Vehicle charging and discharging system

Abstract

The utility model provides a vehicle charging and discharging system. The vehicle charging and discharging system comprises a power supply module, a switch switching module, a motor winding and a motor control module, the positive pole of the power supply module can be connected with the positive pole of a battery pack in a vehicle through the switch switching module, the motor winding and the motor control module in sequence; when the power supply module is connected with the battery pack through the switch switching module and the motor control module, a direct charging loop can be formed. When the power supply module is connected with the battery pack through the switch switching module, the motor winding and the motor control module, a boost charging loop can be formed. The vehicle charging and discharging system provided by the utility model can realize direct charging and boost charging, does not need to add an additional boost circuit, is simple in structure, and has a cost advantage.

Description

Technical Field

[0001] The utility model relates to the technical field of electric vehicles, in particular to a vehicle charging and discharging system. Background Art

[0002] In the related technologies, due to the use anxiety of "short driving range and slow charging" of 400V platform electric vehicles, 800V high-voltage platform electric vehicles have become the route of choice for more and more mainstream car companies at home and abroad to deeply deploy electrification. However, after the car is upgraded to the 800V voltage platform, it needs to be charged with the support of 800V charging piles. Currently, most charging piles are 400V charging piles, so 800V high-voltage platform electric vehicles face the pain point of difficult charging.

[0003] Therefore, a technical solution that is compatible with 400V charging piles and 800V charging piles has emerged in the prior art to charge 800V electric vehicles. In one technical solution, a boost DC-DC module is installed to increase the charging pile voltage to above 800V for charging the battery, but this technical solution has the problem of large size and high cost due to the additional DC-DC module. Utility Model Content

[0004] In view of this, the utility model aims to provide a vehicle charging and discharging system to solve the problem that the existing charging system needs to be equipped with an additional boost module, which leads to large volume and high cost.

[0005] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0006] A vehicle charging and discharging system includes a power supply module, a switch module, a motor winding and a motor control module;

[0007] The positive electrode of the power supply module can be connected to the positive electrode of the battery pack in the vehicle through the switch switching module, the motor winding and the motor control module in sequence;

[0008] The negative electrode of the power supply module can be connected to the negative electrode of the battery pack;

[0009] When the power supply module is connected to the battery pack through the switch switching module and the motor control module, a direct charging circuit can be formed;

[0010] When the power supply module is connected to the battery pack through the switch switching module, the motor winding and the motor control module, a boost charging loop can be formed.

[0011] Further, the motor control module includes a first power tube, a second power tube, a third power tube, a fourth power tube, a fifth power tube and a sixth power tube;

[0012] A first control branch formed by the first power tube and the fourth power tube connected in series, a second control branch formed by the third power tube and the sixth power tube connected in series, and a third control branch formed by the fifth power tube and the second power tube connected in series are connected in parallel;

[0013] The first power tube, the third power tube and the fifth power tube are connected to the positive electrode of the battery pack.

[0014] Furthermore, the motor winding is a star-connected three-phase motor winding;

[0015] The first end of the star-connected three-phase motor winding is connected to the common end of the first power tube and the fourth power tube;

[0016] The second end of the star-connected three-phase motor winding is connected to the common end of the third power tube and the sixth power tube;

[0017] The third end of the star-connected three-phase motor winding is connected to the common end of the fifth power tube and the second power tube.

[0018] Further, the switch switching module includes a first relay, a second relay and a third relay arranged in parallel;

[0019] The first relay is connected to a first end of the star-connected three-phase motor winding, and is connected to a common end of the first power tube and the fourth power tube;

[0020] The second relay is connected to the second end of the star-connected three-phase motor winding, and is connected to the common end of the third power tube and the sixth power tube;

[0021] The third relay is connected to the third end of the star-connected three-phase motor winding, and is connected to the common end of the fifth power tube and the second power tube.

[0022] Furthermore, the direct charging circuit includes the first relay, the second relay and the third relay that are closed in the switch switching module, and the first power tube, the third power tube and the fifth power tube that are turned on in the motor control module.

