Charging and discharging system, charging and discharging control method and vehicle

Abstract

The invention provides a charging and discharging system, a charging and discharging control method and a vehicle, and relates to the technical field of charging, the system comprises an inverter, a first switch, a second switch, a fourth switch, a sixth switch, a seventh switch and a diode; two ends of the first switch and the second switch are respectively connected with the charging equipment and the energy storage equipment; the inverter comprises three bridge arms, the first end of each bridge arm is connected with a second switch through a sixth switch, the second end of each bridge arm is connected with energy storage equipment through a seventh switch, the midpoints of the three bridge arms are correspondingly connected with three-phase windings of the motor respectively, the midpoint of each bridge arm is connected with the first end of a fourth switch through a diode, and the second end of the fourth switch is connected with the energy storage equipment through a fifth switch. The charging voltage of the energy storage equipment is adjusted, the wide-range charging voltage requirement of a vehicle battery pack is met, charging piles of different voltage grades can be matched, the vehicle charging speed is increased, and the quick charging requirement of a user is met.

Description

Technical Field

[0001] The present invention relates to the field of charging technology, and in particular to a charging and discharging system, a charging and discharging control method and a vehicle. Background Art

[0002] As the daily use cost of new energy vehicles is low, more and more consumers are attracted to choose this type of vehicle. As the number of users grows, their diversified needs are also increasing, especially the demand for fast charging technology. Users expect to complete the charging process in a shorter time to improve the convenience and efficiency of car use.

[0003] Although most existing new energy vehicle batteries support fast charging, there are many types of charging piles in cities. The output voltage and output power of different types of charging piles are usually different. Existing new energy vehicles are difficult to adapt to a variety of different types of charging piles, resulting in new energy vehicles being unable to charge at the designed maximum charging power on some charging piles, and may even be unable to charge on some charging piles. Summary of the invention

[0004] The problem to be solved by the present invention is that existing new energy vehicles are difficult to adapt to a variety of different types of charging piles, resulting in the new energy vehicles being unable to charge at the designed maximum charging power on some charging piles, and may even be unable to charge at all on some charging piles.

[0005] To solve the above problems, in a first aspect, the present invention provides a charging and discharging system, comprising an inverter, a first switch, a second switch, a fourth switch, a sixth switch and a seventh switch; a first end of the first switch is used to connect to a first electrode of a charging device, a first end of the second switch is used to connect to a second electrode of the charging device, a second end of the first switch is used to connect to a first electrode of an energy storage device, and a second end of the second switch is used to connect to a second electrode of the energy storage device;

[0006] The inverter includes three bridge arms, the first end of each bridge arm is connected to the first end of the sixth switch, the second end of each bridge arm is connected to the first end of the seventh switch, the three bridge arms correspond to the three-phase windings of the motor one by one, the midpoints of the three bridge arms are respectively used to connect the three-phase windings of the motor, the midpoint of each bridge arm is respectively connected to the positive electrode of a diode, the negative electrode of each diode is connected to the first end of the fourth switch, the second end of the fourth switch is used to connect the second electrode of the energy storage device, the second end of the sixth switch is connected to the first end of the second switch, and the second end of the seventh switch is used to connect the first electrode of the energy storage device.

[0007] Optionally, the charging and discharging system also includes a third switch and a fifth switch, the first end of the first switch is also used to connect to the first end of the electrical device, the first end of the second switch is also used to connect to the second end of the electrical device, the first end of the third switch is used to connect to the second end of the electrical device, the second end of the third switch is connected to the cathode of each diode, the first end of the fifth switch is used to connect to the second electrode of the energy storage device, and the second end of the fifth switch is connected to the first end of each bridge arm.

[0008] In a second aspect, the present invention provides a charge and discharge control method. Based on the charge and discharge system as described above, the charge and discharge control method comprises:

[0009] Determine a charging mode according to the obtained output voltage of the charging device and the required voltage of the energy storage device, wherein the charging mode includes a boost charging mode, a direct charging mode and a buck charging mode;

[0010] When the determined charging mode is a boost charging mode, the first switch, the sixth switch, the seventh switch, the lower bridge arm switches in the two first bridge arms in the inverter, and the upper bridge arm switch in the second bridge arm in the inverter are controlled to be closed, so as to charge the three windings of the motor, wherein the inverter includes two of the first bridge arms and one of the second bridge arms, and each bridge arm in the inverter includes the upper bridge arm switch and the lower bridge arm switch;

[0011] When the three windings of the motor are fully charged, the seventh switch and the two lower bridge arm switches of the first bridge arm are controlled to be disconnected, and then the fourth switch is controlled to be closed to boost and charge the energy storage device.

[0012] Optionally, the charge and discharge control method further includes:

[0013] Determine the absolute inductance difference between each two windings according to the inductance of each phase winding of the motor, wherein the absolute inductance difference is the absolute value of the difference between the inductances of the two windings;

[0014] The three absolute inductance differences are compared to determine that the bridge arms corresponding to the two windings corresponding to the smallest absolute inductance difference are the two first bridge arms, and the bridge arms in the inverter except the two first bridge arms are the second bridge arms.

[0015] Optionally, determining the charging mode according to the acquired output voltage of the charging device and the required voltage of the energy storage device includes:

[0016] When the output voltage of the charging device is less than the required voltage of the energy storage device, determining that the charging mode is the boost charging mode;

[0017] When the output voltage of the charging device is equal to the required voltage of the energy storage device, determining that the charging mode is the direct charging mode;

[0018] When the output voltage of the charging device is greater than the required voltage of the energy storage device, the charging mode is determined to be the buck charging mode.

[0019] Optionally, when the determined charging mode is a buck charging mode, the first switch, the sixth switch, the seventh switch, the lower bridge arm switches in the two first bridge arms, and the upper bridge arm switch in the second bridge arm are controlled to be closed to charge the three windings of the motor;

[0020] When the three windings of the motor are fully charged, the two lower bridge arm switches in the first bridge arm, the upper bridge arm switch in the second bridge arm, the first switch and the sixth switch are controlled to be disconnected, and then the fourth switch and the lower bridge arm switch of one bridge arm in the inverter are controlled to be closed to step down and charge the energy storage device.

[0021] Optionally, the charging and discharging system further includes a third switch and a fifth switch, wherein the first end of the first switch is further used to be connected to the first end of the electrical device, the first end of the second switch is further used to be connected to the second end of the electrical device, the first end of the third switch is used to be connected to the second end of the electrical device, the second end of the third switch is connected to the cathode of each diode, the first end of the fifth switch is used to be connected to the second electrode of the energy storage device, and the second end of the fifth switch is connected to the first end of each bridge arm of the inverter;

[0022] The charge and discharge control method further includes:

[0023] Determine a discharge mode according to the obtained output voltage of the energy storage device and the required voltage of the electrical device, wherein the discharge mode includes a boost discharge mode, a direct discharge mode and a buck discharge mode;

[0024] When the determined discharge mode is the boost discharge mode, the fifth switch, the seventh switch, the two lower bridge arm switches in the first bridge arm, and the upper bridge arm switch in the second bridge arm are controlled to be closed, and the three windings of the motor are charged until the three windings of the motor are completely charged;

[0025] The lower bridge arm switches and the seventh switch in the two first bridge arms are controlled to be disconnected, and the first switch and the third switch are controlled to be closed, so that the energy storage device is boosted and discharged.

