Power source control circuit, power source control system, and electric vehicle

Abstract

Provided in the present invention are a power source control circuit, a power source control system, and an electric vehicle. The power source control circuit is applied to an electric drive system (EDS) to which a direct-current voltage is supplied via a direct-current power source module, and branches of the direct-current power source module that supply the direct-current voltage to the EDS comprise a first branch and a second branch. The power source control circuit comprises: a control module, which is used for controlling a first branch to connect and a second branch to disconnect when a first direct-current voltage needs to be supplied to an EDS, such that a direct-current power source module supplies the first direct-current voltage to the EDS via the first branch, and for controlling the second branch to connect and the first branch to disconnect when a second direct-current voltage lower than the first direct-current voltage needs to be supplied to the EDS, such that the direct-current power source module supplies the second direct-current voltage to the EDS via the second branch. Thus, the voltage utilization rate and the WLTC efficiency can be effectively improved.

Description

Power supply control circuit, power supply control system and electric vehicle TECHNICAL FIELD

[0001] The present application relates to the technical field of electric vehicles, and in particular to a power supply control circuit, a power supply control system and an electric vehicle. BACKGROUND

[0002] Generally, the maximum speed of the driven motor must be designed very high to meet the highest vehicle speed requirement. However, the speed and torque cycle of the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) is relatively small, which is really concerned about. This results in very low DC utilization (ratio of motor terminal voltage to DC voltage) under such conditions. Since the Pulse Width Modulated (PWM) harmonic loss is very sensitive to the duty cycle and voltage utilization, the average efficiency of the WLTC (dependent on the DC voltage) can be 1-4% lower than the theoretical value.

[0003] As can be seen from the definition of voltage utilization, the voltage utilization mainly depends on the Back Electromotive Force (EMF) of the motor and the DC voltage. With the increase of voltage level and the highest speed, the voltage utilization of the WLTC is lower and lower, which is very unfavorable to the WLTC efficiency.

[0004] At present, in order to improve the WLTC efficiency, more is from the ways of material improvement, electromagnetic design, manufacturing process, control strategy, etc., but these ways improve the WLTC efficiency is limited. Therefore, the prior art is difficult to substantially improve the WLTC efficiency.

[0005] SUMMARY

[0006] Therefore, the present application provides a power supply control circuit, a power supply control system and an electric vehicle, so as to improve the WLTC efficiency by improving the voltage utilization.

[0007] According to a first aspect of the present application, there is provided a power supply control circuit applied to an electric drive system (EDS) supplied with a direct current voltage via a direct current power supply module, the branches of the direct current power supply module supplying the EDS with the direct current voltage comprising a first branch and a second branch, the power supply control circuit comprising: a control module configured to control the first branch to be turned on and the second branch to be turned off when it is required to supply the EDS with a first direct current voltage, so that the direct current power supply module supplies the EDS with the first direct current voltage via the first branch, and control the second branch to be turned on and the first branch to be turned off when it is required to supply the EDS with a second direct current voltage lower than the first direct current voltage, so that the direct current power supply module supplies the EDS with the second direct current voltage via the second branch.

[0008] In a possible implementation, the direct current power supply module comprises a first battery pack and a second battery pack, and correspondingly, the control module is configured to control the first branch to be turned on and the second branch to be turned off when it is required to supply the EDS with the first direct current voltage, so that the first battery pack and the second battery pack connected in series supply the EDS with the first direct current voltage, and control the second branch to be turned on and the first branch to be turned off when it is required to supply the EDS with the second direct current voltage, so that the second battery pack supplies the EDS with the second direct current voltage.

[0009] In a possible implementation, the branches of the direct current power supply module supplying the EDS with the direct current voltage further comprise a third branch, and correspondingly, the control module is configured to control the third branch to be turned on, the first branch to be turned off and the second branch to be turned off when it is required to supply the EDS with a third direct current voltage lower than the first direct current voltage, so that the direct current power supply module supplies the EDS with the third direct current voltage via the third branch.

[0010] In a possible implementation, the direct current power supply module comprises a first battery pack and a second battery pack, and correspondingly, the control module is configured to: in a case where the first direct current voltage needs to be supplied to the EDS, control the first branch to be turned on, the second branch to be turned off, and the third branch to be turned off, so that the first direct current voltage is supplied to the EDS via the first battery pack and the second battery pack connected in series; in a case where the second direct current voltage needs to be supplied to the EDS, control the second branch to be turned on, the third branch to be turned off, and the first branch to be turned off, so that the second direct current voltage is supplied to the EDS via the second battery pack; and in a case where the third direct current voltage needs to be supplied to the EDS, control the third branch to be turned on, the first branch to be turned off, and the second branch to be turned off, so that the third direct current voltage is supplied to the EDS via the first battery pack.

[0011] In a possible implementation, the control module is configured to: in a case where a fourth direct current voltage needs to be supplied to the EDS, control the first branch to be turned off, the second branch to be turned on, and the third branch to be turned on, so that the fourth direct current voltage is supplied to the EDS by the direct current power supply module via the second branch and the third branch together.

