CN115296370A - Battery pack system and control method thereof - Google Patents

Battery pack system and control method thereof Download PDF

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Publication number
CN115296370A
CN115296370A CN202211001471.5A CN202211001471A CN115296370A CN 115296370 A CN115296370 A CN 115296370A CN 202211001471 A CN202211001471 A CN 202211001471A CN 115296370 A CN115296370 A CN 115296370A
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CN
China
Prior art keywords
regulator
switch
diode
battery pack
transformer
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Application number
CN202211001471.5A
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Chinese (zh)
Inventor
邹莘剑
郭军
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Xingchu Century Technology Shenzhen Co ltd
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Xingchu Century Technology Shenzhen Co ltd
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Priority to CN202211001471.5A priority Critical patent/CN115296370A/en
Publication of CN115296370A publication Critical patent/CN115296370A/en
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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
    • H02J7/0063—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with circuits adapted for supplying loads from the battery
    • 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
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00302—Overcharge protection
    • 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
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00304—Overcurrent protection
    • 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
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00306—Overdischarge protection
    • 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
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00309—Overheat or overtemperature protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • 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
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/20—Charging or discharging characterised by the power electronics converter

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The invention discloses a battery pack system and a control method thereof, wherein the battery pack system comprises a DC/DC regulator, a DC transformer DCX, a control unit and a battery pack system; the input end of the DC/DC regulator is connected with the output end of the battery pack system, and the output end of the DC/DC regulator is connected with the input end of the direct current transformer DCX; the controller is respectively connected with the DC/DC regulator and the DC transformer DCX; the control unit is used for acquiring current flowing through the inductor and first voltage at two ends of the capacitor in the DC/DC regulator so as to obtain a corresponding power value; the control unit is also used for acquiring a second voltage at two ends of a capacitor positioned between the output ends of the DC/DC regulator; the control unit is further configured to output a signal for controlling the charging or discharging of the DC/DC regulator and the DC transformer DCX based on the power value and the second voltage. The invention can realize high efficiency and easy balance, and simultaneously meet the high flexibility configuration requirement of users.

Description

Battery pack system and control method thereof
Technical Field
The invention relates to the technical field of storage, in particular to a battery pack system and a control method thereof.
Background
With the wide use of lithium battery energy storage systems, more and more battery packs are used as hearts of the energy storage systems and are applied to various occasions, such as energy storage systems of electric vehicles, mobile energy storage, household energy storage and the like. With the increasing power demand of users on the energy storage system, the capacity of the battery pack is increased, and the cost is lowered. Because the efficiency advantage of the high-voltage battery pack system is obvious, the high-voltage battery scheme becomes the first choice of the system scheme in a high-capacity energy storage system.
At present, no matter the energy storage system of an electric automobile or a household, a high-voltage battery pack adopts battery series connection to realize high-voltage output of the battery pack, and the most obvious defects of the scheme are that the voltage of the battery pack is higher, the number of series-connected batteries is more, the balance among battery cores is worse, the efficiency of the series-connected system is low, and the flexible configuration of systems with different capacities cannot be met.
In order to solve the problem of equalization caused by series connection of battery packs, a scheme is provided in which an optimizer is added to each battery pack to adjust the output characteristics of the battery packs so as to achieve the effect of optimizing the SOC of the battery packs. The scheme has obvious progress from the aspects of the balance capability of the battery pack and the system efficiency, but the scheme is lack of flexibility for meeting the configuration requirements of different capacities of customers and is also lack of compatibility for PCS with different capacities.
Disclosure of Invention
In view of the above, the present invention provides a battery pack system and a control method thereof to solve the above technical problems.
The invention discloses a battery pack system, which comprises a DC/DC regulator, a DC transformer DCX, a control unit and a battery pack system, wherein the DC/DC regulator is connected with the DC transformer DCX; the input end of the DC/DC regulator is connected with the output end of the battery pack system, and the output end of the DC/DC regulator is connected with the input end of the direct current transformer DCX; the controller is respectively connected with the DC/DC regulator and the DC transformer DCX;
the control unit is used for acquiring current flowing through an inductor and first voltage at two ends of a capacitor in the DC/DC regulator so as to obtain a corresponding power value;
the control unit is further configured to obtain a second voltage across a capacitor located between the output terminals of the DC/DC regulator;
the control unit is further configured to output a signal for controlling charging or discharging of the DC/DC regulator and the DC transformer DCX based on the power value and the second voltage.
