DC charging system, DC charging method and vehicle for distributed electric drive vehicle

Abstract

The present invention relates to the technical field of DC charging of electric vehicles, and discloses a DC charging system, a DC charging method, and a vehicle for a distributed electric drive vehicle. The system comprises: a first controlled switch and a second controlled switch, wherein the first end of the first controlled switch is connected to the center lead of the first motor, and the second end is connected to the second end of the second motor controller; the first end of the second controlled switch is connected to the negative pole of the external DC charging port, and the second end is connected to the center lead of the second motor. The present invention reuses the three-phase winding inductance and busbar capacitance of the two motors of the vehicle itself, and sets two controlled switches to form a boost charging control circuit, thereby realizing DC boost charging and meeting the charging requirements of the high charging voltage of the power battery without the need for an additional external independent boost control box and boost inductor. The overall structure is simple, which reduces the difficulty of vehicle system layout and the failure rate of the system, and improves system stability and safety.

Description

Technical Field

[0001] The present invention relates to the technical field of DC charging of electric vehicles, and in particular to a DC charging system, a DC charging method and a vehicle for distributed electric drive vehicles. Background Art

[0002] Currently, the battery voltage of pure electric vehicles is gradually increasing, reaching approximately 750V or above, and even reaching 900V. However, due to factors such as delayed infrastructure construction, mainstream DC fast charging stations on the market still have many charging stations with low-voltage platforms of 500V and below. There are very few DC charging stations with output voltages above 800V, and the vast majority cannot reach the output capacity of high-voltage DC. When the rated voltage of the charging station is lower than the voltage of the power battery, DC charging of the vehicle cannot be performed. Therefore, when charging vehicles that only support high-voltage direct charging are used with low-voltage DC charging stations, they may not be fully charged or even charge at all.

[0003] In related technologies, an independent fast-charging boost control box is added to control the high-voltage power battery, motor controller, and three-phase drive motor for boost charging. However, since it is a separate circuit, the difficulty of vehicle design layout is increased. Moreover, as the battery charging voltage requirement becomes higher and higher, even reaching 900V, the addition of an independent fast-charging boost control box is difficult to meet the boost demand of such a high charging voltage, and an additional boost inductor must be added, further increasing the difficulty of vehicle design layout. Summary of the Invention

[0004] In view of this, the present invention provides a DC charging system, a DC charging method and a vehicle for a distributed electric drive vehicle, so as to solve the problem that the existing solution of boosting and charging electric vehicles for low-voltage charging piles by adding an independent fast-charging boost control box is difficult to arrange the whole vehicle, and the boosting capacity is limited and it is difficult to meet the high-voltage charging requirements of the battery.

[0005] In a first aspect, the present invention provides a DC charging system for a distributed electric drive vehicle, the distributed electric drive vehicle comprising: a first motor, a second motor, a first motor controller connected to the first motor, a second motor controller connected to the second motor, a power battery, and a bus capacitor arranged between the positive and negative poles of the power battery, the positive pole of the bus capacitor being connected to the first end of the first motor controller and the first end of the second motor controller, respectively, and the negative pole of the bus capacitor being connected to the second end of the first motor controller and the second end of the second motor controller, respectively; the DC charging system comprising: a boost charging control circuit, the boost charging control circuit comprising: a first controlled switch and a second controlled switch, wherein the first end of the first controlled switch is connected to the center lead wire of the first motor, and the second end is connected to the second end of the second motor controller; the first end of the second controlled switch is connected to the negative pole of the external DC charging port, and the second end is connected to the center lead wire of the second motor.

[0006] The present invention reuses the three-phase winding inductance and bus capacitance of the two motors of the distributed electric drive vehicle itself, and sets two controlled switches to form a boost charging control circuit, which can realize DC boost charging of the power battery and meet the charging requirements of the power battery with high charging voltage without the need for additional external independent boost control box and boost inductor. The overall structure is simple, which reduces the manufacturing cost and layout difficulty of the whole vehicle system, reduces the failure rate of the system, and improves the system stability and safety.

[0007] In an optional embodiment, the boost charging control circuit further includes: a fourth controlled switch and a fifth controlled switch, wherein the first end of the fourth controlled switch is connected to the second end of the second motor controller, and the second end is connected to the negative electrode of the power battery; the first end of the fifth controlled switch is connected to the first end of the second motor controller, and the second end is connected to the positive electrode of the power battery.

[0008] By providing a fourth controlled switch and a fifth controlled switch, the present invention can reuse the three-phase winding inductance and bus capacitance inside one of the motors of the distributed electric drive vehicle itself, and combine the two controlled switches to form a boost charging control circuit, thereby realizing DC boost charging when the deviation between the output voltage of the charging pile and the battery voltage of the power battery is relatively small, realizing flexible boost control under different boost scenario requirements, and having a simple overall structure, reducing the manufacturing cost and layout difficulty of the entire vehicle system, and eliminating the need for an additional external independent boost control box, thereby reducing the failure rate of the system and improving the system stability and safety.

[0009] In an optional embodiment, the DC charging system for the distributed electric vehicle further includes:

[0010] A third controlled switch and a boost capacitor, one end of the boost capacitor is connected to the negative electrode of the external DC charging port, and the other end is connected to the first end of the second motor controller through the third controlled switch.

[0011] The present invention can filter out voltage fluctuations by setting a boost capacitor, especially when the controlled switch is in action, by absorbing and releasing charges, reducing voltage spikes and maintaining voltage stability. It can also absorb high pulse currents at the bus end of the motor controller to prevent damage to the equipment due to sudden current changes. By setting a third controlled switch, the charging port is prevented from being charged, meeting the safety requirements of the charging port to avoid affecting the normal operation of the motor under non-DC boost charging.

[0012] In an optional implementation, the first controlled switch, the second controlled switch, the third controlled switch, the fourth controlled switch, and the fifth controlled switch are all relays.

[0013] The present invention utilizes a relay as a controlled switch of the boost charging control circuit, which has good reliability and stability and can withstand a higher output voltage, so that the operation of the entire boost charging control circuit is more stable and reliable.

[0014] In an optional embodiment, the power battery includes: a power battery module, a main positive relay and a fast charging negative relay, wherein the positive pole of the power battery module is connected to the positive pole of the external DC charging port through the main positive relay; the negative pole of the power battery module is connected to the negative pole of the external DC charging port through the fast charging negative relay.

[0015] The present invention sets a main positive relay and a fast charging negative relay on the power battery module of the power battery and connects them to the external DC charging port, so that the external charging port can directly charge the power battery, so that the entire DC charging system has a variety of charging control schemes with different charging modes, which greatly improves the charging flexibility of the entire DC charging system, can meet the charging needs under different charging pile conditions, and enhance the user experience.

[0016] In an optional embodiment, the power battery further includes: a DC fast charging connector and a boost charging connector, wherein the main positive relay is connected to the positive pole of the external DC charging port through the DC fast charging connector, and the main positive relay is also connected to the first end of the second motor controller through the boost charging connector; the negative pole of the power battery module is connected to the negative pole of the external DC charging port through the DC fast charging connector, and the negative pole of the power battery module is also connected to the second end of the first motor controller through the boost charging connector.

