Vehicle power supply circuit, vehicle power supply control method and vehicle

Abstract

The invention relates to a vehicle power supply circuit, a vehicle power supply control method and a vehicle. The vehicle power supply circuit (100) comprises a first battery pack (10) connected with a high-voltage load (40) of the vehicle and used for supplying power to the high-voltage load; the second battery pack (20) is connected with a driving system of the vehicle and used for supplying power to the driving system (50), and the rated voltage of the first battery pack is smaller than that of the second battery pack; and the buck-boost circuit (30) is connected between the first battery pack and the second battery pack. In the scheme, the two battery packs can adapt to different working conditions and adopt different power supply strategies through the connected buck-boost circuit while exerting respective advantages, and the functionality is considered. The vehicle power supply circuit provided by the scheme is simple in structure, fully utilizes the characteristics of the battery pack, and is high in expandability.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicle circuit design, and in particular, to a vehicle power supply circuit, a vehicle power supply control method and a vehicle. Background Art

[0002] With the development of electric vehicle technology, some vehicles are equipped with dual battery packs. In related technologies, two battery packs are usually connected in parallel. While improving the vehicle's range, power performance and charging rate, technicians also hope to make the layout of the vehicle's power supply circuit more reasonable while taking into account the applicability of various working conditions. How to find a balance between the simplicity of the circuit topology and the functionality of the circuit has become a technical problem that needs to be solved in the development of electric vehicles. Summary of the invention

[0003] The object of the present disclosure is to provide a vehicle power supply circuit, a vehicle power supply control method and a vehicle that can fully utilize the advantages of a high-rated voltage battery pack to supply power.

[0004] In order to achieve the above object, the present disclosure provides a vehicle power supply circuit, the vehicle power supply circuit comprising:

[0005] A first battery pack, connected to a high-voltage load of the vehicle, for supplying power to the high-voltage load;

[0006] a second battery pack connected to a drive system of the vehicle and used to supply power to the drive system, wherein a rated voltage of the first battery pack is less than a rated voltage of the second battery pack;

[0007] The buck-boost circuit is connected between the first battery pack and the second battery pack.

[0008] Optionally, the energy density of the first battery pack is greater than the energy density of the second battery pack.

[0009] Optionally, the buck-boost circuit includes a switch tube assembly, a capacitive load and an inductive load, the switch tube assembly is connected in parallel with the second battery pack, the capacitive load is connected in parallel with the first battery pack, and the inductive load is connected between the switch tube assembly and the first battery pack.

[0010] Optionally, the switch tube assembly includes N-phase bridge arms, N≥1, a first bus terminal of the N-phase bridge arm is connected to one end of the second battery pack, and a second bus terminal of the N-phase bridge arm is connected to the other end of the second battery pack.

[0011] Optionally, the inductive load includes N inductors, first ends of the N inductors are connected to the positive electrode of the first battery pack, and second ends of the N inductors are connected one-to-one to N midpoints of the N-phase bridge arms.

[0012] The present disclosure also provides a vehicle power supply control method for controlling the above-mentioned vehicle power supply circuit provided by the present disclosure. The method includes:

[0013] Determine the required power of the drive system of the vehicle, the state parameters of the first battery pack, and the state parameters of the second battery pack;

[0014] Determine the power supply modes of the first battery pack and the second battery pack according to the required power of the drive system, the state parameters of the first battery pack, and the state parameters of the second battery pack.

[0015] Optionally, the determining the power supply modes of the first battery pack and the second battery pack according to the required power of the drive system, the state parameters of the first battery pack, and the state parameters of the second battery pack includes:

[0016] If the following conditions are met, control the first battery pack to supply power only to the high-voltage load and control the second battery pack to supply power only to the drive system:

[0017] P≥Pd, P2≥Pmax / λ, SOC2≥SOC21, P1≥Pa;

[0018] Or, P<Pd, Pa≤P1<Pd / μ + Pa;

[0019] Wherein, P is the required power of the drive system, Pd is the required power threshold, P1 is the maximum allowable discharge power of the first battery pack currently, P2 is the maximum allowable discharge power of the second battery pack currently, Pa is the current power of the high-voltage load, Pmax is the maximum power of the drive system, SOC2 is the state of charge of the second battery pack, SOC21 is the first SOC threshold, λ is the efficiency of the drive system, and μ is the boost efficiency of the buck-boost circuit.

[0020] Optionally, the determining the power supply modes of the first battery pack and the second battery pack according to the required power of the drive system, the state parameters of the first battery pack, and the state parameters of the second battery pack includes:

[0021] If the following conditions are met, control the first battery pack to supply power to the high-voltage load and supply power to the drive system and charge the second battery pack through the buck-boost circuit:

[0022] P≥Pd, SOC2<SOC21, P1≥Pa, I4*U2≥Pdc;

[0023] Or, P<Pd, P1≥Pd / μ + Pa, SOC2<SOC22;

[0024] Wherein, P is the required power of the drive system, Pd is the required power threshold, P1 is the maximum allowable discharge power of the first battery pack at present, Pa is the current power of the high-voltage load, Pdc is the current power of the drive system, SOC2 is the state of charge of the second battery pack, SOC21 is the first SOC threshold, SOC22 is the second SOC threshold, SOC21 > SOC22, μ is the boost efficiency of the buck-boost circuit, U2 is the voltage of the second battery pack, I4 is the target current value of the buck-boost circuit, I4 = min{Ic2, (P1 - Pa) / U2, I3}, Ic2 is the maximum allowable charging current of the second battery pack at present, and I3 is the maximum allowable current of the buck-boost circuit.