[0023] Furthermore, the boost charging circuit includes a boost energy storage circuit and a boost energy discharge circuit;

[0024] The boost energy storage circuit includes the motor winding, some closed relays in the switch switching module and a conducting power tube in the motor control module, and the conducting power tube is connected to some disconnected relays in the switch switching module and the negative electrode of the battery pack;

[0025] The boost energy dissipation circuit includes the motor winding, some closed relays in the switch switching module and a conducting power tube in the motor control module, and the conducting power tube is connected to some disconnected relays in the switch switching module and the positive pole of the battery pack.

[0026] Furthermore, the vehicle charging and discharging system also includes a filtering module;

[0027] The power supply module is connected with the switch module through the filter module.

[0028] Further, the filtering module has a first capacitor;

[0029] The motor control module further includes a second capacitor connected in parallel with the first control branch, the second control branch and the third control branch;

[0030] When the battery pack is connected to the power supply module through the motor control module, the motor winding, the switch switching module and the filter module, a step-down discharge loop can be formed.

[0031] Furthermore, the voltage-reducing discharge circuit includes a voltage-reducing energy storage circuit and a voltage-reducing energy discharge circuit;

[0032] The step-down energy storage circuit includes the motor winding, some closed relays in the switch switching module and a conducting power tube in the motor control module, and the conducting power tube is connected to some disconnected relays in the switch switching module and the positive electrode of the battery pack;

[0033] The step-down energy dissipation circuit includes the motor winding, some closed relays in the switch switching module and a conducting power tube in the motor control module, and the conducting power tube is connected to some disconnected relays in the switch switching module and the negative pole of the battery pack.

[0034] Furthermore, the vehicle charging and discharging system also includes a discharging module;

[0035] The power supply module is connected to the filter module through the discharge module;

[0036] The discharge module is used to reduce the voltage of the first capacitor and / or the second capacitor after charging is completed and / or under preset working conditions.

[0037] Compared with the prior art, the utility model has the following advantages:

[0038] The vehicle charging and discharging system described in the utility model connects the power supply module to the battery pack to form a direct charging circuit through the switch switching module and the motor control module, and can realize the high-voltage direct charging function when the power supply module is an 800V charging pile. The power supply module is connected to the battery pack to form a boost charging circuit through the switch switching module, the motor winding and the motor control module, and can realize the boost charging function when the power supply module is a 400V charging pile. The vehicle charging and discharging system of the utility model does not need to set up an additional boost circuit, has a simple structure, and has the advantages of small size and low cost.

[0039] In addition, in the utility model, the motor winding is arranged as a star-connected three-phase motor winding, the motor control module is arranged to include a first power tube, a second power tube, a third power tube, a fourth power tube, a fifth power tube and a sixth power tube, and the switch switching module is arranged to include a first relay, a second relay and a third relay arranged in parallel. By specifically setting the connection method, it is possible to achieve zero torque control of the motor without leading out the neutral point of the motor and the rotor at any angle, thereby having the advantages of small charging ripple current and no risk of unexpected movement of the vehicle.

[0040] In addition, the filter module can not only filter out the ripples during the charging process, but also form a step-down discharge circuit when the battery pack is connected to the power supply module through the motor control module, the motor winding, the switch switching module and the filter module, so that V2V charging can be realized when the power supply module is the power battery of other vehicles, or when the power supply module is other DC loads, the load can be powered. And, by setting the discharge module, the first capacitor and / or the second capacitor can be discharged to realize the capacitor discharge function of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0042] Figure 1 A schematic diagram of the structure of a vehicle charging and discharging system provided by an embodiment of the utility model;

[0043] Figure 2 A schematic diagram of the circuit structure of a vehicle charging and discharging system provided by an embodiment of the utility model;

[0044] Figure 3 This is a schematic diagram of the circuit structure of the second boost charging solution in the prior art;

[0045] Figure 4 This is a schematic diagram of the circuit structure of the second boost charging solution in the prior art;