[0012] In a possible implementation, the direct current power supply module comprises a first battery pack and a second battery pack, and correspondingly, the control module is configured to: in a case where the first direct current voltage needs to be supplied to the EDS, control the first branch to be turned on, the second branch to be turned off, and the third branch to be turned off, so that the first direct current voltage is supplied to the EDS via the first battery pack and the second battery pack connected in series; in a case where the second direct current voltage needs to be supplied to the EDS, control the second branch to be turned on, the third branch to be turned off, and the first branch to be turned off, so that the second direct current voltage is supplied to the EDS via the second battery pack; in a case where the third direct current voltage needs to be supplied to the EDS, control the third branch to be turned on, the first branch to be turned off, and the second branch to be turned off, so that the third direct current voltage is supplied to the EDS via the first battery pack; and in a case where the fourth direct current voltage needs to be supplied to the EDS, control the first branch to be turned off, the second branch to be turned on, and the third branch to be turned on, so that the fourth direct current voltage is supplied to the EDS via the first battery pack and the second battery pack connected in parallel.

[0013] In a possible implementation, the power supply control circuit further comprises: a first switch device arranged in the first branch, wherein the first branch is turned on when the first switch device is turned on, and the first branch is turned off when the first switch device is turned off; and a second switch device arranged in the second branch, wherein the second branch is turned on when the second switch device is turned on, and the second branch is turned off when the second switch device is turned off.

[0014] In a possible implementation, the first switch device is a switch device capable of disconnecting the first branch when the first switch device is turned off by itself, and the second switch device is a switch device capable of disconnecting the second branch when the second switch device is turned off by itself.

[0015] In a possible implementation, the power supply control circuit further comprises: a first switch device arranged in the first branch, wherein the first branch is turned on when the first switch device is turned on, and the first branch is turned off when the first switch device is turned off; a second switch device arranged in the second branch, wherein the second branch is turned on when the second switch device is turned on, and the second branch is turned off when the second switch device is turned off; and a third switch device arranged in the third branch, wherein the third branch is turned on when the third switch device is turned on, and the third branch is turned off when the third switch device is turned off.

[0016] In a possible implementation, the first switch device is a switch device capable of disconnecting the first branch when the first switch device is turned off by itself, the second switch device is a switch device capable of disconnecting the second branch when the second switch device is turned off by itself, and the third switch device is a switch device capable of disconnecting the third branch when the third switch device is turned off by itself.

[0017] In a possible implementation, the switch device comprises a circuit breaker and / or a triode without a body diode.

[0018] According to a second aspect of the present application, a power supply control system is provided, comprising the direct current power supply module, the power supply control circuit and the EDS as described above, and the EDS comprises an inverter and a motor.

[0019] According to a third aspect of the present application, there is provided an electric vehicle comprising the power supply control system and a vehicle control unit (VCU) configured to determine whether to switch the power supply mode of the DC power supply module according to the running speed of the electric vehicle and the torque of the motor, and in the case of determining to switch the power supply mode, determine the power supply mode to be switched to according to the running speed, the torque and the state of the DC power supply module, and issue a command to the control module indicating to switch to the determined power supply mode, wherein the control module determines whether to supply the DC voltage to the EDS according to the command, and controls the DC power supply module to supply the DC voltage to the EDS according to the determined result.

[0020] In a possible implementation, the power supply modes include at least one of: a first power supply mode of supplying a first DC voltage to the EDS via the series connection of the first battery pack and the second battery pack of the DC power supply module; a second power supply mode of supplying a second DC voltage to the EDS via the first battery pack; a third power supply mode of supplying a third DC voltage to the EDS via the second battery pack; and a fourth power supply mode of supplying a fourth DC voltage to the EDS via the parallel connection of the first battery pack and the second battery pack.

[0021] In a possible implementation, the VCU is configured to: in the case that the running speed is lower than a first speed threshold and the torque is lower than a first torque threshold, determine to switch the power supply mode, and determine which one of the second power supply mode, the third power supply mode and the fourth power supply mode to be switched to according to the running speed, the torque and the state of the first battery pack and the second battery pack; and in the case that the running speed is higher than a second speed threshold greater than the first speed threshold and the torque is higher than a second torque threshold greater than the first torque threshold, determine to switch the power supply mode, and determine to switch to the first power supply mode according to the running speed, the torque and the state of the first battery pack and the second battery pack.

[0022] The power supply control circuit, the power supply control system and the electric vehicle according to the present application can effectively reduce the voltage (bus voltage) supplied to the EDS when a lower DC voltage (such as the second DC voltage) needs to be supplied to the EDS, so as to not only improve the voltage utilization rate, but also improve the PWM duty cycle of the bus voltage, reduce the PWM harmonic loss, and further effectively improve the WLTC efficiency. In this way, the voltage utilization rate and the WLTC efficiency can be considered at the same time.

[0023] Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the present application and serve to explain the principles of the present application.

[0025] FIG. 1 is a block diagram of a power supply control system according to the present exemplary embodiment.

[0026] FIG. 2 is a schematic diagram of a power supply control system according to the present exemplary embodiment.

[0027] FIG. 3 is a block diagram of a power supply control system according to the present exemplary embodiment.

[0028] FIG. 4 is a schematic diagram of a power supply control system according to the present exemplary embodiment.

[0029] FIG. 5 is a table of four power supply modes according to the present exemplary embodiment.

[0030] FIG. 6 is a schematic diagram of a power supply control system in a first power supply mode according to the present exemplary embodiment.

[0031] FIG. 7 is a schematic diagram of a power supply control system in a second power supply mode according to the present exemplary embodiment.

[0032] FIG. 8 is a schematic diagram of a power supply control system in a third power supply mode according to the present exemplary embodiment.