[0025] Optionally, determining the power supply modes of the first battery pack and the second battery pack according to the required power of the drive system, the state parameters of the first battery pack, and the state parameters of the second battery pack includes:

[0026] If the following conditions are met, then control the first battery pack to supply power to the high-voltage load, supply power to the drive system through the buck-boost circuit, and control the second battery pack to only supply power to the drive system:

[0027] P ≥ Pd, SOC2 < SOC21, P1 ≥ Pa, I4 * U2 < Pdc;

[0028] Wherein, P is the required power of the drive system, Pd is the required power threshold, P1 is the maximum allowable discharge power of the first battery pack at present, Pa is the current power of the high-voltage load, Pdc is the current power of the drive system, SOC2 is the state of charge of the second battery pack, SOC21 is the first SOC threshold, U2 is the voltage of the second battery pack, I4 is the target current value of the buck-boost circuit, I4 = min{Ic2, (P1 - Pa) / U2, I3}, Ic2 is the maximum allowable charging current of the second battery pack at present, and I3 is the maximum allowable current of the buck-boost circuit.

[0029] Optionally, determining the power supply modes of the first battery pack and the second battery pack according to the required power of the drive system, the state parameters of the first battery pack, and the state parameters of the second battery pack includes:

[0030] If P1 < Pa and P ≥ Pd are satisfied, then control the first battery pack to only supply power to the high-voltage load, control the second battery pack to supply power to the drive system, and supply power to the high-voltage load through the buck-boost circuit.

[0031] Wherein, P is the required power of the drive system (50), Pd is the required power threshold, P1 is the maximum allowable discharge power of the first battery pack at present, and Pa is the current power of the high-voltage load.

[0032] Optionally, determining the power supply modes of the first battery pack and the second battery pack according to the required power of the drive system, the state parameters of the first battery pack, and the state parameters of the second battery pack includes:

[0033] If the following conditions are satisfied or the second battery pack fails, control the first battery pack to supply power to the high-voltage load, supply power to the drive system through the buck-boost circuit, and control the second battery pack not to supply power:

[0034] P < Pd, P1 ≥ Pd / μ + Pa, SOC2 ≥ SOC22;

[0035] Wherein, P is the required power of the drive system, Pd is the required power threshold, P1 is the maximum allowable discharge power of the first battery pack at present, Pa is the current power of the high-voltage load, Pdc is the current power of the drive system, SOC2 is the state of charge of the second battery pack, SOC22 is the second SOC threshold, and μ is the boost efficiency of the buck-boost circuit.

[0036] Optionally, determining the power supply modes of the first battery pack and the second battery pack according to the required power of the drive system, the state parameters of the first battery pack, and the state parameters of the second battery pack includes:

[0037] If the first battery pack fails, control the second battery pack to supply power to the drive system, supply power to the high-voltage load through the buck-boost circuit, and control the first battery pack not to supply power.

[0038] The present disclosure further provides a vehicle, including a drive system, a high-voltage load, and the above vehicle power supply circuit provided by the present disclosure.

[0039] Through the above technical solution, two battery packs are provided in the vehicle, one with a lower rated voltage and the other with a higher rated voltage. The buck-boost circuit isolates the drive system from the high-voltage load. The high-voltage load is a low-voltage platform (for example, 300V), and the drive system is a high-voltage platform (for example, 600V). The battery pack with a high rated voltage (the second battery pack) can directly supply power to the drive system to provide better power performance for the vehicle. Moreover, while giving full play to its own advantages, the second battery pack with a high rated voltage can also adopt different power supply strategies according to different working conditions through the connected buck-boost circuit, taking into account functionality. The vehicle power supply circuit provided by this solution has a simple structure, makes full use of the characteristics of the battery pack with a high rated voltage, and has strong scalability.

[0040] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the accompanying drawings:

[0042] Figure 1 is a block diagram of the structure of a vehicle power supply circuit provided by an exemplary embodiment.

[0043] Figure 2 is a schematic diagram of the structure of a vehicle power supply circuit provided by an exemplary embodiment.

[0044] Figure 3 is a schematic diagram of the structure of a vehicle power supply circuit provided by another exemplary embodiment.

[0045] Figure 4 is a schematic diagram of the structure of a vehicle power supply circuit when applied in a vehicle provided by an exemplary embodiment.

[0046] Figure 5 is a flowchart of a vehicle power supply control method provided by an exemplary embodiment.

[0047] Figure 6 is a schematic diagram of the current flow direction of vehicle power supply in the first mode provided by an exemplary embodiment.

[0048] Figure 7 and Figure 8 is a schematic diagram of the current flow direction of vehicle power supply in the second mode provided by an exemplary embodiment.

[0049] Figure 9 and Figure 10 is a schematic diagram of the current flow direction of vehicle power supply in the third mode provided by an exemplary embodiment.

[0050] Figure 11 and Figure 12 is a schematic diagram of the current flow direction of vehicle power supply in the fourth mode provided by an exemplary embodiment.

[0051] Figure 13 and Figure 14 is a schematic diagram of the current flow direction of vehicle power supply in the fifth mode provided by an exemplary embodiment.

[0052] Figure 15 and Figure 16 is a schematic diagram of the current flow direction of vehicle power supply in the sixth mode provided by an exemplary embodiment.

[0053] Figure 17 It is a structural block diagram of a vehicle provided by an exemplary embodiment. Detailed implementation manners

[0054] The following will describe in detail the specific implementation manners of the present disclosure with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only for explaining and understanding the present disclosure, and are not used to limit the present disclosure.