[0046] Figure 5 A schematic diagram of the circuit structure of a direct charging circuit provided in an embodiment of the utility model;

[0047] Figure 6 A schematic diagram of the angle, current and magnetic field of the motor rotor provided by an embodiment of the utility model;

[0048] Figure 7 This is a schematic diagram of the circuit structure of the boost energy storage circuit described in the embodiment of the utility model;

[0049] Figure 8 This is a schematic diagram of the circuit structure of the boost and energy dissipation circuit described in an embodiment of the utility model;

[0050] Fig. 9 This is a schematic diagram of the circuit structure of the voltage-reducing energy storage circuit described in an embodiment of the utility model;

[0051] Fig.10 It is a schematic diagram of the circuit structure of the voltage-reducing energy storage circuit described in an embodiment of the utility model.

[0052] Description of reference numerals:

[0053] 1. Power supply module; 2. Motor control module; 3. Switch switching module; 4. Motor winding; 5. Battery pack in the vehicle. DETAILED DESCRIPTION

[0054] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0055] In the description of the present invention, it should be noted that if there are terms such as "upper", "lower", "inner", "outer" and the like indicating orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, if there are terms such as "first" and "second", they are also used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0056] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection" and "connector" 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 it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances.

[0057] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0058] Embodiment 1

[0059] This embodiment relates to a vehicle charging and discharging system, the overall structure of which is as follows: Figure 1 As shown, it includes a power supply module 1, a switch module 2, a motor winding 3 and a motor control module 4.

[0060] Among them, the positive electrode of the power supply module 1 can be connected to the positive electrode of the battery pack 5 in the vehicle through the switch switching module 2, the motor winding 3 and the motor control module 4 in sequence.

[0061] The negative electrode of the power supply module 1 can be connected to the negative electrode of the battery pack 5. When the power supply module 1 is connected to the battery pack 5 through the switch switching module 2 and the motor control module 4, a direct charging circuit can be formed. At the same time, when the power supply module 1 is connected to the battery pack 5 through the switch switching module 2, the motor winding 3 and the motor control module 4, a boost charging circuit can be formed.

[0062] At this time, as set above, the power supply module 1 is connected to the battery pack 5 through the switch switching module 2 and the motor control module 4 to form a direct charging circuit. This embodiment can realize the high-voltage direct charging function when the power supply module 1 is an 800V charging pile. At the same time, the power supply module 1 is connected to the battery pack 5 through the switch switching module 2, the motor winding 3 and the motor control module 4 to form a boost charging circuit. This embodiment can realize the boost charging function when the power supply module 1 is a 400V charging pile. In addition, the vehicle charging and discharging system of this embodiment has a simple structure because it does not require an additional boost circuit, and thus has the advantages of small size and low cost.

[0063] Based on the above overall introduction, specifically, in this embodiment, as a preferred implementation form, Figure 2 As shown, the motor control module of this embodiment includes a first power tube Q 1 , the second power tube Q 2 、The third power tube Q 3 、The fourth power tube Q 4 、The fifth power tube Q 5 And the sixth power tube Q 6 .

[0064] Among them, the first power tube Q 1 With the fourth power tube Q 4 The first control branch formed in series, the third power tube Q 3 With the sixth power tube Q 6 The second control branch formed in series, and the fifth power tube Q 5 With the second power tube Q 2The third control branch formed in series is connected in parallel. 1 , the third power tube Q 3 And the fifth power tube Q 5 Connect to the positive electrode of the above-mentioned battery pack BT1.

[0065] In addition, as a preferred embodiment, Figure 2 As shown, the motor winding is a star-connected three-phase motor winding, and the first end of the star-connected three-phase motor winding is connected to the first power tube Q 1 With the fourth power tube Q 4 The public end of the

[0066] The second end of the star-connected three-phase motor winding is connected to the third power tube Q 3 With the sixth power tube Q 6 The third end of the star-connected three-phase motor winding is connected to the fifth power tube Q 5 With the second power tube Q 2 The public end of the

[0067] As a preferred implementation form, continue as Figure 2 As shown, as a preferred implementation form, the switch switching module of this embodiment includes a first relay S1, a second relay S2 and a third relay S3 which are arranged in parallel.