[0033] FIG. 9 is a schematic diagram of a power supply control system in a fourth power supply mode according to the present exemplary embodiment.

[0034] FIG. 10 is a schematic diagram of a typical implementation of an EDS using the first to fourth power supply modes according to the present exemplary embodiment.

[0035] FIG. 11a and FIG. 11b are tables showing two sets of efficiencies of the EDS or motor drive unit measured when the first DC voltage and the second DC voltage are supplied to the EDS in the low speed low torque region, respectively.

[0036] FIG. 12 shows the difference between the two sets of efficiencies shown in FIG. 11a and FIG. 11b. DETAILED DESCRIPTION

[0037] Various exemplary embodiments, features, and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numbers in different drawings denote the same or similar elements. Although various aspects of the embodiments are illustrated in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

[0038] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0039] In addition, for the purpose of convenience and brevity, detailed descriptions of well-known functions and structures incorporated in the present application can be omitted. It will be appreciated that those skilled in the art will be able to devise various modes of implementing the application without the benefits of these particulars. Further, like reference numerals refer to like elements throughout the description of the drawings.

[0040] As shown in FIG. 1, the power control system of the present exemplary embodiment can include a DC power module 100, a power control circuit 200, and an electric drive system (EDS) 300. The DC power module 100 is connected to the EDS 300 through the power control circuit 200 to supply a required DC voltage to the EDS 300.

[0041] The DC power module 100 can include first and second battery packs connected in series, such as the first and second battery packs can be connected in series through a controllable switch. In one possible implementation, the power control system can divide the DC power module 100 into two identical battery packs, or can divide the DC power module 100 into two different battery packs. The identical means that the two battery packs are identical in shape, size, and resistance value, and the different means that the two battery packs are different in shape, size, and resistance value.

[0042] The power supply control circuit 200 controls the DC power supply module 100 to use one of the battery packs or both of the battery packs to output different DC voltages to supply the EDS 300 with DC voltage. Thus, the DC power supply module 100 can supply the EDS 300 with different DC voltages in different power supply modes under the control of the power supply control circuit 200.

[0043] The EDS 300 is configured to supply torque to a wheel set of the electric vehicle, and can include an inverter and a motor. As shown in FIG. 2, the EDS 300 includes an inverter 310 and a motor 320. The inverter 310 can supply three-phase current to the motor 320, and can include three bridge arms connected to three-phase windings respectively, each of the bridge arms can include an upper bridge arm and a lower bridge arm, each of the upper bridge arm and the lower bridge arm can include MOS tubes and diodes connected in parallel. The motor 320 can be a synchronous motor used to drive the wheels of the electric vehicle to rotate, and can be a three-phase motor including a stator and a rotor, the stator can include three-phase windings including an A-phase winding, a B-phase winding and a C-phase winding. One end of each of the three-phase windings is connected together to form a neutral point, and the other end of each of the three-phase windings is a free end respectively, and the free end is connected to the inverter 310 respectively. The operation principle of the inverter and the motor is similar to that of the prior art, and will not be described here.

[0044] It should be understood that during the use of the electric vehicle, the electric vehicle has a plurality of different working conditions, and in different working conditions, the speed and torque of the electric vehicle are different, and accordingly the required power is also different. For example, the speed and torque of the electric vehicle in urban working conditions are obviously lower than those of the electric vehicle in high-speed working conditions, and accordingly the required DC voltage of the EDS 300 in urban working conditions is lower than that in high-speed working conditions.

[0045] Therefore, in a possible implementation, the power supply control circuit 200 can selectively cause the DC power supply module 100 to supply the EDS 300 with corresponding DC voltage according to the working condition of the electric vehicle. For example, the vehicle controller VCU of the electric vehicle can determine the power supply mode of the DC power supply module 100 according to the working condition of the electric vehicle, send a command to the power supply control circuit 200, and the power supply control circuit 200 controls in response to receiving the command to cause the DC power supply module 100 to supply the EDS 300 with DC voltage in the power supply mode. Details will be described below when describing the power supply control circuit 200.

[0046] As shown in FIG. 3, the power supply control circuit 200 can comprise a control module 210, which can control the DC power supply module 100 to supply a DC voltage to the EDS 300 via a corresponding branch, such as the first branch or the second branch. The control module 210 is configured to control the first branch to be turned on and the second branch to be turned off when it is required to supply the first DC voltage to the EDS 300, so that the DC power supply module 100 supplies the first DC voltage to the EDS 300 via the first branch. The control module 210 is configured to control the second branch to be turned on and the first branch to be turned off when it is required to supply the second DC voltage, which is lower than the first DC voltage, to the EDS 300, so that the DC power supply module 100 supplies the second DC voltage to the EDS 300 via the second branch.

[0047] In one possible implementation, when the electric vehicle is in the urban working condition, it is indicated that a lower DC voltage, such as the second DC voltage, is required to be supplied to the EDS 300. At this time, the control module 210 controls the branch for supplying the lower DC voltage, such as the second branch, to be turned on, so as to control the DC power supply module 100 to supply the second DC voltage to the EDS 300 via the turned-on second branch.

[0048] Correspondingly, when the electric vehicle is in the high-speed working condition, it is indicated that a higher DC voltage, such as the first DC voltage, is required to be supplied to the EDS 300. At this time, the control module 210 controls the branch for supplying the higher DC voltage, such as the first branch, to be turned on, so as to control the DC power supply module 100 to supply the first DC voltage to the EDS 300 via the turned-on first branch.