[0026] Optionally, determining the discharge mode according to the acquired output voltage of the energy storage device and the required voltage of the power-consuming device includes:

[0027] When the output voltage of the energy storage device is less than the required voltage of the electrical device, determining that the discharge mode is a boost discharge mode;

[0028] When the output voltage of the energy storage device is equal to the required voltage of the power-consuming device, determining the charging mode to be a direct discharge mode;

[0029] When the output voltage of the energy storage device is greater than the required voltage of the power-consuming device, the charging mode is determined to be a step-down discharge mode.

[0030] Optionally, when the determined discharge mode is the buck discharge mode, the fifth switch, the seventh switch, the two lower bridge arm switches in the first bridge arm, and the upper bridge arm switch in the second bridge arm are controlled to be closed, and the three windings of the motor are charged until the three windings of the motor are completely charged;

[0031] The lower bridge arm switches in the two first bridge arms, the upper bridge arm switch in the second bridge arm and the fifth switch are controlled to be disconnected, and the first switch, the third switch and the lower bridge arm switch of one bridge arm in the inverter are controlled to be closed, so that the energy storage device can be discharged at a reduced voltage.

[0032] In a third aspect, the present invention provides a vehicle comprising the above-mentioned charging and discharging system, energy storage device and control device; the charging and discharging system is connected to the energy storage device, the control device is connected to the charging and discharging system, and the control device is used to implement the above-mentioned charging and discharging control method.

[0033] The beneficial effects of a charging and discharging system, a charging and discharging control method and a vehicle of the present invention are:

[0034] By controlling the on and off of different switch combinations, it is possible to switch between multiple charging and discharging modes to adapt to charging devices of different voltage levels or power levels. For example: when the battery pack needs to be directly charged, the first switch and the second switch are controlled to be closed so that the charging device can directly charge the energy storage device; when the battery pack needs to be boosted and charged, the first switch, the sixth switch and the seventh switch are controlled to be closed, and the lower bridge arm switches in the two bridge arms and the upper bridge arm switch in one bridge arm are controlled to be closed, and the remaining switches remain open to achieve charging of the three windings. After the charging is completed, the seventh switch and the two lower bridge arm switches are first controlled to be disconnected, and then the fourth switch is controlled to be closed. At this time, the three windings and the charging pile are allowed to charge the battery pack at the same time, completing the boost charging of the battery pack, and the voltage is increased, which not only meets the charging needs of the battery pack, but also can charge the battery pack quickly. When the battery pack needs to be charged at a reduced voltage, after charging is completed, the previously closed upper bridge arm switch, two lower bridge arm switches, the first switch and the sixth switch are first controlled to be disconnected, and then the fourth switch and the lower bridge arm switch of a bridge arm in the inverter are controlled to be closed, so that the output current of the three windings passes through two diodes and reaches the battery pack. At this time, the three windings are allowed to charge the battery pack separately to realize the reduced voltage charging of the battery pack. When the energy storage device requires a small voltage, only the energy storage of the winding is used to charge the energy storage device at a reduced voltage to meet the charging requirements of the energy storage device and ensure the safety of the energy storage device. In addition, during the reduced voltage charging, multiple windings are discharged at the same time, and the discharge current becomes larger than that of direct charging, so that the battery pack can be charged quickly. For charging devices with different output powers or different output voltages, a suitable charging mode can be selected so that the vehicle battery pack can match different types of charging piles, improve the charging speed, meet the wide range of charging voltage requirements of the battery pack, and improve the applicability of the charging and discharging system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of the structure of a charging and discharging system provided by an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a current path in a direct charging mode provided by an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of a current route for charging a winding by a charging pile provided in an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of a current path in a boost charging mode provided by an embodiment of the present invention;

[0039] Figure 5 A schematic diagram of a current path in a buck charging mode provided by an embodiment of the present invention;

[0040] Figure 6A schematic diagram of a current path in a direct discharge mode provided by an embodiment of the present invention;

[0041] Figure 7 A schematic diagram of a current route for charging a winding by a battery pack provided in an embodiment of the present invention;

[0042] Figure 8 A schematic diagram of the current path of a battery pack in a boost discharge mode provided by an embodiment of the present invention;

[0043] Fig. 9 A schematic diagram of the current path of a battery pack in a step-down discharge mode provided by an embodiment of the present invention;

[0044] Fig.10 A schematic flow chart of a charge and discharge control method provided by an embodiment of the present invention;

[0045] Fig.11 A schematic diagram of the structure of a vehicle in an embodiment of the present invention;

[0046] Fig.12 The figure is a schematic diagram of the structure of an electronic device in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0048] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0049] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0050] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0051] The names of the messages or information exchanged between multiple devices in the embodiments of the present invention are only used for illustrative purposes, and are not used to limit the scope of these messages or information.

[0052] In the related technologies, the batteries of existing new energy vehicles support high-power charging. The existing boost charging technology generally adopts the method of adding external windings. This method also requires the addition of supporting and protective structures for the external windings, which takes up the vehicle installation space. Some other boost charging technologies use the windings in the motor, but the windings act as heating components, and the balance between the three windings is not considered, resulting in unstable charging. Therefore, the effect of boost charging is not ideal, and the charging speed and charging stability need to be further improved.

[0053] In the existing technology, V2G (Vehicle-to-Grid) technology refers to the technology of electric vehicles supplying electricity to the power grid, using the energy storage of a large number of electric vehicles as a buffer and backup for the power grid and renewable energy. V2V (Vehicle-to-Vehicle) technology refers to the technology of new energy vehicles charging new energy vehicles, for example, one electric vehicle can provide electricity for another electric vehicle that is insufficient in power.

[0054] like Figure 1As shown, a charging and discharging system provided by an embodiment of the present invention includes an inverter, a first switch S1, a second switch S2, a fourth switch S4, a sixth switch S6 and a seventh switch S7; the first end of the first switch is used to connect to the first electrode of the charging device, the first end of the second switch is used to connect to the second electrode of the charging device, the second end of the first switch is used to connect to the first electrode of the energy storage device, and the second end of the second switch is used to connect to the second electrode of the energy storage device; the inverter includes three bridge arms, the first end of each bridge arm is connected to the first end of the sixth switch, the second end of each bridge arm is connected to the first end of the seventh switch, the three bridge arms correspond to the three-phase windings of the motor one by one, the midpoints of the three bridge arms are respectively used to connect to the three-phase windings of the motor, the midpoints of each bridge arm are respectively connected to the positive electrode of a diode, the negative electrode of each diode is connected to the first end of the fourth switch, the second end of the fourth switch is used to connect to the second electrode of the energy storage device, the second end of the sixth switch is connected to the first end of the second switch, and the second end of the seventh switch is used to connect to the first electrode of the energy storage device.