[0068] The first relay S1 is connected to the first end of the star-connected three-phase motor winding and is connected to the first power tube Q 1 With the fourth power tube Q 4 The second relay S2 is connected to the second end of the star-connected three-phase motor winding and is connected to the third power tube Q 3 With the sixth power tube Q 6 The third relay S3 is connected to the third end of the star-connected three-phase motor winding and is connected to the fifth power tube Q 5 With the second power tube Q 2 The public end of the

[0069] In this embodiment, in order to better understand the above, the motor winding adopts the star-connected three-phase motor winding, so that the motor control module includes the first power tube Q 1 , the second power tube Q 2 、The third power tube Q 3 、The fourth power tube Q 4 、The fifth power tube Q 5 And the sixth power tube Q 6, so that the switch switching module includes a first relay S1, a second relay S2 and a third relay S3 arranged in parallel, and the technical effect produced by the specific connection method between the above components will be specifically combined with Figure 3 , Figure 4 , which is explained below.

[0070] in, Figure 3 A schematic diagram of the circuit structure of the first boost charging scheme in the prior art is shown. In this scheme, the neutral point tap of the three-phase permanent magnet synchronous motor or the AC asynchronous motor is connected to the positive pole of the charging port, and the three-phase winding of the motor and the drive control module of the motor controller are reused to form a boost circuit, thereby increasing the voltage of the 400V charging pile to 800V to charge the battery pack. However, this scheme requires the neutral point tap of the motor to be led out and the charging ripple current is large, which affects the battery life.

[0071] in, Figure 4 A schematic diagram of the circuit structure of the second boost charging solution in the prior art is shown. In this solution, a phase winding of the motor is connected to the positive pole of the charging port, and then a boost circuit is formed through the other two-phase windings and the drive control module of the motor controller, thereby increasing the voltage of the 400V charging pile to 800V for charging the battery. This solution does not require the motor neutral point tap to be brought out, but zero torque control of the motor cannot be achieved in some rotor positions, and there is a risk of unexpected movement of the vehicle.

[0072] At this point, compared with the above existing circuit structure, it is obvious that the setting method of the motor control module, motor winding and switch switching module of this embodiment, as well as the connection method therebetween, do not require the motor neutral point to be led out and have a small charging ripple current compared with the first solution; compared with the second solution, it can solve the problem that some rotor positions cannot achieve zero torque control of the motor, and thus there will be no risk of unexpected movement of the vehicle.

[0073] In this embodiment, as a feasible implementation method, Figure 5 As shown, the direct charging circuit includes the motor winding (i.e. Figure 5 The motor in the above-mentioned switch module, the above-mentioned first relay S1, the above-mentioned second relay S2 and the above-mentioned third relay S3 closed, and the above-mentioned first power tube Q turned on in the above-mentioned motor control module 1 , the third power tube Q 3 And the fifth power tube Q 5 .

[0074] At this time, when the charging pile voltage is higher than the battery pack voltage, relays S1, S2 and S3 are closed, and the first power tube Q 1 , the third power tube Q 3 And the fifth power tube Q5 It is turned on and can form a direct charging circuit with the motor winding. Moreover, it should be noted that if the power tube Q 1 -Q 6 For IGBT (Insulated Gate Bipolar Transistor), Q 1 -Q 6 , if the power tube Q 1 -Q 6 If it is a SiC MOSFET (Metal Oxide Semiconductor Field Effect Transistor), the second power tube Q should be turned off. 2 、The fourth power tube Q 4 And the sixth power tube Q 6 , turn on the first power tube Q 1 、The third power tube Q 3 And the fifth power tube Q 5 .