[0017] The present invention can realize the switching of different charging signals by providing a DC fast charging connector and a boost charging connector, making the structural layout of the entire DC charging system simpler.

[0018] In a second aspect, the present invention provides a DC charging method for a distributed electric vehicle, which is applied to the DC charging system for the distributed electric vehicle in the first aspect and any optional embodiment thereof, wherein the distributed electric vehicle includes: a first motor, a second motor, a first motor controller connected to the first motor, a second motor controller connected to the second motor, a power battery, and a bus capacitor disposed between the positive and negative poles of the power battery, wherein the positive pole of the bus capacitor is connected to the first end of the first motor controller and the first end of the second motor controller, respectively, and the negative pole of the bus capacitor is connected to the second end of the first motor controller and the second end of the second motor controller, respectively. The method includes:

[0019] Get the maximum allowable output voltage of the external DC charging port;

[0020] Based on the relationship between the maximum allowable output voltage and the battery voltage of the power battery of the distributed electric drive vehicle, the first controlled switch and the second controlled switch in the boost charging control circuit are controlled to operate so that the charging voltage of the power battery meets the battery voltage.

[0021] The present invention controls the actions of the first controlled switch and the second controlled switch in the boost charging control circuit by comparing the maximum allowable output voltage of the external DC charging port with the battery voltage of the power battery, thereby realizing DC boost charging of the power battery and meeting the charging demand of the power battery with a high charging voltage. In this way, even when the output voltage of the charging pile does not meet the battery voltage of the power battery, normal charging of the power battery can still be guaranteed, thereby realizing automatic control of boost charging and improving user experience.

[0022] In an optional embodiment, controlling the actions of the first controlled switch and the second controlled switch in the boost charging control circuit based on the relationship between the maximum allowable output voltage and the battery voltage of the power battery of the distributed electric drive vehicle includes:

[0023] determining whether the maximum allowable output voltage is less than the battery voltage;

[0024] When the maximum allowable output voltage is less than the battery voltage, both the first controlled switch and the second controlled switch are controlled to be turned on.

[0025] The present invention controls the first controlled switch and the second controlled switch in the boost charging control circuit to be turned on when the maximum allowable output voltage of the external DC charging port is lower than the battery voltage of the power battery, thereby realizing DC boost charging of the power battery. In this way, even when the output voltage of the charging pile does not meet the battery voltage of the power battery, normal charging of the power battery can still be guaranteed, automatic control of boost charging is realized, and user experience is improved.

[0026] In an optional implementation, before controlling both the first controlled switch and the second controlled switch to be turned on, the method further includes:

[0027] Calculating a voltage difference between the battery voltage and the maximum allowable output voltage;

[0028] Determining whether the voltage difference is greater than a preset voltage difference threshold;

[0029] When the voltage difference is greater than a preset voltage difference threshold, both the first controlled switch and the second controlled switch are controlled to be turned on.

[0030] The present invention compares the voltage difference between the battery voltage and the maximum allowable output voltage, and performs boost charging control when the voltage difference between the two is greater than a preset voltage difference threshold, thereby significantly increasing the charging voltage to meet the charging requirements of the power battery and achieving precise control of boost charging.

[0031] In an optional embodiment, the method further includes:

[0032] When the voltage difference is not greater than a preset voltage difference threshold, the fourth controlled switch, the fifth controlled switch, and the second controlled switch in the boost charging control circuit are controlled to be turned on, and the first controlled switch is controlled to be turned off.

[0033] The present invention achieves a slight increase in charging voltage to match the charging requirements of the power battery by controlling the corresponding controlled switch action of the boost charging control circuit when the voltage difference between the battery voltage and the maximum allowable output voltage is small. While achieving precise control of boost charging, the entire DC charging system can achieve flexible switching of multiple charging modes, expand the scope of application, and enhance the user experience.

[0034] In an optional embodiment, the method further includes:

[0035] When the voltage difference is greater than a preset voltage difference threshold, the fourth controlled switch and the fifth controlled switch are controlled to be disconnected.

[0036] The present invention controls the fourth controlled switch and the fifth controlled switch to be disconnected when the voltage difference between the battery voltage and the maximum allowable output voltage is large, thereby isolating the two different charging modes, avoiding mutual interference, and ensuring the stability of the entire DC charging system.

[0037] In an optional embodiment, the method further includes:

[0038] When the maximum allowable output voltage is not less than the battery voltage, the first controlled switch and the second controlled switch are both controlled to be turned off, and the fast charging negative relay and the main positive relay of the power battery are controlled to be turned on.

[0039] The present invention does not start the DC charging system when the output voltage of the charging pile can meet the battery voltage requirement, and directly uses the charging pile to charge the power battery, thereby realizing automatic charging control under different charging conditions of the charging pile and improving the user experience.

[0040] In an optional embodiment, when the second controlled switch is controlled to be turned on, the main positive relay of the power battery and the third controlled switch are synchronously controlled to be turned on; when the second controlled switch is controlled to be turned off, the third controlled switch is synchronously controlled to be turned off.

[0041] The present invention realizes the charging function of the power battery under different boost charging modes by synchronously controlling the main positive relay and the third controlled switch of the power battery to be turned on when the second controlled switch is turned on, and synchronously controlling the third controlled switch to be turned off when the second controlled switch is turned off, thereby ensuring the normal operation of the entire DC charging system.

[0042] In an optional embodiment, the method further includes:

[0043] During the charging process of the power battery, monitoring whether the battery voltage requirement of the power battery changes;

[0044] When a change in the battery voltage requirement of the power battery is detected, the battery voltage is updated based on the changed battery voltage requirement, and the actions of the controlled switches in the boost charging control circuit are controlled again based on the relationship between the maximum allowable output voltage and the updated battery voltage, so that the charging voltage of the power battery meets the updated battery voltage.

[0045] The present invention monitors the charging voltage requirement of the power battery in real time during the charging process, and flexibly controls and adjusts the actions of each controlled switch in the boost charging control circuit according to the dynamic change relationship between the charging voltage requirement and the maximum allowable output voltage of the charging pile, thereby realizing flexible switching and control of different charging modes during the charging process, so as to maximize the charging efficiency and enhance the user's charging experience of the vehicle.

[0046] In a third aspect, the present invention provides a vehicle, which is a distributed electric drive vehicle, comprising: a first motor, a second motor, a first motor controller connected to the first motor, a second motor controller connected to the second motor, a power battery, and a bus capacitor disposed between the positive and negative poles of the power battery, wherein the positive pole of the bus capacitor is respectively connected to the first end of the first motor controller and the first end of the second motor controller, and the negative pole of the bus capacitor is respectively connected to the second end of the first motor controller and the second end of the second motor controller. The vehicle further comprises: a controller and a DC charging system for a distributed electric drive vehicle according to the first aspect and any optional embodiment thereof, wherein the controller comprises:

[0047] The memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method described in the second aspect and any one of its optional embodiments by executing the computer instructions.

