Pressure reduction device and system of driving motor and vehicle

Abstract

The invention discloses a voltage reduction device and system of a driving motor and a vehicle. The device comprises a controller and a voltage reduction circuit. The controller is connected with the step-down circuit and is used for sending a step-down signal to the step-down circuit if the required working voltage of the first driving motor is smaller than the voltage of the power battery; the step-down circuit is used for reducing the voltage provided by the power battery to the required working voltage in response to the step-down signal and then transmitting the voltage to the first driving motor. Therefore, according to the device, the voltage provided by the power battery is reduced to the required working voltage and then transmitted to the first driving motor, it can be guaranteed that the first driving motor works at a high-efficiency point, and therefore the energy consumption of the whole vehicle is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicle technology, and in particular to a voltage reduction device, system and vehicle for a drive motor. Background Art

[0002] With the development of the new energy vehicle industry, more and more new energy vehicle drive motors are moving towards high voltage platforms and high power. The advantage of a high voltage platform is that it can increase the torque boundary of the drive motor, thereby increasing the range of each efficiency range of the drive motor and reducing power loss. However, under low load conditions, a high voltage platform will cause the motor to operate in a low efficiency zone. Summary of the invention

[0003] A voltage reduction device, system and vehicle for a drive motor can reduce the voltage provided by a power battery to a required operating voltage and then transmit it to a first drive motor, thereby ensuring that the first drive motor operates at a high efficiency point, thereby reducing the energy consumption of the entire vehicle.

[0004] In a first aspect, the present disclosure proposes a voltage step-down device for a drive motor, the voltage step-down device comprising: a controller and a voltage step-down circuit; the controller is connected to the voltage step-down circuit, and is used to send a voltage step-down signal to the voltage step-down circuit if the required working voltage of the first drive motor is less than the voltage of the power battery; the voltage step-down circuit is used to respond to the voltage step-down signal, reduce the voltage provided by the power battery to the required working voltage, and then transmit it to the first drive motor.

[0005] According to the voltage reduction device of the drive motor of the embodiment of the present disclosure, by reducing the voltage provided by the power battery to the required working voltage and then transmitting it to the first drive motor, it can ensure that the first drive motor operates at a high efficiency point, thereby reducing the energy consumption of the entire vehicle.

[0006] In a second aspect, the present disclosure proposes a voltage reduction system for a drive motor, the voltage reduction system comprising: a first motor inverter and the above-mentioned voltage reduction device for the drive motor, the voltage reduction device being connected between a power battery and the first motor inverter.

[0007] According to the voltage reduction system of the drive motor of the embodiment of the present disclosure, by reducing the voltage provided by the power battery to the required operating voltage and then transmitting it to the first drive motor, it can ensure that the first drive motor operates at a high efficiency point, thereby reducing the energy consumption of the entire vehicle.

[0008] In a third aspect, the present disclosure proposes a vehicle, comprising a power battery, a generator, a first drive motor and a voltage reduction system for the drive motor, wherein the voltage reduction system is connected between the power battery and the first drive motor, the second motor inverter in the voltage reduction system reuses the inverter of the generator, and the energy storage device in the voltage reduction system reuses the coil of the generator.

[0009] According to the vehicle of the embodiment of the present disclosure, voltage reduction is achieved by reusing the inverter of the generator and the coil of the generator, without adding a new voltage reduction circuit in the vehicle. While reducing costs, the reuse rate of devices in the vehicle is improved, making the voltage reduction device simple and highly feasible.

[0010] In a fourth aspect, the present disclosure proposes a vehicle, comprising a power battery, a second drive motor, a first drive motor and a step-down system for the above-mentioned drive motor, wherein the step-down system is connected between the power battery and the first drive motor, the second motor inverter in the step-down system reuses the inverter of the second drive motor, and the energy storage device in the step-down system reuses the coil of the second drive motor.

[0011] According to the vehicle of the embodiment of the present disclosure, voltage reduction is achieved by reusing the inverter of the second drive motor and the coil of the second drive motor, without adding a new voltage reduction circuit in the vehicle. While reducing costs, the reuse rate of devices in the vehicle is improved, making the voltage reduction device simple and highly feasible.