[0075] It can be understood that through the above direct charging circuit, the charging pile can directly charge the battery pack through the power tube in the motor control module. And the charging path at this time is: charging pile positive electrode → relay S1&S2&S3 → power tube Q 1 &Q 3 &Q 5 → high voltage battery BT1 → negative pole of charging pile. When power tubes Q1-Q6 are IGBTs, the charging path passes through the first power tube Q 1 、The third power tube Q 3 And the fifth power tube Q 5 The anti-parallel diode, when the power tube Q 1 -Q 6 When it is SiC MOSFET, the charging path goes through the first power tube Q 1 、The third power tube Q 3 And the fifth power tube Q 5 .

[0076] In this embodiment, as a feasible implementation method, Figure 7 and Figure 8 As shown, the boost charging circuit includes a boost energy storage circuit and a boost energy discharge circuit. The boost energy storage circuit specifically includes the motor winding (i.e. Figure 7 The motor in the switch module), some of the relays closed in the switch switching module and the power tube turned on in the motor control module, and the power tube turned on is connected to some of the relays disconnected in the switch switching module and the negative pole of the battery pack.

[0077] The boost and energy dissipation circuit specifically includes the motor winding (i.e. Figure 8 The motor in the switch switching module), some of the relays closed in the switch switching module and the power tubes turned on in the motor control module, and the power tubes turned on are connected to some of the relays disconnected in the switch switching module and the positive pole of the battery pack.

[0078] In this embodiment, it is worth noting that when the charging pile voltage is lower than the battery pack voltage, the relay state can be selected according to the motor rotor position, as shown in one of the six combinations in Table 1, so as to charge the battery pack after boosting the motor winding and the motor control module. For example, the combination state 001 means that the relay S1 is disconnected, the relay S2 is disconnected, and the relay S3 is closed.

[0079] Table 1

[0080] Serial number Combined state S1 S2 S3 1 001 disconnect disconnect closure 2 010 disconnect closure disconnect 3 011 disconnect closure closure 4 100 closure disconnect disconnect 5 101 closure disconnect closure 6 110 closure closure disconnect

[0081] In addition, it is worth mentioning that when the vehicle is parked and charged, the direction of the rotor magnetic field is random within the electrical angle range of 0° to 360°. Therefore, in order to make the torque generated at the motor shaft end zero at any rotor electrical angle, it is necessary to completely decouple the motor output torque from the rotor magnetic field position, that is, no matter what the rotor magnetic field position is, the output torque is always zero after current is passed through the motor stator.

[0082] According to vector control theory and electromagnetic field theory, the torque generated by the motor shaft end is related to the real-time position of the rotor and the direction of the superposition of the three-phase stator magnetic field vectors after the stator winding is energized by current. Figure 6 As shown, in order to make the output torque of the motor shaft end 0N.m, according to the vector control theory, after the three-phase electricity is synthesized through the space vector, the component of the vector current on the dotted line q must be 0A, and the current component on the dotted line d can be 0A or not 0A (weakening or increasing magnetization).

[0083] In this embodiment, each of the three-phase windings is externally connected to a relay for selecting the boost inductor, so the current in the three-phase winding can be one phase flowing in and two phases flowing out, two phases flowing in and one phase flowing out, or one phase flowing in and one phase flowing out. Before charging starts, the winding into which the current flows in and the winding from which the current flows out are selected according to the current position of the rotor, and then the relay of the corresponding winding is closed or opened, so that the torque generated at the motor shaft end is zero at any rotor electrical angle, thereby eliminating the risk of unexpected movement of the vehicle.

[0084] The following specifically takes the combination state 001 as an example to illustrate the working process of the system boost charging.

[0085] The first stage of the boost charging process is to form a boost energy storage circuit. Figure 7As shown, the current path is as follows: positive pole of charging pile → relay S3 → motor W phase winding → motor U phase winding → fourth power tube Q 4 → Negative pole of charging pile, and positive pole of charging pile → Relay S3 → Motor W phase winding → Motor V phase winding → Sixth power tube Q 6 →Charging pile negative pole, where the fourth power tube Q 4 And the sixth power tube Q 6 During this working process, the charging pile increases the current of the three-phase winding of the motor, thereby charging and storing energy.