Further, the control unit comprises a first differentiator, a power regulator connected with the first differentiator, a second differentiator, a voltage regulator connected with the second differentiator, a first comparator, a third differentiator connected with the first comparator, and a current regulator connected with the third differentiator;
the first differentiator is used for subtracting the reference power from the power value and inputting the difference value into the power regulator;
the second difference device is used for subtracting the difference value of the second voltage and the reference voltage and inputting the difference value into the voltage regulator;
the first comparator is used for comparing the output quantities of the power regulator and the voltage regulator and outputting the minimum value to the third differentiator;
the third differentiator is used for making a difference between the output quantity of the third differentiator and the current in the DC/DC regulator, and inputting the difference into the current regulator;
the current regulator is configured to output a control signal to control the fifth switch and the sixth switch in the DC/DC regulator and the first switch, the second switch, the third switch, and the fourth switch in the DC transformer DCX to be turned on or off.
Further, the DC/DC regulator includes a first capacitor, a current sensor, a first inductor, a fifth switch, a fifth diode, a sixth switch, a sixth diode, and a second capacitor;
the first capacitor is connected with one end of the first inductor through the current sensor; the other end of the first inductor is connected with the input end of the fifth diode and the output end of the sixth diode respectively;
the fifth diode and the sixth diode are connected in series; the fifth switch and the sixth switch are respectively connected with the fifth diode and the sixth diode in parallel; and the second capacitor is respectively connected with the output end of the fifth diode and the input end of the sixth diode.
Further, the dc transformer DCX includes a first switch with a reversed first diode, a second switch with a reversed second diode, a third switch with a reversed third diode, and a fourth switch with a reversed fourth diode;
the direct current transformer DCX further comprises a transformer, a second inductor, a third capacitor and a fourth capacitor;
one end of the primary winding of the transformer is connected with the input end of the first diode; the other end of the primary winding of the transformer is connected with the input end of the second diode; one end of the secondary winding of the transformer is connected with one end of the second inductor; the other end of the secondary winding of the transformer is connected with the input end of the fourth diode; the other end of the second inductor is connected with the output end of the fourth diode and the input end of the third diode through the third capacitor respectively; and the fourth capacitor is respectively connected with the output end of the third diode and the input end of the fourth diode.
Further, the transformer is a high-frequency transformer;
the transformer comprises two primary windings and a secondary winding; the input end of the sixth diode is connected with the common end of the two primary windings of the transformer; and the output end of the fifth diode is connected with the output end of the first diode.
Further, the battery pack system comprises a battery pack, an isolating switch, a soft start switch, a resistor and a BMS;
the positive electrode of the battery pack is connected with the common end of the isolating switch and the soft start switch through a fuse; the negative pole of the battery pack is connected with the DC/DC regulator;
the isolating switch is connected with the soft start switch in parallel and used for cutting off the connection between the battery cell and a load or a power supply so as to protect the safety of the battery pack system; the soft start switch is connected with the resistor in series and is used for slowly starting the output voltage of the battery pack system;
the common end of the resistor and the isolating switch is connected with the DC/DC regulator;
the BMS is used for sampling voltage and current of each battery cell in the series battery pack, sampling temperature of each component in the battery pack system, and generating driving signals of the isolating switch and the soft start switch.
Further, the battery pack includes a plurality of battery cells connected in series.
The invention also discloses a control method of the battery pack system, which is applied to any one of the battery pack systems, and the method comprises the following steps:
step 1: acquiring a power value in the DC/DC regulator and a voltage value at two ends of a second capacitor;
step 2: and obtaining control signals of the DC/DC regulator and the DC transformer DCX based on the power value, the voltage value at two ends of the second capacitor, the reference power value and the reference voltage.
Further, the obtaining the power value in the DC/DC regulator includes:
acquiring a current value flowing through a first inductor and voltage values at two ends of a first capacitor in the DC/DC regulator to obtain corresponding power values;
the step 2 comprises the following steps:
step 21: subtracting the power value from the reference power value, and inputting the subtraction result into a power regulator; subtracting the reference voltage from the voltage value at the two ends of the capacitor, and inputting the subtraction result into the voltage regulator;
step 22: acquiring the minimum value of output results of the power regulator and the voltage regulator;
step 23: subtracting the minimum value from a current value obtained from the DC/DC regulator, and inputting the subtraction result to the current regulator;
step 24: an output signal of the current regulator is obtained.
Further, the output signals in step 24 are control signals for turning on or turning off the fifth switch and the sixth switch in the DC/DC regulator and the first switch, the second switch, the third switch and the fourth switch in the DC transformer DCX.
Due to the adoption of the technical scheme, the invention has the following advantages: the DC/DC regulator, the DC transformer DCX circuit and the control method of the corresponding circuit are added in the traditional battery pack, so that the flexible configuration of the output voltage, the cell capacity and the series quantity of the battery pack is realized, the high efficiency of a battery pack system can be kept, the control system is simple and low in cost, the requirement on a PCS interface is greatly reduced, the requirements of multiple battery packs on direct parallel connection and direct hanging of PCS buses are met, and great convenience is provided for capacity expansion of an energy storage system.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments described in the embodiments of the present invention, and it is obvious for those skilled in the art that other drawings may be obtained according to the drawings.
Fig. 1 is a schematic diagram of a battery pack system according to an embodiment of the invention;
fig. 2 is a schematic diagram of a dc-dc converter and a dc transformer of a battery pack and a connection relationship with a controller according to an embodiment of the invention;
FIG. 3 is a schematic diagram of a DC-DC converter control method according to an embodiment of the present invention;
fig. 4 is a control block diagram of a dc transformer according to an embodiment of the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and examples, it being understood that the examples described are only some of the examples and are not intended to limit the invention to the embodiments described herein. All other embodiments available to those of ordinary skill in the art are intended to be within the scope of the embodiments of the present invention.
At present, the battery capacity requirement of a user for energy storage is generally 5-30kwh, and different battery capacities are required by the client according to different client application scenes in different regions. However, the grid voltage is usually 220/380VAC, which results in that different battery configurations are required to be applied in the same grid voltage system, either the efficiency of battery charging and discharging is sacrificed, or a converter for adjusting the output impedance of the battery is added to the battery interface, so as to realize the high-efficiency charging and discharging of different battery configurations to the unified grid system. At present, a primary battery converter is added in a converter in a mainstream manner so as to meet the requirement that the converter adapts to different client battery pack configurations. This method is low cost and therefore widely used. But the most obvious problem is that the battery configuration of part of users causes low system efficiency, and the capacity limit of the single battery is also large, for example, the battery pack which limits 51v voltage is below 50 Ah. The charging and discharging of the 100AH battery are limited or even impossible. This seriously affects the adaptation problem between the converter and the battery, and thus indirectly affects the economic efficiency of the energy storage system.
Under the condition, the battery pack system avoids the problems, can effectively adjust the output impedance characteristic of the battery, and can efficiently meet the requirements of different batteries on a uniform power grid system.
Referring to fig. 1, a battery pack system of the present invention is applied to a low-voltage large-capacity battery pack with a BMS function, the system including: the battery pack comprises a battery pack with N +1 battery saving cores connected in series, a FUSE FUSE, an isolating switch K1, a soft start switch K2, a resistor R1, a DC/DC regulator, a DC transformer DCX, a BMS and a controller. The input end of the DC/DC regulator is connected with the output end of the battery pack system, and the output end of the DC/DC regulator is connected with the input end of the direct current transformer DCX; the controller is respectively connected with the DC/DC regulator and the DC transformer DCX;
the control unit is used for acquiring current flowing through the inductor and first voltage at two ends of the capacitor in the DC/DC regulator so as to obtain a corresponding power value;
the control unit is further configured to obtain a second voltage across a capacitor located between the output terminals of the DC/DC regulator;
the control unit is further configured to output a signal for controlling charging or discharging of the DC/DC regulator and the DC transformer DCX based on the power value and the second voltage.