[0012] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a structural schematic diagram of a voltage reduction device for a drive motor according to an embodiment of the present disclosure;

[0014] Figure 2 is a structural schematic diagram of a voltage reduction device for a driving motor according to a specific embodiment of the present disclosure;

[0015] Figure 3 is a topological diagram of a voltage reduction device for a driving motor according to a first specific embodiment of the present disclosure;

[0016] Figure 4 is a topological diagram of a voltage reduction device for a driving motor according to a second specific embodiment of the present disclosure;

[0017] Figure 5 is a structural schematic diagram of a voltage reduction system for a drive motor according to an embodiment of the present disclosure;

[0018] Figure 6 is a schematic structural diagram of a vehicle according to an embodiment of the present disclosure;

[0019] Figure 7 It is a schematic structural diagram of a vehicle according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] Embodiments of the present disclosure are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0021] Please refer to the following Figure 1-7 A voltage reduction device, system and vehicle for a drive motor according to an embodiment of the present disclosure are described.

[0022] Figure 1 FIG. 1 is a schematic diagram of the structure of a voltage reduction device for a drive motor according to an embodiment of the present disclosure. Figure 2 As shown, the voltage reduction device 100 for driving a motor includes: a controller 10 and a voltage reduction circuit 20 .

[0023] In this embodiment, the controller 10 is connected to the step-down circuit 20, and is used to send a step-down signal to the step-down circuit 20 if the required operating voltage of the first drive motor is lower than the voltage of the power battery; the step-down circuit 20 is used to respond to the step-down signal, reduce the voltage provided by the power battery to the operating voltage, and then transmit it to the first drive motor.

[0024] The required operating voltage of the first drive motor is the voltage value at which the first drive motor has the highest operating efficiency, thereby ensuring that the first drive motor operates at a high efficiency point, thereby reducing the energy consumption of the entire vehicle.

[0025] The controller 10 is used to obtain the operating parameters of the first drive motor and determine the required operating voltage based on the operating parameters. The operating parameters may include the operating speed n1 and / or the torque T1.

[0026] It can be understood that, when the operating parameters remain unchanged, different voltages of the first drive motor result in different operating efficiencies of the first drive motor.

[0027] The controller 10 pre-stores the corresponding relationship between parameters and voltages, and the voltage corresponding to each parameter in the corresponding relationship is the voltage value at which the first drive motor has the highest working efficiency when the first drive motor operates according to the parameter. The controller 10 can determine the required working voltage corresponding to the operating parameter from the corresponding relationship, so that when the first drive motor operates according to the operating parameter, the required working voltage of the first drive motor is the voltage value at which the first drive motor has the highest working efficiency, ensuring that the first drive motor operates at a high efficiency point, thereby reducing the energy consumption of the entire vehicle.

[0028] Therefore, when the high-power drive motor operates in a low-load condition, a high-efficiency required operating voltage can be selected according to the operating parameters of the first drive motor, so that the first drive motor operates at a high efficiency point, thereby reducing the energy consumption of the entire vehicle.

[0029] Specifically, the controller 10 can obtain the required power P1 of the vehicle. If the required power P1 is less than the power threshold P0, the vehicle is controlled to be in two-wheel drive mode, and then the operating parameters of the first drive motor are obtained. The required working voltage Ug is determined based on the corresponding relationship of the operating parameters, and when the required working voltage Ug is less than the voltage of the power battery, a step-down signal is sent to the step-down circuit 20. In response to the step-down signal sent by the controller 10, the step-down circuit 20 reduces the voltage provided by the power battery to the required working voltage and transmits it to the first drive motor. As a result, when the high-power drive motor operates in a low-load condition, a high-efficiency required working voltage can be selected according to the operating parameters of the first drive motor, so that the first drive motor operates at a high efficiency point, thereby reducing the energy consumption of the whole vehicle.

[0030] When the vehicle is in operation, the controller 10 obtains the required power P1 of the vehicle when it is determined that the vehicle meets the following target conditions. The target conditions may include: the vehicle is an EV (electric vehicle, pure electric drive mode); or, when the vehicle is not an EV and the second drive motor (i.e., the rear drive motor) of the vehicle is not working, the vehicle is a four-wheel drive vehicle and the power demand is not high, and the second drive motor is in an idle state.

