each monomer in the series-parallel battery pack is less thaneWhen so, the equalization topology stops working.
The specific working process of the balanced topology is as follows:
when the number of the maximum SOC monomer and the minimum SOC monomer is 1: through inductance energy storage, the maximum SOC monomer is discharged and balanced, the minimum SOC monomer is charged and balanced, and the balance energy is directly transferred from the maximum SOC monomer to the minimum SOC monomer.
When the maximum SOC single number is not 1 and the minimum SOC single number is 1: if the number of the series battery packs with the highest average SOC is 1 in all the series battery packs containing the maximum SOC monomers, discharging and balancing the maximum SOC monomers in the series battery packs with the highest average SOC, and charging and balancing the minimum SOC monomers; and if the number of the series battery packs with the highest average SOC in all the series battery packs containing the maximum SOC monomers is not 1, discharging and balancing the highest SOC monomer closest to the sequence number of the minimum SOC monomer, and charging and balancing the minimum SOC monomer.
When the maximum SOC single number is 1 and the minimum SOC single number is not 1: if the number of the series battery packs with the lowest average SOC is 1 in all the series battery packs containing the minimum SOC, the minimum SOC monomer in the series battery packs with the lowest average SOC is charged and balanced, and the maximum SOC monomer is discharged and balanced; and if the number of the series battery packs with the lowest average SOC is not 1 in all the series battery packs containing the minimum SOC, the minimum SOC monomer with the lowest average SOC is charged and balanced, and the maximum SOC monomer is discharged and balanced.
And when the number of the maximum SOC monomer and the minimum SOC monomer is not 1, performing corresponding charge-discharge balance on a pair of the maximum SOC monomer and the minimum SOC monomer with the closest sequence numbers.
Through the process, the quick equalization of the series-parallel battery packs is finally realized.
When all the single bodies in the series-parallel battery pack are balanced, the single body B is assumedxiHas the highest SOC of (B)yjWherein x and y are connected in parallelThe serial number of the series battery pack, i and j are the serial numbers of the single bodies in the series battery pack.
The equalization process is divided into two stages:
as shown in fig. 2, it is the first phase operation principle of the equalization process of the series-parallel battery pack. First stage, monomer BxiCorresponding switch unit Sx(2i-1)And Sx(2i)Conducting, monomer BxiEnergy is stored in the inductor.
As shown in fig. 3, the second phase of the equalization process of the series-parallel battery pack works. Second stage, switch unit Sx(2i-1)And Sx(2i)Breaking, monomer ByjCorresponding switch unit Sy(2j-2)And Sy(2j+1)Conducting and inductance to monomer ByjAnd (6) charging.
As shown in fig. 4, is a timing diagram of the duty cycle of the control signal. Vx(2i-1)/Vx(2i)Indicating switch Sx(2i-1)And Sx(2i)Drive signal of Vy(2j-2)/Vy(2j+1)Indicating switch Sy(2j-2)And Sy(2j+1)The equalization period is T, and the PWM wave duty ratios corresponding to the switches are α and α', respectively.
As shown in fig. 5, it is a series-parallel battery equalization control strategy according to the present invention. And taking the SOC as a single body inconsistency index, and taking the maximum difference value of the SOC of each single body as a threshold condition for judging whether the equilibrium topology works or not.
As shown in fig. 6, the battery pack simulation model is a four-string two-parallel-series-parallel battery pack simulation model built in MATLAB/Simulink. The four-string two-parallel mode indicates that each group of series battery pack comprises 4 monomers, and 2 groups of series battery packs are connected in parallel and comprise a switch array module, a control strategy module, a detection module and the like. The specific parameter settings of the simulation model are shown in table 1.
TABLE 1 simulation parameter Table of simulation model
Figure BDA0002515516170000091
As shown in fig. 7, the operating condition current is input to the balanced topology simulation model for the four-string two-parallel-series-parallel battery pack. In order to simulate the actual working state, the load is set according to the working condition of UDDS (ultra dynamic meter Driving schedule), the average value of current output is 0.94A, the maximum value is 2.64A, the total simulation time is 700s, and the whole working condition comprises the processes of charging, discharging, accelerating and decelerating.
As shown in fig. 8, the simulation curve of SOC equalization of each cell in the four-string two-parallel-series-parallel battery pack is shown. As shown in fig. 8, when the simulation starts, the SOC difference of each cell satisfies the equilibrium topology working condition, the equilibrium topology works, and the maximum SOC difference of each cell gradually decreases. After a period of time, the balancing topology stops working, and the SOC difference value of each monomer in the series-parallel battery pack does not meet the working condition of the balancing topology any more.
As shown in fig. 9, are the P1 and P2 average SOC equalization simulation curves for a four string two parallel-to-serial parallel battery pack. As seen from fig. 9, the average SOC difference of the P1 and P2 battery packs is also reduced after the equalization is completed.
As shown in fig. 10, it is a variation curve of the maximum difference of SOC of each cell in the four-string two-parallel-serial-parallel battery pack. As can be seen from fig. 10, when the balancing starts, the maximum difference of the SOC of each cell reaches the balancing start operation threshold, the balancing topology operates, and the maximum difference of the SOC of each cell gradually decreases. And at 667s, the maximum difference value of the SOC of each single body reaches an equalization stop working threshold, and the maximum difference value of the SOC of each single body in the group is kept unchanged. The maximum difference value of the SOC of each monomer meets the requirement of the balance precision. In summary, the given equalization target is met.