[0049] In one possible implementation, when the speed of the electric vehicle is low and the torque is also low, it is indicated that a lower DC voltage is required to be supplied to the EDS 300. At this time, the control module 210 controls the second branch for supplying the lower DC voltage to be turned on, so as to control the DC power supply module 100 to supply the second DC voltage to the EDS 300 via the turned-on second branch.

[0050] Correspondingly, when the speed of the electric vehicle is high and the torque is also high, it is indicated that a higher DC voltage is required to be supplied to the EDS 300. At this time, the control module 210 controls the first branch for supplying the higher DC voltage to be turned on, so as to control the DC power supply module 100 to supply the first DC voltage to the EDS 300 via the turned-on first branch.

[0051] It should be understood that, in the case of supplying the second DC voltage to the EDS 300 via the second branch, the first branch is turned off; similarly, in the case of supplying the first DC voltage to the EDS 300 via the first branch, the second branch is turned off.

[0052] It should be noted that the present application is not limited thereto, and other any suitable manner can also be adopted to determine whether the first DC voltage or the second DC voltage needs to be supplied to the EDS, for example, the control module 210 can determine whether the first DC voltage or the second DC voltage needs to be supplied to the EDS according to the command carrying the indication of the power supply mode of the DC power supply module 100 received from the VCU.

[0053] According to the present embodiment, in the case where the lower second DC voltage needs to be supplied to the EDS, the second branch for supplying the second DC voltage to the EDS is turned on and the first branch for supplying the higher first DC voltage to the EDS is turned off, so that the DC power supply module can supply the lower second DC voltage to the EDS via the second branch, which can effectively reduce the voltage (bus voltage) supplied to the EDS, thereby not only improving the voltage utilization rate, but also improving the PWM duty cycle of the bus voltage, reducing the PWM harmonic loss, and further effectively improving the WLTC efficiency. In this way, the voltage utilization rate and the WLTC efficiency can be considered at the same time.

[0054] In a possible implementation, the DC power supply module 100 includes a first battery pack and a second battery pack, and correspondingly, the control module 210 is configured to: in the case where the first DC voltage needs to be supplied to the EDS, control the first branch to be turned on and the second branch to be turned off, so that the first DC voltage is supplied to the EDS via the first battery pack and the second battery pack connected in series; in the case where the second DC voltage needs to be supplied to the EDS, control the second branch to be turned on and the first branch to be turned off, so that the second DC voltage is supplied to the EDS via the second battery pack.

[0055] In the present embodiment, as shown in FIG. 2, the DC power supply module 100 includes a first battery pack capable of supplying a DC voltage U dc1 and a second battery pack capable of supplying a DC voltage U dc2 , the first battery pack and the second battery pack are connected in series between the positive terminal and the negative terminal of the EDS 300 through the first branch, and the second battery pack is connected between the positive terminal and the negative terminal of the EDS 300 through the second branch.

[0056] In the case where the first DC voltage needs to be supplied to the EDS 300, the control module 210 turns on the first branch and turns off the second branch, so that the first battery pack and the second battery pack are connected in series between the positive terminal and the negative terminal of the EDS 300, thereby the first DC voltage can be supplied to the EDS 300 via the two battery packs connected in series, for example, as shown in FIG. 2, the first DC voltage is equal to Udc1 +U dc2 .

[0057] In the case where the second DC voltage needs to be supplied to the EDS 300, the control module 210 causes the second branch to be turned on and the first branch to be turned off, so that the positive electrode and the negative electrode of the second battery pack are connected to the positive terminal and the negative terminal of the EDS 300 respectively, while the positive electrode of the first battery pack is connected to the positive terminal of the EDS 300, but the negative electrode of the first battery pack is disconnected and not connected to the negative terminal of the EDS 300 nor to the positive electrode of the second battery pack, so that only the second DC voltage is supplied to the EDS 300 via the second battery pack, which, taking the example of Fig. 2, is equal to U dc2 .

[0058] In a possible implementation, the branch of the DC power supply module 100 for supplying the DC voltage to the EDS 300 further comprises a third branch, and accordingly, the control module 210 is configured to, in the case where a third DC voltage lower than the first DC voltage needs to be supplied to the EDS 300, control the third branch to be turned on, the first branch to be turned off and the second branch to be turned off, so that the DC power supply module 100 supplies the third DC voltage to the EDS 300 via the third branch.

[0059] In the present embodiment, similar to the determination of whether the second DC voltage lower than the first DC voltage needs to be supplied to the EDS 300, it is determined whether another lower DC voltage, such as the third DC voltage, needs to be supplied to the EDS 300. If it is determined that the third DC voltage needs to be supplied to the EDS 300, the control module 210 causes the branch for supplying the another lower DC voltage, such as the third branch, to be turned on, so as to control the DC power supply module 100 to supply the third DC voltage to the EDS 300 via the turned-on third branch. It should be understood that in the case where the third DC voltage is supplied to the EDS 300 via the third branch, the first branch and the second branch are both turned off.