[0031] It should be noted that when the vehicle is in EV mode and the required power P1 is greater than or equal to the power threshold P0, or when the vehicle is not EV and the second drive motor of the four-wheel drive vehicle is working, the controller 10 controls the vehicle to be in four-wheel drive mode, does not reduce the voltage, and controls it according to the vehicle torque distribution strategy.

[0032] See also Figure 2 The step-down circuit 20 may include a second motor inverter 21, an energy storage device 22 and a switch circuit 23. The second motor inverter 21 is connected to the power battery 301 and the first end of the energy storage device 22 respectively; the first end of the switch circuit 23 is connected to the second end of the energy storage device 22, the second end of the switch circuit 23 is connected to the first motor inverter 201 of the first drive motor 303, and the third end of the switch circuit 23 is connected to the power battery 301.

[0033] Specifically, a first end of the second motor inverter 21 is used to be connected to the power battery 301 , and a second end of the second motor inverter 21 is connected to a first end of the energy storage device 22 .

[0034] In this example, the second motor inverter 21 responds to the step-down signal, the switch circuit 23 is in the first switch state, and the energy storage device 22 is connected to the first motor inverter 201 to reduce the voltage provided by the power battery 301 to the required operating voltage.

[0035] Specifically, the second motor inverter 21 is used to receive a step-down signal sent by the controller 10, and in response to the step-down signal, controls the switch circuit 23 to be in a first switch state to conduct between the energy storage device 22 and the first motor inverter 201, and repeats the charge and discharge process of the energy storage device 22 to reduce the voltage provided by the power battery 301 to the required working voltage; wherein, the charge and discharge process of the energy storage device 22 includes: controlling the power battery 301 to supply power to the energy storage device 22 and the first drive motor 303 in a first time period, and controlling the energy storage device 22 to supply power to the first drive motor 303 in a second time period; the second time period is located after the first time period.

[0036] It should be noted that the second motor inverter 21 may be an inverter of a generator or an inverter of a second drive motor, and the energy storage device 22 may be a coil of a generator or a coil of a second drive motor. Among them, when the vehicle is an EV, the inverter of the generator and the coil of the generator will be idle, so they can be reused. When the vehicle is not an EV and the second drive motor of the vehicle is not working, when the inverter of the second drive motor and the coil of the second drive motor are idle, the inverter of the second drive motor and the second drive motor can be reused.

[0037] As a first example, see Figure 3 The switch circuit 23 may include a first switch S1 and a second switch S2; wherein the first switch S1 is connected between the power battery 301 and the first motor inverter 201; and the second switch S2 is connected between the first motor inverter 201 and the energy storage device 22.

[0038] Specifically, the control end of the first switch S1 is connected to the second motor inverter 21, the first end of the first switch S1 is used to connect to the output end of the power battery 301, and the second end of the first switch S1 is respectively connected to the first motor inverter 201 and the first end of the second switch S2; the control end of the second switch S2 is connected to the second motor inverter 21, and the second end of the second switch S2 is connected to the second end of the energy storage device 22. Among them, the first switch state may include: the first switch S1 is disconnected, and the second switch S2 is closed.

[0039] Specifically, the second motor inverter 21 may be an inverter of a generator, and the energy storage device 22 may be a coil of a generator, wherein, when the vehicle is an EV, the inverter of the generator and the coil of the generator will be idle, and the inverter of the generator and the coil of the generator may be reused. The second motor inverter 21 receives a step-down signal sent by the controller 10. In response to the step-down signal, the second motor inverter 21 controls the switch circuit 23 to be in a first switch state (i.e., the first switch S1 is disconnected and the second switch S2 is closed) to conduct between the energy storage device 22 and the first motor inverter 201, and repeats the charge and discharge process of the energy storage device 22 to reduce the voltage provided by the power battery 301 to the required operating voltage. In addition, see Figure 3 The step-down circuit 20 may further include a capacitor C1.

[0040] The charging and discharging process of the energy storage device 22 includes:

[0041] During the first time period, the controllable switches V1, V2, and V3 in the second motor inverter 21 are controlled to be turned on, and the current flows from the positive electrode of the power battery 301 through the controllable switches V1, V2, and V3 to the coils L1, L2, and L3 of the energy storage device 22, and then through the two-phase bridge arm of the first motor inverter 201 to the first drive motor 303, and finally through the one-phase bridge arm of the first motor inverter 201 back to the negative electrode of the power battery 301, thereby powering the energy storage device 22 and the first drive motor 303 through the power battery 301.