[0055] Specifically, the first electrode of the charging device may be a negative electrode, and the second electrode may be a positive electrode. The first electrode of the energy storage device may be a negative electrode, and the second electrode of the energy storage device may be a positive electrode. The charging device may be Figure 1 The charging pile shown can also be a charging battery, a charging station or a car charger, etc. Any device that can charge the energy storage device can be used as a charging device, and there is no restriction on the specific type of charging device. The energy storage device can be as follows: Figure 1 The battery pack shown can also be a battery or a battery pack, etc. As long as it can store electrical energy and supply electrical energy to the vehicle, it can be used as an energy storage device. The above example does not limit the energy storage device. The upper bridge arm switch and the lower bridge arm switch in the three bridge arms of the inverter can be power transistors, MOS tubes (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET, Metal-Oxide Semiconductor Field-Effect Transistor), IGBT (Insulated Gate Bipolar Transistor, Insulated Gate Bipolar Transistor) or relays and other switching devices.

[0056] For example, Figure 1As shown, the inverter includes three bridge arms, each of which includes two switches, namely, an upper bridge arm switch M1 and a lower bridge arm switch M2, an upper bridge arm switch M3 and a lower bridge arm switch M4, an upper bridge arm switch M5 and a lower bridge arm switch M6. A diode is connected to the midpoint of each bridge arm, namely, diode K1, diode K2 and diode K3; in each bridge arm, the first end of the upper bridge arm switch is connected to the first end of the lower bridge arm switch. The motor includes three windings, namely a first winding L1, a second winding L2 and a third winding L3. The first end of the first winding L1 is connected to the midpoint of the bridge arm between the upper bridge arm switch M1 and the lower bridge arm switch M2, the first end of the second winding L2 is connected to the midpoint of the bridge arm between the upper bridge arm switch M3 and the lower bridge arm switch M4, and the first end of the third winding L3 is connected to the midpoint of the bridge arm between the upper bridge arm switch M5 and the lower bridge arm switch M6. The second ends of the first winding L1, the second winding L2 and the third winding L3 are connected together to reuse the windings of the motor without adding an additional winding structure, thereby saving installation space and reducing costs.

[0057] For example, Figure 2 or Figure 3 As shown, by controlling the on and off of the first switch S1 and the second switch S2, the current flow direction between the charging pile and the battery pack can be changed. Figure 2 As shown, when the first switch S1 and the second switch S2 are fully closed, the charging pile is directly connected to the battery pack, and the charging pile directly charges the battery pack. This is the direct charging mode of the battery pack. Figure 3 As shown, when the charging voltage of the battery pack needs to be raised or lowered, the first switch S1, the sixth switch S6, the seventh switch S7, the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are controlled to close, and the output current path of the charging pile is changed, so that the current of the charging pile passes through the sixth switch S6, the upper bridge arm switch M1 to reach the motor winding, and then passes through the lower bridge arm switch M4 and the lower bridge arm switch M6, flows out of the inverter, and finally passes through the first switch S1 and the seventh switch S7 to form a loop with the charging pile to realize the charging of the three windings. Figure 4 As shown, when the three windings are fully charged, first control the lower bridge arm switch M4, the lower bridge arm switch M6 and the seventh switch to be disconnected, and then control the fourth switch S4 to be closed, changing the output current path of the charging pile, allowing the current of the charging pile to pass through the sixth switch S6 and the upper bridge arm switch M1 in turn to reach the motor winding, and then pass through the diode K2 and the diode K3, flow out of the inverter, and flow from the fourth switch S4 into the battery pack. The battery pack is connected to the charging pile through the first switch S1. At this time, the three windings and the charging pile charge the battery pack at the same time, completing the boost charging of the battery pack. The voltage increases, which not only meets the charging demand of the battery pack, but also can charge the battery pack quickly. Figure 5As shown, when the three windings are charged, the first switch S1, the sixth switch S6, the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are first controlled to be disconnected, and then the fourth switch S4 and the lower bridge arm switch M2 are controlled to be closed, so that the output current of the three windings is output through the second winding L2 and the third winding L3, and passes through the diode K2 and the diode K3, and reaches the positive electrode of the battery pack through the fourth switch S4. The output current at the negative electrode of the battery pack passes through the seventh switch S7 and the lower bridge arm switch M2 to reach the first winding L1, forming a current loop. At this time, the three windings are allowed to charge the battery pack separately to achieve voltage reduction charging of the battery pack. When the energy storage device requires a small voltage, only the energy storage of the winding is used to reduce the voltage of the energy storage device to meet the charging requirements of the energy storage device, avoid damage to the energy storage device caused by excessive charging voltage, and ensure the safety of the energy storage device. In addition, during voltage reduction charging, multiple windings are discharged at the same time, and the discharge current becomes larger than that of direct charging, so that the battery pack can be quickly charged.

[0058] It should be noted that when charging the three windings, the upper bridge arm switch M3, the lower bridge arm switch M2 and the lower bridge arm switch M6 can also be controlled to be closed, so that the first inductor L1 and the third inductor L3 are connected in parallel and then in series with the second inductor L2; or the upper bridge arm switch M1, the upper bridge arm switch M3 and the lower bridge arm switch M6 are controlled to be closed, so that the first inductor L1 and the second inductor L2 are connected in parallel and then in series with the third inductor L3. As long as the upper bridge arm switch of one of the bridge arms and the lower bridge arm switches of the other two bridge arms are controlled to be closed, and the remaining bridge arm switches are disconnected; or the upper bridge arm switches of the two bridge arms and the lower bridge arm switches of the other bridge arm are closed, and the remaining bridge arm switches are disconnected; it is possible to realize that two windings are connected in parallel and then in series with one winding to complete the charging of the three windings. Similarly, when performing boost charging, it is only necessary to control the upper bridge arm switch of any bridge arm to be closed, and the remaining bridge arm switches to be disconnected; when performing step-down discharge, it is sufficient to control the lower bridge arm switch of any bridge arm to be closed, and the remaining bridge arm switches to be disconnected. There are many types of motors, and the original connection methods of the three windings in different types of motors may also be different. For example, the connection methods of the three windings in the motor include star connection method and triangle connection method. The three windings in the star connection method have a common connection center point, while the three windings in the triangle connection method do not have a common connection center point. The charging and discharging system of the present application does not rely on the original connection method of the three windings in the motor, is not limited by the type of motor, and does not need to use the connection center point in the original connection method of the three windings. It only needs to connect one end of the three windings and the other end to the corresponding bridge arm center point. By changing the on and off of multiple bridge arm switches in the inverter through the above-mentioned logic control, it is possible to connect any two of the three windings of the motor in parallel and then connect them in series with the third winding. The connection relationship between the three windings can be flexibly changed, and is not limited by the original connection method of the three windings in the motor. In addition, due to the influence of the actual manufacturing process or the use environment, the induced current generated between the three windings may be unbalanced. If the three windings are connected in parallel or in series, the three windings are in the same position. The imbalance between the three windings will interfere with each other, and the side effects generated will be superimposed on each other. For example, the induced currents in the three windings are 1.3A, 1A and 1.8A respectively. If the three windings are in the same position, the maximum current difference among the three windings is 0.8A, and the other two current differences are 0.3A and 0.5A respectively. The imbalance between the three windings is large, and there will be three different current differences. The heat caused by the current differences is superimposed on each other, and more heat is generated.Using the same example as above, let the two windings with induced currents of 1.3A and 1A be connected in parallel first. The currents are relatively close, the current difference is 0.3A, and the heat generated is less. The currents of the two parallel windings are combined to be 2.3A. The induced current of the remaining winding is 1.8A. The current after parallel connection differs from the induced current of the remaining winding by 0.5A. At this time, the maximum current difference is only 0.5A, which eliminates the previous current difference of 0.8A, reduces the adverse effects caused by current imbalance, and greatly reduces the generated heat and the imbalance between the three windings. In this embodiment, by controlling the on and off of the switches in each bridge arm in the inverter, two windings with the same or closest inductance can be selected in parallel, and then connected in series with the remaining winding. The induced current will not produce large unbalanced fluctuations, eliminate the impact of the imbalance of the three-phase windings, and make the charging and discharging of the windings stable. Connecting the remaining winding in series with the two parallel windings is equivalent to extending the length of the winding, increasing the size of the winding, and can also increase the energy storage. Therefore, the "two parallel and one series" approach can not only ensure the stability of the induced current, but also maximize the induced voltage.