[0048] Beneficial effects of the present invention:

[0049] The DC charging system for a distributed electric vehicle provided in an embodiment of the present invention reuses the three-phase winding inductance and bus capacitance of the two motors of the distributed electric vehicle itself, and sets two controlled switches to form a boost charging control circuit. This can realize DC boost charging of the power battery and meet the charging requirements of the power battery with high charging voltage without the need for additional external independent boost control box and boost inductor. The overall structure is simple, which reduces the manufacturing cost and layout difficulty of the entire vehicle system, reduces the failure rate of the system, and improves the system stability and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1is an architectural diagram of a distributed DC charging system for electric vehicles according to an embodiment of the present invention;

[0052] Figure 2 is a schematic diagram of the circuit structure of a distributed DC charging system for electric vehicles according to an embodiment of the present invention;

[0053] Figure 3 is a flow chart of a DC charging method for a distributed electric drive vehicle according to an embodiment of the present invention;

[0054] Figure 4 is a flow chart of another DC charging method for a distributed electric drive vehicle according to an embodiment of the present invention;

[0055] Figure 5 is a schematic diagram of fast charge boost mode 1 according to an embodiment of the present invention;

[0056] Figure 6 is a schematic diagram of fast charge boost mode 2 according to an embodiment of the present invention;

[0057] Figure 7 is an overall control logic diagram of a distributed DC charging system for electric vehicles according to an embodiment of the present invention;

[0058] Figure 8 2 is a schematic structural diagram of a controller in a vehicle according to an embodiment of the present invention.

[0059] Figure markings: 1-boost control circuit, 2-power battery, 3-external DC charging port, 21-power battery module, 22-pre-charging resistor, 23-DC fast charging connector, 24-boost charging connector, K1-main positive relay, K2-pre-charging relay, K3-fast charging negative relay, K4-fourth controlled switch, K5-first controlled switch, K6-second controlled switch, K7-third controlled switch, K8-fifth controlled switch, C1-bus capacitor, C2-boost capacitor, F1-first motor controller, F2-second motor controller, M1-first motor, M2-second motor. DETAILED DESCRIPTION

[0060] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0061] Currently, the battery voltage of pure electric vehicles is gradually increasing, reaching approximately 750V or above, and even reaching 900V. However, due to factors such as delayed infrastructure construction, mainstream DC fast charging stations on the market still have many charging stations with low-voltage platforms of 500V and below. There are very few DC charging stations with output voltages above 800V, and the vast majority cannot reach the output capacity of high-voltage DC. When the rated voltage of the charging station is lower than the voltage of the power battery, DC charging of the vehicle cannot be performed. Therefore, when charging vehicles that only support high-voltage direct charging are used with low-voltage DC charging stations, they may not be fully charged or even charge at all.

[0062] In related technologies, an independent fast-charging boost control box is added to control the high-voltage power battery, motor controller, and three-phase drive motor for boost charging. However, the solution of adding an independent fast-charging boost control box increases the manufacturing cost of the entire vehicle. At the same time, since it is a separate circuit, it increases the difficulty of vehicle design layout.

[0063] Based on the above problems, an embodiment of the present invention provides a DC charging system for distributed electric vehicles, which is applied to DC charging of distributed electric vehicles, such as Figure 1 As shown, a distributed electric drive vehicle includes: a first motor M1, a second motor M2, a first motor controller F1 correspondingly connected to the first motor M1, a second motor controller F2 correspondingly connected to the second motor M2, a power battery 2, and a bus capacitor C1 arranged between the positive and negative poles of the power battery 2, wherein the positive pole of the bus capacitor C1 is respectively connected to the first end of the first motor controller F1 and the first end of the second motor controller F2, and the negative pole of the bus capacitor C1 is respectively connected to the second end of the first motor controller F1 and the second end of the second motor controller F2. The DC charging system of the distributed electric drive vehicle includes: a boost charging control circuit 1, which includes: a first controlled switch K5 and a second controlled switch K6, wherein the first end of the first controlled switch K5 is connected to the center lead wire of the first motor M1, and the second end is connected to the second end of the second motor controller F2; the first end of the second controlled switch K6 is connected to the negative pole of the external DC charging port 3, and the second end is connected to the center lead wire of the second motor M2.

[0064] The embodiment of the present invention reuses the three-phase winding inductance and bus capacitance of the two motors of the distributed electric drive vehicle itself, and sets two controlled switches to form a boost charging control circuit. This can realize DC boost charging of the power battery and meet the charging requirements of the power battery with high charging voltage without the need for additional external independent boost control box and boost inductor. The overall structure is simple, which reduces the manufacturing cost and layout difficulty of the entire vehicle system, reduces the failure rate of the system, and improves the system stability and safety.

[0065] Specifically, if Figure 2As shown, the first motor controller F1 includes field-effect transistors Q11, Q12, Q13, Q14, Q15, and Q16. Field-effect transistors Q11 and Q14 constitute a power electronic bridge arm, which is defined as the first bridge arm of the first motor controller F1 in the embodiment of the present invention. Q12 and Q15 constitute a power electronic bridge arm, which is defined as the second bridge arm of the first motor controller F1 in the embodiment of the present invention. Q13 and Q16 constitute a power electronic bridge arm, which is defined as the third bridge arm of the first motor controller F1 in the embodiment of the present invention. It should be noted that these three bridge arms can be composed of other types of power electronic power components and are not limited to field-effect transistors.

[0066] The first motor M1 includes a first inductor L11 , a second inductor L12 , and a third inductor L13 .

[0067] The neutral point lead of the three-phase stator winding of the first motor M1 is connected to the upper end of the three-phase bridge arm of the second motor controller F2, and the other end of the three-phase stator winding of the first motor M1 is respectively connected to the midpoint of the three-phase bridge arm of the first motor controller F1.

[0068] The second motor controller F2 includes field effect transistors Q21 , Q22 , Q23 , Q24 , Q25 and Q26 .

[0069] Among them, field-effect transistors Q21 and Q24 constitute a power electronic bridge arm, which is defined as the first bridge arm of the second motor controller F2 in the embodiment of the present invention. Q22 and Q25 constitute a power electronic bridge arm, which is defined as the second bridge arm of the second motor controller F2 in the embodiment of the present invention. Q23 and Q26 constitute a power electronic bridge arm, which is defined as the third bridge arm of the second motor controller F2 in the embodiment of the present invention. It should be noted that these three bridge arms can be composed of other types of power electronic power components and are not limited to field-effect transistors.

[0070] The second motor M2 includes a fourth inductor L21 , a fifth inductor L22 , and a sixth inductor L23 .

[0071] The neutral point lead of the three-phase stator winding of the second motor M2 is connected to the first end of the second controlled switch K6, and the other end of the three-phase stator winding of the second motor M2 is respectively connected to the midpoint of the three-phase bridge arm of the second motor controller F2.

