AC charging / discharging system for vehicle and control method for AC charging / discharging

Abstract

The invention provides an alternating current charging and discharging system of a vehicle and an alternating current charging and discharging control method. The system comprises a plurality of first windings of a first motor of an electric drive system, a plurality of first inverters of the electric drive system, a direct current bus, an active front end rectifier and a controller. The first windings are correspondingly connected with the first inverters respectively; the plurality of first inverters are connected in parallel to the direct-current bus, and a first isolating switch is arranged on the direct-current bus between two adjacent first inverters; one end of the direct-current bus is connected to a battery of the vehicle, and the other end of the direct-current bus is connected to the active front-end rectifier; the controller is configured to control opening and closing of the first isolation switch, when the first isolation switch is controlled to be closed, the first motor outputs torque, when the first isolation switch is controlled to be disconnected, the multiple first windings and the multiple first inverters achieve DC / DC energy transmission and electrical insulation isolation of alternating current charging and discharging, and after the first isolation switch is controlled to be disconnected, the multiple second windings and the multiple first inverters achieve DC / DC energy transmission and electrical insulation isolation of alternating current charging and discharging. And controlling the bridge arm end of the first inverter to generate high-frequency pulse voltage.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle-mounted charging, and in particular relates to an AC charging and discharging system of a vehicle and a control method for the AC charging and discharging of the vehicle. Background Art

[0002] AC charging and discharging is an important function of electric vehicles. Compared with DC charging, AC charging does not require power electronic converter equipment in charging station construction, and the cost of station construction and user charging is low. However, the power of AC charging is currently lower than that of DC charging, and the charging time of the car is long, which directly affects the user experience. In addition, AC charging and discharging requires a high-power on-board OBC (On-Board Charger) to be configured on the vehicle, which will greatly increase the cost of the vehicle and occupy a considerable amount of vehicle space and weight. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an AC charging and discharging system and a control method for AC charging and discharging of a vehicle, so as to realize the AC charging and discharging function by reusing the inverter and winding of the vehicle electric drive system, thereby solving the problems of increased cost, increased vehicle weight and occupied vehicle space caused by configuring an on-board OBC.

[0004] In order to solve or improve the above technical problems to a certain extent, according to one aspect of the present invention, there is provided an AC charging and discharging system for a vehicle, comprising a plurality of first windings of a first motor of an electric drive system of a vehicle, a plurality of first inverters of the electric drive system, a DC bus, an active front-end rectifier and a controller;

[0005] Wherein, each of the plurality of the first windings is respectively connected to one of the plurality of the first inverters;

[0006] A plurality of the first inverters are connected in parallel to the DC bus, and a first isolating switch is provided on the DC bus between two adjacent first inverters;

[0007] One end of the DC bus is connected to a battery of the vehicle, and the other end of the DC bus is connected to the active front-end rectifier;

[0008] The controller is connected to the first isolating switch and the first inverter, and the controller is configured to control the opening and closing of the first isolating switch. When the first isolating switch is controlled to be closed, the first motor outputs torque. When the first isolating switch is controlled to be open, the plurality of first windings and the plurality of first inverters realize DC / DC energy transmission and electrical insulation isolation of AC charging and discharging, and

[0009] After the first isolating switch is controlled to be disconnected, the bridge arm end of the first inverter is controlled to generate a high-frequency pulse voltage.

[0010] In some embodiments, the controller is configured to select at least two bridge arms from the multiple bridge arms of each of the first inverters as target bridge arms based on the excitation inductance of the first motor when the first isolating switch is disconnected, and control the on and off of the target bridge arms to generate the high-frequency pulse voltage.

[0011] In some implementations, the controller is configured to control the rotor of the first motor to rotate to a target electrical angle so that the first motor generates a maximum excitation inductance.

[0012] In some embodiments, the active front end rectifier is a unidirectional AC / DC rectifier, or is configured as a bidirectional AC / DC rectifier.

[0013] In some embodiments, the system further includes the second inverter and the first motor including a second winding, the second winding is connected to the second inverter, and a second isolation switch is provided between the second winding and the second inverter, and the second inverter is connected to the DC bus;

[0014] The controller is configured to control the opening and closing of the second isolating switch. When the second isolating switch is controlled to be closed, the first motor outputs torque. When the second isolating switch is controlled to be open, the second inverter is configured as the active front-end rectifier.

[0015] In some embodiments, the system further includes a third inverter of the vehicle electric drive system and a third winding of the second motor, the third winding is connected to the third inverter, and a third isolation switch is provided between the third winding and the third inverter, and the third inverter is connected to the DC bus;

[0016] The controller is configured to control the opening and closing of the third isolating switch. When the third isolating switch is controlled to be closed, the first motor and / or the second motor outputs torque. When the third isolating switch is controlled to be open, the third inverter is configured as the active front-end rectifier.