[0059] In this embodiment, when the battery pack needs direct charging, the first switch and the second switch are controlled to be closed, so that the charging device can directly charge the energy storage device; when the battery pack needs to be boosted and charged, the first switch S1, the sixth switch S6 and the seventh switch S7 are controlled to be closed, and the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are also controlled to be closed, and the other switches remain disconnected to realize the charging of the three windings. After the charging is completed, the seventh switch S7, the lower bridge arm switch M4 and the lower bridge arm switch M6 are first controlled to be disconnected, and then the fourth switch S4 is controlled to be closed. At this time, the three windings and the charging pile are charged to the battery pack at the same time, and the boost charging of the battery pack is completed. The voltage increases, which not only meets the charging demand of the battery pack, but also can charge the battery pack quickly. When the battery pack needs to be charged at a reduced voltage, after charging is completed, the upper bridge arm switch M1, the lower bridge arm switch M4, the lower bridge arm switch M6, the first switch and the sixth switch are first controlled to be disconnected, and then the fourth switch S4 and the lower bridge arm switch of a bridge arm in the inverter (for example, the lower bridge arm switch M2) are controlled to be closed, so that the output current of the three windings passes through two diodes and reaches the battery pack. At this time, the three windings are allowed to charge the battery pack separately to realize the reduced voltage charging of the battery pack. When the voltage required by the energy storage device is relatively small, only the energy storage of the winding is used to charge the energy storage device at a reduced voltage to meet the charging requirements of the energy storage device and ensure the safety of the energy storage device. In addition, during the reduced voltage charging, multiple windings are discharged at the same time, and the discharge current becomes larger than that of the direct charge, so that the battery pack can be quickly charged. By controlling the on and off of different switch combinations, the switching of multiple charging and discharging modes can be realized. For charging devices with different output powers or different output voltages, a suitable charging mode can be selected, so that the vehicle battery pack can match different types of charging piles, improve the charging speed, and meet the charging voltage requirements of the battery pack in a wide range, thereby improving the applicability of the charging and discharging system.

[0060] Optionally, the charging and discharging system also includes a third switch S3 and a fifth switch S5, the first end of the first switch is also used to connect to the first end of the electrical equipment, the first end of the second switch is also used to connect to the second end of the electrical equipment, the first end of the third switch is used to connect to the second end of the electrical equipment, the second end of the third switch is connected to the cathode of each diode, the first end of the fifth switch is used to connect to the second electrode of the energy storage device, and the second end of the fifth switch is connected to the first end of each bridge arm.

[0061] Specifically, Figure 1As shown, the electric device may be a V2V module or a V2G module, etc., the first end of the electric device may be a negative electrode, and the second end of the electric device may be a positive electrode. In actual use, the first end of the first switch S1 may be switched to be connected to the negative electrode of the electric device or the negative electrode of the charging pile, and the first end of the second switch S2 may be switched to be connected to the positive electrode of the electric device or the positive electrode of the charging pile, so as to realize the charging and discharging of the energy storage device.

[0062] For example, Figure 6 or Figure 7 As shown, by controlling the on and off of the first switch S1 and the second switch S2, the current flow direction between the battery pack and the electrical device can be changed. Figure 6 As shown, the first switch S1 and the second switch S2 are completely closed, the battery pack is directly connected to the power-consuming device, and the battery pack directly supplies power to the power-consuming device. This is the direct discharge mode of the battery pack. Figure 7 As shown, the fifth switch S5, the seventh switch S7, the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are controlled to be closed, so that the current of the battery pack passes through the sixth switch S6 and the upper bridge arm switch M1 to reach the motor winding in sequence, and then passes through the lower bridge arm switch M4 and the lower bridge arm switch M6, flows out of the inverter, and finally passes through the seventh switch S7 to form a loop with the battery pack to realize the charging of the three windings. Figure 8 As shown, when the voltage required by the electrical equipment is relatively large, after the three windings are charged, the lower bridge arm switch M4, the lower bridge arm switch M6 and the seventh switch S7 are first controlled to be disconnected, and then the first switch S1 and the third switch S3 are controlled to be closed, so that the current of the battery pack passes through the fifth switch S5 and the upper bridge arm switch M1 in turn to reach the motor winding, and then passes through the diode K2 and the diode K3, flows out of the inverter, and flows from the third switch S3 to the positive electrode of the electrical equipment. The negative electrode of the electrical equipment is connected to the battery pack through the first switch S1, completing the boost power supply to the electrical equipment. At this time, the three windings and the battery pack are used together to supply power to the electrical equipment, realizing the boost discharge of the battery pack and improving the charging speed. Fig. 9 As shown, when the required voltage of the electrical equipment is relatively small, after the three windings are charged, the fifth switch S5, the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are first controlled to be disconnected, and then the first switch S1, the third switch S3 and the lower bridge arm switch M2 are controlled to be closed, so that the output current of the three windings passes through the diodes K2 and K3, and then reaches the positive electrode of the electrical equipment through the third switch S3. The negative electrode of the electrical equipment is connected to the first winding L1 through the seventh switch S7 and the lower bridge arm switch M2 to form a current loop. At this time, the three windings are allowed to supply power to the electrical equipment separately, and the voltage reduction power supply to the electrical equipment is completed. When the battery pack is discharged at a reduced voltage, it is equivalent to charging the three windings first, and then the three windings supply power to the electrical equipment. Although the voltage drops, due to the simultaneous discharge of multiple windings, the discharge current becomes larger than the current during direct discharge, thereby increasing the charging speed.