[0072] Specifically, the specific working principle and working process of the DC charging system of the above-mentioned distributed electric drive vehicle can be found in the relevant description of the method embodiment below, which will not be repeated here.

[0073] In some optional embodiments, such as Figure 1As shown, the boost charging control circuit 1 also includes: a fourth controlled switch K4 and a fifth controlled switch K8, wherein the first end of the fourth controlled switch K4 is connected to the second end of the second motor controller F2, and the second end is connected to the negative electrode of the power battery 2; the first end of the fifth controlled switch K8 is connected to the first end of the second motor controller F2, and the second end is connected to the positive electrode of the power battery 2.

[0074] The embodiment of the present invention provides a fourth controlled switch and a fifth controlled switch, thereby reusing the three-phase winding inductance and bus capacitance inside one of the motors of the distributed electric drive vehicle itself, and combining the two controlled switches to form a boost charging control circuit. This can realize DC boost charging when the deviation between the output voltage of the charging pile and the battery voltage of the power battery is relatively small, and realizes flexible boost control under different boost scenario requirements. The overall structure is simple, reducing the manufacturing cost and layout difficulty of the entire vehicle system, and no additional external independent boost control box is required, thereby reducing the failure rate of the system and improving the system stability and safety.

[0075] In some optional embodiments, such as Figure 1 As shown, the DC charging system of the distributed electric drive vehicle also includes: a third controlled switch K7 and a boost capacitor C2, one end of the boost capacitor C2 is connected to the negative electrode of the external DC charging port 3, and the other end is connected to the first end of the second motor controller F2 through the third controlled switch K7.

[0076] The embodiment of the present invention can filter out voltage fluctuations by setting a boost capacitor, especially when the controlled switch is in action, by absorbing and releasing charges, reducing voltage spikes and maintaining voltage stability. It can also absorb high pulse currents at the bus end of the motor controller to prevent damage to the equipment due to sudden current changes. By setting a third controlled switch, the charging port can be prevented from being energized, meeting the safety requirements of the charging port to avoid affecting the normal operation of the motor under non-DC boost charging.

[0077] Specifically, in the embodiment of the present invention, the first controlled switch K5, the second controlled switch K6, the third controlled switch K7, the fourth controlled switch K4, and the fifth controlled switch K8 are all relays. By using relays as the controlled switches of the boost charging control circuit, the entire boost charging control circuit operates more stably and reliably due to their excellent reliability and stability and ability to withstand higher output voltages.

[0078] It should be noted that, in actual applications, the first controlled switch K5, the second controlled switch K6, the third controlled switch K7, the fourth controlled switch K4, and the fifth controlled switch K8 may also be implemented by transistors, MOS transistors, IGBT switches, etc., as long as the on-off control of the circuit can be achieved. When using different controlled switches, corresponding peripheral circuits need to be adapted. The specific peripheral circuits themselves are existing technologies and will not be described in detail here.

[0079] In some optional embodiments, such as Figure 1 As shown, the power battery 2 includes: a power battery module 21, a main positive relay K1 and a fast charging negative relay K3, wherein the positive pole of the power battery module 21 is connected to the positive pole of the external DC charging port 3 through the main positive relay K1; the negative pole of the power battery module 21 is connected to the negative pole of the external DC charging port 3 through the fast charging negative relay K3.

[0080] The embodiment of the present invention provides a main positive relay and a fast charging negative relay in the power battery module of the power battery and connects them to the external DC charging port, so that the external charging port can directly charge the power battery, so that the entire DC charging system has a variety of charging control schemes with different charging modes, greatly improving the charging flexibility of the entire DC charging system, meeting the charging needs under different charging pile conditions, and improving the user experience.

[0081] In addition, if Figure 1 As shown, in actual application, the power battery 2 further includes: a pre-charging relay K2 and a pre-charging resistor 22 , wherein the pre-charging relay K2 and the pre-charging resistor 22 are connected in series and then connected in parallel with the main positive relay K1 .

[0082] In some optional embodiments, such as Figure 1 As shown, the power battery 2 also includes: a DC fast charging connector 23 and a boost charging connector 24, wherein the main positive relay K1 is connected to the positive pole of the external DC charging port 3 through the DC fast charging connector 23, and the main positive relay K1 is also connected to the first end of the second motor controller F2 through the boost charging connector 24; the negative pole of the power battery module 21 is connected to the negative pole of the external DC charging port 3 through the DC fast charging connector 23, and the negative pole of the power battery module 21 is also connected to the second end of the first motor controller F1 through the boost charging connector 24.

[0083] The embodiment of the present invention can realize the switching of different charging signals by providing a DC fast charging connector and a boost charging connector, making the structural layout of the entire DC charging system simpler.

[0084] According to an embodiment of the present invention, an embodiment of a DC charging method for a distributed electric vehicle is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0085] In this embodiment, a DC charging method for a distributed electric vehicle is provided, which is applied to Figure 1 The DC charging system for distributed electric vehicles shown in the figure is Figure 3 FIG. 1 is a flow chart of DC charging of a distributed electric drive vehicle according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps:

[0086] Step S301: Obtain the maximum allowable output voltage of the external DC charging port.

[0087] Among them, the external DC charging port is the charging port of the charging pile connected to the distributed electric drive vehicle for charging, and its maximum allowable output voltage is the design parameter of the charging pile itself, such as: 500V, 750V, 1000V, etc. This is only an example, and the present invention is not limited to this.

[0088] Step S302 , based on the relationship between the maximum allowable output voltage and the battery voltage of the power battery of the distributed electric drive vehicle, controls the actions of the first controlled switch and the second controlled switch in the boost charging control circuit so that the charging voltage of the power battery meets the battery voltage.

[0089] Specifically, when the maximum allowable output voltage is less than the battery voltage of the power battery of the distributed electric drive vehicle, it means that the output voltage of the charging pile cannot meet the charging requirements of the power battery, and it needs to be boosted to reach the battery voltage of the power battery. Conversely, if the maximum allowable output voltage is not less than the battery voltage of the power battery of the distributed electric drive vehicle, it means that the charging pile can directly charge the power battery and meet the battery voltage requirements of the power battery.

[0090] The embodiment of the present invention controls the actions of the first controlled switch and the second controlled switch in the boost charging control circuit by comparing the maximum allowable output voltage of the external DC charging port with the battery voltage of the power battery, thereby realizing DC boost charging of the power battery and meeting the charging requirements of the power battery for high charging voltage. In this way, even when the output voltage of the charging pile does not meet the battery voltage of the power battery, normal charging of the power battery can still be guaranteed, thereby realizing automatic control of boost charging and improving the user experience.

[0091] In this embodiment, a DC charging method for a distributed electric vehicle is also provided, which is applied to Figure 1The DC charging system for distributed electric vehicles shown in the figure is Figure 4 FIG. 1 is a flow chart of DC charging of a distributed electric drive vehicle according to an embodiment of the present invention. Figure 4 As shown, the process includes the following steps:

[0092] Step S401: Obtain the maximum allowable output voltage of the external DC charging port.

[0093] Specifically, the external DC charging port is the charging port corresponding to the charging pile, and the maximum allowable output voltage is the maximum allowable output voltage of the charging pile. In actual applications, the maximum allowable output voltage of the charging pile can be obtained through communication between the vehicle's battery management system and the charging pile. For example, the maximum allowable output voltage is 500V, 750V, 1000V, etc. This is only an example and the present invention is not limited to this.

[0094] Step S402 , based on the relationship between the maximum allowable output voltage and the battery voltage of the power battery of the distributed electric drive vehicle, controls the actions of the first controlled switch and the second controlled switch in the boost charging control circuit so that the charging voltage of the power battery meets the battery voltage.

[0095] Specifically, by comparing the maximum allowable output voltage with the battery voltage of the power battery, it can be determined whether the charging pile can meet the charging voltage requirements of the power battery. For example, assuming the battery voltage of the power battery is 800V, the required charging voltage of the power battery is above 800V. If the maximum allowable output voltage of the charging pile is 750V, direct charging cannot meet the required charging voltage of the power battery. Therefore, it is necessary to control the first, second, and third controlled switches in the boost charging control circuit to conduct, and utilize the bus capacitor, the first, second, and third controlled switches, and the three-phase winding inductance of the first and second motors to form a boost circuit to boost the output voltage of the charging pile to meet the charging requirements of the power battery. In addition, if the maximum allowable output voltage of the charging pile is 1000V, the first, second, and third controlled switches in the boost charging control circuit can be controlled to remain closed, and the power battery can be charged directly using the output voltage of the charging pile itself to meet the charging requirements of the power battery.

[0096] Specifically, the above step S402 includes:

[0097] Step S4021, determining whether the maximum allowable output voltage is less than the battery voltage.

[0098] Step S4022: When the maximum allowable output voltage is less than the battery voltage, the first controlled switch and the second controlled switch are both controlled to be turned on.

[0099] The embodiment of the present invention controls the first controlled switch and the second controlled switch in the boost charging control circuit to be turned on when the maximum allowable output voltage of the external DC charging port is less than the battery voltage of the power battery, thereby achieving DC boost charging of the power battery. This ensures that the power battery can be normally charged even when the output voltage of the charging pile does not meet the battery voltage of the power battery, realizes automatic control of boost charging, and improves the user experience.

[0100] Furthermore, the above step S4022 specifically includes the following steps:

[0101] Step a1: When the maximum allowable output voltage is less than the battery voltage, calculate the voltage difference between the battery voltage and the maximum allowable output voltage.

[0102] Step a2: determine whether the voltage difference is greater than a preset voltage difference threshold.

[0103] Step a3: When the voltage difference is greater than a preset voltage difference threshold, controlling the first controlled switch and the second controlled switch to be turned on.

[0104] The embodiment of the present invention compares the voltage difference between the battery voltage and the maximum allowable output voltage, and performs boost charging control when the voltage difference between the two is greater than a preset voltage difference threshold, thereby significantly increasing the charging voltage to meet the charging requirements of the power battery and achieving precise control of boost charging.

[0105] Step a4: When the voltage difference is not greater than the preset voltage difference threshold, the fourth controlled switch, the fifth controlled switch, and the second controlled switch in the boost charging control circuit are controlled to be turned on, and the first controlled switch is controlled to be turned off.

[0106] At this time, the boost capacitor, the fourth controlled switch, the fifth controlled switch, the second controlled switch and the three-phase winding inductance of the second motor form a boost circuit. Compared with the boost circuit formed by the three-phase winding inductance of the first motor and the second motor connected in series, the boost capacity of the boost circuit at this time is reduced, but it can meet the charging voltage requirements of the power battery.

[0107] Specifically, the preset voltage difference threshold can be flexibly set according to the actual charging requirements of the power battery. In an embodiment of the present invention, the preset voltage difference threshold is the maximum boost value achieved by a single motor in a distributed electric drive vehicle participating in the boost. That is, when the voltage difference is less than the preset voltage difference threshold, the power battery charging voltage requirement can be met by a single motor participating in the boost. If the voltage difference is greater than the preset voltage difference threshold, two motors are required to participate in the boost at the same time to meet the impulse voltage requirement of the power battery. By way of example, in an embodiment of the present invention, the preset voltage difference threshold is 200V. This is only an example, and the present invention is not limited to this.

[0108] The embodiments of the present invention achieve a slight increase in charging voltage to match the charging requirements of the power battery by controlling the corresponding controlled switch action of the boost charging control circuit when the voltage difference between the battery voltage and the maximum allowable output voltage is small. While achieving precise control of boost charging, the entire DC charging system can achieve flexible switching between multiple charging modes, expanding its application range and improving the user experience.

[0109] Furthermore, in practical applications, step a3 further includes controlling the fourth and fifth controlled switches to be disconnected when the voltage difference is greater than a preset voltage difference threshold. This prevents the original circuit connection structure of the first and second motors from affecting the operation of the boost circuit, and enables independent control of the two boost circuits to prevent mutual influence and ensure circuit stability.

[0110] In the embodiment of the present invention, when the voltage difference between the battery voltage and the maximum allowable output voltage is significantly different, the fourth controlled switch and the fifth controlled switch are controlled to be disconnected, thereby isolating the two different charging modes, avoiding mutual interference, and ensuring the stability of the entire DC charging system.

[0111] Step S4023: When the maximum allowable output voltage is not less than the battery voltage, the first controlled switch and the second controlled switch are both controlled to be turned off, and the fast charge negative relay and the main positive relay of the power battery are controlled to be turned on.

[0112] Specifically, when the maximum allowable output voltage is not less than the battery voltage, it means that the output voltage of the charging pile does not need to be boosted to meet the needs of the power battery, so there is no need to connect to the boost charging control circuit. The power battery can be charged directly by using the conventional charging pile charging scheme of the power battery's fast charging negative relay and the main positive relay, thereby realizing switching control of multiple different charging modes.

[0113] In the embodiment of the present invention, when the output voltage of the charging pile can meet the battery voltage requirement, the DC charging system is not started, and the charging pile is directly used to charge the power battery, thereby realizing automatic charging control under different charging conditions of the charging pile and improving the user experience.

[0114] In some optional embodiments, the above-mentioned DC charging method for distributed electric vehicles further includes: when controlling the second controlled switch to be turned on, synchronously controlling the main positive relay of the power battery and the third controlled switch to be turned on; when controlling the second controlled switch to be turned off, synchronously controlling the third controlled switch to be turned off.

[0115] Specifically, when the second controlled switch is turned on, the boost charging control circuit is engaged. To ensure normal charging of the power battery, the main positive relay of the power battery is synchronously controlled to turn on, and the third controlled switch is controlled to establish a complete charging circuit, achieving boost charging of the power battery. This solves the problem of normal charging of vehicles that only support high-voltage direct charging when used with low-voltage DC charging stations. Furthermore, when the second controlled switch is turned off, indicating that the power battery does not need boost charging or that boost charging has been completed, the third controlled switch is synchronously controlled to turn off, allowing the energy stored in the boost capacitor to be discharged in a timely manner, avoiding any impact on the normal operation of the motor.

[0116] The embodiment of the present invention realizes the charging function of the power battery in different boost charging modes by synchronously controlling the main positive relay and the third controlled switch of the power battery to be turned on when the second controlled switch is turned on, thereby ensuring the normal operation of the entire DC charging system.

[0117] In some optional embodiments, such as Figure 4 As shown, the DC charging method for the distributed electric drive vehicle further includes:

[0118] Step S403 : During the process of charging the power battery, monitoring is performed to determine whether the battery voltage requirement of the power battery changes.

[0119] Step S404: When a change in the battery voltage requirement of the power battery is detected, the battery voltage is updated based on the changed battery voltage requirement, and the actions of the controlled switches in the boost charging control circuit are controlled based on the relationship between the maximum allowable output voltage and the updated battery voltage, so that the charging voltage of the power battery meets the updated battery voltage.

[0120] Specifically, when the vehicle's power battery is charging, its battery voltage requirement is constantly changing, and as the charging progresses, the battery voltage requirement continues to increase. For example, when the power battery is just starting to charge, its battery voltage requirement is 470V. When the charging voltage reaches 470V, its charging voltage may increase to 530V, or even continue to increase. During this process, the maximum allowable output voltage of the charging pile is fixed, assuming it is 500V. At the beginning of charging, the charging pile can meet the 470V charging voltage of the power battery through direct charging. As the charging time changes, when the charging voltage requirement exceeds 500V, the direct charging method of the charging pile will not be able to meet the charging voltage requirement. In this embodiment of the present invention, when a change in the charging voltage requirement of the rechargeable battery is detected during the charging process, the maximum allowable output voltage of the charging pile is compared with the charging voltage corresponding to the current charging voltage requirement. If the voltage difference is not greater than the preset voltage difference threshold, the charging mode defined in step a4 is switched back to. Furthermore, if the charging voltage requirement continues to increase, and the voltage difference is greater than the preset voltage difference threshold, the charging mode defined in step a3 is directly switched to. This ensures that the actual charging voltage of the power battery can meet its actual charging voltage requirement, thereby maximizing charging efficiency.

[0121] The embodiment of the present invention monitors the charging voltage requirement of the power battery in real time during the charging process, and flexibly controls and adjusts the actions of each controlled switch in the boost charging control circuit according to the dynamic change relationship between the charging voltage requirement and the maximum allowable output voltage of the charging pile, thereby realizing flexible switching and control of different charging modes during the charging process, thereby maximizing charging efficiency and improving the user's charging experience of the vehicle.

[0122] The working principle and working process of the DC charging solution for distributed electric vehicles provided by the embodiments of the present invention will be described in detail below with reference to specific application examples.

[0123] As Figure 1 Taking the DC charging system of the distributed electric drive vehicle shown in the figure as an example, its specific working principle is as follows:

[0124] The vehicle's battery management system obtains the maximum allowable output voltage of the charging pile; if the maximum allowable output voltage is greater than the battery voltage of the power battery, the battery management system sends a control signal to control the DC boost charger to perform DC charging on the power battery. Real-time monitoring of the voltage difference ΔU = U 电池 -U 充电桩 If the difference is greater than 0, it switches to fast charge boost mode 2 for DC boost charging.

[0125] The maximum allowable output voltage is less than the battery voltage of the power battery, the battery management system continues to determine the voltage difference ΔU=U电池 -U 充电桩 If it is greater than a certain initial value, such as 200V, a control signal is sent to control the boost charging control circuit 1, the first motor controller F1, the second motor controller F2, the first motor M1 and the second motor M2 to construct a series DC boost circuit to perform DC boost charging according to the fast charging boost mode 1.

[0126] If the battery management system determines that the voltage difference ΔU = U 电池 -U 充电桩 If the voltage difference ΔU=U is greater than 0 and less than or equal to a certain initial value, such as 200V, a control signal is sent to control the boost charging control circuit 1, the second motor controller F2 and the second motor M2 to perform DC boost charging according to the fast charge boost mode 2. When charging according to the fast charge boost mode 2, the voltage difference ΔU=U is monitored in real time. 电池 -U 充电桩 If the difference is greater than a certain initial value, it switches to fast charge boost mode 1 for DC boost charging.

[0127] Specifically, the charging logic based on the above devices is as follows:

[0128] After the charging gun is plugged in and the card is swiped for charging, when the vehicle's battery management system recognizes that the maximum allowable output voltage of the charging pile is greater than the battery voltage, it controls the first controlled switch K5, the second controlled switch K6, and the third controlled switch K7 to open, controls the fast-charge negative relay K3 and the pre-charge relay K2 to close, controls the main positive relay K1 to close, and then controls the pre-charge relay K2 to open. At this time, the charging pile directly charges the power battery with DC power, and the charging is completed when the battery is fully charged in real time. Before charging is completed, the voltage difference ΔU = U battery - U charging pile is monitored in real time. If the difference is greater than 0, the fast-charge negative relay K3 is disconnected and the vehicle switches to fast-charge boost mode 2 for DC boost charging. That is, the first controlled switch K5 is controlled to open, and the main positive relay K1, the fourth controlled switch K4, the second controlled switch K6, the third controlled switch K7, and the fifth controlled switch K8 are controlled to close.

[0129] When the vehicle's battery management system identifies that the maximum allowable output voltage of the charging pile is less than the battery voltage, it enters the DC boost charging process. At this time, the battery management system continues to determine the voltage difference ΔU = U battery - U charging pile. If it is greater than 200V, it sends a control signal to control the boost charging control circuit 1, the first motor controller F1, the second motor controller F2, the first motor M1 and the second motor M2 to construct a series DC boost circuit to perform DC boost charging in accordance with fast charging boost mode 1. That is, the main positive relay K1, the first controlled switch K5, the second controlled switch K6 and the third controlled switch K7 are controlled to be closed, and the remaining switches are disconnected. The circuit structure formed is as follows Figure 5 shown.

[0130] When using an external DC charging pile to charge the power battery 2, the on / off of the field effect transistors in the first motor controller F1 and the second motor controller F2 are controlled, and the voltage of the DC power input to the DC charging port 3 is boosted by the charging control circuit 1 to charge the power battery.

[0131] The specific working principle is divided into the winding inductance energy storage and winding inductance discharge process. The winding inductance energy storage process and principle: the FETs Q11, Q12, Q13 of the first motor controller F1, Q21, Q22, and Q23 of the second motor controller F2 are controlled to be on for a period of time, while the FETs Q14, Q15, and Q16 of the first motor controller F1, Q24, Q25, and Q26 of the second motor controller F2 are controlled to be off.