[0042] During the second time period, the controllable switches V1, V2, and V3 in the second motor inverter 21 are controlled to be turned off, and the coils L1, L2, and L3 of the energy storage device 22 are discharged. The current flows through the freewheeling diodes VD1, VD2, and VD3 in the second motor inverter 21, the capacitor C1, and the two-phase bridge arms of the first motor inverter 201 to the first drive motor 303, and then returns to the coils L1, L2, and L3 of the energy storage device 22 through the one-phase bridge arm of the first motor inverter 201. Thus, the first drive motor 303 is powered by the energy storage device 22.

[0043] Therefore, by reusing the inverter and coil of the generator, the voltage is reduced, thereby reducing the energy consumption of the entire vehicle.

[0044] It should be noted that the second motor inverter 21 may also include controllable switches V4, V5, V6, and freewheeling diodes VD4, VD5, VD6. During the charging and discharging process of the above-mentioned energy storage device 22, the controllable switches V4, V5, V6 and freewheeling diodes VD4, VD5, VD6 are controlled to be turned off.

[0045] As a second example, see Figure 4 The switch circuit 23 may further include a third switch S3 . The third switch S3 is connected between the power battery 301 and the first motor inverter 201 .

[0046] Specifically, the control end of the third switch S3 is connected to the second motor inverter 21 , the first end of the third switch S3 is used to be connected to the output end of the power battery 301 , and the second end of the third switch S3 is connected to the first motor inverter 201 .

[0047] In this example, the first switch state may further include the third switch S3 being opened, and the second switch state may further include the third switch S3 being closed.

[0048] Specifically, the second motor inverter 21 may be the inverter of the second drive motor (i.e., the second drive motor electronic control), and the energy storage device 22 may be the coil of the second drive motor, wherein, when the vehicle is not an EV and the second drive motor of the vehicle is not working, the inverter of the second drive motor and the coil of the second drive motor can be reused when they are idle. After the second motor inverter 21 receives the step-down signal sent by the controller 10, it can respond to the step-down signal and control the switch circuit 23 to be in the first switch state (i.e., the first switch S1 is disconnected, the second switch S2 is closed, and the third switch S3 is disconnected) so that the energy storage device 22 is connected to the first motor inverter 201, and the charge and discharge process of the energy storage device 22 is repeated to reduce the voltage of the power battery 301 to the required operating voltage. In addition, see Figure 4 The step-down circuit 20 may further include a capacitor C1.

[0049] The charging and discharging process of the energy storage device 22 includes:

[0050] During the first time period, the controllable switches V1, V2, and V3 in the second motor inverter 21 are controlled to be turned on, and the current flows from the positive electrode of the power battery 301 through the controllable switches V1, V2, and V3 to the coils L1, L2, and L3 of the energy storage device 22, and then through the two-phase bridge arm of the first motor inverter 201 to the first drive motor 303, and finally through the one-phase bridge arm of the first motor inverter 201 back to the negative electrode of the power battery 301, thereby powering the energy storage device 22 and the first drive motor 303 through the power battery 301.

[0051] During the second time period, the controllable switches V1, V2, and V3 in the second motor inverter 21 are controlled to be turned off, and the coils L1, L2, and L3 of the energy storage device 22 are discharged. The current flows through the freewheeling diodes VD1, VD2, and VD3 in the second motor inverter 21, the capacitor C1, and the two-phase bridge arms of the first motor inverter 201 to the first drive motor 303, and then returns to the coils L1, L2, and L3 of the energy storage device 22 through the one-phase bridge arm of the first motor inverter 201. Thus, the first drive motor 303 is powered by the energy storage device 22.

[0052] Therefore, by reusing the inverter of the second drive motor and the coil of the second drive motor, voltage reduction is achieved, thereby reducing the energy consumption of the entire vehicle.

[0053] It should be noted that the second motor inverter 21 may also include controllable switches V4, V5, V6, and freewheeling diodes VD4, VD5, VD6. During the charging and discharging process of the above-mentioned energy storage device 22, the controllable switches V4, V5, V6 and freewheeling diodes VD4, VD5, VD6 are controlled to be turned off.