[0060] In a possible implementation, the direct-current power supply module 100 comprises a first battery pack and a second battery pack, and correspondingly, the control module 210 is configured to: in a case where the first direct-current voltage needs to be supplied to the EDS 300, control the first branch to be turned on, the second branch to be turned off, and the third branch to be turned off, so that the first direct-current voltage is supplied to the EDS 300 via the first battery pack and the second battery pack connected in series; in a case where the second direct-current voltage needs to be supplied to the EDS 300, control the second branch to be turned on, the third branch to be turned off, and the first branch to be turned off, so that the second direct-current voltage is supplied to the EDS 300 via the second battery pack; and in a case where the third direct-current voltage needs to be supplied to the EDS 300, control the third branch to be turned on, the first branch to be turned off, and the second branch to be turned off, so that the third direct-current voltage is supplied to the EDS 300 via the first battery pack.

[0061] In the embodiment, in a case where the third direct-current voltage needs to be supplied to the EDS 300, the control module 210 controls the third branch to be turned on and the first branch and the second branch to be turned off, so that the positive electrode and the negative electrode of the first battery pack are connected to the positive electrode terminal and the negative electrode terminal of the EDS 300 respectively, and the negative electrode of the second battery pack is connected to the negative electrode terminal of the EDS 300, but the positive electrode of the second battery pack is disconnected and is not connected to the positive electrode terminal of the EDS 300 or the negative electrode of the first battery pack, so that the first direct-current voltage is supplied to the EDS 300 only via the first battery pack. For example, in FIG. 2, the first direct-current voltage is equal to U dc1 .

[0062] In a possible implementation, the control module 210 is configured to: in a case where the fourth direct-current voltage needs to be supplied to the EDS 300, control the first branch to be turned off, the second branch to be turned on, and the third branch to be turned on, so that the direct-current power supply module 100 supplies the fourth direct-current voltage to the EDS 300 via the second branch and the third branch together.

[0063] In this embodiment, similar to determining whether the second and third lower DC voltages need to be supplied to the EDS 300, it is determined whether another lower DC voltage, such as a fourth DC voltage, needs to be supplied to the EDS 300. If it is determined that the fourth DC voltage needs to be supplied to the EDS 300, the control module 210 causes both the second branch and the third branch for supplying the lower DC voltage to be turned on, so as to control the DC power supply module 100 to collectively supply the fourth DC voltage to the EDS 300 via the turned-on second branch and the turned-on third branch. It should be understood that in the case of supplying the fourth DC voltage to the EDS 300 via the second branch and the third branch, the first branch is turned off.

[0064] In a possible implementation, the DC power supply module 100 includes a first battery pack and a second battery pack, and the control module 210 is configured to: in the case of needing to supply the first DC voltage to the EDS 300, control the first branch to be turned on, the second branch to be turned off, and the third branch to be turned off, so as to supply the first DC voltage to the EDS 300 via the first battery pack and the second battery pack connected in series; in the case of needing to supply the second DC voltage to the EDS 300, control the second branch to be turned on, the third branch to be turned off, and the first branch to be turned off, so as to supply the second DC voltage to the EDS 300 via the second battery pack; in the case of needing to supply the third DC voltage to the EDS 300, control the third branch to be turned on, the first branch to be turned off, and the second branch to be turned off, so as to supply the third DC voltage to the EDS 300 via the first battery pack; and in the case of needing to supply the fourth DC voltage to the EDS 300, control the first branch to be turned off, the second branch to be turned on, and the third branch to be turned on, so as to supply the fourth DC voltage to the EDS 300 via the first battery pack and the second battery pack connected in parallel.

[0065] In this embodiment, in the case of needing to supply the fourth DC voltage to the EDS 300, the control module 210 causes the first branch to be turned off and the second branch and the third branch to be turned on, so that the positive electrode and the negative electrode of the first battery pack are connected to the positive electrode terminal and the negative electrode terminal of the EDS 300 respectively, and the positive electrode and the negative electrode of the second battery pack are also connected to the positive electrode terminal and the negative electrode terminal of the EDS 300 respectively, so that the first battery pack and the second battery pack are connected in parallel between the positive electrode terminal and the negative electrode terminal of the EDS 300, and the fourth DC voltage is collectively supplied to the EDS 300 via the first battery pack and the second battery pack connected in parallel. For example, in the case of the fourth DC voltage being equal to U dc1 / / U dc2 .

[0066] In a possible implementation, the power supply control circuit 200 further includes: a first switch device arranged in the first branch, wherein the first branch is turned on when the first switch device is turned on, and the first branch is turned off when the first switch device is turned off; and a second switch device arranged in the second branch, wherein the second branch is turned on when the second switch device is turned on, and the second branch is turned off when the second switch device is turned off.

[0067] In this embodiment, the first switch device and the second switch device are arranged in the first branch and the second branch respectively, the first branch is turned on in response to the turn-on of the first switch device, and the second branch is turned on in response to the turn-on of the second switch device. In this way, the power supply control circuit 200 can control the turn-on and turn-off of the branches by controlling the turn-on and turn-off of the switch devices arranged in the branches.

[0068] In a possible implementation, the first switch device is a switch device capable of disconnecting the first branch when the first switch device is turned off, and the second switch device is a switch device capable of disconnecting the second branch when the second switch device is turned off.

[0069] In this embodiment, the first switch device and the second switch device are both switch devices capable of being completely turned off, that is, the branch in which the switch device is arranged can be completely disconnected when the switch device is turned off.

[0070] In a possible implementation, the power supply control circuit 200 further includes: a first switch device arranged in the first branch, wherein the first branch is turned on when the first switch device is turned on, and the first branch is turned off when the first switch device is turned off; a second switch device arranged in the second branch, wherein the second branch is turned on when the second switch device is turned on, and the second branch is turned off when the second switch device is turned off; and a third switch device arranged in the third branch, wherein the third branch is turned on when the third switch device is turned on, and the third branch is turned off when the third switch device is turned off.