[0017] In some embodiments, the system further includes a fourth inverter of the vehicle electric drive system and a fourth winding of the third motor, the fourth winding is connected to the fourth inverter, the neutral point of the fourth winding is connected to a power grid or a load, and a short-circuit switch is provided between the neutral point of the fourth winding and the power grid;

[0018] The controller is configured to control the opening and closing of the short-circuit switch. When the circuit breaker is controlled to be closed, the neutral point of the fourth winding is short-circuited, and the first motor and / or the third motor outputs torque. When the circuit breaker is controlled to be open, the fourth inverter is configured as the active front-end rectifier or the AC load output, and the fourth winding is configured as the grid-connected inductor or the AC output filter inductor of the active front-end rectifier.

[0019] According to an embodiment of the present invention, there is provided an AC charging and discharging control method for a vehicle, characterized in that it is applied to the AC charging and discharging system of the vehicle described in any one of the above embodiments, and the method comprises:

[0020] When the vehicle is in a charge and discharge mode, controlling a first isolating switch provided on the DC bus between two adjacent first inverters to be disconnected, and controlling the on and off of at least two target bridge arms among a plurality of bridge arms of the first inverter to generate a high-frequency pulse voltage at a bridge arm end of the first inverter;

[0021] When the vehicle is in a driving mode, the first isolation switch is controlled to be closed, and the battery supplies power to the first motor, so that the first motor generates torque.

[0022] In some embodiments, the method further comprises:

[0023] When the first isolating switch is controlled to be disconnected, at least two of the bridge arms are selected as the target bridge arms from the plurality of bridge arms of each of the first inverters based on the magnetizing inductance of the motor; and / or

[0024] The motor rotor is controlled to rotate to a target electrical angle so that the motor generates a maximum excitation inductance.

[0025] According to an embodiment of the present invention, a vehicle is provided, comprising the AC charging and discharging system for the vehicle described in any one of the above embodiments.

[0026] According to one embodiment of the present invention, a controller is provided, which includes a memory and a processor, wherein the memory stores a computer program, and when the program is executed by the processor, the steps of the vehicle battery pack heating control method described in any of the above embodiments can be implemented.

[0027] According to an embodiment of the present invention, a computer-readable storage medium is provided for storing a computer program, which, when executed by a computer or a processor, implements the steps of the vehicle battery pack heating control method described in any of the above embodiments.

[0028] Compared with the prior art, the present invention has obvious advantages and beneficial effects. By means of the above technical solution, the AC charging and discharging system and the AC charging and discharging control method of the vehicle of the present invention can achieve considerable technical advancement and practicality, and have wide industrial utilization value, and at least have the following advantages:

[0029] The present invention realizes AC charging and discharging of the vehicle by reusing the isolator and winding of the vehicle's electric drive system, so that there is no need to configure an OBC separately on the vehicle, which reduces the production cost of the vehicle, saves the configuration space of the vehicle, and can reduce the weight of the vehicle itself. At the same time, reusing the vehicle's electric drive system to realize AC charging can greatly reduce the cost required to set up a DC charging pile, and users can experience faster AC charging and lower charging costs.

[0030] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A topological diagram of an AC charging and discharging system for a vehicle according to a first embodiment of the present invention;

[0032] Figure 2 A topological diagram of an AC charging and discharging system for a vehicle according to a second embodiment of the present invention;

[0033] Figure 3 A topological diagram of an AC charging and discharging system for a vehicle according to a third embodiment of the present invention;

[0034] Figure 4 A topological diagram of an AC charging and discharging system for a vehicle according to a fourth embodiment of the present invention;

[0035] Figure 5 is a schematic diagram of a waveform of an output voltage of a first inverter according to an embodiment of the present invention;

[0036] Figure 6 is a schematic diagram of a waveform of an output voltage of a first inverter according to another embodiment of the present invention;

[0037] Figure 7 A schematic diagram of the corresponding relationship between the rotor position and the inductance of a two-phase motor according to an embodiment of the present invention;

[0038] Figure 8 A schematic diagram of the corresponding relationship between the rotor position and the inductance of a two-phase motor according to another embodiment of the present invention;

[0039] Fig. 9The figure is a flow chart of an AC charging and discharging control method for a vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods and effects of the AC charging and discharging system and AC charging and discharging control method of the vehicle proposed in the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0041] Figure 1-4 FIG. 1 shows a topological schematic diagram of the AC charging and discharging system of a vehicle of the present invention. Figure 1-4 As shown, the vehicle's AC charging and discharging system includes multiple first windings of the first motor of the vehicle's electric drive system, multiple first inverters of the vehicle's electric drive system, a DC bus, an active front-end rectifier and a controller (not shown in the figure).

[0042] Among them, each of the multiple first windings is respectively connected to one of the multiple first inverters, that is, the first windings are connected to the first inverters in a one-to-one correspondence.