[0055] Figure 1 It is a structural block diagram of a vehicle power supply circuit provided by an exemplary embodiment. As Figure 1 shown, the vehicle power supply circuit 100 includes a first battery pack 10, a second battery pack 20, and a buck-boost circuit 30.

[0056] The first battery pack 10 is connected to the high-voltage load 40 of the vehicle and is used to supply power to the high-voltage load 40.

[0057] The second battery pack 20 is connected to the drive system 50 of the vehicle and is used to supply power to the drive system 50. The rated voltage of the first battery pack 10 is less than the rated voltage of the second battery pack 20.

[0058] The buck-boost circuit 30 is connected between the first battery pack 10 and the second battery pack 20.

[0059] The high-voltage load 40 may include an on-board charger (OBC), a compressor, etc. The drive system 50 may include a drive motor, a motor controller, etc.

[0060] In addition to the first battery pack directly supplying power to the high-voltage load and the second battery pack directly supplying power to the drive system, the first battery pack can also supply power to the drive system and / or charge the second battery pack after being boosted by the buck-boost circuit, and the second battery pack can also supply power to the high-voltage load and / or charge the first battery pack after being stepped down by the buck-boost circuit.

[0061] Through the above technical solutions, two battery packs are provided in the vehicle, one with a lower rated voltage and the other with a higher rated voltage. The buck-boost circuit isolates the drive system from the high-voltage load. The high-voltage load is a low-voltage platform (for example, 300V), and the drive system is a high-voltage platform (for example, 600V). The battery pack with a high rated voltage (the second battery pack) can directly supply power to the drive system to provide better power performance for the vehicle. And, while the second battery pack with a high rated voltage plays its own advantages, it can also adopt different power supply strategies according to different working conditions through the connected buck-boost circuit, taking into account functionality. The vehicle power supply circuit provided by this solution has a simple structure, makes full use of the characteristics of the battery pack with a high rated voltage, and has strong scalability.

[0062] In another embodiment, the energy density of the first battery pack 10 is greater than that of the second battery pack 20.

[0063] The energy of a battery pack refers to the electrical energy that the battery pack can output, with the unit of kW·h (kilowatt-hour). The energy density of a battery pack refers to the energy released by the battery per unit mass or unit volume. After a battery pack is used for a period of time, its energy density will decrease. The energy density in this solution can be the initial value of the battery pack when it is not in use. The first battery pack with a high energy density can directly supply power to high-voltage loads to reduce the number of charging times of the battery pack. Both battery packs play their own advantages. In addition, the first battery pack can also adopt different power supply strategies according to different working conditions through the connected buck-boost circuit.

[0064] In another embodiment, the second battery pack can also be a power-type battery pack that can meet high-rate charge and discharge. In this way, using the vehicle power supply circuit of this solution, it is possible to find a balance between high energy density and high-rate charge and discharge, and the scalability is further enhanced.

[0065] In another embodiment, the buck-boost circuit 30 includes a switching tube assembly, a capacitive load, and an inductive load. The switching tube assembly is connected in parallel with the second battery pack 20, the capacitive load is connected in parallel with the first battery pack 10, and an inductive load is connected between the switching tube assembly and the first battery pack 10.

[0066] The switching tube assembly can include multiple switching tubes. For example, diodes, triodes, Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs), etc.

[0067] The capacitive load can include a capacitor and a resistor, and the inductive load can include an inductor and a resistor. By controlling the conduction and cutoff of the switching tubes in the switching tube assembly and using the energy storage and release of the capacitive load and inductive load, it is possible to boost the voltage output by the first battery pack and transmit it to the second battery pack, and it is also possible to step down the voltage output by the second battery pack and output it to the first battery pack.

[0068] In this embodiment, the structure is simple, the buck-boost efficiency is high, the reliability is high, and the cost is low.

[0069] In another embodiment, the switching tube assembly includes an N-phase bridge arm, N≥1. The first busbar end of the N-phase bridge arm is connected to one end of the second battery pack 20, and the second busbar end of the N-phase bridge arm is connected to the other end of the second battery pack 20.

[0070] That is, the N-phase bridge arm is connected in parallel with the second battery pack 20. By setting the N-phase bridge arm as the switching tube assembly, it is easy to select components and the assembly is simple.

[0071] In yet another embodiment, the inductive load includes N inductors. The first ends of the N inductors are connected to the positive electrode of the first battery pack 10, and the second ends of the N inductors are correspondingly connected to the N midpoints of the N-phase bridge arm.

[0072] Figure 2 It is a schematic structural diagram of a vehicle power supply circuit provided by an exemplary embodiment. As Figure 2 shown, N = 1. The inductive load includes inductor L1, and the capacitive load includes capacitor C1. The switching tube assembly includes a phase bridge arm composed of an upper bridge arm VT7 and a lower bridge arm VT8. Capacitor C1 is connected in parallel with the first battery pack. One end of inductor L1 is connected to the positive electrode of the first battery pack, and the other end is connected to the midpoint of a phase bridge arm.

[0073] Figure 3 It is a schematic structural diagram of a vehicle power supply circuit provided by another exemplary embodiment. As Figure 2 shown, N = 3. The inductive load includes three inductors, and the capacitive load includes a capacitor C1. The switching tube assembly includes a three-phase bridge arm. Capacitor C1 is connected in parallel with the first battery pack. The first ends of the three inductors are all connected to the positive electrode of the first battery pack 10, and the second ends of the three inductors are correspondingly connected to the three midpoints of the three-phase bridge arm.

[0074] When N = 1, the circuit structure is simple. When N = 3, multiple paths can be selected and controlled, which are redundant and backup to each other, and the reliability is higher.

[0075] Figure 4 It is a schematic structural diagram of the vehicle power supply circuit provided by an exemplary embodiment when applied in a vehicle. As Figure 4 shown, the drive system 50 may include a three-phase motor and a motor controller composed of a three-phase bridge arm (VT1~VT6). Both ends of the motor control bus capacitor C2 are respectively connected to the first busbar end and the second busbar end of the three-phase bridge arm. The positive electrode of the first battery pack 10 is connected to the outside through the first positive contactor K4, and the negative electrode of the first battery pack 10 is connected to the outside through the first negative contactor K5. The positive electrode of the second battery pack 20 is connected to the outside through the second positive contactor K6, and the negative electrode of the second battery pack 20 is connected to the outside through the second negative contactor K7.

[0076] The DC charging port 60 in the vehicle is connected to the positive electrode of the second battery pack 20 through the first direct positive contactor K1, connected to the positive electrode of the first battery pack 10 through the second direct positive contactor K2, and connected to the negative electrodes of the first battery pack 10 and the second battery pack 20 through the direct negative contactor K3.

[0077] In Figure 4 the circuit structure, it is possible to control the DC charging gun to directly charge the first battery pack 10 or the second battery pack 20.

[0078] The present disclosure also provides a vehicle power supply control method, which controls the above-mentioned vehicle power supply circuit 100 to implement various discharge modes of the battery pack. For example, by controlling the on and off of the positive contactor and negative contactor of the first battery pack 10 and the second battery pack 20, and the switches in the switch tube assembly, various forms of power supply can be achieved.

[0079] Figure 5 is a flowchart of a vehicle power supply control method provided by an exemplary embodiment. As Figure 5 shown, the method includes:

[0080] In step S101, determine the required power of the drive system 50 of the vehicle, the state parameters of the first battery pack 10, and the state parameters of the second battery pack 20.

[0081] In step S102, according to the required power of the drive system 50, the state parameters of the first battery pack 10, and the state parameters of the second battery pack 20, determine the power supply methods of the first battery pack 10 and the second battery pack 20.

[0082] Among them, the required power of the drive system 50 can be the required power indicated by the driver or the required power according to the strategy of autonomous driving. For example, it can be determined by information such as the opening degree of the accelerator pedal, the opening degree of the brake pedal, and the gear position. The state parameter is a physical quantity representing the state and characteristics of the battery pack. For example, it can include the state of charge, voltage, current, maximum allowable discharge current, maximum allowable discharge current, etc.

[0083] In this embodiment, while the two battery packs give full play to their respective advantages, through the connected buck-boost circuit, different power supply strategies are adopted to adapt to different working conditions. On the basis of making full use of the characteristics of each battery pack, the function has strong scalability.

[0084] In one embodiment, according to the required power of the drive system 50, the state parameters of the first battery pack 10, and the state parameters of the second battery pack 20, determining the power supply methods of the first battery pack 10 and the second battery pack 20 includes:

[0085] If the following condition (1) or condition (2) is satisfied, then control the power supply in the first mode, that is, control the first battery pack 10 to supply power only to the high-voltage load 40, and control the second battery pack 20 to supply power only to the drive system 50.

[0086] Condition (1): P≥Pd, P2≥Pmax / λ, SOC2≥SOC21, P1≥Pa;

[0087] Condition (2): P<Pd, Pa≤P1<Pd / μ+Pa.

[0088] Wherein, P is the required power of the drive system 50, Pd is the required power threshold, P1 is the maximum allowable discharge power of the first battery pack 10 currently, P2 is the maximum allowable discharge power of the second battery pack 20 currently, Pa is the current power of the high-voltage load 40, Pmax is the maximum power of the drive system 50, SOC2 is the state of charge of the second battery pack 20, SOC21 is the first SOC threshold, λ is the efficiency of the drive system 50, and μ is the boost efficiency of the buck-boost circuit 30.

[0089] If P≥Pd, it can be considered that the required power of the drive system 50 is large, and the current scenario is a high-power discharge requirement scenario. Conversely, if P<Pd, it can be considered that the required power of the drive system 50 is small, and the current scenario is a low-power discharge requirement scenario. P1 and P2 can be determined in real time according to the methods in related technologies. λ, μ, and Pmax can be predetermined values.

[0090] When condition (1) is satisfied, it can be considered that the required power of the drive system 50 is large, the state of charge of the second battery pack 20 is high, the first battery pack 10 can meet the current power requirement of the high-voltage load 40, and the second battery pack 20 can also meet the current power requirement of the drive system 50.

[0091] When condition (2) is satisfied, it can be considered that the required power of the drive system 50 is small, the first battery pack 10 can meet the current power requirement of the high-voltage load 40, but it is not enough to meet the current power requirement of the drive system 50 at the same time.

[0092] Figure 6 It is a schematic diagram of the current flow for vehicle power supply in the first mode provided by an exemplary embodiment. As Figure 6 shown, control the first positive contactor K4, the first negative contactor K5, the second positive contactor K6, and the second negative contactor K7 to close, and the upper bridge arm VT7 and the lower bridge arm VT8 to open. The first battery pack 10 forms a separate loop with the high-voltage load 40, and the second battery pack 20 forms a separate loop with the drive system 50.

[0093] In another embodiment, according to the required power of the drive system 50, the state parameters of the first battery pack 10, and the state parameters of the second battery pack 20, determine the power supply methods of the first battery pack 10 and the second battery pack 20, including:

[0094] If the following condition (3) or condition (4) is satisfied, then control the power supply in the second mode, that is, control the first battery pack 10 to supply power to the high-voltage load 40, and supply power to the drive system 50 and charge the second battery pack 20 through the buck-boost circuit 30:

[0095] Condition (3) P≥Pd, SOC2<SOC21, P1≥Pa, I4*U2≥Pdc;

[0096] Condition (4): P < Pd, P1 ≥ Pd / μ + Pa, SOC2 < SOC22.