[0071] In this embodiment, the first switch device, the second switch device, and the third switch device are arranged in the first branch, the second branch, and the third branch respectively, the first branch is turned on in response to the turn-on of the first switch device, the second branch is turned on in response to the turn-on of the second switch device, and the third branch is turned on in response to the turn-on of the third switch device. In this way, the power supply control circuit 200 can control the turn-on and turn-off of the branches by controlling the turn-on and turn-off of the switch devices arranged in the branches.

[0072] In a possible implementation, the first switch device is a switch device capable of disconnecting the first branch when the first switch device is turned off by itself, the second switch device is a switch device capable of disconnecting the second branch when the second switch device is turned off by itself, and the third switch device is a switch device capable of disconnecting the third branch when the third switch device is turned off by itself.

[0073] In this embodiment, the first switch device, the second switch device, and the third switch device are all switch devices capable of being completely turned off, that is, when the switch device is turned off, the branch in which the switch device is located can be completely disconnected.

[0074] In a possible implementation, the switch device includes a circuit breaker and / or a triode without a body diode.

[0075] As shown in FIG. 4, the power supply control circuit 200 can include switches S1, S2, and S3, and the control module 210 can control the conduction and turn-off of the switches. As shown in FIGS. 5 and 6, when the switch S1 is turned on, the switch S2 is turned off, and the switch S3 is turned off, the first battery pack and the second battery pack are connected in series between the positive terminal and the negative terminal of the EDS 300 to supply the EDS with a higher direct-current voltage, that is, a first direct-current voltage of U dc1 +U dc2 As shown in FIGS. 5 and 7, when the switch S1 is turned off, the switch S2 is turned off, and the switch S3 is turned on, only the first battery pack is connected between the positive terminal and the negative terminal of the EDS 300 to supply the EDS with a lower direct-current voltage, that is, a third direct-current voltage of U dc1 .

[0076] As shown in FIGS. 5 and 8, when the switch S1 is turned off, the switch S2 is turned on, and the switch S3 is turned off, only the second battery pack is connected between the positive terminal and the negative terminal of the EDS 300 to supply the EDS with a lower direct-current voltage, that is, a second direct-current voltage of U dc2 . dc1 As shown in FIGS. 5 and 9, when the switch S1 is turned off, the switch S2 is turned on, and the switch S3 is turned on, the first battery pack and the second battery pack are connected in parallel between the positive terminal and the negative terminal of the EDS 300 to supply the EDS with a lower direct-current voltage, that is, a fourth direct-current voltage of U dc2 / / U dc2 .

[0077] Therefore, the power supply mode of the direct current power supply module 100 can include a first operation mode, i.e., a power supply mode 1, of jointly supplying the first direct current voltage to the EDS 300 via the series connection of the first battery pack and the second battery pack, a second operation mode, i.e., a power supply mode 2, of supplying the third direct current voltage to the EDS 300 only via the first battery pack, a third operation mode, i.e., a power supply mode 3, of supplying the second direct current voltage to the EDS 300 only via the second battery pack, and a fourth operation mode, i.e., a power supply mode 4, of jointly supplying the fourth direct current voltage to the EDS 300 via the parallel connection of the first battery pack and the second battery pack.

[0078] In the related art, the WLTC efficiency is improved by optimizing the electromagnetic design, the control algorithm, and even the material, and the improvement of the WLTC efficiency by optimizing the electromagnetic design and the control algorithm focuses more on the optimization of the electromagnetic design and the software and hardware optimization of the control unit design, and the effect of the improvement of the WLTC efficiency is not good. Compared with the related art, the WLTC efficiency is improved by optimizing the direct current voltage in the present application, and a switching device is additionally arranged between the direct current power supply module 100 and the EDS 300 in order to realize the concept. Although the switching device can be additionally arranged between the battery and the motor winding or the inverter in the prior art, the purpose is to heat the battery, rather than to improve the WLTC efficiency.

[0079] Therefore, the present application proposes a scheme of reducing the direct current voltage by changing the power supply mode of the direct current power supply module 100, such as the connection state between the battery packs of the direct current power supply module 100. For example, the switching topology structure shown in FIG. 4 is additionally arranged between the direct current power supply module 100 and the EDS 300, and the direct current power supply module 100 is designed as two battery packs (U dc1 and U dc2 ), which are connected in series through the switching S1, and can be crossed with each other to be connected to the inverter 310 via the switching S2 and / or the switching S3 to improve the WLTC efficiency.

[0080] Therefore, the direct current power supply module 100 can supply the direct current voltage to the EDS 300 in four power supply modes, and the two battery packs can realize four direct current voltage levels and their power supply modes. The direct current voltage can be adjusted in a wide range at any time. For example, when the electric vehicle runs in the low-speed and low-torque region, the EDS 300 is powered by one of the battery packs or the parallel battery packs. Since the direct current voltage is reduced by half or more, the voltage utilization and the average efficiency can be effectively improved. When the electric vehicle runs in the high-speed and high-torque region, the EDS 300 is powered by the two battery packs in series, i.e., by the full direct current voltage, so that the high-speed running performance is not affected.