[0043] Optionally, the first motor is a plug-in permanent magnet synchronous motor. The multiple first windings of the first motor are electrically insulated and isolated from each other, and the multiple first inverter high-voltage circuits of the electric drive system are electrically isolated from each other.

[0044] A plurality of first inverters are connected in parallel to a DC bus, and a first isolating switch is provided on the DC bus between two adjacent first inverters. One end of the DC bus is connected to a battery of the vehicle, and the other end of the DC bus is connected to an active front-end rectifier.

[0045] The DC bus includes two positive and negative DC bus bars, and a first isolating switch is correspondingly arranged on each of the positive and negative DC bus bars. When the first isolating switch is closed, the first inverter and the corresponding first winding are connected in parallel with other first inverters and corresponding first windings to realize the torque output of the electric drive system. When the first isolating switch is disconnected, multiple first inverters and multiple first windings are configured as an isolation transformer connected to the AC output port of the first inverter, and the first inverter and the first winding realize the DC / DC energy transmission and electrical insulation isolation function during the AC charging and discharging process.

[0046] Optionally, the first inverter and the first winding are configured as a DAB (Dual Active Bridge) DC / DC converter, and DC / DC energy transmission is achieved by controlling the output voltage pulse width and / or phase difference of the first inverter, or / and by controlling the active front-end rectifier to control the bus voltage of the first inverter.

[0047] Optionally, the first inverter at the energy transmitting end among the multiple first inverters is configured as a high-frequency pulse generator, and the first inverter at the energy receiving end among the multiple first inverters is configured as an uncontrolled rectifier or a synchronous rectifier. The DC bus voltage of the first inverter at the energy receiving end is controlled by an active front-end rectifier to achieve energy transmission from the inverter at the transmitting end with a high DC bus voltage to the first inverter at the energy receiving end with a low DC bus voltage.

[0048] The controller is connected to the first isolating switch and the first inverter. The controller is configured to control the opening and closing of the first isolating switch. When the first isolating switch is controlled to be closed, the first motor outputs torque to meet the control state of the vehicle power output function. When the controller controls the first isolating switch to be disconnected, the plurality of first windings and the plurality of first inverters realize DC / DC energy transmission and electrical insulation isolation of AC charging and discharging, and after the first isolating switch is controlled to be disconnected, the bridge arm end of the first inverter is controlled to generate a high-frequency pulse voltage.

[0049] Specifically, when the controller controls the first isolating switch to disconnect, multiple first inverters and multiple first windings operate in DC / DC mode, and the controller controls the bridge arm end of the first inverter to output a high-frequency pulse voltage. The high-frequency pulse energy output by the first inverter is isolated via the first winding and periodically transmitted.

[0050] The AC charging and discharging system of the vehicle of the present invention reuses the electric drive system of the vehicle to realize the isolated AC charging and discharging function, so that the vehicle does not need to be equipped with an OBC separately, saving the production cost of the vehicle, reducing the space occupied by the vehicle, and reducing the weight of the vehicle. In addition, by reusing the electric drive system of the vehicle to realize the AC charging and discharging of the vehicle, the construction cost of building an AC charging pile is greatly reduced. At the same time, by controlling the inverter of the electric drive system of the vehicle to generate a high-frequency pulse voltage, the charging speed of the vehicle can be effectively improved.

[0051] In one embodiment, the controller is configured to select at least two bridge arms from multiple bridge arms of each first inverter as target bridge arms based on the excitation inductance of the motor when the first isolating switch is disconnected, and control the on and off of the target bridge arms to generate a high-frequency pulse voltage.

[0052] In this embodiment, in order to enable the first motor to generate a larger excitation inductance, the controller will select from the multiple bridge arms in the first inverter so that when the selected bridge arm outputs a pulse voltage, the motor can generate a larger excitation inductance, thereby reducing the iron loss and magnetic steel loss of the motor while reducing the working resistance of the motor and reducing the copper loss of the motor.

[0053] Optionally, when two bridge arms are selected from the multiple bridge arms of the first inverter as the target bridge arms, the two target bridge arms are connected in series and then output a high-frequency pulse voltage. As shown in Table 1, the correspondence between the two target bridge arms and the electrical angle of the motor is disclosed. The electrical angle of the motor in Table 1 is the angle between the d-axis where the rotor flux of the motor is located and the A-axis of the stator flux of the winding A phase. The bridge arms of the first inverter shown in Table 1 include three bridge arms A, B, and C.

[0054] Table 1

[0055]

[0056] Further, the controller is configured to control the rotor of the first motor to rotate to a target electrical angle so that the first motor generates a maximum excitation inductance.

[0057] Figure 7 The corresponding relationship between the rotor position and inductance of a two-phase motor is shown. Figure 7 As shown in FIG. 1 , M1-M6 are the maximum excitation inductances generated by the motor rotor of the first motor at multiple different target electrical angles. In order to further reduce the loss of the motor, the controller controls the output torque of the first motor shaft so that the rotor of the first motor rotates to the working angle at which the maximum excitation inductance generated by the first motor is generated, that is, the target electrical angle, as shown in FIG. Figure 7 As shown, when the maximum excitation inductance generated by the first motor is reached, the corresponding target electrical angle of the motor rotor is 0 (360), 60, 120, 180, 240, 300.