[0086] The second stage of the boost charging process is to form a boost energy dissipation circuit. Figure 8 As shown, the current path is as follows: positive pole of charging pile → relay S3 → motor W phase winding → motor U phase winding → first power tube Q 1 →Battery pack→negative pole of charging pile, and positive pole of charging pile→relay S3→motor W phase winding→motor V phase winding→third power tube Q 3 →Battery pack→Charging pile negative electrode, where the first power tube Q 1 And the third power tube Q 3 During this working process, the current of the three-phase winding of the motor decreases, and the winding voltage increases, through the first power tube Q 1 And the third power tube Q 3 Then the high voltage battery BT1 is charged. 1 -Q 6 If it is IGBT, the power tube Q is turned off. 1 -Q 6 , if the power tube Q 1 -Q 6 If it is SiC MOSFET, the second power tube Q is turned off. 2 、The fourth power tube Q 4 、The sixth power tube Q 6 And the fifth power tube Q 5 , turn on the first power tube Q 1 And the third power tube Q 3 .

[0087] It is understandable that in practical applications, the power tube Q can be controlled by PWM (Pulse Width Modulation). 1 -Q 6 The opening or closing of the PWM can continuously repeat the first and second stages of the boost charging process, so as to increase the voltage to charge the battery when the charging pile voltage is lower than the battery pack voltage. The frequency and duty cycle of PWM are set according to the voltage of the charging pile, the battery pack voltage, the ripple current requirements and the capability range of the power device.

[0088] Based on the above introduction, the structure of the boost charging circuit in other combination states in Table 1 of this embodiment and its working process can refer to the description when the combination state is 001, and will not be repeated here.

[0089] As a preferred implementation form, the vehicle charging and discharging system of this embodiment further includes a filtering module. Figure 2 As shown, the power supply module is connected through the above-mentioned filter module and the above-mentioned switch switching module.

[0090] In a specific implementation, the filtering module may include a first capacitor C1 and a first inductor L1 to filter out ripples during the charging process.

[0091] Among them, as a preferred implementation form, still as Figure 2 As shown, the above-mentioned filter module has a first capacitor C1, and the above-mentioned motor control module also includes a second capacitor C2 arranged in parallel with the above-mentioned first control branch, the above-mentioned second control branch and the above-mentioned third control branch. When the above-mentioned battery pack is connected to the above-mentioned power supply module through the above-mentioned motor control module, the above-mentioned motor winding, the above-mentioned switch switching module and the above-mentioned filter module, a step-down discharge circuit can be formed.

[0092] At this time, as a feasible implementation method, Fig. 9 and Fig.10 As shown, the step-down discharge circuit includes a step-down energy storage circuit and a step-down energy release circuit. Among them, the step-down energy storage circuit specifically includes the motor winding (i.e. Fig. 9 The motor in the switch switching module), some of the relays closed in the switch switching module and the power tubes turned on in the motor control module, and the power tubes turned on are connected to some of the relays disconnected in the switch switching module and the positive electrode of the battery pack.

[0093] The above-mentioned voltage reduction and energy dissipation circuit specifically includes the above-mentioned motor winding (i.e. Fig.10 The motor in the switch switching module), some of the relays closed in the switch switching module and the power tube turned on in the motor control module, and the power tube turned on is connected to some of the relays disconnected in the switch switching module and the negative pole of the battery pack.

[0094] In this embodiment, the power supply module may be a power battery pack of other vehicles, such as Fig. 9 and Fig.10 BT2 shown in the figure may also be other DC loads. In the buck discharge circuit, the energy stored in BT1 can be charged to BT2 after bucking through the BUCK circuit composed of the motor control module, the motor winding and the first capacitor in the filter module, thereby realizing V2V charging.

[0095] At this time, the first stage of the step-down discharge process constitutes a step-down energy storage circuit, such as Fig. 9 As shown, the current path is as follows: BT1 positive electrode → first power tube Q 1 →Motor U phase winding →Motor W phase winding →Relay S3 →Filter module →BT2 positive pole →BT2 negative pole →Filter module →BT1 negative pole, and BT1 positive pole →Third power tube Q 3 →Motor V phase winding →Motor W phase winding →Relay S3 →Filter module →BT2 positive pole →BT2 negative pole →Filter module →BT1 negative pole, where the first power tube Q 1 And the third power tube Q 3 During this operation, the energy of the battery BT1 flows to the motor winding, and the winding current increases.

[0096] The second stage of the step-down discharge process is to form a step-down energy dissipation circuit. Fig.10 As shown, the current path is as follows: The fourth power tube Q 4 →Motor U phase winding→Motor W phase winding→Relay S3→Filter module→BT2 positive pole→BT2 negative pole→Filter module→Fourth power tube Q 4 , and the sixth power tube Q 6 →Motor V-phase winding→Motor W-phase winding→Relay S3→Filter module→BT2 positive pole→BT2 negative pole→Filter module→Sixth power tube Q 6 It should be noted that, during this operation, if the power tube Q 1 -Q 6 If it is IGBT, Q is turned off 1 -Q 6 , the group passes through the anti-parallel diodes of the fourth power tube Q4 and the sixth power tube Q6 for freewheeling. If the power tube Q 1 -Q 6 If it is SiC MOSFET, the first power tube Q is turned off. 1 , the second power tube Q 2 、The third power tube Q 3 And the fifth power tube Q 5 , turn on the fourth power tube Q 4 And the sixth power tube Q 6 , the motor winding current decreases.

[0097] It is understandable that, as mentioned above, in practical applications, the power tube Q can be controlled by PWM. 1 -Q 6 The on and off of the battery pack BT1 can continuously repeat the first and second stages of the step-down discharge process, thereby reducing the voltage to charge the battery pack BT2 when the voltage of the battery pack BT1 is higher than that of the battery pack BT2.

[0098] As a preferred embodiment, see Figure 2 The vehicle charging and discharging system of this embodiment further includes a discharging module. The power supply module is connected to the filter module through the discharging module, and the discharging module is used to reduce the voltage of the first capacitor and / or the second capacitor after charging is completed and / or under preset working conditions.

[0099] In a specific implementation, the above-mentioned discharge module may include a first resistor R1 and a seventh power tube Q7, wherein the first resistor R1 serves as a discharge resistor, and the seventh power tube Q7 may adopt a MOSFET. When the boost charging is completed, the voltage of the capacitor C1 in the filter module can be reduced to below the safe voltage within a specified time through the discharge module. If the specified discharge time is long, only the first resistor R1 can be used for discharge. It should be noted that the preset working condition is set according to the actual use scenario. For example, when a special working condition occurs in the vehicle charging and discharging system, the voltage of the capacitor C1 is actively reduced through the discharge module to ensure the safety of the system.

[0100] In addition, according to actual needs, the discharge module can also be used to release the electric energy stored in the second capacitor C2 in the motor control module when needed. Specifically, by closing any one of the first relay S1, the second relay S2, and the third relay S3, the discharge module can reduce the voltage of the second capacitor C2 to below the safe voltage within a specified time.

[0101] The vehicle charging and discharging system of this embodiment adopts the above configuration, and the power supply module is connected to the battery pack to form a direct charging circuit through the switch switching module and the motor control module. When the power supply module is an 800V charging pile, the high-voltage direct charging function can be realized. The power supply module is connected to the battery pack to form a boost charging circuit through the switch switching module, the motor winding and the motor control module. When the power supply module is a 400V charging pile, the boost charging function can also be realized. At the same time, the vehicle charging and discharging system does not need to set up an additional boost circuit, or lead out the neutral point of the motor, and there is no risk of unexpected movement of the vehicle. It has a simple structure, low cost, and good practicality.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vehicle charging and discharging system, characterized in that: It includes a power supply module, a switch switching module, a motor winding and a motor control module; The positive electrode of the power supply module can be connected to the positive electrode of the battery pack in the vehicle through the switch switching module, the motor winding and the motor control module in sequence; The negative electrode of the power supply module can be connected to the negative electrode of the battery pack; When the power supply module is connected to the battery pack through the switch switching module and the motor control module, a direct charging circuit can be formed; When the power supply module is connected to the battery pack through the switch switching module, the motor winding and the motor control module, a boost charging loop can be formed.