The battery pack with the N +1 electricity-saving cores connected in series forms the required battery capacity, wherein the capacity of the single electricity-saving core can flexibly select the electricity core scheme with the optimal electricity consumption cost on the market, so that the optimal cost performance of the whole battery pack and the energy storage system is ensured.
The FUSE is used for ensuring the safety of the battery pack during fault, and can disconnect the battery core under extreme conditions to avoid out of control;
the isolating switch K1 is used for cutting off the connection between the battery cell and a load or a power supply, and ensures that the battery pack can effectively perform protection actions such as overcharge, overdischarge, overcurrent, short circuit and the like;
the soft start switch K2 and the resistor R1 are used for slowly starting the output voltage of the battery pack;
the BMS control unit is used for sampling voltage and current of each battery cell in series, sampling temperature of each component of the battery pack, generating a driving signal of the isolating switch and the soft start switch, and simultaneously realizing functions of SOC, SOH, balance control, over-charge and discharge protection, over-temperature protection and the like on the battery cells.
The DC/DC regulator is used for regulating the voltage of the battery pack, realizing the charging and discharging of the battery pack and the characteristic regulation of the output port of the battery pack, and meeting the requirements of direct parallel connection of a plurality of battery pack outputs and parallel connection of the battery pack outputs and a PCS direct current bus.
The direct current transformer DCX is used for high-rate direct current voltage conversion so as to meet the flexible configuration of the interface voltage of the battery pack and the voltage of the battery pack and keep the system efficient.
The controller unit is used for sampling voltage and current of the DC/DC regulator and the DC transformer DCX, driving signals of the semiconductor device, and realizing the functions of controlling the output voltage and current and power of the battery pack, protecting faults and the like for the DC/DC regulator and the DC transformer DCX.
The battery pack outputs positive and negative B + B-, the DC/DC regulator outputs positive and negative DCLINK + DCLINK-, and the direct current transformer DCX outputs positive and negative ends P + P-.
The output of the battery pack is connected with positive and negative B + B-which are connected with the input of the DC/DC regulator, the output of the DC/DC regulator is connected with DCLINK + DCLINK-which is connected with the input of a direct current transformer DCX, and the output of the direct current transformer DCX is connected with the output of the battery pack P + P-. And the controller is connected with the BMS module through a communication line and is respectively connected with the DC/DC regulator and the DC transformer DCX through a sampling signal and a driving signal, wherein the sampling signal comprises a voltage and current sampling signal of the input and output interface.
Referring to fig. 2, the control unit is configured to obtain a current flowing through the inductor and a first voltage across the capacitor in the DC/DC regulator, so as to obtain a corresponding power value;
the control unit is also used for acquiring a second voltage at two ends of a capacitor positioned between the output ends of the DC/DC regulator;
the control unit is further configured to output a signal for controlling the charging or discharging of the DC/DC regulator and the DC transformer DCX based on the power value and the second voltage.
The control unit comprises a first differentiator, a power regulator connected with the first differentiator, a second differentiator, a voltage regulator connected with the second differentiator, a first comparator, a third differentiator connected with the first comparator and a current regulator connected with the third differentiator;
the first differentiator is used for subtracting the reference power from the power value and inputting the difference value into the power regulator;
the second difference device is used for subtracting the difference value of the second voltage and the reference voltage and inputting the difference value into the voltage regulator;
the first comparator is used for comparing the output quantities of the power regulator and the voltage regulator and outputting the minimum value to the third differentiator;
the third differentiator is used for making a difference between the output quantity of the third differentiator and the current in the DC/DC regulator and inputting the difference into the current regulator;
the current regulator is used for outputting control signals to control the fifth switch and the sixth switch in the DC/DC regulator and the first switch, the second switch, the third switch and the fourth switch in the DC transformer DCX to be turned on or turned off.
The DC/DC regulator comprises a first capacitor, a current sensor, a first inductor, a fifth switch, a fifth diode, a sixth switch, a sixth diode and a second capacitor;
the first capacitor is connected with one end of the first inductor through the current sensor; the other end of the first inductor is connected with the input end of the fifth diode and the output end of the sixth diode respectively;
the fifth diode and the sixth diode are connected in series; the fifth switch and the sixth switch are respectively connected with the fifth diode and the sixth diode in parallel; and the second capacitor is respectively connected with the output end of the fifth diode and the input end of the sixth diode.