[0058] Optionally, when three bridge arms are selected from the multiple bridge arms of the first inverter as the target bridge arms, two of the three target bridge arms are connected in series, and then connected in parallel with the other target bridge arm to output a high-frequency pulse voltage. As shown in Table 2, the correspondence between the three target bridge arms and the electrical angle of the motor is disclosed. The electrical angle of the motor in Table 2 is the angle between the d-axis where the rotor flux of the motor is located and the A-axis of the stator flux of the winding A phase. The bridge arms of the first inverter shown in Table 2 include three bridge arms A, B, and C.

[0059] Table 2

[0060]

[0061] Further, the controller is configured to control the rotor of the first motor to rotate to a target electrical angle so that the first motor generates a maximum excitation inductance.

[0062] According to the above control of the target bridge arm and in coordination with the output torque of the motor shaft, the maximum excitation inductance can be obtained, thereby further reducing the loss of the motor.

[0063] Figure 8The corresponding relationship between the rotor position and inductance of a three-phase motor is shown in Figure 1. Figure 8 As shown, M1-M6 are the maximum excitation inductances generated by the motor rotor of the first motor at multiple different target electrical angles. In order to further reduce the loss of the motor, the controller controls the output torque of the first motor shaft so that the rotor of the first motor rotates to a working angle that can generate the maximum excitation inductance of the first motor, the target electrical angle, such as Figure 8 As shown, when the maximum excitation inductance generated by the first motor corresponds to the target electrical angle of the motor rotor is 30, 90, 150, 210, 270, 330.

[0064] In one embodiment, the configuration of the active front end rectifier can realize the AC-DC conversion of two-phase electricity, and can also realize the AC-DC conversion of three-phase electricity.

[0065] In one embodiment, the active front end rectifier is a unidirectional AC / DC rectifier, or is configured as a bidirectional AC / DC rectifier to simultaneously realize the charging and discharging functions of the vehicle's AC charging and discharging system.

[0066] In one embodiment, the AC charging and discharging system of the vehicle also includes a second inverter and the first motor includes a second winding, the second winding is connected to the second inverter, and a second isolating switch is arranged between the second winding and the second inverter, and the second inverter is connected to the DC bus; the controller is configured to control the opening and closing of the second isolating switch, when the second isolating switch is controlled to be closed, the first motor outputs torque, and when the second isolating switch is controlled to be open, the second inverter is configured as an active front-end rectifier.

[0067] In this embodiment, the vehicle's AC charging and discharging system also includes a second inverter of the electric drive system and a second winding of the first motor. The second inverter and the second winding are connected in a switchable manner via a second isolating switch. The second inverter is connected to the DC bus and is connected in parallel with the first inverter.

[0068] When the controller controls the second isolating switch to close, and controls the first isolating switch to close, the second inverter is connected to the second winding, and the first inverter is connected to the first winding, and it is in the driving mode at this time, and the torque output of the first motor is realized. When the controller controls the second isolating switch to open, and controls the first isolating switch to open, the second inverter is disconnected from the second winding, and the DC bus between the multiple first inverters is disconnected, and it is in the AC charging and discharging mode at this time, and the second inverter is configured as an active front-end rectifier.

[0069] In one embodiment, the AC charging and discharging system of the vehicle also includes a third inverter of the vehicle electric drive system and a third winding of the second motor, the third winding is connected to the third inverter, and a third isolating switch is arranged between the third winding and the third inverter, and the third inverter is connected to the DC bus; the controller is configured to control the opening and closing of the third isolating switch, and when the third isolating switch is controlled to be closed, the first motor and / or the second motor outputs torque, and when the third isolating switch is controlled to be opened, the third inverter is configured as an active front-end rectifier.

[0070] In this embodiment, the vehicle's AC charging and discharging system also includes a third inverter of the electric drive system and a third winding of the second motor. The third inverter and the third winding are connected in a switchable manner via a third isolating switch. The third inverter is connected to the DC bus and is connected in parallel with the first inverter.

[0071] When the controller controls the third isolating switch to close, and controls the first isolating switch to close, the third inverter is connected to the third winding, and the first inverter is connected to the first winding. At this time, it is in the driving mode, and the torque output of the first motor and / or the second motor is realized. When the controller controls the third isolating switch to open, and controls the first isolating switch to open, the third inverter is disconnected from the third winding, and the DC bus between the multiple first inverters is disconnected. At this time, it is in the AC charging and discharging mode, and the second inverter is configured as an active front-end rectifier.