Claims (5)

1. A series-parallel battery pack active equalization method based on a single inductor is characterized in that: the series-parallel battery pack is formed by connecting m series-parallel battery packs in parallel, and each series-parallel battery pack comprises n monomers;
the balanced topology comprises (2m × n +2m) MOS tubes, (2m × n +2m) diodes and an inductor;
in each group of series-connected battery packs, the left and right bridge arms of the single anode are respectively connected with an MOS tube diode series circuit, and the left and right bridge arms of the single cathode are respectively connected with an MOS tube diode series circuit; the MOS tube diode series circuit comprises an MOS tube and a diode which are connected in series, and the conduction directions of the diode and a freewheeling diode in the MOS tube are opposite;
the tail ends of the left bridge arm and the right bridge arm of each group of series battery packs are respectively connected with the two ends of the inductor;
the active balancing method is that the SOC of all the monomers in the series-parallel battery pack tends to be consistent through a balancing topology.
2. The active equalization method for the series-parallel battery pack based on the single inductor according to claim 1, characterized in that:
the series battery packs in the series-parallel battery packs are respectively marked as P1，P2…Pm；
In each group of series-connected battery packs, each monomer is marked as B in sequencex1，Bx2，…，BxnEach MOS tube is marked as S in sequencex0，Sx1，…，Sx(2n+1)Wherein x is the serial number of each series battery pack connected together in parallel; the inductance is marked L;
the aim of the balanced topology is to make the SOC of all monomers in the series-parallel battery pack tend to be consistent;
the above object is achieved by the steps of:
respectively setting starting working threshold values of balanced topologysAnd a shutdown thresholdeWhen the maximum difference value of the SOC of each monomer in the series-parallel battery pack is larger thansWhen the topology is balanced, the topology starts to work; when the maximum difference value of SOC of each monomer in the series-parallel battery pack is less thaneWhen the topology is in a normal state, the balancing topology stops working;
the specific working process of the balanced topology is as follows:
when the number of the maximum SOC monomer and the minimum SOC monomer is 1: discharging balance is carried out on the maximum SOC monomer and charging balance is carried out on the minimum SOC monomer through inductive energy storage, and the balance energy is directly transferred from the maximum SOC monomer to the minimum SOC monomer;
when the maximum SOC single number is not 1 and the minimum SOC single number is 1: if the number of the series battery packs with the highest average SOC is 1 in all the series battery packs containing the maximum SOC monomers, discharging and balancing the maximum SOC monomers in the series battery packs with the highest average SOC, and charging and balancing the minimum SOC monomers; if the number of the series battery packs with the highest average SOC in all the series battery packs containing the maximum SOC monomers is not 1, discharging and balancing the highest SOC monomer closest to the sequence number of the minimum SOC monomer, and charging and balancing the minimum SOC monomer;
when the maximum SOC single number is 1 and the minimum SOC single number is not 1: if the number of the series battery packs with the lowest average SOC is 1 in all the series battery packs containing the minimum SOC, the minimum SOC monomer in the series battery packs with the lowest average SOC is charged and balanced, and the maximum SOC monomer is discharged and balanced; if the number of the series battery packs with the lowest average SOC is not 1 in all the series battery packs containing the minimum SOC monomers, the minimum SOC monomers with the lowest average SOC are charged and balanced, and the maximum SOC monomers are discharged and balanced;
when the number of the maximum SOC monomer and the minimum SOC monomer is not 1, performing corresponding charge-discharge balance on a pair of the maximum SOC monomer and the minimum SOC monomer with the closest sequence numbers;
through the process, the quick equalization of the series-parallel battery packs is finally realized.
3. The active equalization method for the series-parallel battery pack based on the single inductor according to claim 2, characterized in that: the balance topology is controlled by a control circuit, and the frequency of a control signal of the control circuit is determined according to parameters of an inductor, the switching loss of an MOS (metal oxide semiconductor) tube, the voltage of a battery of the whole series battery pack and the voltage of a single battery.
4. The active equalization method of the series-parallel battery pack based on the single inductor as claimed in claim 3, wherein the active equalization method comprises the following steps: the control circuit outputs the duty ratio of the driving signal to reset the energy stored in the inductor in each signal period, namely the current of the inductor firstly rises from zero and finally falls to zero.
5. The active equalization method for the series-parallel battery pack based on the single inductor according to any one of claims 1 to 4, characterized in that: the single batteries of the series-parallel battery pack are secondary batteries; the secondary battery is one of a lead-acid battery, a lithium ion battery, a nickel-metal hydride battery and a super capacitor.
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CN112350403A (en) * 2020-11-03 2021-02-09 山东大学 Battery equalization topology based on half-bridge structure and wave trap and control method
CN112737015A (en) * 2020-12-22 2021-04-30 西安科技大学 Lithium battery equalization control system and control method based on SOC
CN113746174A (en) * 2021-09-09 2021-12-03 河南理工大学 Self-adaptive active equalization method for single-inductor single-capacitor series battery pack

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CN112350403A (en) * 2020-11-03 2021-02-09 山东大学 Battery equalization topology based on half-bridge structure and wave trap and control method
CN112737015A (en) * 2020-12-22 2021-04-30 西安科技大学 Lithium battery equalization control system and control method based on SOC
CN112737015B (en) * 2020-12-22 2023-05-16 西安科技大学 Lithium battery balance control system and control method based on SOC
CN113746174A (en) * 2021-09-09 2021-12-03 河南理工大学 Self-adaptive active equalization method for single-inductor single-capacitor series battery pack
CN113746174B (en) * 2021-09-09 2023-06-27 河南理工大学 Self-adaptive active equalization method for single-inductance single-capacitance series battery pack

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