The direct current transformer DCX comprises a first switch with a reverse first diode, a second switch with a reverse second diode, a third switch with a reverse third diode and a fourth switch with a reverse fourth diode;
the direct current transformer DCX also comprises a transformer, a second inductor, a third capacitor and a fourth capacitor;
one end of a primary winding of the transformer is connected with the input end of the first diode; the other end of the primary winding of the transformer is connected with the input end of a second diode; one end of a secondary winding of the transformer is connected with one end of the second inductor; the other end of the secondary winding of the transformer is connected with the input end of a fourth diode; the other end of the second inductor is connected with the output end of the fourth diode and the input end of the third diode through a third capacitor; and the fourth capacitor is respectively connected with the output end of the third diode and the input end of the fourth diode.
Wherein the transformer is a high-frequency transformer;
the transformer comprises two primary windings and a secondary winding; the input end of the sixth diode is connected with the common end of the two primary windings of the transformer; and the output end of the fifth diode is connected with the output end of the first diode.
Referring to fig. 3 and 4, the DC/DC regulator uses a conventional DC/DC converter topology, such as BUCK, BOOST, and other DC/DC converters with a voltage stabilizing function. It includes inductor current sampling, input and output voltage sampling, and switch drive signals. The control module comprises a power regulator, a voltage regulator and a current regulator. And obtaining a power measurement value Pmeas through voltage and current sampling calculation, then making a difference with Pref, and inputting the difference to the power regulator. The method comprises the steps of obtaining a voltage measured value through voltage sampling, making a difference with a voltage given value Vref, inputting the voltage measured value into a voltage regulator, making a difference between the voltage measured value Imeas and a current measured value Imeas through comparing the output of the voltage regulator and the output of the current regulator, inputting the difference into the current regulator, and generating a PWM (pulse width modulation) driving signal through operation by the current regulator so as to control the fifth switch and the sixth switch in the DC/DC regulator and the first switch, the second switch, the third switch and the fourth switch in a DC transformer DCX to be conducted or closed.
The DCX dc transformer uses commonly used dc transformer topologies such as LLC, CLLC, charge pump, SRC, etc. Including but not limited to the drive signal of the power switch tube. The driving signal of the power tube is generated by adopting a mode of fixing the switching frequency or the duty ratio, so that the converter has the characteristic of a direct current transformer, and the input voltage and the output voltage of the converter meet the set transformation ratio.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (10)

1. A battery pack system is characterized by comprising a DC/DC regulator, a DC transformer DCX, a control unit and a battery pack system; the input end of the DC/DC regulator is connected with the output end of the battery pack system, and the output end of the DC/DC regulator is connected with the input end of the direct current transformer DCX; the controller is respectively connected with the DC/DC regulator and the DC transformer DCX;
the control unit is used for acquiring current flowing through an inductor in the DC/DC regulator and first voltage at two ends of a capacitor so as to obtain a corresponding power value;
the control unit is further configured to obtain a second voltage across a capacitor located between the output terminals of the DC/DC regulator;
the control unit is further configured to output a signal for controlling charging or discharging of the DC/DC regulator and the DC transformer DCX based on the power value and the second voltage.
2. The battery pack system of claim 1, wherein the control unit comprises a first differentiator, a power regulator connected to the first differentiator, a second differentiator, a voltage regulator connected to the second differentiator, a first comparator, a third differentiator connected to the first comparator, and a current regulator connected to the third differentiator;
the first differentiator is used for subtracting the reference power from the power value and inputting the difference value into the power regulator;
the second difference device is used for subtracting the difference value of the second voltage and the reference voltage and inputting the difference value into the voltage regulator;
the first comparator is used for comparing the output quantities of the power regulator and the voltage regulator and outputting the minimum value to the third differentiator;
the third differentiator is used for making a difference between the output quantity of the third differentiator and the current in the DC/DC regulator, and inputting the difference into the current regulator;
the current regulator is configured to output a control signal to control the fifth switch and the sixth switch in the DC/DC regulator and the first switch, the second switch, the third switch, and the fourth switch in the DC transformer DCX to be turned on or off.