[0072] In one embodiment, the system also includes a fourth inverter of the vehicle electric drive system and a fourth winding of the third motor, the fourth winding is connected to the fourth inverter, the neutral point of the fourth winding is connected to the power grid, and a short-circuit switch is arranged between the neutral point of the fourth winding and the power grid; the controller is configured to control the opening and closing of the short-circuit switch, when the control circuit breaker is closed, the neutral point of the fourth winding is short-circuited, the first motor and / or the third motor outputs torque, when the control circuit breaker is opened, the fourth inverter is configured as an active front-end rectifier or an AC load output, and the fourth winding is configured as a grid-connected inductor or an AC output filter inductor of the active front-end rectifier.

[0073] In this embodiment, the vehicle's AC charging and discharging system also includes a fourth inverter of the electric drive system and a fourth winding of the third motor. The fourth inverter is connected to the fourth winding, and the fourth winding can be connected and disconnected to the power grid or the load through a circuit breaker. The fourth inverter is connected to the DC bus and is connected in parallel with the first inverter.

[0074] When the controller controls the short-circuit switch to close, the neutral point of the fourth winding is short-circuited and the third motor operates in the driving mode. When the controller controls the short-circuit switch to open, the fourth inverter is configured as an active front-end rectifier or load output, and the fourth winding is configured as a grid-connected inductor or an AC output filter inductor of the active front-end rectifier.

[0075] In a specific embodiment, Figure 1 As shown, the first winding of the first motor includes winding 1 and winding 2, and winding 1 and winding 2 are insulated and highly coupled, the first inverter includes inverter 1 and inverter 2, winding 1 and winding 2 are connected to inverter 1 and inverter 2 respectively. There are two first isolating switches (K1, K2), which are respectively set on the positive and negative DC bus between inverter 1 and inverter 2. A unidirectional or bidirectional DA / AC converter is configured to realize the AC-DC conversion function of AC charging and discharging, and the power grid or load is connected to the unidirectional or bidirectional DA / AC converter.

[0076] When the controller controls the first isolating switch (K1, K2) to close, the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2 operate in parallel to achieve torque output of the vehicle's electric drive system.

[0077] When the controller controls the first isolating switch (K1, K2) to be disconnected, DC / DC energy transmission and electrical isolation are achieved between the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2, and the battery charging and discharging functions are achieved through the configured unidirectional or bidirectional DA / AC converter.

[0078] Alternatively, if Figure 5 As shown, after the controller controls the first isolating switch (K1, K2) to be disconnected, the controller controls the opening and closing of the power switch tube of inverter 1, and two phases in the three-phase bridge arm of inverter 1 (or a single phase in the three-phase bridge arm of inverter 1) output high-frequency pulse voltage, +Vdc1, 0, -Vdc1 (where Vdc1 is the DC bus voltage of inverter 1); and the controller controls the opening and closing of the power switch tube of inverter 2, and the two-phase (or single-phase) bridge arm with the same phase as the bridge arm of inverter 1 outputting the high-frequency pulse voltage outputs another set of high-frequency pulse voltage, +Vdc2, 0, -Vdc2 (where Vdc2 is the DC bus voltage of inverter 2). That is, inverters 1 and 2 are in the DAB (Dual Active Bridge) working mode of the DCDC converter, and energy transmission is achieved by relying on the amplitude difference or pulse width difference or / and phase difference of the output voltages of inverters 1 and 2.

[0079] Alternatively, if Figure 6As shown, after the controller controls the first isolating switch (K1, K2) to disconnect, the controller controls the opening and closing of the power switch tube of inverter 1, and two-phase (or single-phase) bridge arms of the three-phase bridge arm of inverter 1 output high-frequency pulse voltage, +Vdc1, 0, -Vdc1 (where Vdc1 is the DC bus voltage of inverter 1); while inverter 2 is in a diode rectification state (or synchronous rectification state), and the two-phase (or single-phase) bridge arms of inverter 2 and inverter 1 that output high-frequency pulse voltage work output +Vdc2, 0, -Vdc2 (Vdc2 is the DC bus voltage of inverter 2). In this mode, Vdc1≥Vdc2 is required. When reverse energy transmission is required, inverter 2 switches, the inverter rectifies, and Vdc2≥Vdc1.

[0080] In a specific embodiment, Figure 2 As shown, the first winding of the first motor includes winding 1 and winding 2, and winding 1 and winding 2 are insulated and highly coupled. The first inverter includes inverter 1 and inverter 2, and winding 1 and winding 2 are connected to inverter 1 and inverter 2 respectively. There are two first isolating switches (K1, K2), which are respectively arranged on the positive and negative DC bus between inverter 1 and inverter 2. The second winding of the first motor includes winding 3, and the second inverter includes inverter 3. Winding 3 is connected to inverter 3, and a second isolating switch (K3, K4, K5) is arranged between them. Figure 2 The number of second isolating switches shown in FIG is three. Of course, according to actual use requirements, the number of second isolating switches can also be two. The power grid or load is connected between the second isolating switches ( K3 , K4 , K5 ) and the inverter 3 .