[0063] It should be noted that when charging the three windings, the upper bridge arm switch M3, the lower bridge arm switch M2 and the lower bridge arm switch M6 can also be controlled to be closed, so that the first inductor L1 and the third inductor L3 are connected in parallel and then in series with the second inductor L2; or the upper bridge arm switch M1, the upper bridge arm switch M3 and the lower bridge arm switch M6 are controlled to be closed, so that the first inductor L1 and the second inductor L2 are connected in parallel and then in series with the third inductor L3. As long as the upper bridge arm switch of one of the bridge arms and the lower bridge arm switches of the other two bridge arms are controlled to be closed, and the remaining bridge arm switches are disconnected; or the upper bridge arm switches of the two bridge arms and the lower bridge arm switches of the other bridge arm are closed, and the remaining bridge arm switches are disconnected; it is possible to realize that two windings are connected in parallel and then in series with one winding to complete the charging of the three windings. Similarly, when performing boost discharge, the upper bridge arm switch of any bridge arm is controlled to be closed, and the remaining bridge arm switches are disconnected; when performing step-down discharge, the lower bridge arm switch of any bridge arm is controlled to be closed, and the remaining bridge arm switches are disconnected.

[0064] In this embodiment, the three windings of the motor are reused and charged so that the windings can assist the battery pack in completing the voltage boost supply, or the three windings can work independently to complete the voltage step-down supply to the electrical equipment (i.e., the battery pack voltage step-down discharge), thereby expanding the discharge voltage range of the energy storage device, not being limited by the output voltage of the energy storage device itself, meeting the diverse power demands of the electrical equipment, and improving the applicability of the vehicle battery pack.

[0065] Optionally, the charging and discharging system also includes a bus capacitor, a first end of the bus capacitor is connected to the second end of the upper bridge arm switch in each of the bridge arms, and a second end of the bus capacitor is connected to the second end of the lower bridge arm switch in each of the bridge arms.

[0066] In this embodiment, the bus capacitor can absorb and release electrical energy, reduce the ripple of the output current, suppress and reduce the noise from the power supply and other interference sources, balance the voltage fluctuation, increase the stability of the output voltage, and improve the output quality and the anti-interference ability of the inverter.

[0067] like Fig.10 As shown, an embodiment of the present invention provides a charging and discharging control method, based on the above-mentioned charging and discharging system, the charging and discharging control method includes:

[0068] S100: Determine a charging mode according to the acquired output voltage of the charging device and the required voltage of the energy storage device, wherein the charging mode includes a boost charging mode, a direct charging mode and a buck charging mode.

[0069] Specifically, in the actual charging process, there are many charging piles on the market with various types. The output voltage of the charging pile selected by the car owner may not match the required voltage of the vehicle battery pack. Therefore, it is necessary to judge the charging mode suitable for the current battery pack based on the output voltage of the charging pile and the required voltage of the battery pack.

[0070] S200: When the determined charging mode is the boost charging mode, the first switch, the sixth switch, the seventh switch, the lower bridge arm switches in the two first bridge arms in the inverter, and the upper bridge arm switch in the second bridge arm in the inverter are controlled to close to charge the three windings of the motor, wherein the inverter includes two of the first bridge arms and one of the second bridge arms, and each bridge arm in the inverter includes the upper bridge arm switch and the lower bridge arm switch.

[0071] Specifically, Figure 3 As shown, when the charging voltage of the battery pack needs to be raised or lowered, the first switch S1, the sixth switch S6, the seventh switch S7, the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are controlled to close, and the output current path of the charging pile is changed, so that the current of the charging pile passes through the sixth switch S6 and the upper bridge arm switch M1 to reach the motor winding in sequence, and then passes through the lower bridge arm switch M4 and the lower bridge arm switch M6, flows out of the inverter, and finally passes through the first switch S1 and the seventh switch S7, and forms a loop with the charging pile to realize the charging of the three windings. Specifically, when the winding is fully charged, no current will be generated in the winding. At this time, whether the winding is fully charged can be monitored by detecting whether there is current in the winding.

[0072] S300: When the three windings of the motor are fully charged, the seventh switch and the two lower bridge arm switches of the first bridge arm are controlled to be disconnected, and the fourth switch is controlled to be closed to boost and charge the energy storage device.

[0073] Specifically, Figure 4 As shown, after the three windings are charged, the lower bridge arm switch M4, the lower bridge arm switch M6 and the seventh switch are first controlled to be disconnected, and then the fourth switch S4 is controlled to be closed, so that the current of the charging pile passes through the sixth switch S6 and the upper bridge arm switch M1 in sequence to reach the motor winding, and then passes through the diode K2 and the diode K3, flows out of the inverter, and flows into the battery pack from the fourth switch S4. The battery pack is connected to the charging pile through the first switch S1. At this time, the three windings and the charging pile charge the battery pack at the same time, completing the boost charging of the battery pack. The voltage increases, which not only meets the charging demand of the battery pack, but also can charge the battery pack quickly.

[0074] In this embodiment, the charging mode is determined according to the output voltage of the charging device and the required voltage of the energy storage device; by controlling the on and off of different switch combinations, the switching of multiple charging and discharging modes is realized. When the battery pack needs to be boosted and charged, the first switch S1, the sixth switch S6 and the seventh switch S7 are controlled to be closed, and the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are also controlled to be closed, and the remaining switches are disconnected to realize the charging of the three windings. After the charging is completed, the seventh switch S7, the lower bridge arm switch M4 and the lower bridge arm switch M6 are first controlled to be disconnected, and then the fourth switch S4 is controlled to be closed. At this time, the three windings and the charging pile are charged to the battery pack at the same time, and the boost charging of the battery pack is completed. The voltage increases, which not only meets the charging demand of the battery pack, but also can charge the battery pack quickly.

[0075] Optionally, the charge and discharge control method further includes:

[0076] Determine the absolute inductance difference between each two windings according to the inductance of each phase winding of the motor, wherein the absolute inductance difference is the absolute value of the difference between the inductances of the two windings;

[0077] The three absolute inductance differences are compared to determine that the bridge arms corresponding to the two windings corresponding to the smallest absolute inductance difference are the two first bridge arms, and the bridge arms in the inverter except the two first bridge arms are the second bridge arms.

[0078] Specifically, in actual production, the manufacturing process will cause differences between the three-phase windings of the motor, and there may be an unbalanced state between the three-phase windings. In addition, during use, the three-phase windings are affected by factors such as the environment and temperature, and the actual inductance in the windings may change with the environment and temperature. In order to reduce the impact of this difference, two windings with similar performance among the three windings are preferentially connected in parallel, and the remaining winding is used as a common winding in series with the two parallel windings. The inductance of the parallel windings is equivalent, and the currents generated are similar or equal, which will not cause a large current imbalance and reduce the generation of heat. The common winding is not connected in parallel with the other two windings, and even if the current difference is large, it will not cause much impact. Therefore, the connection method of "two parallel and one series" not only eliminates the current imbalance problem, but also increases the output current. The three windings work together to give full play to the role of the three windings and improve the winding utilization rate. The operating parameters of the windings can be parameters such as winding current or winding inductance. Monitor the inductance or current in the three windings of the motor during motor operation, winding charging, or winding discharge, and judge the balance of the three-phase winding by the size of the three-phase current, or directly use a winding measuring instrument to directly measure the inductance of the winding and analyze the balance of the three windings.