[0097] Wherein, P is the required power of the drive system 50, Pd is the required power threshold, P1 is the maximum current discharge power currently allowed for the first battery pack 10, Pa is the current power of the high-voltage load 40, Pdc is the current power of the drive system 50, SOC2 is the state of charge of the second battery pack 20, SOC21 is the first SOC threshold, SOC22 is the second SOC threshold, SOC21 > SOC22, μ is the boost efficiency of the buck-boost circuit 30, U2 is the voltage of the second battery pack 20, I4 is the target current value of the buck-boost circuit 30, I4 = min{Ic2, (P1 - Pa) / U2, I3}, Ic2 is the maximum current charge currently allowed for the second battery pack 20, and I3 is the maximum current allowed for the buck-boost circuit 30. I4*U2 ≥ Pdc indicates that when the buck-boost circuit 30 outputs at the target current value I4, it can meet the current power of the drive system 50. U2 can be a real-time detection value, and I3 and Ic2 can be values determined according to the methods in related technologies and real-time detected parameters.

[0098] When condition (3) is satisfied, it can be considered that the required power of the drive system 50 is relatively large, the state of charge of the second battery pack 20 is relatively low, and the first battery pack 10 can meet the current power demand of the high-voltage load 40. If the buck-boost circuit 30 operates at the above target current value I4, the first battery pack 10 can also output electrical energy through the buck-boost circuit 30 to meet the power supply to the drive system 50 and the charging of the second battery pack 20.

[0099] When condition (4) is satisfied, it can be considered that the required power of the drive system 50 is relatively small, and the state of charge of the second battery pack 20 is very low. The first battery pack 10 can simultaneously meet the current power demand of the high-voltage load 40 and the power supply to the drive system 50.

[0100] Figure 7 and Figure 8 is a schematic diagram of the current flow for vehicle power supply in the second mode provided by an exemplary embodiment. The boosting of the first battery pack 10 to supply power to the drive system and charge the second battery pack 20 is divided into Figure 7 and Figure 8 in two stages.

[0101] Such as Figure 7As shown, control the first positive contactor K4, the first negative contactor K5, the second positive contactor K6, and the second negative contactor K7 to close. In one loop of the first battery pack 10, power is supplied to the high-voltage load 40. Control the lower arm VT8 to close and the upper arm VT7 to open. In another loop of the first battery pack 10, electrical energy flows through the inductor L1 and the lower arm VT8 to charge the inductor L1. The motor control bus capacitor C2 supplies power to the drive system and charges the second battery pack 20.

[0102] As Figure 8 shown, control the first positive contactor K4, the first negative contactor K5, the second positive contactor K6, and the second negative contactor K7 to close. Control the lower arm VT8 to open and the upper arm VT7 to open. The electrical energy of the first battery pack 10 is superimposed on the electrical energy stored in the inductor L1 and supplies power to the drive system and charges the second battery pack 20 through the diode in the upper arm VT7.

[0103] In another embodiment, according to the required power of the drive system 50, the state parameters of the first battery pack 10, and the state parameters of the second battery pack 20, determine the power supply modes of the first battery pack 10 and the second battery pack 20, including:

[0104] If the following condition (5) is satisfied, then control to supply power in the third mode, that is, control the first battery pack 10 to supply power to the high-voltage load 40 and supply power to the drive system 50 through the buck-boost circuit 30, and control the second battery pack 20 to only supply power to the drive system 50.

[0105] Condition (5): P≥Pd, SOC2<SOC21, P1≥Pa, I4*U2<Pdc.

[0106] Wherein, P is the required power of the drive system 50, Pd is the required power threshold, P1 is the maximum allowable discharge power of the first battery pack 10 currently, Pa is the current power of the high-voltage load 40, Pdc is the current power of the drive system 50, SOC2 is the state of charge of the second battery pack 20, SOC21 is the first SOC threshold, U2 is the voltage of the second battery pack 20, I4 is the target current value of the buck-boost circuit 30, I4 = min{Ic2, (P1 - Pa) / U2, I3}, Ic2 is the maximum allowable charging current of the second battery pack 20 currently, and I3 is the maximum allowable current of the buck-boost circuit 30.

[0107] Under the operating condition of power supply in the third mode, the power of the drive system can be controlled to satisfy: Pdmax ≤ (P1 - Pa) * μ + P2 * λ, where Pdmax is the current maximum allowable power of the drive system 50, λ is the efficiency of the drive system 50, μ is the boost efficiency of the buck-boost circuit 30, and P2 is the current maximum allowable discharge power of the second battery pack 20. In this way, the drive system limits its own power according to the battery pack discharge power to prevent the battery pack from overcurrent.

[0108] I4 * U2 < Pdc means that when the buck-boost circuit 30 outputs at the target current value I4, it still cannot meet the current power of the drive system 50.

[0109] If the condition (5) is satisfied, it can be considered that the required power of the drive system 50 is relatively large, the state of charge of the second battery pack 20 is relatively low, the first battery pack 10 can meet the current power demand of the high-voltage load 40, and if the buck-boost circuit 30 operates at the above target current value I4, the first battery pack 10 cannot output electrical energy through the buck-boost circuit 30 to simultaneously supply power to the drive system 50 and charge the second battery pack 20.