[0081] When the controller controls the first isolating switch (K1, K2) and the second isolating switch (K3, K4, K5) to close, the combination of winding 1 and inverter 1, the combination of winding 2 and inverter 2, and the combination of winding 3 and inverter 3 operate in parallel to achieve torque output of the vehicle's electric drive system.

[0082] When the controller controls the first isolating switch (K1, K2) and the second isolating switch (K3, K4, K5) to be disconnected, DC / DC energy transmission and electrical isolation are realized between the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2, and the inverter 3 is cooperated to realize the AC / DC conversion function of unidirectional or bidirectional DA / AC AC charging and discharging.

[0083] In one embodiment, if Figure 3As shown, the first winding of the first motor includes winding 1 and winding 2, and winding 1 and winding 2 are insulated and highly coupled. The first inverter includes inverter 1 and inverter 2, and winding 1 and winding 2 are connected to inverter 1 and inverter 2 respectively. There are two first isolating switches (K1, K2), which are respectively set on the positive and negative DC bus between inverter 1 and inverter 2. The third winding of the second motor includes winding 3, and the third inverter includes inverter 3. Winding 3 is connected to inverter 3, and a third isolating switch (K3, K4, K5) is set between them. Figure 3 The third isolating switches shown in FIG. 3 are three, and of course, according to actual use requirements, the third isolating switches can also be set to two. The power grid or load is connected between the third isolating switches ( K3 , K4 , K5 ) and the inverter 3 .

[0084] When the controller controls the first isolating switch (K1, K2) to close, the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2 operate in parallel, thereby realizing the torque output of the first motor of the vehicle's electric drive system.

[0085] When the controller controls the first isolating switch (K1, K2) and the second isolating switch (K3, K4, K5) to close, the combination of winding 1 and inverter 1, the combination of winding 2 and inverter 2, and the combination of winding 3 and inverter 3 operate in parallel to achieve torque output of the first motor and / or the second motor of the vehicle's electric drive system.

[0086] When the controller controls the first isolating switch (K1, K2) and the second isolating switch (K3, K4, K5) to be disconnected, DC / DC energy transmission and electrical isolation are realized between the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2, and the inverter 3 is cooperated to realize the AC / DC conversion function of unidirectional or bidirectional DA / AC AC charging and discharging.

[0087] In a specific embodiment, Figure 4 As shown, the first winding of the first motor includes winding 1 and winding 2, and winding 1 and winding 2 are insulated and highly coupled. The first inverter includes inverter 1 and inverter 2, and winding 1 and winding 2 are connected to inverter 1 and inverter 2 respectively. There are two first isolating switches (K1, K2), which are respectively set on the positive and negative DC bus between inverter 1 and inverter 2. The fourth winding of the third motor includes winding 3, and the fourth inverter includes inverter 3. Winding 3 is connected to inverter 3, and a short-circuit switch (K3, K5) is set between the power grid or load and winding 3.

[0088] When the controller controls the first isolating switch (K1, K2) to close, the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2 operate in parallel, thereby realizing the torque output of the first motor of the vehicle's electric drive system.

[0089] When the controller controls the first isolating switch (K1, K2) and the second isolating switch (K3, K5) to close, the combination of winding 1 and inverter 1, the combination of winding 2 and inverter 2, and the combination of winding 3 and inverter 3 operate in parallel to achieve torque output of the first motor and / or the third motor of the vehicle's electric drive system.

[0090] When the controller controls the first isolating switch (K1, K2) and the second isolating switch (K3, K5) to be disconnected, DC / DC energy transmission and electrical isolation are realized between the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2, and the AC / DC conversion function of unidirectional or bidirectional DA / AC AC charging and discharging is realized in cooperation with inverter 3. Winding 3 is configured as the grid-connected inductor or AC output filter inductor of inverter 3.

[0091] According to another embodiment of the present invention, a method for controlling AC charging and discharging of a vehicle is provided. The method is applied to the AC charging and discharging system of the vehicle in any of the above embodiments. Fig. 9 As shown, the method includes:

[0092] Step S10, when the vehicle is in the charge and discharge mode, the first isolating switch provided on the DC bus between two adjacent first inverters is controlled to be disconnected, the two-phase (or single-phase) bridge arms of the same phase of the bridge arm of the high-frequency pulse voltage are output, and at least two target bridge arms among the multiple bridge arms of the first inverter are controlled to be turned on and off at high frequency to generate a high-frequency pulse voltage on the first winding. The high frequency is a frequency of at least KHZ.

[0093] Specifically, when the controller controls the first isolating switch to disconnect, and multiple first inverters and multiple first windings operate in DC / DC mode, the controller controls the high-frequency switching of the target bridge arm of the first inverter to output a high-frequency pulse voltage. The high-frequency pulse energy output by the first inverter is isolated via the first winding and periodically transmitted.