[0079] Exemplarily, the inductance of the three windings is measured by a winding measuring instrument, and the inductance difference between every two windings is determined to obtain three inductance differences, namely, the inductance difference between the inductance of the first winding L1 and the inductance of the second winding L2, the inductance difference between the inductance of the first winding L1 and the inductance of the third winding L3, and the inductance difference between the inductance of the second winding L2 and the inductance of the third winding L3. The inductance difference is an absolute value. The two windings corresponding to the smallest inductance difference among the three inductance differences are determined to be connected in parallel, and the bridge arm corresponding to the two parallel windings is the first bridge arm, which is then connected in series with the remaining winding. The remaining winding is connected in series as a common winding, and the bridge arm corresponding to the common winding is the second bridge arm, such as Figure 3 As shown, by controlling the upper bridge arm switch M1 to open, the first winding L1 is used as a common winding, the upper bridge arm switches in the other two bridge arms remain disconnected, and the other two windings are connected in parallel. It can be measured regularly. When the inductance of the three windings changes, the connection relationship between the three windings is adjusted again by adjusting the on and off of the three upper bridge arm switches in the inverter. By turning the bridge arm switches on and off, the connection relationship between the three windings can be flexibly changed, so that the three windings can always work in the optimal connection mode, thereby improving the stability and charging speed of the system.

[0080] Optionally, determining the charging mode according to the acquired output voltage of the charging device and the required voltage of the energy storage device includes:

[0081] When the output voltage of the charging device is equal to the required voltage of the energy storage device, the charging mode is determined to be the direct charging mode. Figure 2 As shown, the first switch S1 and the second switch S2 are controlled to be closed, so that the charging pile is directly connected to the battery pack for direct charging.

[0082] When the output voltage of the charging device is less than the required voltage of the energy storage device, the charging mode is determined to be a boost charging mode, such as Figure 3 and Figure 4 shown.

[0083] When the output voltage of the charging device is greater than the required voltage of the energy storage device, the charging mode is determined to be a step-down charging mode, such as Figure 3 and Figure 5 shown.

[0084] Specifically, before charging starts or within a short period of time after charging starts, the output voltage of the charging device and the required voltage of the energy storage device are monitored, and by comparing the two voltages, the appropriate charging mode is switched to increase the charging speed while ensuring safety, thereby meeting the user's demand for fast charging of the battery pack.

[0085] Optionally, when the determined charging mode is a buck charging mode,

[0086] When the determined charging mode is the buck charging mode, the first switch, the sixth switch, the seventh switch, the lower bridge arm switches in the two first bridge arms, and the upper bridge arm switch in the second bridge arm are controlled to close to charge the three windings of the motor. Figure 3 According to the description, the charging pile completes the charging of the three windings.

[0087] When the three windings of the motor are fully charged, the two lower bridge arm switches in the first bridge arm, the upper bridge arm switch in the second bridge arm, the first switch and the sixth switch are controlled to be disconnected, and then the fourth switch and the lower bridge arm switch of one bridge arm in the inverter are controlled to be closed to step down and charge the energy storage device.

[0088] Specifically, Figure 5 As shown, when the three windings are charged, the first switch S1, the sixth switch S6, the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are first controlled to be disconnected, and then the fourth switch S4 and the lower bridge arm switch M2 are controlled to be closed, so that the output current of the three windings is output through the second winding L2 and the third winding L3, and passes through the diode K2 and the diode K3, and reaches the positive electrode of the battery pack through the fourth switch S4. The output current at the negative electrode end of the battery pack passes through the seventh switch S7 and the lower bridge arm switch M2 of the first bridge arm to reach the first winding L1, forming a current loop. At this time, the three windings are allowed to charge the battery pack separately to achieve voltage reduction charging of the battery pack. When the energy storage device requires a small voltage, only the energy storage of the winding is used to reduce the voltage of the energy storage device to meet the charging requirements of the energy storage device, avoid damage to the energy storage device caused by excessive charging voltage, and ensure the safety of the energy storage device. In addition, during voltage reduction charging, multiple windings are discharged at the same time, and the discharge current becomes larger than that of direct charging, so that the battery pack can be quickly charged.

[0089] In this embodiment, through the logic control of each switch, a suitable charging mode is selected, and the charging pile and the three windings work together, so that the voltage provided by the charging and discharging system matches the actual required voltage of the energy storage device, thereby improving the charging speed, shortening the charging time, and ensuring charging stability and safety.

[0090] Optionally, the charging and discharging system also includes a third switch and a fifth switch, the first end of the first switch is also used to connect to the first end of the electrical device, the first end of the second switch is also used to connect to the second end of the electrical device, the first end of the third switch is used to connect to the second end of the electrical device, the second end of the third switch is connected to the cathode of each diode, the first end of the fifth switch is used to connect to the second electrode of the energy storage device, and the second end of the fifth switch is connected to the first end of each bridge arm of the inverter.

[0091] The charge and discharge control method further includes:

[0092] A discharge mode is determined according to the obtained output voltage of the energy storage device and the required voltage of the electrical device, wherein the discharge mode includes a boost discharge mode, a direct discharge mode and a buck discharge mode.

[0093] Specifically, in the actual discharge process, there are many types of electrical equipment, especially in the power grid where the voltage fluctuates greatly. When the owner connects different electrical equipment to the battery pack, the required voltages of different electrical equipment may be different, and the output voltage of the battery pack will also change when the battery pack is at different power storage levels. Therefore, by switching the discharge mode of the battery pack, the output voltage of the battery pack can be flexibly changed to adapt to the power needs of various electrical equipment.

[0094] When the determined discharge mode is the boost discharge mode, the fifth switch, the seventh switch, the two lower bridge arm switches in the first bridge arm, and the upper bridge arm switch in the second bridge arm are controlled to close, and the three windings of the motor are charged until the three windings of the motor are completely charged.

[0095] Specifically, Figure 7 As shown, the fifth switch S5, the seventh switch S7, the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are controlled to be closed, so that the current of the battery pack passes through the sixth switch S6 and the upper bridge arm switch M1 in sequence to reach the motor winding, and then passes through the lower bridge arm switch M4 and the lower bridge arm switch M6 to flow out of the inverter, and finally passes through the seventh switch S7 to form a loop with the battery pack to realize the charging of the three windings.

[0096] When the three windings of the motor are fully charged, the lower bridge arm switches in the two first bridge arms and the seventh switch are controlled to be disconnected, and then the first switch and the third switch are controlled to be closed, so that the energy storage device is boosted and discharged.