[0081] As shown in Fig. 5, the switching states corresponding to the four operating modes of the circuit shown in Fig. 4 are listed. Among them, mode 4 is available or not depending on the voltage levels of the first battery pack and the second battery pack, i.e., mode 4 is not always available. As shown in Fig. 10, in the low speed and low torque region, any one of the power supply modes 2-4 can be adopted, and in the high speed and high torque region, the power supply mode 1 can be adopted.

[0082] As shown in Figs. 11a and 11b, which show the two sets of EDS or EMDU (electric motor drive unit) efficiencies measured when the first DC voltage and the second DC voltage are supplied to the EDS 300 respectively in the low speed and low torque region. Fig. 12 shows the difference between the efficiencies of Figs. 11a and 11b, from which it can be seen that in the very low speed region, the overall efficiency is improved by at least 1%, and even more than 30%. Therefore, the power supply control circuit 200 and the power supply control system thereof according to the present application can effectively improve the WLTC efficiency, and also improve the voltage utilization.

[0083] In a possible implementation, the present embodiment provides an electric vehicle comprising the power supply control system described above; a vehicle control unit VCU, configured to determine whether to switch the power supply mode of the DC power supply module 100 according to the running speed of the electric vehicle and the torque of the electric motor, and in the case of determining to switch the power supply mode, determine the power supply mode to be switched to according to the running speed, the torque and the state of the DC power supply module 100, and issue a command to the control module 210 for instructing to switch to the determined power supply mode, wherein the control module 210 determines whether to supply a DC voltage to the EDS 300 according to the command, and controls the DC power supply module 100 to supply the DC voltage to the EDS 300 according to the determined result.

[0084] In the present embodiment, the VCU determines whether to switch the power supply mode according to the running speed of the vehicle and the torque of the electric motor, and in the case of switching the power supply mode, determines which power supply mode to switch to according to the speed, the torque and the state of the DC power supply module 100.

[0085] In a possible implementation, the VCU is configured to: determine to switch the power supply mode when the running speed is lower than a first speed threshold and the torque is lower than a first torque threshold, and determine which one of the second power supply mode, the third power supply mode and the fourth power supply mode to switch to according to the running speed, the torque and the states of the first battery pack and the second battery pack; determine to switch the power supply mode when the running speed is higher than a second speed threshold greater than the first speed threshold and the torque is higher than a second torque threshold greater than the first torque threshold, and determine to switch to the first power supply mode according to the running speed, the torque and the states of the first battery pack and the second battery pack.

[0086] In this embodiment, the running speed lower than the first speed threshold indicates that the vehicle is running at a low speed, and the torque lower than the first torque threshold indicates that the torque of the motor is low. The vehicle running at a speed lower than the first speed threshold and at a torque lower than the first torque threshold works in an urban working condition, and thus the VCU determines to switch to a low power supply mode such as one of the power supply modes 2-4. Then, which one of the power supply modes 2-4 to switch to finally can be determined in combination with the direct-current voltage that the direct-current power module 100 can supply at present. The first speed threshold is, for example, 5000 r / s, 4500 r / s, 4800 r / s, 5200 r / s, etc., and the first torque threshold is, for example, 35 N·m, 40 N·m, 55 N·m, etc.

[0087] The running speed higher than the second speed threshold indicates that the vehicle is running at a high speed, and the torque higher than the second torque threshold indicates that the torque of the motor is high. The vehicle running at a speed higher than the second speed threshold and at a torque higher than the second torque threshold works in a high-speed working condition, and thus the VCU determines to switch to a high power supply mode such as the power supply mode 1. Then, which one of the power supply modes 1 to switch to finally can be determined in combination with the direct-current voltage that the direct-current power module 100 can supply at present. The second speed threshold is, for example, 15000 r / s, 16000 r / s, 17000 r / s, etc., and the second torque threshold is, for example, 280 N·m, 290 N·m, 300 N·m, etc.

[0088] For example, in the case that the vehicle is running in a region of low speed and low torque, the VCU determines to switch to one of the power supply modes 2-4 according to the low running speed and the low torque, and determines the power supply mode to which to finally switch according to the speed, the torque and the direct current voltage that the direct current power supply module 100 is currently able to supply, and assumes that the direct current voltage required by the current speed and torque is exactly consistent with the direct current voltage that the first battery pack is able to provide, it can be determined to switch to the power supply mode 2, and a command for switching the power supply mode to the power supply mode 2 can be sent to the control module 210, and the control module 210 makes the switches S1 and S2 off but makes the switch S3 on in response to the command, so as to supply the third direct current voltage to the EDS 300 via the first battery pack.

[0089] Correspondingly, in the case that the vehicle is running in a region of high speed and high torque, the VCU determines to switch to the power supply mode 1 according to the high running speed and the high torque, and assumes that the direct current voltage required by the current speed and torque is exactly consistent with the direct current voltage that the first battery pack and the second battery pack are able to provide when connected in series, it can be determined to switch to the power supply mode 1, and a command for switching the power supply mode to the power supply mode 1 can be sent to the control module 210, and the control module 210 makes the switch S1 on but makes the switches S2 and S3 off in response to the command, so as to supply the first direct current voltage to the EDS 300 via the first battery pack and the second battery pack connected in series.