[0094] In one embodiment, the AC charging and discharging control method of a vehicle also includes: when the first isolating switch is controlled to be disconnected, based on the excitation inductance of the motor, selecting at least two bridge arms from multiple bridge arms of each first inverter as target bridge arms; and / or controlling the motor rotor to rotate to a target electrical angle so that the motor generates maximum excitation inductance.

[0095] In this embodiment, in order to enable the first motor to generate a larger excitation inductance, the controller will select from the multiple bridge arms in the first inverter so that when the selected bridge arm outputs a pulse voltage, the motor can generate a larger excitation inductance, thereby reducing the iron loss and magnetic steel loss of the motor while reducing the working resistance of the motor and reducing the copper loss of the motor.

[0096] Optionally, when two bridge arms are selected from the multiple bridge arms of the first inverter as the target bridge arms, the two target bridge arms are connected in series and then output a high-frequency pulse voltage. As shown in Table 3, the correspondence between the two target bridge arms and the motor electrical angle is disclosed. The motor electrical angle in Table 3 is the angle between the d-axis where the rotor flux of the motor is located and the A-axis of the stator flux of the winding A phase. The bridge arms of the first inverter shown in Table 3 include three bridge arms A, B, and C.

[0097] Table 3

[0098]

[0099] Further, the controller is configured to control the rotor of the first motor to rotate to a target electrical angle so that the first motor generates a maximum excitation inductance.

[0100] Figure 7 The corresponding relationship between the rotor position and inductance of a two-phase motor is shown. Figure 7 As shown in FIG. 1 , M1-M6 are the maximum excitation inductances generated by the motor rotor of the first motor at multiple different target electrical angles. In order to further reduce the loss of the motor, the controller controls the output torque of the first motor shaft so that the rotor of the first motor rotates to the working angle at which the maximum excitation inductance generated by the first motor is generated, that is, the target electrical angle, as shown in FIG. Figure 7 As shown, when the maximum excitation inductance generated by the first motor is reached, the corresponding target electrical angle of the motor rotor is 0 (360), 60, 120, 180, 240, 300.

[0101] Optionally, when three bridge arms are selected from the multiple bridge arms of the first inverter as the target bridge arms, two of the three target bridge arms are connected in series, and then connected in parallel with the other target bridge arm to output a high-frequency pulse voltage. As shown in Table 4, the correspondence between the three target bridge arms and the electrical angle of the motor is disclosed. The electrical angle of the motor in Table 4 is the angle between the d-axis where the rotor flux of the motor is located and the A-axis of the stator flux of the winding A phase. The bridge arms of the first inverter shown in Table 4 include three bridge arms A, B, and C.

[0102] Table 4

[0103]

[0104] Further, the controller is configured to control the rotor of the first motor to rotate to a target electrical angle so that the first motor generates a maximum excitation inductance.

[0105] According to the above control of the target bridge arm and in coordination with the output torque of the motor shaft, the maximum excitation inductance can be obtained, thereby further reducing the loss of the motor.

[0106] Figure 8The corresponding relationship between the rotor position and inductance of a three-phase motor is shown in Figure 1. Figure 8 As shown, M1-M6 are the maximum excitation inductances generated by the motor rotor of the first motor at multiple different target electrical angles. In order to further reduce the loss of the motor, the controller controls the output torque of the first motor shaft so that the rotor of the first motor rotates to a working angle that can generate the maximum excitation inductance of the first motor, the target electrical angle, such as Figure 8 As shown, when the maximum excitation inductance generated by the first motor corresponds to the target electrical angle of the motor rotor is 30, 90, 150, 210, 270, 330.

[0107] Step S20, when the vehicle is in the driving mode, the first isolating switch is controlled to be closed, and the battery supplies power to the first motor, so that the first motor generates torque.

[0108] In this step, when the first isolating switch is controlled to be closed, the first motor outputs torque to meet the control state of the vehicle power output function.

[0109] It should be noted that step S10 and step S20 are control methods in two different scenarios, and there is no limitation on the order of the steps.

[0110] According to another embodiment of the present invention, a vehicle is provided, comprising the AC charging and discharging system for the vehicle described in any one of the above embodiments.

[0111] According to another embodiment of the present invention, a controller is provided, which includes a memory and a processor, wherein the memory stores a computer program, and when the program is executed by the processor, the steps of the AC charging and discharging control method for a vehicle in any of the above-mentioned embodiments can be implemented.

[0112] According to another embodiment of the present invention, a readable storage medium is provided for storing a computer program, wherein when the program is executed by a computer or a processor, the steps of the AC charging and discharging control method for a vehicle in any of the above-mentioned embodiments are implemented.

[0113] The present invention realizes AC charging and discharging of the vehicle by reusing the isolator and winding of the vehicle's electric drive system, so that there is no need to configure an OBC separately on the vehicle, which reduces the production cost of the vehicle, saves the configuration space of the vehicle, and can reduce the weight of the vehicle itself. At the same time, reusing the vehicle's electric drive system to realize AC charging can greatly reduce the cost required to set up a DC charging pile, and users can experience faster AC charging and lower charging costs.