[0097] Specifically, Figure 8 As shown, when the required voltage of the electrical equipment is relatively large, after the three windings are charged, the lower bridge arm switch M4, the lower bridge arm switch M6 and the seventh switch S7 are first controlled to be disconnected, and then the first switch S1 and the third switch S3 are controlled to be closed, so that the current of the battery pack passes through the fifth switch S5 and the upper bridge arm switch M1 in sequence to reach the motor winding, and then passes through the diode K2 and the diode K3, flows out of the inverter, and flows into the positive electrode of the electrical equipment from the third switch S3. The negative electrode of the electrical equipment is connected to the battery pack through the first switch S1, completing the boosted power supply to the electrical equipment. At this time, the three windings and the battery pack are used together to supply power to the electrical equipment, realizing the boosted discharge of the battery pack.

[0098] Optionally, determining the discharge mode according to the acquired output voltage of the energy storage device and the required voltage of the power-consuming device includes:

[0099] When the output voltage of the energy storage device is equal to the required voltage of the power-consuming device, the charging mode is determined to be the direct discharge mode. Figure 6 As shown, the first switch S1 and the second switch S2 are controlled to be closed, so that the electrical device is directly connected to the battery pack, the battery pack works alone, and the discharge is directly supplied to the electrical device.

[0100] When the output voltage of the energy storage device is lower than the required voltage of the electrical device, the discharge mode is determined to be a boost discharge mode.

[0101] When the output voltage of the energy storage device is greater than the required voltage of the power-consuming device, the charging mode is determined to be a step-down discharge mode.

[0102] When the determined discharge mode is the step-down discharge mode, the fifth switch, the seventh switch, the two lower bridge arm switches in the first bridge arm, and the upper bridge arm switch in the second bridge arm are controlled to close, and the three windings of the motor are charged until the three windings of the motor are fully charged. Figure 7 As described above, the battery pack completes the charging of the three windings.

[0103] When the three windings of the motor are fully charged, the two lower bridge arm switches in the first bridge arm and the upper bridge arm switch in the second bridge arm are controlled to be closed and the fifth switch is disconnected, and then the first switch, the third switch and the lower bridge arm switch of one bridge arm in the inverter are controlled to be closed, so that the energy storage device can be discharged at a reduced voltage.

[0104] Specifically, Fig. 9 As shown, when the required voltage of the electrical equipment is relatively small, after the three windings are charged, the fifth switch S5, the upper bridge arm switch M1, the lower bridge arm switch M4 and the lower bridge arm switch M6 are first controlled to be disconnected, and then the first switch S1, the third switch S3 and the lower bridge arm switch M2 are controlled to be closed, so that the output current of the three windings passes through the diodes K2 and K3, and then reaches the positive electrode of the electrical equipment through the third switch S3. The negative electrode of the electrical equipment is connected to the first winding L1 through the seventh switch S7 and the lower bridge arm switch M2 to form a current loop. At this time, the three windings are allowed to supply power to the electrical equipment separately, and the voltage reduction power supply to the electrical equipment is completed. When the battery pack is discharged at a reduced voltage, it is equivalent to charging the three windings first, and then the three windings supply power to the electrical equipment. Although the voltage drops, due to the simultaneous discharge of multiple windings, the discharge current becomes larger than the current during direct discharge, thereby increasing the charging speed.

[0105] In this embodiment, through the logic control of each switch, a suitable discharge mode is selected to allow the battery pack to work in conjunction with the three windings, so that the voltage provided by the charging and discharging system matches the actual required voltage of the electrical equipment, thereby ensuring the stability and safety of power consumption.

[0106] like Fig.11 As shown, a vehicle 110 provided by an embodiment of the present invention includes the charging and discharging system 112, the energy storage device 113 and the control device 111 as described above; the charging and discharging system 112 is connected to the energy storage device 113, the control device 111 is connected to the charging and discharging system 112, the charging and discharging system 112 is used to be connected to the charging device, and the control device 111 is used to implement the charging and discharging control method as described above, and control the charging and discharging system 112 to switch the charging mode to charge the energy storage device 113.

[0107] The beneficial effects of the vehicle of this embodiment are the same as those of the charging and discharging system, which will not be described in detail here.

[0108] like Fig.12 As shown, an electronic device 120 provided in an embodiment of the present invention includes a memory 121 and a processor 122;

[0109] The memory 121 is used to store computer programs;

[0110] The processor 122 is used to implement the above-mentioned charge and discharge control method when executing the computer program.

[0111] In other words, the electronic device 120 includes a memory 121 and a processor 122 coupled to the memory 121; the memory 121 is configured to store a computer program; and the processor 122 is configured to perform the following operations when executing the computer program:

[0112] Determine a charging mode according to the obtained output voltage of the charging device and the required voltage of the energy storage device, wherein the charging mode includes a boost charging mode, a direct charging mode and a buck charging mode;

[0113] When the determined charging mode is a boost charging mode, the first switch, the sixth switch, the seventh switch, the lower bridge arm switches in the two first bridge arms in the inverter, and the upper bridge arm switch in the second bridge arm in the inverter are controlled to be closed, so as to charge the three windings of the motor, wherein the inverter includes two of the first bridge arms and one of the second bridge arms, and each bridge arm in the inverter includes the upper bridge arm switch and the lower bridge arm switch;

[0114] When the three windings of the motor are fully charged, the seventh switch and the two lower bridge arm switches of the first bridge arm are controlled to be disconnected, and then the fourth switch is controlled to be closed to boost and charge the energy storage device.

[0115] The beneficial effects of the electronic device of this embodiment are the same as those of the charging and discharging system, which will not be described in detail here.

[0116] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the charge and discharge control method described above is implemented.

[0117] In other words, a non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor performs the following operations:

[0118] Determine a charging mode according to the obtained output voltage of the charging device and the required voltage of the energy storage device, wherein the charging mode includes a boost charging mode, a direct charging mode and a buck charging mode;

[0119] When the determined charging mode is a boost charging mode, the first switch, the sixth switch, the seventh switch, the lower bridge arm switches in the two first bridge arms in the inverter, and the upper bridge arm switch in the second bridge arm in the inverter are controlled to be closed, so as to charge the three windings of the motor, wherein the inverter includes two of the first bridge arms and one of the second bridge arms, and each bridge arm in the inverter includes the upper bridge arm switch and the lower bridge arm switch;

[0120] When the three windings of the motor are fully charged, the seventh switch and the two lower bridge arm switches of the first bridge arm are controlled to be disconnected, and then the fourth switch is controlled to be closed to boost and charge the energy storage device.

[0121] The beneficial effects of the storage medium of this embodiment are the same as those of the charging and discharging system, and will not be described in detail here.