[0110] Figure 9 and Figure 10 is a schematic diagram of the current flow direction of vehicle power supply in the third mode provided by an exemplary embodiment. The first battery pack 10 is boosted to supply power to the drive system and is divided into Figure 9 and Figure 10 two stages in

[0111] As Figure 9 shown, control the first positive contactor K4, the first negative contactor K5, the second positive contactor K6, and the second negative contactor K7 to close. In one loop of the first battery pack 10, power is supplied to the high-voltage load 40. Control the lower arm VT8 to close and the upper arm VT7 to open. In another loop of the first battery pack 10, electrical energy flows through the inductor L1 and the lower arm VT8 to charge the inductor L1.

[0112] As Figure 10 shown, control the first positive contactor K4, the first negative contactor K5, the second positive contactor K6, and the second negative contactor K7 to close. Control the lower arm VT8 to open and the upper arm VT7 to open. The electrical energy of the first battery pack 10 is superimposed on the electrical energy stored in the inductor L1 and is supplied to the drive system through the diode in the upper arm VT7.

[0113] In another embodiment, according to the required power of the drive system 50, the state parameters of the first battery pack 10, and the state parameters of the second battery pack 20, determine the power supply methods of the first battery pack 10 and the second battery pack 20, including:

[0114] If P1 < Pa and P ≥ Pd are satisfied, the power supply is controlled in the fourth mode, that is, it is controlled that the first battery pack 10 only supplies power to the high-voltage load 40, the second battery pack 20 supplies power to the drive system 50, and supplies power to the high-voltage load 40 through the buck-boost circuit 30.

[0115] Wherein, P is the required power of the drive system 50, Pd is the required power threshold, P1 is the maximum current discharge power currently allowed by the first battery pack 10, and Pa is the current power of the high-voltage load 40.

[0116] Under the condition of power supply in the fourth mode, it can be controlled that the power of the drive system satisfies: Pdmax ≤ (P2 - (Pa - P1) / μ1) * λ, where Pdmax is the maximum current power allowed by the drive system 50, λ is the efficiency of the drive system 50, μ1 is the buck efficiency of the buck-boost circuit 30, and P2 is the maximum current discharge power allowed by the second battery pack 20. In this way, the drive system limits its own power according to the battery pack discharge power to prevent the battery pack from overcurrent.

[0117] If P1 < Pa and P ≥ Pd are satisfied, it can be considered that the required power of the drive system 50 is large, and the first battery pack 10 cannot meet the current power demand of the high-voltage load 40.

[0118] Figure 11 and Figure 12 is a schematic diagram of the current flow direction of vehicle power supply in the fourth mode provided by an exemplary embodiment. After the second battery pack 20 steps down the voltage, it supplies power to the high-voltage load and is divided into Figure 11 and Figure 12 in two stages.

[0119] As Figure 11 shown, control the first positive contactor K4, the first negative contactor K5, the second positive contactor K6, and the second negative contactor K7 to close. The first battery pack 10 supplies power to the high-voltage load 40. Control the lower arm VT8 to disconnect and the upper arm VT7 to close. The electric energy of the second battery pack 20 flows through the upper arm VT7 and the inductor L1 and then charges the capacitor C1 and supplies power to the high-voltage load. Due to the current suppression effect of the inductor L1, after the voltage at the capacitor C1 terminal gradually increases to the target value, the first stage ends.

[0120] As Figure 12 shown, control the first positive contactor K4, the first negative contactor K5, the second positive contactor K6, and the second negative contactor K7 to close. Control the lower arm VT8 to disconnect and the upper arm VT7 to disconnect, and the capacitor C1 supplies power to the high-voltage load.

[0121] In another embodiment, according to the required power of the drive system 50, the state parameters of the first battery pack 10, and the state parameters of the second battery pack 20, determining the power supply modes of the first battery pack 10 and the second battery pack 20 includes:

[0122] If the following condition (6) is satisfied or the second battery pack 20 fails (or K6 and K7 cannot be closed), then control the power supply in the fifth mode, that is, control the first battery pack 10 to supply power to the high-voltage load 40 and supply power to the drive system 50 through the buck-boost circuit 30, and control the second battery pack 20 not to supply power.

[0123] Condition (6): P < Pd, P1 ≥ Pd / μ + Pa, SOC2 ≥ SOC22.

[0124] Wherein, P is the required power of the drive system 50, Pd is the required power threshold, P1 is the maximum allowable discharge power of the first battery pack 10 currently, Pa is the current power of the high-voltage load 40, Pdc is the current power of the drive system 50, SOC2 is the state of charge of the second battery pack 20, SOC22 is the second SOC threshold, and μ is the boost efficiency of the buck-boost circuit 30.

[0125] In the case of the failure of the second battery pack 20, the power of the drive system can be controlled to satisfy: Pdmax ≤ (P1 - Pa) * μ * λ, where Pdmax is the currently allowable maximum power of the drive system 50, λ is the efficiency of the drive system 50, and μ is the boost efficiency of the buck-boost circuit 30. In this way, the drive system limits its own power according to the battery pack discharge power limit to prevent the first battery pack from overcurrent.

[0126] When condition (6) is satisfied, it can be considered that the required power of the drive system 50 is small, and the state of charge of the second battery pack 20 is not particularly low, and the first battery pack 10 can simultaneously meet the current power demand of the high-voltage load 40 and supply power to the drive system 50. The first battery pack 10 can simultaneously meet the current power demand of the high-voltage load 40 and supply power to the drive system 50.