[0090] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A power control circuit, characterized by comprising: The application is applied to a power drive system EDS supplied with a direct current voltage via a direct current power module, a branch of the direct current power module supplying the EDS with a direct current voltage comprises a first branch and a second branch, The power supply control circuit comprises: A control module is configured to, in a case where the first direct current voltage needs to be supplied to the EDS, control the first branch to be turned on and the second branch to be turned off, so that the direct current power module supplies the EDS with the first direct current voltage via the first branch, and in a case where the second direct current voltage lower than the first direct current voltage needs to be supplied to the EDS, control the second branch to be turned on and the first branch to be turned off, so that the direct current power module supplies the EDS with the second direct current voltage via the second branch.

2. The power control circuit of claim 1, wherein, The direct current power module comprises a first battery pack and a second battery pack, and correspondingly, the control module is configured to: In a case where the first direct current voltage needs to be supplied to the EDS, control the first branch to be turned on and the second branch to be turned off, so that the first direct current voltage is supplied to the EDS via the first battery pack and the second battery pack connected in series; In a case where the second direct current voltage needs to be supplied to the EDS, control the second branch to be turned on and the first branch to be turned off, so that the second direct current voltage is supplied to the EDS via the second battery pack.

3. The power supply control circuit according to claim 1, wherein The branch of the direct current power module supplying the EDS with a direct current voltage further comprises a third branch, and correspondingly, the control module is configured to: In a case where the third direct current voltage lower than the first direct current voltage needs to be supplied to the EDS, control the third branch to be turned on, the first branch to be turned off and the second branch to be turned off, so that the direct current power module supplies the EDS with the third direct current voltage via the third branch.

4. The power control circuit of claim 3, wherein The direct current power module comprises a first battery pack and a second battery pack, and correspondingly, the control module is configured to: In a case where the first direct current voltage needs to be supplied to the EDS, control the first branch to be turned on, the second branch to be turned off and the third branch to be turned off, so that the first direct current voltage is supplied to the EDS via the first battery pack and the second battery pack connected in series; In a case where the second direct current voltage needs to be supplied to the EDS, control the second branch to be turned on, the third branch to be turned off and the first branch to be turned off, so that the second direct current voltage is supplied to the EDS via the second battery pack; In a case where the third direct current voltage needs to be supplied to the EDS, control the third branch to be turned on, the first branch to be turned off and the second branch to be turned off, so that the third direct current voltage is supplied to the EDS via the first battery pack.

5. The power control circuit of claim 3, wherein The control module is configured to: In a case where the fourth direct current voltage is required to be supplied to the EDS, the first branch is controlled to be turned off, the second branch is controlled to be turned on, and the third branch is controlled to be turned on, so that the direct current power module supplies the fourth direct current voltage to the EDS via the second branch and the third branch.

6. The power control circuit of claim 5, wherein, The direct current power module comprises a first battery pack and a second battery pack, and correspondingly, the control module is configured to: In a case where the first direct current voltage is required to be supplied to the EDS, the first branch is controlled to be turned on, the second branch is controlled to be turned off, and the third branch is controlled to be turned off, so that the first direct current voltage is supplied to the EDS via the first battery pack and the second battery pack connected in series; In a case where the second direct current voltage is required to be supplied to the EDS, the second branch is controlled to be turned on, the third branch is controlled to be turned off, and the first branch is controlled to be turned off, so that the second direct current voltage is supplied to the EDS via the second battery pack; In a case where the third direct current voltage is required to be supplied to the EDS, the third branch is controlled to be turned on, the first branch is controlled to be turned off, and the second branch is controlled to be turned off, so that the third direct current voltage is supplied to the EDS via the first battery pack; In a case where the fourth direct current voltage is required to be supplied to the EDS, the first branch is controlled to be turned off, the second branch is controlled to be turned on, and the third branch is controlled to be turned on, so that the fourth direct current voltage is supplied to the EDS via the first battery pack and the second battery pack connected in parallel.

7. The power control circuit of any one of claims 1-6, wherein, Further comprising: a first switch device arranged in the first branch, wherein the first branch is turned on in a case where the first switch device is turned on, and the first branch is turned off in a case where the first switch device is turned off; a second switch device arranged in the second branch, wherein the second branch is turned on in a case where the second switch device is turned on, and the second branch is turned off in a case where the second switch device is turned off.

8. The power control circuit of any one of claims 3-6, wherein, Further comprising: a first switch device arranged in the first branch, wherein the first branch is turned on in a case where the first switch device is turned on, and the first branch is turned off in a case where the first switch device is turned off; a second switch device arranged in the second branch, wherein the second branch is turned on in a case where the second switch device is turned on, and the second branch is turned off in a case where the second switch device is turned off; a third switch device arranged in the third branch, wherein the third branch is turned on in a case where the third switch device is turned on, and the third branch is turned off in a case where the third switch device is turned off.

9. A power control system characterized by, The direct current power module, the power control circuit, and the EDS of any one of claims 1-8, wherein the EDS comprises an inverter and a motor.

10. An electric vehicle characterized by comprising: Further comprising: the power control system of claim 9; A vehicle control unit VCU is configured to determine whether to switch a power supply mode of the DC power supply module according to an operating speed of the electric vehicle and a torque of the motor, and, in a case where it is determined to switch the power supply mode, determine a power supply mode to which to switch according to the operating speed, the torque, and a state of the DC power supply module, and issue a command to the control module to instruct switching to the determined power supply mode, wherein the control module determines whether to supply a DC voltage to the EDS according to the command, and controls the DC power supply module to supply the DC voltage to the EDS according to a result of the determination.

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