[0132] The direction of current flow in this process is as follows Figure 5 As shown by the dashed arrow in the middle, current flows from the positive electrode of the external DC charging port 3, passes through the FETs Q11, Q12, and Q13 of the first motor controller F1, flows through the three-phase winding inductors L11, L12, and L13 of the first motor M1, and then passes through the FETs Q21, Q22, and Q23 of the second motor controller F2, flows through the three-phase winding inductors L21, L22, and L23 of the second motor M2, and finally flows to the negative electrode of the external DC charging port 3. In this process, the two motor winding inductors of the distributed electric drive store the DC power input to the DC charging port 3 as secondary electrical energy.

[0133] Winding inductance discharge process and principle: After controlling the field effect tube Q11 of the first motor controller F1, the field effect tube Q12 of the first motor controller F1, the field effect tube Q13 of the first motor controller F1, the field effect tube Q21 of the second motor controller F2, and the field effect tube Q22 of the second motor controller F2, the field effect tube Q23 of the second motor controller F2 are turned on for a period of time, the field effect tube Q11 of the first motor controller F1, the field effect tube Q12 of the first motor controller F1, and the field effect tube Q13 of the first motor controller F1 are controlled to be turned off for a period of time. At this time, the reverse diodes in the FETs Q14, Q15, and Q16 of the first motor controller F1 are turned on for a period of time, and the FETs Q21, Q22, and Q23 of the second motor controller F2 are controlled to remain turned on, while the FETs Q24, Q25, and Q26 of the second motor controller F2 are controlled to remain turned off.

[0134] The direction of current flow in this process is as follows Figure 5 As shown by the solid arrows, current flows from the positive electrode of the external DC charging port 3 to the positive electrode of the power battery module 21, then flows out of the negative electrode of the power battery module 21, passing through the FETs Q14, Q15, and Q16 of the first motor controller F1, through the three-phase winding inductors L11, L12, and L13 of the first motor M1, and then through the FETs Q21, Q22, and Q23 of the second motor controller F2, through the three-phase winding inductors L21, L22, and L23 of the second motor M2, ultimately flowing to the negative electrode of the external DC charging port 3. This process discharges the second electrical energy stored in the winding inductors of the two motors of the distributed electric drive, thereby boosting and charging the power battery.

[0135] All FETs repeat the above process at a high frequency of 10-20 kHz until the power battery 2 is fully charged. After charging is complete, the second and third controlled switches K6 and K7 are first disconnected, followed by the first controlled switch K5, and finally the fourth and fifth controlled switches K4 and K8 are closed.

[0136] When the vehicle's battery management system determines that the voltage difference ΔU = U battery - U charging pile is greater than 0 and less than or equal to 200V, it sends a control signal to control the boost charging control circuit 1, the second motor controller F2, and the second motor M2 to construct a series DC boost circuit to perform DC boost charging according to fast charging boost mode 2. That is, the first controlled switch K5 is controlled to be disconnected, and the main positive relay K1, the fourth controlled switch K4, the second controlled switch K6, the third controlled switch K7, and the fifth controlled switch K8 are controlled to be closed. The circuit structure formed is as follows: Figure 6 shown.

[0137] When using an external DC charging pile to charge the power battery 2, the field effect transistor in the second motor controller F2 is controlled to be turned on and off, and the voltage of the DC power input to the DC charging port 3 is boosted by the boost circuit to charge the power battery.

[0138] The specific working principle is divided into the winding inductance energy storage and winding inductance discharge process. The winding inductance energy storage process and principle: the second motor controller F2's field effect transistor Q21, the second motor controller F2's field effect transistor Q22, the second motor controller F2's field effect transistor Q23 are controlled to be on for a period of time, while the second motor controller F2's field effect transistor Q24, the second motor controller F2's field effect transistor Q25, and the second motor controller F2's field effect transistor Q26 are controlled to be off.

[0139] The direction of current flow in this process is as follows Figure 6 As shown by the dashed arrow, current flows from the positive electrode of the external DC charging port 3, passes through the FETs Q21, Q22, and Q23 of the second motor controller F2, and flows through the three-phase winding inductors L21, L22, and L23 of the second motor M2, ultimately flowing to the negative electrode of the external DC charging port 3. During this process, the winding inductor of the second motor M2 of the distributed electric drive stores the DC power input to the DC charging port 3 as secondary electrical energy.

[0140] The winding inductance discharge process and principle: After the FETs Q21, Q22, and Q23 of the second motor controller F2 are turned on for a period of time, they are then turned off for a period of time. The reverse diodes in the FETs Q24, Q25, and Q26 of the second motor controller F2 are then turned on for a period of time. At this point, the FETs Q24, Q25, and Q26 of the second motor controller F2 and the bus capacitor C1 form a boost circuit, allowing the second electrical energy stored in the winding inductance of the second motor M2 to be adjusted by the boost circuit and continue to charge the power battery.

[0141] The direction of current flow in this process is as follows Figure 6 As shown by the solid arrow, current flows from the positive electrode of the external DC charging port 3, into the positive electrode of the power battery module 21, out of the negative electrode of the power battery module 21, through the field-effect transistors Q24, Q25, and Q26 of the second motor controller F2, through the three-phase winding inductors L21, L22, and L23 of the second motor M2, and ultimately to the negative electrode of the external DC charging port 3. This process discharges the second electrical energy stored in the winding inductor of the second motor M2 of the distributed electric drive, thereby boosting and charging the power battery.

[0142] All field-effect transistors repeat the above process at a high frequency of 10-20 kHz. When charging in fast-charge boost mode 2, the battery management system monitors the voltage difference ΔU = Ubattery - Ucharging pile in real time. If the difference is greater than 200V, it switches to fast-charge boost mode 1 for DC boost charging. This controls the fourth controlled switch K4 and the fifth controlled switch K8 to be disconnected, and controls the main positive relay K1, the first controlled switch K5, the second controlled switch K6, and the third controlled switch K7 to be closed until the power battery 2 is fully charged. After charging is completed, the second controlled switch K6 and the third controlled switch K7 are first disconnected, followed by the first controlled switch K5, and finally the fourth controlled switch K4 and the fifth controlled switch K8 are closed.

[0143] Based on the above process, Figure 7As shown, it is an overall control logic diagram of the DC charging system of the distributed electric drive vehicle provided by the embodiment of the present invention. The technical solution provided by the embodiment of the present invention can switch the DC charging mode and the fast charging boost mode according to the capacity of the charging pile, and further can select and switch the fast charging boost mode 1 and the fast charging boost mode 2 according to the range of the required boost voltage, and switch the boost mode according to the changing battery voltage. While covering the DC charging scenarios in all aspects, it reduces the loss and heat of the system, making the DC charging system more automated and universal. In addition, the fast charging boost mode 1 in the embodiment of the present invention reuses the motor windings to a great extent through the control method of boosting the voltage in series with dual motor windings, improves the inductance of the boost inductor, avoids the additional addition of an external independent inductor module, improves the DC boost charging capability, and greatly reduces the manufacturing cost and layout difficulty of the whole vehicle system.