2. The vehicle charging and discharging system according to claim 1, characterized in that: The motor control module includes a first power tube, a second power tube, a third power tube, a fourth power tube, a fifth power tube and a sixth power tube; A first control branch formed by the first power tube and the fourth power tube connected in series, a second control branch formed by the third power tube and the sixth power tube connected in series, and a third control branch formed by the fifth power tube and the second power tube connected in series are connected in parallel; The first power tube, the third power tube and the fifth power tube are connected to the positive electrode of the battery pack.

3. The vehicle charging and discharging system according to claim 2, characterized in that: The motor winding is a star-connected three-phase motor winding; The first end of the star-connected three-phase motor winding is connected to the common end of the first power tube and the fourth power tube; The second end of the star-connected three-phase motor winding is connected to the common end of the third power tube and the sixth power tube; The third end of the star-connected three-phase motor winding is connected to the common end of the fifth power tube and the second power tube.

4. The vehicle charging and discharging system according to claim 3, characterized in that: The switch switching module includes a first relay, a second relay and a third relay arranged in parallel; The first relay is connected to a first end of the star-connected three-phase motor winding, and is connected to a common end of the first power tube and the fourth power tube; The second relay is connected to the second end of the star-connected three-phase motor winding, and is connected to the common end of the third power tube and the sixth power tube; The third relay is connected to the third end of the star-connected three-phase motor winding, and is connected to the common end of the fifth power tube and the second power tube.

5. The vehicle charging and discharging system according to claim 4, characterized in that: The direct charging circuit includes the first relay, the second relay and the third relay which are closed in the switch switching module, and the first power tube, the third power tube and the fifth power tube which are turned on in the motor control module.

6. The vehicle charging and discharging system according to claim 4, characterized in that: The boost charging circuit includes a boost energy storage circuit and a boost energy discharge circuit; The boost energy storage circuit includes the motor winding, some closed relays in the switch switching module and a conducting power tube in the motor control module, and the conducting power tube is connected to some disconnected relays in the switch switching module and the negative electrode of the battery pack; The boost energy dissipation circuit includes the motor winding, some closed relays in the switch switching module and a conducting power tube in the motor control module, and the conducting power tube is connected to some disconnected relays in the switch switching module and the positive pole of the battery pack.

7. The vehicle charging and discharging system according to claim 6, characterized in that: Also includes a filtering module; The power supply module is connected with the switch module through the filter module.

8. The vehicle charging and discharging system according to claim 7, characterized in that: The filter module has a first capacitor; The motor control module further includes a second capacitor connected in parallel with the first control branch, the second control branch and the third control branch; When the battery pack is connected to the power supply module through the motor control module, the motor winding, the switch switching module and the filter module, a step-down discharge loop can be formed.

9. The vehicle charging and discharging system according to claim 8, characterized in that: The step-down discharge circuit includes a step-down energy storage circuit and a step-down energy discharge circuit; The step-down energy storage circuit includes the motor winding, some closed relays in the switch switching module and a conducting power tube in the motor control module, and the conducting power tube is connected to some disconnected relays in the switch switching module and the positive electrode of the battery pack; The step-down energy dissipation circuit includes the motor winding, some closed relays in the switch switching module and a conducting power tube in the motor control module, and the conducting power tube is connected to some disconnected relays in the switch switching module and the negative pole of the battery pack.

10. The vehicle charging and discharging system according to claim 8, characterized in that: Also includes a discharge module; The power supply module is connected to the filter module through the discharge module; The discharge module is used to reduce the voltage of the first capacitor and / or the second capacitor after the boost charging is completed and / or under a preset working condition.

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