[0127] Figure 13 And Figure 14 is a schematic diagram of the current flow of vehicle power supply in the fifth mode provided by an exemplary embodiment. The boosting of the first battery pack 10 to supply power to the drive system is divided into Figure 13 and Figure 14 in two stages:

[0128] Such as Figure 13As shown, control the first positive contactor K4 and the first negative contactor K5 to close, and the second positive contactor K6 and the second negative contactor K7 to open. Control the lower arm VT8 to close and the upper arm VT7 to open. The electrical energy of the first battery pack 10 flows through the inductor L1 and the lower arm VT8 to charge the inductor L1, and the motor control bus capacitor C2 supplies power to the drive system.

[0129] As Figure 14 shown, control the first positive contactor K4 and the first negative contactor K5 to close, and the second positive contactor K6 and the second negative contactor K7 to open. Control the lower arm VT8 to open and the upper arm VT7 to open. The electrical energy of the first battery pack 10 is superimposed on the electrical energy stored in the inductor L1, and is supplied to the drive system through the diode of the upper arm VT7.

[0130] In another embodiment, according to the required power of the drive system 50, the state parameters of the first battery pack 10, and the state parameters of the second battery pack 20, determine the power supply methods of the first battery pack 10 and the second battery pack 20, including:

[0131] If the first battery pack 10 fails (or K4 and K5 cannot be closed), then control to supply power in the sixth mode, that is, control the second battery pack 20 to supply power to the drive system 50, and supply power to the high-voltage load 40 through the buck-boost circuit 30, and control the first battery pack 10 not to supply power.

[0132] Figure 15 and Figure 16 is a schematic diagram of the current flow of vehicle power supply in the sixth mode provided by an exemplary embodiment. The second battery pack 20 is boosted to supply power to the drive system and is divided into Figure 15 and Figure 16 two stages in.

[0133] As Figure 15 shown, control the first positive contactor K4 and the first negative contactor K5 to open, and the second positive contactor K6 and the second negative contactor K7 to close. Control the upper arm VT7 to close and the lower arm VT8 to open. The electrical energy of the second battery pack 20 flows through the upper arm VT7 and the inductor L1 to charge the capacitor C1 and supply power to the high-voltage load. Due to the current suppression effect of the inductor L1, after the terminal voltage of the capacitor C1 gradually increases to the target value, the first stage ends.

[0134] As Figure 16 shown, control the first positive contactor K4 and the first negative contactor K5 to open, and the second positive contactor K6 and the second negative contactor K7 to close. Control the upper arm VT7 to open, and the capacitor C1 supplies power to the high-voltage load.

[0135] In the case of a fault in the first battery pack 10, the power of the drive system can be controlled to satisfy: Pdmax ≤ (P2 - Pa / μ1) * λ, where Pdmax is the current maximum allowable power of the drive system 50, λ is the efficiency of the drive system 50, μ1 is the buck efficiency of the buck-boost circuit 30, P2 is the current maximum allowable discharge power of the second battery pack 20, and Pa is the current power of the high-voltage load 40. In this way, the drive system limits its own power according to the battery pack discharge power to prevent overcurrent in the second battery pack.

[0136] The present disclosure also provides a vehicle. Figure 17 It is a structural block diagram of a vehicle provided by an exemplary embodiment. As Figure 17 shown, the vehicle 200 includes a drive system 50, a high-voltage load 40, and a vehicle power supply circuit 100 provided by the present disclosure.

[0137] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0138] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

[0139] Furthermore, any combination can be made between various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A vehicle power supply circuit (100), characterized in that, the vehicle power supply circuit (100) comprises: a first battery pack (10), connected to a high-voltage load (40) of the vehicle, for supplying power to the high-voltage load (40); a second battery pack (20), connected to a drive system (50) of the vehicle, for supplying power to the drive system (50), and a rated voltage of the first battery pack (10) is less than a rated voltage of the second battery pack (20); a buck-boost circuit (30), connected between the first battery pack (10) and the second battery pack (20).

2. The vehicle power supply circuit (100) according to claim 1, characterized in that, an energy density of the first battery pack (10) is greater than an energy density of the second battery pack (20).

3. The vehicle power supply circuit (100) according to claim 1 or 2, characterized in that, the buck-boost circuit (30) comprises a switching tube assembly, a capacitive load and an inductive load, the switching tube assembly is connected in parallel with the second battery pack (20), the capacitive load is connected in parallel with the first battery pack (10), and the inductive load is connected between the switching tube assembly and the first battery pack (10).

4. The vehicle power supply circuit (100) according to claim 3, characterized in that, the switching tube assembly comprises N phase legs, N≥1, a first busbar end of the N phase legs is connected to one end of the second battery pack (20), and a second busbar end of the N phase legs is connected to the other end of the second battery pack (20).

5. The vehicle power supply circuit (100) according to claim 4, characterized in that, the inductive load comprises N inductors, a first end of the N inductors is connected to a positive electrode of the first battery pack (10), and a second end of the N inductors is connected to N midpoints of the N phase legs in one-to-one correspondence.

6. A vehicle power supply control method, characterized in that, for controlling the vehicle power supply circuit (100) according to any one of claims 1-5, the method comprises: determining a required power of the drive system (50) of the vehicle, state parameters of the first battery pack (10), and state parameters of the second battery pack (20); determining a power supply mode of the first battery pack (10) and the second battery pack (20) according to the required power of the drive system (50), the state parameters of the first battery pack (10), and the state parameters of the second battery pack (20).