[0114] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. An AC charging and discharging system for a vehicle, characterized in that: The invention comprises a plurality of first windings of a first motor of an electric drive system of a vehicle, a plurality of first inverters of the electric drive system, a DC bus, an active front end rectifier and a controller; Wherein, each of the plurality of the first windings is respectively connected to one of the plurality of the first inverters; A plurality of the first inverters are connected in parallel to the DC bus, and a first isolating switch is provided on the DC bus between two adjacent first inverters; One end of the DC bus is connected to a battery of the vehicle, and the other end of the DC bus is connected to the active front-end rectifier; The controller is connected to the first isolating switch and the first inverter, and the controller is configured to control the opening and closing of the first isolating switch. When the first isolating switch is controlled to be closed, the first motor outputs torque. When the first isolating switch is controlled to be open, the plurality of first windings and the plurality of first inverters realize DC / DC energy transmission and electrical insulation isolation of AC charging and discharging, and After the first isolating switch is controlled to be disconnected, the bridge arm end of the first inverter is controlled to generate a high-frequency pulse voltage.

2. The AC charging and discharging system for a vehicle according to claim 1, characterized in that: The controller is configured to select at least two bridge arms from the multiple bridge arms of each of the first inverters as target bridge arms based on the excitation inductance of the first motor when the first isolating switch is disconnected, and control the on and off of the target bridge arms to generate the high-frequency pulse voltage.

3. The AC charging and discharging system for a vehicle according to claim 2, characterized in that: The controller is configured to control a rotor of the first motor to rotate to a target electrical angle so that the first motor generates a maximum excitation inductance.

4. The AC charging and discharging system for a vehicle according to claim 1, characterized in that: The active front end rectifier is a unidirectional AC / DC rectifier, or is configured as a bidirectional AC / DC rectifier.

5. The AC charging and discharging system for a vehicle according to claim 1, characterized in that: The system further includes a second inverter and a second winding of the first motor, the second winding is connected to the second inverter, a second isolating switch is provided between the second winding and the second inverter, and the second inverter is connected to the DC bus; The controller is configured to control the opening and closing of the second isolating switch. When the second isolating switch is controlled to be closed, the first motor outputs torque. When the second isolating switch is controlled to be open, the second inverter is configured as the active front-end rectifier.

6. The AC charging and discharging system for a vehicle according to claim 1, characterized in that: The system further includes a third inverter of the vehicle electric drive system and a third winding of the second motor, the third winding is connected to the third inverter, and a third isolating switch is provided between the third winding and the third inverter, and the third inverter is connected to the DC bus; The controller is configured to control the opening and closing of the third isolating switch. When the third isolating switch is controlled to be closed, the first motor and / or the second motor outputs torque. When the third isolating switch is controlled to be open, the third inverter is configured as the active front-end rectifier.

7. The AC charging and discharging system for a vehicle according to claim 1, characterized in that: The system further includes a fourth inverter of the vehicle electric drive system and a fourth winding of the third motor, the fourth winding is connected to the fourth inverter, a neutral point of the fourth winding is connected to a power grid or a load, and a short-circuit switch is provided between the neutral point of the fourth winding and the power grid; The controller is configured to control the opening and closing of the short-circuit switch. When the circuit breaker is controlled to be closed, the neutral point of the fourth winding is short-circuited, and the first motor and / or the third motor outputs torque. When the circuit breaker is controlled to be open, the fourth inverter is configured as the active front-end rectifier or the AC load output, and the fourth winding is configured as the grid-connected inductor or the AC output filter inductor of the active front-end rectifier.

8. A method for controlling AC charging and discharging of a vehicle, characterized in that: The AC charging and discharging system for a vehicle according to any one of claims 1 to 7, the method comprising: When the vehicle is in a charge and discharge mode, controlling a first isolating switch provided on the DC bus between two adjacent first inverters to be disconnected, and controlling the on and off of at least two target bridge arms among a plurality of bridge arms of the first inverter to generate a high-frequency pulse voltage at a bridge arm end of the first inverter; When the vehicle is in a driving mode, the first isolation switch is controlled to be closed, and the battery supplies power to the first motor, so that the first motor generates torque.

9. The AC charging and discharging control method for a vehicle according to claim 8, characterized in that: The method further comprises: When the first isolating switch is controlled to be disconnected, at least two of the bridge arms are selected as the target bridge arms from the plurality of bridge arms of each of the first inverters based on the magnetizing inductance of the motor; and / or The motor rotor is controlled to rotate to a target electrical angle so that the motor generates a maximum excitation inductance.

10. A vehicle, characterized in that: An AC charging and discharging system for a vehicle comprising any one of claims 1 to 7.

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