[0122] Electronic device 120 is intended to represent various forms of digital electronic computer equipment, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic device 120 can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices and other similar computing devices. The examples described above can be used as electronic devices 120 of the server or client of the present invention, which are examples of hardware devices that can be applied to various aspects of the present invention. The components shown herein, their connections and relationships, and their functions are only examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0123] The electronic device 120 includes a computing unit, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) or a computer program loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for the operation of the device can also be stored. The computing unit, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0124] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc. In the present application, the unit described as a separate component may or may not be physically separated, and the component displayed as a unit may or may not be a physical unit, that is, it may be located in one place, or it may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment of the present invention. In addition, each functional unit in each embodiment of the present invention can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0125] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A charging and discharging system, characterized in that: The invention comprises an inverter, a first switch, a second switch, a fourth switch, a sixth switch and a seventh switch; the first end of the first switch is used to be connected to the first electrode of the charging device, the first end of the second switch is used to be connected to the second electrode of the charging device, the second end of the first switch is used to be connected to the first electrode of the energy storage device, and the second end of the second switch is used to be connected to the second electrode of the energy storage device; The inverter includes three bridge arms, the first end of each bridge arm is connected to the first end of the sixth switch, the second end of each bridge arm is connected to the first end of the seventh switch, the three bridge arms correspond to the three-phase windings of the motor one by one, the midpoints of the three bridge arms are respectively used to connect the three-phase windings of the motor, the midpoint of each bridge arm is respectively connected to the positive electrode of a diode, the negative electrode of each diode is connected to the first end of the fourth switch, the second end of the fourth switch is used to connect the second electrode of the energy storage device, the second end of the sixth switch is connected to the first end of the second switch, and the second end of the seventh switch is used to connect the first electrode of the energy storage device.

2. The charging and discharging system according to claim 1, characterized in that: It also includes a third switch and a fifth switch, wherein the first end of the first switch is also used to connect to the first end of the electrical device, the first end of the second switch is also used to connect to the second end of the electrical device, the first end of the third switch is used to connect to the second end of the electrical device, the second end of the third switch is connected to the cathode of each diode, the first end of the fifth switch is used to connect to the second electrode of the energy storage device, and the second end of the fifth switch is connected to the first end of each bridge arm.

3. A charge and discharge control method, characterized in that: Based on the charging and discharging system according to any one of claims 1 to 2, the charging and discharging control method comprises: Determine a charging mode according to the obtained output voltage of the charging device and the required voltage of the energy storage device, wherein the charging mode includes a boost charging mode, a direct charging mode and a buck charging mode; When the determined charging mode is a boost charging mode, the first switch, the sixth switch, the seventh switch, the lower bridge arm switches in the two first bridge arms in the inverter, and the upper bridge arm switch in the second bridge arm in the inverter are controlled to be closed, so as to charge the three windings of the motor, wherein the inverter includes two of the first bridge arms and one of the second bridge arms, and each bridge arm in the inverter includes the upper bridge arm switch and the lower bridge arm switch; When the three windings of the motor are fully charged, the seventh switch and the two lower bridge arm switches of the first bridge arm are controlled to be disconnected, and then the fourth switch is controlled to be closed to boost and charge the energy storage device.

4. The charge and discharge control method according to claim 3, characterized in that: Also includes: Determine the absolute inductance difference between each two windings according to the inductance of each phase winding of the motor, wherein the absolute inductance difference is the absolute value of the difference between the inductances of the two windings; The three absolute inductance differences are compared to determine that the bridge arms corresponding to the two windings corresponding to the smallest absolute inductance difference are the two first bridge arms, and the bridge arms in the inverter except the two first bridge arms are the second bridge arms.

5. The charge and discharge control method according to claim 3, characterized in that: Determining the charging mode according to the obtained output voltage of the charging device and the required voltage of the energy storage device includes: When the output voltage of the charging device is less than the required voltage of the energy storage device, determining that the charging mode is the boost charging mode; When the output voltage of the charging device is equal to the required voltage of the energy storage device, determining that the charging mode is the direct charging mode; When the output voltage of the charging device is greater than the required voltage of the energy storage device, the charging mode is determined to be the buck charging mode.

6. The charge and discharge control method according to claim 3, characterized in that: When the determined charging mode is the buck charging mode, controlling the first switch, the sixth switch, the seventh switch, the lower bridge arm switches in the two first bridge arms, and the upper bridge arm switch in the second bridge arm to close, so as to charge the three windings of the motor; When the three windings of the motor are fully charged, the two lower bridge arm switches in the first bridge arm, the upper bridge arm switch in the second bridge arm, the first switch and the sixth switch are controlled to be disconnected, and then the fourth switch and the lower bridge arm switch of one bridge arm in the inverter are controlled to be closed to step down and charge the energy storage device.

7. The charge and discharge control method according to claim 3, characterized in that: The charging and discharging system further includes a third switch and a fifth switch, wherein the first end of the first switch is also used to be connected to the first end of the electric device, the first end of the second switch is also used to be connected to the second end of the electric device, the first end of the third switch is used to be connected to the second end of the electric device, the second end of the third switch is connected to the cathode of each diode, the first end of the fifth switch is used to be connected to the second electrode of the energy storage device, and the second end of the fifth switch is connected to the first end of each bridge arm of the inverter; The charge and discharge control method further includes: Determine a discharge mode according to the obtained output voltage of the energy storage device and the required voltage of the electrical device, wherein the discharge mode includes a boost discharge mode, a direct discharge mode and a buck discharge mode; When the determined discharge mode is the boost discharge mode, the fifth switch, the seventh switch, the two lower bridge arm switches in the first bridge arm, and the upper bridge arm switch in the second bridge arm are controlled to be closed, and the three windings of the motor are charged until the three windings of the motor are completely charged; The lower bridge arm switches and the seventh switch in the two first bridge arms are controlled to be disconnected, and the first switch and the third switch are controlled to be closed, so that the energy storage device is boosted and discharged.

8. The charge and discharge control method according to claim 7, characterized in that: Determining the discharge mode according to the obtained output voltage of the energy storage device and the required voltage of the power-consuming device includes: When the output voltage of the energy storage device is less than the required voltage of the electrical device, determining that the discharge mode is a boost discharge mode; When the output voltage of the energy storage device is equal to the required voltage of the power-consuming device, determining the charging mode to be a direct discharge mode; When the output voltage of the energy storage device is greater than the required voltage of the power-consuming device, the charging mode is determined to be a step-down discharge mode.

9. The charge and discharge control method according to claim 7, characterized in that: When the determined discharge mode is the step-down discharge mode, the fifth switch, the seventh switch, the two lower bridge arm switches in the first bridge arm, and the upper bridge arm switch in the second bridge arm are controlled to be closed, and the three windings of the motor are charged until the three windings of the motor are completely charged; The lower bridge arm switches in the two first bridge arms, the upper bridge arm switch in the second bridge arm and the fifth switch are controlled to be disconnected, and the first switch, the third switch and the lower bridge arm switch of one bridge arm in the inverter are controlled to be closed, so that the energy storage device can be discharged at a reduced voltage.

10. A vehicle, characterized in that: It comprises the charging and discharging system, energy storage device and control device as described in any one of claims 1-2; the charging and discharging system is connected to the energy storage device, the control device is connected to the charging and discharging system, and the control device is used to implement the charging and discharging control method as described in any one of claims 3 to 9.

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