[0144] The embodiment of the present invention further provides a vehicle, which is a distributed electric drive vehicle, such as Figure 1 As shown, the vehicle includes: a first motor M1, a second motor M2, a first motor controller F1 correspondingly connected to the first motor M1, a second motor controller F2 correspondingly connected to the second motor M2, a power battery 2, and a bus capacitor C1 arranged between the positive and negative electrodes of the power battery 2, the positive electrode of the bus capacitor C1 being connected to the first end of the first motor controller F1 and the first end of the second motor controller F2, and the negative electrode of the bus capacitor C1 being connected to the second end of the first motor controller F1 and the second end of the second motor controller F2, respectively. The vehicle also includes: a controller ( Figure 1 (not shown) and a DC charging system for distributed electric vehicles, wherein, as Figure 8 As shown, the controller includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components utilize different buses to communicate with each other and can be installed on a common mainboard or installed in other ways as needed. The processor can process instructions executed in the computer device, including instructions stored in or on the memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 8 A processor 10 is taken as an example.

[0145] The processor 10 may be a central processing unit, a network processor, or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0146] The memory 20 stores instructions that can be executed by at least one processor 10, so as to enable at least one processor 10 to execute the method shown in the above embodiment.

[0147] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created based on the use of a computer device for displaying a small program landing page, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0148] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0149] The controller further includes a communication interface 30 for the control unit to communicate with other devices or a communication network.

[0150] The embodiment of the present invention also provides a computer-readable storage medium. The above-mentioned method according to the embodiment of the present invention can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0151] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A DC charging method for a distributed electric vehicle, applied to a DC charging system for a distributed electric vehicle, wherein the distributed electric vehicle comprises: A first motor, a second motor, a first motor controller connected to the first motor, a second motor controller connected to the second motor, a power battery, and a bus capacitor arranged between the positive and negative electrodes of the power battery, wherein the positive electrode of the bus capacitor is respectively connected to the first end of the first motor controller and the first end of the second motor controller, and the negative electrode of the bus capacitor is respectively connected to the second end of the first motor controller and the second end of the second motor controller. It is characterized in that the DC charging system includes: a boost charging control circuit, and the boost charging control circuit includes: a first controlled switch and a second controlled switch, wherein, A first end of the first controlled switch is connected to a central lead wire of the first motor, and a second end of the first controlled switch is connected to a second end of the second motor controller; A first end of the second controlled switch is connected to the negative electrode of the external DC charging port, and a second end is connected to the central lead wire of the second motor; The boost charging control circuit further includes: a fourth controlled switch and a fifth controlled switch, wherein: The first end of the fourth controlled switch is connected to the second end of the second motor controller, and the second end is connected to the negative electrode of the power battery; The first end of the fifth controlled switch is connected to the first end of the second motor controller, and the second end is connected to the positive electrode of the power battery; The method comprises: Get the maximum allowable output voltage of the external DC charging port; Based on the relationship between the maximum allowable output voltage and the battery voltage of the power battery of the distributed electric drive vehicle, controlling the operation of a first controlled switch and a second controlled switch in the boost charging control circuit so that the charging voltage of the power battery meets the battery voltage; The controlling the actions of the first controlled switch and the second controlled switch in the boost charging control circuit based on the relationship between the maximum allowable output voltage and the battery voltage of the power battery of the distributed electric drive vehicle includes: When the maximum allowable output voltage is less than the battery voltage, calculating a voltage difference between the battery voltage and the maximum allowable output voltage; When the voltage difference is not greater than a preset voltage difference threshold, the fourth controlled switch, the fifth controlled switch, and the second controlled switch in the boost charging control circuit are controlled to be turned on, and the first controlled switch is controlled to be turned off.

2. The method according to claim 1, characterized in that The method further comprises: When the voltage difference is greater than a preset voltage difference threshold, both the first controlled switch and the second controlled switch are controlled to be turned on.

3. The method according to claim 2, characterized in that The method further comprises: When the voltage difference is greater than a preset voltage difference threshold, the fourth controlled switch and the fifth controlled switch are controlled to be disconnected.

4. The method according to claim 1, wherein The method further comprises: When the maximum allowable output voltage is not less than the battery voltage, the first controlled switch and the second controlled switch are both controlled to be turned off, and the fast charging negative relay and the main positive relay of the power battery are controlled to be turned on.

5. The method according to claim 4, characterized in that When the second controlled switch is controlled to be turned on, the main positive relay and the third controlled switch of the power battery are synchronously controlled to be turned on; when the second controlled switch is controlled to be turned off, the third controlled switch is synchronously controlled to be turned off.

6. The method according to claim 4, characterized in that The method further comprises: During the charging process of the power battery, monitoring whether the battery voltage requirement of the power battery changes; When a change in the battery voltage requirement of the power battery is detected, the battery voltage is updated based on the changed battery voltage requirement, and the actions of the controlled switches in the boost charging control circuit are controlled again based on the relationship between the maximum allowable output voltage and the updated battery voltage, so that the charging voltage of the power battery meets the updated battery voltage.

7. The method according to claim 1, characterized in that The DC charging system for the distributed electric drive vehicle further includes: A third controlled switch and a boost capacitor, one end of the boost capacitor is connected to the negative electrode of the external DC charging port, and the other end is connected to the first end of the second motor controller through the third controlled switch.

8. The method according to claim 7, characterized in that The first controlled switch, the second controlled switch, the third controlled switch, the fourth controlled switch, and the fifth controlled switch are all relays.

9. The method according to any one of claims 1 to 8, characterized in that The power battery includes: a power battery module, a main positive relay and a fast charge negative relay, wherein, The positive electrode of the power battery module is connected to the positive electrode of the external DC charging port through the main positive relay; The negative electrode of the power battery module is connected to the negative electrode of the external DC charging port through the fast charging negative relay.

10. The method according to claim 9, characterized in that The power battery further includes: a DC fast charging connector and a boost charging connector, wherein: The main positive relay is connected to the positive terminal of the external DC charging port through the DC fast charging connector, and the main positive relay is also connected to the first terminal of the second motor controller through the boost charging connector; The negative electrode of the power battery module is connected to the negative electrode of the external DC charging port through a DC fast charging connector, and the negative electrode of the power battery module is also connected to the second end of the first motor controller through the boost charging connector.

11. A vehicle, the vehicle being a distributed electric drive vehicle, comprising: A first motor, a second motor, a first motor controller connected to the first motor, a second motor controller connected to the second motor, a power battery, and a bus capacitor disposed between the positive and negative electrodes of the power battery, wherein the positive electrode of the bus capacitor is respectively connected to the first end of the first motor controller and the first end of the second motor controller, and the negative electrode of the bus capacitor is respectively connected to the second end of the first motor controller and the second end of the second motor controller. The vehicle further comprises: a controller and a DC charging system for a distributed electric drive vehicle according to the method of any one of claims 1 to 10, wherein the controller comprises: The memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method according to any one of claims 1 to 10 by executing the computer instructions.

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