7. The method according to claim 6, characterized in that, the determining the power supply mode of the first battery pack (10) and the second battery pack (20) according to the required power of the drive system (50), the state parameters of the first battery pack (10), and the state parameters of the second battery pack (20) comprises: if the following conditions are met, then controlling the first battery pack (10) to supply power only to the high-voltage load (40), and controlling the second battery pack (20) to supply power only to the drive system (50): P ≥ Pd, P2 ≥ Pmax / λ, SOC2 ≥ SOC21, P1 ≥ Pa; Or, P < Pd, Pa ≤ P1 < Pd / μ + Pa; Wherein, P is the required power of the drive system (50), Pd is the required power threshold, P1 is the maximum allowable discharge power currently allowed by the first battery pack (10), P2 is the maximum allowable discharge power currently allowed by the second battery pack (20), Pa is the current power of the high-voltage load (40), Pmax is the maximum power of the drive system (50), SOC2 is the state of charge of the second battery pack (20), SOC21 is the first SOC threshold, λ is the efficiency of the drive system (50), and μ is the boost efficiency of the buck-boost circuit (30).

8. The method according to claim 6, characterized in that, determining the power supply modes of the first battery pack (10) and the second battery pack (20) according to the required power of the drive system (50), the state parameters of the first battery pack (10), and the state parameters of the second battery pack (20) includes: If the following conditions are met, then control the first battery pack (10) to supply power to the high-voltage load (40), and supply power to the drive system (50) and charge the second battery pack (20) through the buck-boost circuit (30): P ≥ Pd, SOC2 < SOC21, P1 ≥ Pa, I4*U2 ≥ Pdc; Or, P < Pd, P1 ≥ Pd / μ + Pa, SOC2 < SOC22; Wherein, P is the required power of the drive system (50), Pd is the required power threshold, P1 is the maximum allowable discharge power currently allowed by the first battery pack (10), Pa is the current power of the high-voltage load (40), Pdc is the current power of the drive system (50), SOC2 is the state of charge of the second battery pack (20), SOC21 is the first SOC threshold, SOC22 is the second SOC threshold, SOC21 > SOC22, μ is the boost efficiency of the buck-boost circuit (30), U2 is the voltage of the second battery pack (20), I4 is the target current value of the buck-boost circuit (30), I4 = min{Ic2, (P1 - Pa) / U2, I3}, Ic2 is the maximum allowable charging current currently allowed by the second battery pack (20), and I3 is the maximum allowable current of the buck-boost circuit (30).

9. The method according to claim 6, characterized in that, determining the power supply modes of the first battery pack (10) and the second battery pack (20) according to the required power of the drive system (50), the state parameters of the first battery pack (10), and the state parameters of the second battery pack (20) includes: If the following conditions are met, then control the first battery pack (10) to supply power to the high-voltage load (40), and supply power to the drive system (50) through the buck-boost circuit (30), and control the second battery pack (20) to only supply power to the drive system (50): P ≥ Pd, SOC2 < SOC21, P1 ≥ Pa, I4 * U2 < Pdc; Wherein, P is the required power of the drive system (50), Pd is the required power threshold, P1 is the maximum allowable discharge power currently allowed by the first battery pack (10), Pa is the current power of the high-voltage load (40), Pdc is the current power of the drive system (50), SOC2 is the state of charge of the second battery pack (20), SOC21 is the first SOC threshold, U2 is the voltage of the second battery pack (20), I4 is the target current value of the buck-boost circuit (30), I4 = min{Ic2, (P1 - Pa) / U2, I3}, Ic2 is the maximum allowable charge current currently allowed by the second battery pack (20), and I3 is the maximum allowable current of the buck-boost circuit (30).

10. The method according to claim 6, characterized in that, determining the power supply modes of the first battery pack (10) and the second battery pack (20) according to the required power of the drive system (50), the state parameters of the first battery pack (10), and the state parameters of the second battery pack (20) includes: If P1 < Pa and P ≥ Pd are satisfied, control the first battery pack (10) to supply power only to the high-voltage load (40), control the second battery pack (20) to supply power to the drive system (50), and supply power to the high-voltage load (40) through the buck-boost circuit (30); Wherein, P is the required power of the drive system (50), Pd is the required power threshold, P1 is the maximum allowable discharge power currently allowed by the first battery pack (10), and Pa is the current power of the high-voltage load (40).

11. The method according to claim 6, characterized in that, determining the power supply modes of the first battery pack (10) and the second battery pack (20) according to the required power of the drive system (50), the state parameters of the first battery pack (10), and the state parameters of the second battery pack (20) includes: If the following conditions are satisfied or the second battery pack (20) fails, control the first battery pack (10) to supply power to the high-voltage load (40) and supply power to the drive system (50) through the buck-boost circuit (30), and control the second battery pack (20) not to supply power: P < Pd, P1 ≥ Pd / μ + Pa, SOC2 ≥ SOC22; Wherein, P is the required power of the drive system (50), Pd is the required power threshold, P1 is the maximum allowable discharge power currently allowed by the first battery pack (10), Pa is the current power of the high-voltage load (40), SOC2 is the state of charge of the second battery pack (20), SOC22 is the second SOC threshold, and μ is the boost efficiency of the buck-boost circuit (30).

12. The method according to claim 6, characterized in that, Determining the power supply modes of the first battery pack (10) and the second battery pack (20) according to the required power of the drive system (50), the state parameters of the first battery pack (10), and the state parameters of the second battery pack (20) includes: If the first battery pack (10) fails, control the second battery pack (20) to supply power to the drive system (50), supply power to the high-voltage load (40) through the buck-boost circuit (30), and control the first battery pack (10) not to supply power.

13. A vehicle, characterized in that, it includes a drive system (50), a high-voltage load (40), and a vehicle power supply circuit (100) according to any one of claims 1-5.

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