3. The battery pack system of claim 2, wherein the DC/DC regulator comprises a first capacitor, a current sensor, a first inductor, a fifth switch, a fifth diode, a sixth switch, a sixth diode, a second capacitor;
the first capacitor is connected with one end of the first inductor through the current sensor; the other end of the first inductor is connected with the input end of the fifth diode and the output end of the sixth diode respectively;
the fifth diode and the sixth diode are connected in series; the fifth switch and the sixth switch are respectively connected with the fifth diode and the sixth diode in parallel; and the second capacitor is respectively connected with the output end of the fifth diode and the input end of the sixth diode.
4. The battery pack system of claim 3, wherein the DC transformer DCX comprises a first switch with a first diode in reverse, a second switch with a second diode in reverse, a third switch with a third diode in reverse, and a fourth switch with a fourth diode in reverse;
the direct current transformer DCX further comprises a transformer, a second inductor, a third capacitor and a fourth capacitor;
one end of a primary winding of the transformer is connected with the input end of the first diode; the other end of the primary winding of the transformer is connected with the input end of the second diode; one end of the secondary winding of the transformer is connected with one end of the second inductor; the other end of the secondary winding of the transformer is connected with the input end of the fourth diode; the other end of the second inductor is connected with the output end of the fourth diode and the input end of the third diode through the third capacitor; and the fourth capacitor is respectively connected with the output end of the third diode and the input end of the fourth diode.
5. The battery pack system of claim 4, wherein the transformer is a high frequency transformer;
the transformer comprises two primary windings and a secondary winding; the input end of the sixth diode is connected with the common end of the two primary windings of the transformer; and the output end of the fifth diode is connected with the output end of the first diode.
6. The battery pack system of claim 1, wherein the battery pack system comprises a battery pack, a disconnector, a soft start switch, a resistor, and a BMS;
the positive electrode of the battery pack is connected with the common end of the isolating switch and the soft start switch through a fuse; the negative pole of the battery pack is connected with the DC/DC regulator;
the isolating switch is connected with the soft start switch in parallel and used for cutting off the connection between the battery cell and a load or a power supply so as to protect the safety of the battery pack system; the soft start switch is connected with the resistor in series and is used for slowly starting the output voltage of the battery pack system;
the common end of the resistor and the isolating switch is connected with the DC/DC regulator;
the BMS is used for sampling voltage and current of each battery cell in the series battery pack, sampling temperature of each component in the battery pack system, and generating driving signals of the isolating switch and the soft start switch.
7. The battery pack system of claim 6, wherein the battery pack comprises a plurality of battery cells connected in series.
8. A control method of a battery pack system, which is applied to the battery pack system according to any one of claims 1 to 7, the method comprising:
step 1: acquiring a power value in the DC/DC regulator and a voltage value at two ends of a second capacitor;
and 2, step: and obtaining control signals of the DC/DC regulator and the DC transformer DCX based on the power value, the voltage value at two ends of the second capacitor, the reference power value and the reference voltage.
9. The method of claim 8, wherein obtaining the power value in the DC/DC regulator comprises:
acquiring a current value flowing through a first inductor and voltage values at two ends of a first capacitor in the DC/DC regulator to obtain corresponding power values;
the step 2 comprises the following steps:
step 21: subtracting the reference power value from the power value, and inputting the subtraction result into the power regulator; subtracting the reference voltage from the voltage value at the two ends of the capacitor, and inputting the subtraction result into the voltage regulator;
step 22: acquiring the minimum value of output results of the power regulator and the voltage regulator;
step 23: subtracting the minimum value from a current value obtained from the DC/DC regulator, and inputting the subtraction result to the current regulator;
step 24: an output signal of the current regulator is obtained.
10. The method according to claim 9, wherein the output signals in step 24 are control signals for turning on or turning off the fifth switch and the sixth switch in the DC/DC regulator and the first switch, the second switch, the third switch, and the fourth switch in the DC transformer DCX.
CN202211001471.5A 2022-08-19 2022-08-19 Battery pack system and control method thereof Pending CN115296370A (en)

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