Alternating current charging and discharging system of vehicle and control method of alternating current charging and discharging

Abstract

The application provides an alternating current charging and discharging system and an alternating current charging and discharging control method of a vehicle, which 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 respectively connected to the first inverters; the plurality of first inverters are connected in parallel to the direct current bus, and a first isolation 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 the opening and closing of the first isolation switch; when the first isolation switch is closed, the first motor outputs a torque; when the first isolation switch is opened, the plurality of first windings and the plurality of first inverters realize DC / DC energy transmission and electrical insulation isolation of alternating current charging and discharging; and after the first isolation switch is opened, a high-frequency pulse voltage is generated at the bridge arm end of the first inverter.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vehicle charging, and particularly relates to an alternating current (AC) charging and discharging system of a vehicle and an AC charging and discharging control method of the vehicle. BACKGROUND

[0002] The AC charging and discharging function is an important function of an electric vehicle. Compared with direct current (DC) charging, the AC charging does not require a power electronic converter device for construction of a charging station, and has low construction cost and low user charging cost. However, the power of the current AC charging is smaller than that of the DC charging, and the charging time of the vehicle is long, which directly affects the use experience of the user. In addition, the AC charging and discharging needs to be configured with a large-power on-board charger (OBC) on the vehicle, so that the cost of the vehicle is greatly increased, and the vehicle space and weight are occupied. SUMMARY

[0003] The application aims to solve the technical problem of providing an AC charging and discharging system of a vehicle and an AC charging and discharging control method, so as to realize the function of AC charging and discharging by multiplexing the inverters and windings of the electric drive system of the vehicle, and solve the problems of cost increase, vehicle weight increase and vehicle space occupation caused by the configuration of the on-board charger.

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

[0005] Each of the plurality of first windings is connected to one of the plurality of first inverters.

[0006] The plurality of first inverters are connected in parallel to the DC bus, and a first disconnector is arranged 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 disconnector and the first inverters, and is configured to control the opening and closing of the first disconnector. When the first disconnector is closed, the first motor outputs torque, and when the first disconnector is opened, the plurality of first windings and the plurality of first inverters realize DC / DC energy transmission and electrical insulation isolation for AC charging and discharging.

[0009] The controller is configured to control the first isolating switch to be closed, and control the bridge arms of the first inverter to generate the high-frequency pulse voltage when the first isolating switch is controlled to be opened.

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

[0011] In some embodiments, 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 comprises a second inverter and a second winding of the first motor, the second winding being connected to the second inverter, and a second isolating switch being arranged between the second winding and the second inverter, the second inverter being connected to the DC bus;

[0014] The controller is configured to control the opening and closing of the second isolating switch, and 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 opened, the second inverter is configured as the active front-end rectifier.

[0015] In some embodiments, the system further comprises a third inverter of the vehicle electric drive system and a third winding of the second motor, the third winding being connected to the third inverter, and a third isolating switch being arranged between the third winding and the third inverter, the third inverter being connected to the DC bus;

[0016] 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 the active front-end rectifier.

[0017] In some embodiments, the system further comprises a fourth inverter of the vehicle electric drive system and a fourth winding of the third motor, the fourth winding being connected to the fourth inverter, a neutral point of the fourth winding being connected to a power grid or a load, and a short-circuit switch being arranged 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 switch is 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 switch is opened, the fourth inverter is configured to output the active front-end rectifier or the AC load, and the fourth winding is configured to be the grid-connected inductor of the active front-end rectifier or the AC output filter inductor.

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

[0020] When the vehicle is in the charging and discharging mode, the first disconnector provided on the DC bus between the two adjacent first inverters is controlled to be opened, and the on-off of at least two target bridge arms in the plurality of bridge arms of the first inverter is controlled to generate a high-frequency pulse voltage at the bridge arm end of the first inverter.

[0021] When the vehicle is in the driving mode, the first disconnector 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 disconnector is controlled to be opened, at least two bridge arms in the plurality of bridge arms of each first inverter are selected as the target bridge arms based on the excitation inductance of the motor; and / or

[0024] The motor rotor is controlled to rotate to a target electrical angle to make the motor generate the maximum excitation inductance.

[0025] According to an embodiment of the present application, a vehicle is provided, comprising the AC charging and discharging system of the vehicle according to any one of the above-mentioned embodiments.

[0026] According to an embodiment of the present application, a controller is provided, comprising a memory and a processor, the memory stores a computer program, and the program can implement the steps of the heating control method of the vehicle battery pack according to any one of the above-mentioned embodiments when executed by the processor.

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

[0028] Compared with the prior art, the vehicle AC charging and discharging system and the AC charging and discharging control method have obvious advantages and beneficial effects.

[0029] The isolator and the winding of the electric drive system of the vehicle are reused to realize the AC charging and discharging of the vehicle, so that the OBC does not need to be separately arranged on the vehicle, the production cost of the vehicle is reduced, the arrangement space of the vehicle is saved, and the weight of the vehicle itself can be reduced. In addition, the reuse of the electric drive system of the vehicle to realize the AC charging can greatly reduce the cost required for setting a direct-current charging pile, and users can experience faster AC charging and lower charging cost.

[0030] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the contents of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The topological schematic diagram of the AC charging and discharging system of the vehicle of the first embodiment of the present application is shown.

[0032] Figure 2 The topological schematic diagram of the AC charging and discharging system of the vehicle of the second embodiment of the present application is shown.

[0033] