CN210760284U - Electric automobile driving system and driving circuit - Google Patents

Electric automobile driving system and driving circuit Download PDF

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Publication number
CN210760284U
CN210760284U CN201920537692.1U CN201920537692U CN210760284U CN 210760284 U CN210760284 U CN 210760284U CN 201920537692 U CN201920537692 U CN 201920537692U CN 210760284 U CN210760284 U CN 210760284U
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battery
battery pack
circuit
bridge arm
cells
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李亚伦
郭东旭
欧阳明高
卢兰光
杜玖玉
李建秋
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Tsinghua University
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Tsinghua University
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    • 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
    • Y02T10/64—Electric machine technologies in electromobility
    • 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

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  • Electric Propulsion And Braking For Vehicles (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The application provides an electric automobile driving system and a driving circuit. The driving circuit comprises a power supply unit and an inverter circuit. The power supply unit includes two battery packs. The inverter circuit includes three bridge arms. One end of the first battery pack is connected with the upper bridge arm of the first bridge arm through a first bus. And one end of the second battery pack is respectively connected with the upper bridge arm of the second bridge arm and the upper bridge arm of the third bridge arm through a second bus. The other end of each battery is collinear with the other end of the other battery. And the lower bridge arms of the three bridge arms are collinear. The collinear lower bridge arm is connected with the collinear end of the battery pack. The two battery packs are independent of each other, so that the driving circuit has more degrees of freedom. The driving circuit can realize the heating function and the parking balance function of the battery on the basis of not adding other devices.

Description

Electric automobile driving system and driving circuit
Technical Field
The application relates to the field of new energy automobiles, in particular to an electric automobile driving system and a driving circuit.
Background
The characteristics of the lithium battery are degraded at low temperature. In winter or cold areas, the battery is heated firstly during the use process of the electric automobile, so that the driving range and the charging performance of the electric automobile can be improved.
In the traditional scheme, the heating scheme of the battery pack comprises the step of carrying out external heating on the battery through a charger/charging pile, but the scheme is only available when the electric automobile is charged, and the problem of low-temperature shelving starting when the electric automobile is not connected with the charging pile cannot be solved. In the traditional scheme, the heating scheme of the battery pack also comprises a method of adding a heating nickel sheet into the battery, but the scheme reduces the energy density of the battery, improves the cost of the battery and has certain safety risk.
In the conventional scheme, the heating scheme of the battery pack further comprises installing a heating element in the battery pack, and raising the temperature of the battery by means of external heating. This increases the cost of the battery and the heating efficiency and heating power are not high.
SUMMERY OF THE UTILITY MODEL
In view of the above, it is necessary to provide a driving system and a driving circuit for an electric vehicle, which are aimed at the problem of low heating power and heating efficiency of the conventional battery pack.
A drive circuit, comprising:
a power supply unit including a first battery pack and a second battery pack; and
the inverter circuit comprises a first bridge arm, a second bridge arm and a third bridge arm;
a first electrode of the first battery pack is connected with an upper bridge arm of the first bridge arm through a first bus, and a first electrode of the second battery pack is respectively connected with an upper bridge arm of the second bridge arm and an upper bridge arm of the third bridge arm through a second bus;
the second electrode of the first battery and the second electrode of the second battery are collinear to form a first end;
the lower bridge arm of the first bridge arm, the lower bridge arm of the second bridge arm and the lower bridge arm of the third bridge arm are collinear to form a second end;
the first end is connected with the second end bus.
An electric vehicle drive system comprising:
the drive circuit of any of the above embodiments;
the battery management circuit is electrically connected with the driving circuit;
the first controller is electrically connected with the driving circuit; and
and the second detection circuit is electrically connected with the first controller.
The application provides an electric automobile driving system and a driving circuit. The driving circuit comprises a power supply unit and an inverter circuit. The power supply unit includes two battery packs. The inverter circuit includes three bridge arms. One end of the first battery pack is connected with the upper bridge arm of the first bridge arm through a first bus. And one end of the second battery pack is respectively connected with the upper bridge arm of the second bridge arm and the upper bridge arm of the third bridge arm through a second bus. The other end of each battery is collinear with the other end of the other battery. And the lower bridge arms of the three bridge arms are collinear. The collinear lower bridge arm is connected with the collinear end of the battery pack. The two battery packs are independent of each other, so that the driving circuit has more degrees of freedom. The driving circuit can realize the heating function and the parking balance function of the battery on the basis of not adding other devices.
Drawings
Fig. 1 is a driving circuit diagram according to an embodiment of the present application;
fig. 2 is a driving circuit diagram according to an embodiment of the present application;
FIG. 3 is a diagram of an electric vehicle drive system according to an embodiment of the present application;
FIG. 4 is a diagram of an electric vehicle drive system according to an embodiment of the present application;
fig. 5 is a flowchart illustrating a battery heating process of an electric vehicle according to an embodiment of the present application;
fig. 6 is a flowchart illustrating a battery heating process of an electric vehicle according to an embodiment of the present application;
fig. 7 is a flowchart illustrating a battery heating process of an electric vehicle according to an embodiment of the present application;
fig. 8 is a graph of a battery current according to an embodiment of the present application.
Description of the main element reference numerals
Drive circuit 100 second bypass switch 130 battery management circuit 40
First detection circuit 41 of inverter circuit 20 of power supply unit 10
First bridge arm 21 voltage detection unit 411 of first battery pack 11
Second leg 22 current detection unit 412 of second battery pack 12
Temperature monitoring unit 413 of third bridge arm 23 of state switch 140
First end 101 second end 201 second controller 42
Battery unit 110 power switching device 211 first controller 50
Second detection circuit 60 of electric core 111 three-phase motor 30
First bypass switch 120 electric vehicle drive system 200
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and those skilled in the art will be able to make similar modifications without departing from the spirit of the application and it is therefore not intended to be limited to the embodiments disclosed below.
It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, an embodiment of the present application provides a driving circuit 100. The driving circuit 100 includes a power supply unit 10 and an inverter circuit 20.
The power supply unit 10 includes a first battery pack 11 and a second battery pack 12. Inverter circuit 20 includes a first leg 21, a second leg 22, and a third leg 23. The first electrode of first battery pack 11 is connected to the upper arm bus of first arm 21. The first electrode of the second battery pack 12 is connected to the upper arm bus of the second arm 22 and the upper arm bus of the third arm 23, respectively. The second electrode of the first cell stack 11 and the second electrode of the second cell stack 12 are collinear to form a first end 101. The lower leg of first leg 21, the lower leg of second leg 22, and the lower leg of third leg 23 are collinear to form a second end 201. The first end 101 is busbar connected to the second end 201. The first battery pack 11 has an equivalent resistance R1. The second battery pack 12 has an equivalent resistance R2.
The first electrode may be a positive electrode of a battery. The first electrode may also be the negative electrode of the battery. The second electrode may be a positive electrode of the battery. The second electrode may also be the negative electrode of the battery. When the positive electrode of the first cell group 11 and the positive electrode of the second cell group 12 are first electrodes. Only one end of the three arms of the inverter 20 is connected in parallel to the same potential point. Two of the three bridge arms are connected in parallel to the same potential point at the other end. The other end of the remaining one of the three bridge arms is independently connected to another potential point.
In this embodiment, the power supply unit 10 includes two battery packs. The inverter circuit 20 includes three bridge arms. One end of first battery pack 11 is connected to the upper arm of first arm 21 via a first bus bar. One end of the second battery pack 12 is connected to the upper arm of the second arm 22 and the upper arm of the third arm 23 through a second bus bar. The other end of one cell group is collinear with the other end of the other cell group. And the lower bridge arms of the three bridge arms are collinear. The collinear lower bridge arm is connected with the collinear end of the battery pack. The two battery packs are independent of each other, so that the driving circuit 100 has more degrees of freedom. The driving circuit 100 can realize the heating function and the parking balance function of the battery without adding other devices. The driving circuit 100 includes two battery packs, and compared with a conventional three-battery-pack power supply mode, the power supply implementation mode in this embodiment reduces one battery pack, so that one voltage sampling circuit can be reduced, and the cost of the battery management system can be reduced to a certain extent.
Referring to fig. 2, in an embodiment, the driving circuit 100 further includes a state switch 140. The state switch 140 is disposed between the first bus bar and the second bus bar. The driving circuit 100 may be provided as an electric vehicle driving circuit. When the electric vehicle is in a driving state, the state changeover switch 140 is closed. When the electric vehicle is in the low-temperature heating state, the state changeover switch 140 is turned off.
In this embodiment, when the electric vehicle is in different states, the relationship between the power supply unit 10 and the inverter circuit 20 can be effectively changed by the state switch 140. When the electric vehicle is in a driving state, the state changeover switch 140 is closed. At this time, the upper arms of the three arms of the inverter circuit 20 are collinear. The lower arms of the three arms of the inverter circuit 20 are collinear. At this time, the driving of the electric vehicle can be realized by controlling the inverter circuit 20 through a conventional vector, which reduces the cost of controlling the inverter circuit 20. When the electric vehicle is in a low-temperature heating state and needs to heat the battery pack in the power supply unit 10, the state switch 140 is turned off. At this time, only one end of the three arms of the inverter 20 is connected in parallel to the same potential point. Two of the three bridge arms are connected in parallel to the same potential point at the other end. The other end of the remaining one of the three bridge arms is independently connected to another potential point. The two battery packs are independent of each other, so that the driving circuit has more degrees of freedom. The driving circuit 100 can realize the heating function of the battery without adding other devices.
In one embodiment, each battery pack in the power supply unit 10 includes one battery cell 110 and one first bypass switch 120.
One of the battery cells 110 and one of the first bypass switches 120 are connected in series. The power supply unit 10 includes a plurality of battery cells 111 therein. The types and nominal capacities of the plurality of battery cells 111 may be the same. The plurality of cells 111 may be divided into three groups on average. A plurality of battery cells 111 in each group are connected to each other to form one battery unit 110. The connection manner of the battery cells 111 in one battery unit 110 is the same as that of the battery cells 111 in the other two battery units 110. The connection mode is one of a plurality of the battery cells 111 being connected in series, a plurality of the battery cells 111 being connected in series after being connected in parallel, a plurality of the battery cells 111 being connected in parallel, or a plurality of the battery cells 111 being connected in parallel after being connected in series.
The first bypass switch 120 may be a relay. The first bypass switch 120 may also be a switch circuit formed by connecting a relay and a pre-charge group connected in series in parallel. The first bypass switch 120 is one of an electromagnetic relay, an insulated gate bipolar transistor, or a metal-oxide semiconductor field effect transistor.
In this embodiment, each battery pack is connected to a first bypass switch 120, so that each battery pack can be independently controlled. When one of the battery packs fails, the isolation of the failed battery pack from the normal battery pack can be achieved by opening the first bypass switch 120 connected to the failed battery pack
In one embodiment, the driving circuit 100 further comprises a second bypass switch 130.
The second bypass switch 130 is electrically connected between the first end 101 and the second end 201. The second bypass switch 130 may be a relay. The second bypass switch 130 may also be a switch circuit formed by connecting a relay in parallel with a pre-charge relay and a pre-charge group connected in series. The second bypass switch 130 is one of an electromagnetic relay, an insulated gate bipolar transistor, or a metal-oxide semiconductor field effect transistor. By turning off the second bypass switch 130, the power supply unit 10 and the inverter circuit 20 can be disconnected.
In one embodiment, each leg of the inverter circuit 20 includes two power switches 211 connected in series.
The collector terminal of one 211 of the two series-connected power switches 211 is connected to the positive bus of one battery. The emitter terminal of the other power switch 211 of the two series-connected power switches 211 is connected to the negative bus of one battery. One power switching device 211 of each leg may constitute an upper leg of one leg. The other power switch device 211 of each leg may form the lower leg of one leg. The bridge arm can be an insulated gate bipolar transistor. The three-phase output ends of the inverter circuit 20 are respectively connected to a three-phase bus W, U, V of the three-phase motor 30. The three-phase motor 30 may be a three-phase synchronous motor. The three-phase motor 30 may also be a three-phase asynchronous motor. The inverter circuit 20 may output a frequency as high as several hundreds of thousands of cycles, and may realize driving of motors of various rotation speeds in the driving circuit 100.
Referring to fig. 3, an embodiment of the present application provides an electric vehicle driving system 200. The electric vehicle driving system 200 includes a driving circuit 100, a battery management circuit 40, a first controller 50, and a second detection circuit 60.
The battery management circuit 40 is electrically connected to the driving circuit 100. The first controller 50 is electrically connected to the driving circuit 100. The second detection circuit 60 is electrically connected to the first controller 50. The driving circuit 100 in this embodiment is similar to the driving circuit 100 in the above embodiments, and is not described herein again. The battery management circuit 40 is configured to detect a state of charge of the power supply unit 10 and an operating state of the power supply unit 10. The battery management circuit 40 is also configured to manage the power supply unit 10. For example, the battery management circuit 40 may control the opening and closing of the first bypass switch 120 and the second bypass switch 130 in the power supply unit 10. The first controller 50 is configured to control the inverter circuit 20 to fixedly turn on the power switch device 211 combination. The battery management circuit 40 is electrically connected to the first controller 50 through an isolation signal circuit. The second detection circuit 60 is configured to detect an induced current of the three-phase motor 30. The second detection circuit 60 is further configured to report amplitude information of the induced current to the first controller 50. The first controller 50 may control the inverter circuit 20 according to the amplitude information.
In this embodiment, the electric vehicle driving system 200 includes a driving circuit 100, a battery management circuit 40, and a first controller 50. The power supply unit 10 in the driving circuit 100 includes two battery packs. The inverter circuit 20 includes three bridge arms. One end of first battery pack 11 is connected to the upper arm of first arm 21 via a first bus bar. One end of the second battery pack 12 is connected to the upper arm of the second arm 22 and the upper arm of the third arm 23 through a second bus bar. The other end of one cell group is collinear with the other end of the other cell group. And the lower bridge arms of the three bridge arms are collinear. The collinear lower bridge arm is connected with the collinear end of the battery pack. The two battery packs are independent of each other, so that the driving circuit 100 has more degrees of freedom. The electric vehicle driving system 200 can realize the driving function, the heating function and the parking balancing function of the electric vehicle battery on the basis of not adding other devices.
Referring to fig. 4, in one embodiment, the electric vehicle has a control center. The battery management circuit 40 includes a first detection circuit 41 and a second controller 42.
The first detection circuit 41 includes a voltage detection unit 411, a current detection unit 412, and a temperature detection unit 413, and the voltage detection unit 411, the current detection unit 412, and the temperature detection unit 413 are electrically connected to the power supply unit 10, respectively. The second controller 42 is electrically connected to the power supply unit 10.
The first detection circuit 41 reports the detected voltage, current and temperature signals to the control center of the electric vehicle. The control center controls driving, braking, heating, and parking equalization of the driving circuit 100 through the first controller 50 and the second controller 42 according to the received signal. The battery management circuit 40 can realize fast and efficient detection of the performance parameters of the two battery packs in the power supply unit 10 through the first detection circuit 41 and the second controller 42.
Referring to fig. 5, an embodiment of the present application provides a method for heating a battery of an electric vehicle. The electric vehicle battery heating method is realized by adopting the electric vehicle driving system 200. The electric vehicle battery heating method comprises the following steps:
and S10, before the electric automobile is started, judging whether the electric automobile needs to be heated by the battery management circuit 40. In step S10, whether the electric vehicle is in a low-temperature heating state may be determined by detecting the temperature of the battery electric core.
S20, when it is determined that the electric vehicle needs to be heated, the first controller 50 controls the inverter circuit 20 to charge the first battery pack 11 to the second battery pack 12. In step S20, by controlling the switching states of the three arms of the inverter circuit 20, the first battery pack 11 can charge the three-phase motor 30 first, and then the first battery pack 11 and the three-phase motor 30 charge the second battery pack 12 together. In this process, the first battery pack 11 charges the second battery pack 12 as a whole, except for the necessary power consumption.
S30, when the charging time from the first battery pack 11 to the second battery pack 12 reaches a first time threshold, the first controller 50 controls the inverter circuit 20 to charge the second battery pack 12 to the first battery pack 11, and the power supply unit 10 polarizes itself during the charging and discharging processes, so as to realize controllable temperature rise of each battery pack in the power supply unit 10.
In step S30, the second battery pack 12 is first charged to the three-phase motor 30, and then the second battery pack 12 and the three-phase motor 30 are charged together to the first battery pack 11 by controlling the switching states of the three arms of the inverter circuit 20. In this process, the second battery pack 12 charges the first battery pack 11 as a whole, except for the necessary power consumption.
In this embodiment, in the method for heating the battery of the electric vehicle, the first controller 50 controls the three arms of the inverter circuit 20 to be opened and closed, so as to complete energy output and energy recovery of the power supply unit 10, and further polarize the power supply unit 10, thereby realizing controllable temperature rise of the battery of the power supply unit 10. The maximum operating current of the power switching device 211 in the inverter circuit 20 and the maximum operating current of the three-phase motor 30 are high. The heating method of the electric vehicle battery can realize high-power heating and effectively improve the heating efficiency. The power switching device 211 serves as a control element, and the three-phase motor 30 serves as an energy storage element. And a special heating element is not required to be added in the battery heating process, so that the cost of the power system of the electric automobile is reduced. The electric vehicle battery heating method achieves electric quantity balance among the battery packs while heating the battery packs.
Referring to fig. 6, in one embodiment, the driving circuit 100 further includes a three-phase motor 30, and each phase bus of the three-phase motor 30 is connected to an output end of one of the bridge arms; the three-phase motor 30 is electrically connected to the second detection circuit 60. The first leg 21 is configured as a first working leg. One of the second leg 22 and the third leg 23 is set as a second working leg. The other of the second leg 22 and the third leg 23 remains open. In an alternative embodiment, the selection of the second operating leg is determined by the rotor position of the electric machine, and the leg connected to the ac busbar close to the rotor orientation position is selected as the second operating leg. In the process of heating the battery pack, the movement amplitude of the motor rotor is small, and the possibility of wheel movement during parking heating is reduced.
In step S20, after it is determined that the electric vehicle needs to be heated, the step of controlling the inverter circuit 20 by the first controller 50 to charge the first battery pack 11 to the second battery pack 12 includes:
s21, the first controller 50 controls the upper arm of the first working arm and the lower arm of the second working arm to be connected, so that the first battery 11 charges the three-phase motor 30.
In step S21, the forward current of the three-phase motor 30 is increased, and as shown in fig. 8, the current may be increased from position 0 to position 1. The current change process in step S21 satisfies the following equation:
Figure BDA0002033535480000111
wherein E is1Is the open circuit voltage of the first sub-battery. R1Is the internal resistance of the first battery. L is the working inductance of the drive motor in the heating process, RLIs the loop resistance during heating.
S22, detecting whether the magnitude of the current in the three-phase motor 30 is greater than or equal to the target heating current upper threshold value by the second detection circuit 60. In step S22, the target heating current upper threshold may be determined according to the performance of the battery and the current endurance capability of the power switch assembly 211 in the inverter circuit 20.
S23, when the current amplitude of the three-phase motor 30 is greater than or equal to the target heating current upper threshold, controlling the lower arm of the second operating arm to be turned off and controlling the upper arm of the second operating arm to be turned on by the first controller 50, so that the first battery pack 11 and the three-phase motor 30 charge the second battery pack 12.
In step S23, the first battery pack 11 and the three-phase motor 30 are discharged, and the second battery pack 12 is charged. The forward current to the three-phase motor 30 is reduced. As shown in fig. 8, the current drops from position 1 to position 2. The current change process in step S23 satisfies the following equation:
Figure BDA0002033535480000112
wherein E is2Open circuit voltage for the second sub-battery. R2Is the internal resistance of the second battery.
In S23, when the current amplitude of the three-phase motor 30 is greater than or equal to the target heating current upper threshold, the step of controlling the lower arm of the second operating arm to be turned off and controlling the upper arm of the second operating arm to be turned on by the first controller 50 so that the first battery pack 11 and the three-phase motor 30 charge the second battery pack 12 includes:
whether the current amplitude in the three-phase motor 30 is less than or equal to a target heating current lower threshold is detected by the second detection circuit 60. When the current amplitude in the three-phase motor 30 is less than or equal to the target heating current lower threshold, the steps S21-S23 are repeated until the charging time of the first battery pack 11 to the second battery pack 12 reaches the first time threshold. As shown in FIG. 8, current travels from position 3 to position 3T+。
In this embodiment, by controlling the switching states of the three arms of the inverter circuit 20, a process in which the first battery pack 11 first charges the three-phase motor 30, and then the first battery pack 11 and the three-phase motor 30 together charge the second battery pack 12 can be realized. In this process, the method achieves the purpose of charging the second battery pack 12 with the first battery pack 11, except for the necessary consumption of electric power.
Referring to fig. 7, in one embodiment, in step S30, after the time that the first battery pack 11 charges the second battery pack 12 reaches the first time threshold, the first controller 50 controls the inverter circuit 20 to charge the second battery pack 12 to the first battery pack 11, and the power supply unit 10 polarizes itself during the charging and discharging processes, so as to realize the controllable temperature rise of each battery pack in the power supply unit 10, which includes:
s31, the first controller 50 controls the lower arm of the first working arm and the upper arm of the second working arm to be connected, so that the second battery pack 12 charges the three-phase motor 30.
In step S31, the positive current of the three-phase motor 30 decreases to zero, and then increases after a negative current is formed. As shown in fig. 8, the current may be drawn from location 3T+Travel to position 4. The current change process in step S31 satisfies the following equation:
Figure BDA0002033535480000121
wherein E is1Is the open circuit voltage of the first sub-battery. R1Is the internal resistance of the first battery. L is the working inductance of the drive motor in the heating process, RLIs the loop resistance during heating.
S32, the second detection circuit 60 detects whether the current amplitude of the three-phase motor 30 is greater than or equal to the target heating current upper threshold. In step S32, the target heating current upper threshold may be determined according to the performance of the battery and the current endurance capability of the power switch assembly 211 in the inverter circuit 20.
S33, when the current amplitude of the three-phase motor 30 is greater than or equal to the target heating current upper threshold, the first controller 50 controls the lower arm of the first operating arm to be turned off, and controls the upper arm of the first operating arm to be turned on, so that the second battery pack 12 and the three-phase motor 30 charge the first battery pack 11.
In step S33, the second battery pack 12 and the three-phase motor 30 are discharged, and the first battery pack 11 is charged. The negative current to the three-phase motor 30 is reduced. As shown in fig. 8, the current travels from position 4 to position 5. The current change process in step S33 satisfies the following equation:
Figure BDA0002033535480000131
wherein E is2Open circuit voltage for the second sub-battery. R2Is the internal resistance of the second battery.
In S33, when the current amplitude in the three-phase motor 30 is greater than or equal to the target heating current upper threshold, the step of controlling the lower arm of the first operating arm to be turned off and controlling the upper arm of the first operating arm to be turned on by the first controller 50 so that the second battery pack 12 and the three-phase motor 30 charge the first battery pack 11 includes:
whether the current amplitude in the three-phase motor 30 is less than or equal to a target heating current lower threshold is detected by the second detection circuit 60. When the current amplitude in the three-phase motor 30 is less than or equal to the target heating current lower threshold, the steps S31-S33 are repeated until the time for which the second battery pack 12 charges the first battery pack 11 reaches a second time threshold.
When the current amplitude in the three-phase motor 30 is less than or equal to the target heating current lower threshold, repeating steps S31-S33 until the step of charging the first battery pack 11 by the second battery pack 12 reaches a second time threshold, further comprising:
whether the cell temperature of the power supply unit 10 is less than a driving threshold temperature is detected by the battery management circuit 40. When the cell temperature is lower than the driving threshold temperature, repeating the steps S10-S30 until the cell temperature is higher than or equal to the driving threshold temperature or a heating stop instruction is received.
In this embodiment, the second battery pack 12 can first charge the three-phase motor 30 by controlling the switching states of the three arms of the inverter circuit 20. Next, a process in which the second battery pack 12 and the three-phase motor 30 together charge the first battery pack 11. In this process, the method achieves the purpose of charging the second battery pack 12 to the first battery pack 11, except for the necessary consumption of electric power.
In one embodiment, in S10, before the electric vehicle is started, the step of determining, by the battery management circuit 40, whether the electric vehicle needs to be heated by a battery includes:
whether the cell temperature of the power supply unit 10 is less than a driving threshold temperature is detected by the battery management circuit 40. And when the cell temperature is lower than the driving threshold temperature, confirming that the electric automobile needs to be heated by the battery. And when the cell temperature is greater than or equal to the driving threshold temperature, the electric automobile is normally started.
In this embodiment, whether the electric vehicle needs to perform low-temperature electric heating or not can be determined by detecting the magnitude relationship between the cell temperature and the driving threshold temperature.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A driver circuit (100), comprising:
a power supply unit (10) comprising a first battery pack (11) and a second battery pack (12); and
an inverter circuit (20) comprising a first leg (21), a second leg (22), and a third leg (23);
a first electrode of the first battery pack (11) is connected with an upper bridge arm of the first bridge arm (21) through a first bus bar, and a first electrode of the second battery pack (12) is respectively connected with an upper bridge arm of the second bridge arm (22) and an upper bridge arm of the third bridge arm (23) through a second bus bar;
a second electrode of the first battery (11) and a second electrode of the second battery (12) are collinear to form a first end (101);
the lower legs of said first leg (21), second leg (22) and third leg (23) being collinear to form a second end (201);
the first end (101) is busbar connected to the second end (201).
2. The driver circuit (100) of claim 1, further comprising:
a state switch (140) disposed between the first bus bar and the second bus bar.
3. The drive circuit (100) according to claim 1, wherein each battery pack in the power supply unit (10) comprises one battery cell (110) and one first bypass switch (120), one battery cell (110) and one first bypass switch (120) being connected in series.
4. The drive circuit (100) of claim 3, wherein each battery cell (110) comprises:
a plurality of cells (111), the number of cells (111) in one of the battery units (110) being the same as the number of cells (111) in another of the battery units (110);
the cells (111) in one of the battery units (110) are connected in the same manner as the cells (111) in the other battery unit (110).
5. The driving circuit (100) of claim 4, wherein the cells in the one battery unit are connected in one of a series connection of a plurality of the cells (111), a series connection of a plurality of the cells (111) after being connected in parallel, a parallel connection of a plurality of the cells (111), or a parallel connection of a plurality of the cells (111) after being connected in series.
6. The driver circuit (100) of claim 1, further comprising:
a second bypass switch (130) electrically connected between the first end (101) and the second end (201).
7. The drive circuit (100) of claim 6, wherein the second bypass switch (130) is one of an electromagnetic relay, an insulated gate bipolar transistor, or a metal-oxide semiconductor field effect transistor.
8. The driver circuit (100) of claim 1, wherein each leg of the inverter circuit (20) comprises:
the collector terminal of one power switch device (211) in the two power switch devices (211) connected in series is connected with the positive bus bar of one battery pack;
the emitter terminal of the other power switch device (211) of the two power switch devices (211) connected in series is connected with the negative bus bar of one battery pack.
9. An electric vehicle drive system (200), comprising:
the driver circuit (100) of any of claims 1-8;
a battery management circuit (40) electrically connected to the drive circuit (100);
a first controller (50) electrically connected to the drive circuit (100); and
a second detection circuit (60) electrically connected to the first controller (50).
10. The electric vehicle drive system (200) of claim 9, wherein the battery management circuit (40) comprises:
a first detection circuit (41) electrically connected to the power supply unit (10); and
a second controller (42) electrically connected to the power supply unit (10).
CN201920537692.1U 2019-04-19 2019-04-19 Electric automobile driving system and driving circuit Active CN210760284U (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110116653A (en) * 2019-04-19 2019-08-13 清华大学 Drive system of electric automobile, driving circuit and batteries of electric automobile heating means
CN113506934A (en) * 2021-06-24 2021-10-15 武汉理工大学 Lithium battery heating system and heating method
CN113928183A (en) * 2020-06-29 2022-01-14 比亚迪股份有限公司 Vehicle, energy conversion device, and control method therefor
WO2023168788A1 (en) * 2022-03-09 2023-09-14 宁德时代新能源科技股份有限公司 Power battery voltage regulation circuit and system, control method therefor and control apparatus thereof

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110116653A (en) * 2019-04-19 2019-08-13 清华大学 Drive system of electric automobile, driving circuit and batteries of electric automobile heating means
CN110116653B (en) * 2019-04-19 2024-02-09 清华大学 Driving system and driving circuit of electric automobile and heating method of battery of electric automobile
CN113928183A (en) * 2020-06-29 2022-01-14 比亚迪股份有限公司 Vehicle, energy conversion device, and control method therefor
CN113928183B (en) * 2020-06-29 2023-06-13 比亚迪股份有限公司 Vehicle, energy conversion device, and control method therefor
CN113506934A (en) * 2021-06-24 2021-10-15 武汉理工大学 Lithium battery heating system and heating method
CN113506934B (en) * 2021-06-24 2023-09-08 武汉理工大学 Lithium battery heating system and heating method
WO2023168788A1 (en) * 2022-03-09 2023-09-14 宁德时代新能源科技股份有限公司 Power battery voltage regulation circuit and system, control method therefor and control apparatus thereof
WO2023168628A1 (en) * 2022-03-09 2023-09-14 宁德时代新能源科技股份有限公司 Traction battery voltage adjustment system, and control method and control apparatus therefor
US11901757B2 (en) 2022-03-09 2024-02-13 Contemporary Amperex Technology Co., Limited Electric vehicle battery voltage regulation system and control method and control apparatus therefor

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