[0054] See also Figure 4 The vehicle 400 may further include an inverter of the generator 302 and a coil of the generator 302 , wherein a first end of the inverter of the generator 302 is respectively connected to the power battery 301 and the switch circuit 23 , and a second end of the inverter of the generator 302 is connected to a first end of the coil of the generator 302 .

[0055] As an example, the controller 10 is also used to send a shutdown signal to the step-down circuit 20 if the required operating voltage is greater than or equal to the voltage of the power battery 301; the second motor inverter 21 in the step-down circuit 20 responds to the shutdown signal, the switching circuit 23 is in the second switching state, and the power battery 301 and the first motor inverter 201 are connected to transmit the voltage provided by the power battery 301 to the first motor inverter 201.

[0056] Specifically, the controller 10 sends a shutdown signal to the step-down circuit 20 when the required working voltage Ug is greater than or equal to the voltage of the power battery 301. The second motor inverter 21 in the step-down circuit 20 responds to the shutdown signal sent by the controller 10, controls the switch circuit 23 to be in the second switch state (i.e., the first switch S1 is closed and the second switch S2 is disconnected), and the power battery 301 and the first motor inverter 201 are connected to transmit the voltage provided by the power battery 301 to the first motor inverter 201. It should be noted that the controller 10 can also send a shutdown signal to the step-down circuit 20 when the required power P1 increases instantaneously. Therefore, by sending a shutdown signal to the step-down circuit when the required working voltage is greater than or equal to the voltage of the power battery, the step-down device can be disconnected when the circuit does not need to step down.

[0057] To summarize, the voltage reduction device of the drive motor achieves voltage reduction by adding a voltage reduction circuit at the front end of the first drive motor, and determines the required high-efficiency working voltage through the operating parameters of the first drive motor. It can make the first drive motor operate at a high efficiency point when the high-power drive motor operates under low-load conditions, thereby reducing the energy consumption of the entire vehicle.

[0058] In addition, voltage reduction is achieved by reusing the inverter of the generator and the coil of the generator, or the inverter of the second drive motor and the coil of the second drive motor. This eliminates the need to add a new voltage reduction circuit in the vehicle, thereby reducing costs and increasing the reuse rate of components in the vehicle, making the voltage reduction device simple and highly feasible.

[0059] Figure 4 FIG. 1 is a schematic diagram of a voltage reduction system for a drive motor according to an embodiment of the present disclosure. Figure 4 As shown, the voltage reduction system 200 of the drive motor includes: a first motor inverter 201 and the above-mentioned voltage reduction device 100 of the drive motor, and the voltage reduction device 100 of the drive motor is connected between the power battery 301 and the first motor inverter 201.

[0060] It should be noted that, for other specific implementations of the voltage reduction system 200 for the drive motor of the embodiment of the present disclosure, reference may be made to the specific implementations of the voltage reduction device 100 for the drive motor of the embodiment of the present disclosure.

[0061] Therefore, the voltage reduction system of the drive motor in the embodiment of the present disclosure can ensure that the first drive motor operates at a high efficiency point by reducing the voltage provided by the power battery to the required operating voltage and then transmitting it to the first drive motor, thereby reducing the energy consumption of the entire vehicle.

[0062] Figure 5 FIG. 1 is a schematic diagram of the structure of a vehicle according to an embodiment of the present disclosure. Figure 6 As shown, the vehicle 300 includes a power battery 301, a generator 302, a first drive motor 303 and a voltage reduction system 200 for the drive motor. The voltage reduction system 200 for the drive motor is connected between the power battery 301 and the first drive motor 303. The second motor inverter 21 in the voltage reduction system 200 for the drive motor reuses the inverter of the generator 302. The energy storage device 22 in the voltage reduction system 200 for the drive motor reuses the coil of the generator 302.

[0063] Therefore, the vehicle of the embodiment of the present disclosure achieves voltage reduction by reusing the inverter of the generator and the coil of the generator, without adding a new voltage reduction circuit in the vehicle. While reducing costs, the reuse rate of devices in the vehicle is improved, making the voltage reduction device simple and highly implementable.

[0064] Figure 6 FIG. 1 is a schematic diagram of the structure of a vehicle according to an embodiment of the present disclosure. Figure 6As shown, the vehicle 400 includes a power battery 301, a second drive motor 401, a first drive motor 303 and the above-mentioned drive motor step-down system 200, the drive motor step-down system 200 is connected between the power battery 301 and the first drive motor 303, the second motor inverter 21 in the drive motor step-down system 200 reuses the inverter of the second drive motor 401, and the energy storage device 22 in the drive motor step-down system 200 reuses the coil of the second drive motor 401.

[0065] Therefore, the vehicle of the embodiment of the present disclosure achieves voltage reduction by reusing the inverter of the second drive motor and the coil of the second drive motor, without adding a new voltage reduction circuit in the vehicle. While reducing costs, the reuse rate of devices in the vehicle is improved, making the voltage reduction device simple and highly feasible.

[0066] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0067] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present disclosure.

[0068] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0069] In the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0070] In the present disclosure, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0071] Although the embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A voltage reduction device for a driving motor, characterized in that: The voltage reduction device comprises: a controller and a voltage reduction circuit; The controller is connected to the step-down circuit and is used to send a step-down signal to the step-down circuit if the required working voltage of the first drive motor is lower than the voltage of the power battery; The step-down circuit is used for responding to the step-down signal to reduce the voltage provided by the power battery to the required working voltage and then transmit it to the first drive motor.

2. The voltage reduction device for a driving motor according to claim 1, characterized in that: The step-down circuit includes a second motor inverter, an energy storage device and a switch circuit; Wherein, the second motor inverter is connected to the power battery and the first end of the energy storage device respectively; The first end of the switch circuit is connected to the second end of the energy storage device, the second end of the switch circuit is connected to the first motor inverter of the first drive motor, and the third end of the switch circuit is connected to the power battery; In response to the voltage reduction signal, the switch circuit is in a first switch state, and the energy storage device is connected to the first motor inverter to reduce the voltage provided by the power battery to the required operating voltage.

3. The voltage reduction device for a driving motor according to claim 2, characterized in that: The controller is further configured to send a shutdown signal to the step-down circuit if the required operating voltage is greater than or equal to the voltage of the power battery; In response to the shutdown signal, the switch circuit is in a second switch state, and the power battery and the first motor inverter are connected to transmit the voltage provided by the power battery to the first motor inverter.

4. The voltage reduction device for a driving motor according to claim 3, characterized in that: The switch circuit includes a first switch and a second switch; Wherein, the first switch is connected between the power battery and the first motor inverter; The second switch is connected between the first motor inverter and the energy storage device; The first switch state includes: the first switch is open, and the second switch is closed; The second switch state includes: the first switch is closed, and the second switch is open.

5. The voltage reduction device for a driving motor according to claim 2, characterized in that: The second motor inverter is an inverter of a generator or an inverter of a second drive motor, and the energy storage device includes a coil of the generator or a coil of the second drive motor.

6. The voltage reduction device for a driving motor according to claim 4, characterized in that: The switch circuit further includes a third switch; Wherein, the third switch is connected between the power battery and the first motor inverter; The first switch state further includes the third switch being opened, and the second switch state further includes the third switch being closed.

7. The voltage reduction device for a driving motor according to any one of claims 1 to 6, characterized in that: The controller is used to obtain operating parameters of the first drive motor and determine the required operating voltage based on the operating parameters.

8. A voltage reduction system for a drive motor, characterized in that: The voltage reduction system comprises: a first motor inverter and a voltage reduction device for a drive motor as claimed in any one of claims 1 to 7, wherein the voltage reduction device is connected between a power battery and the first motor inverter.

9. A vehicle, characterized in that: The vehicle includes a power battery, a generator, a first drive motor and a step-down system for the drive motor as described in claim 8, wherein the step-down system is connected between the power battery and the first drive motor, the second motor inverter in the step-down system reuses the inverter of the generator, and the energy storage device in the step-down system reuses the coil of the generator.

10. A vehicle, characterized in that: The vehicle includes a power battery, a second drive motor, a first drive motor and a step-down system for the drive motor as described in claim 8, wherein the step-down system is connected between the power battery and the first drive motor, the second motor inverter in the step-down system reuses the inverter of the second drive motor, and the energy storage device in the step-down system reuses the coil of the second drive motor.

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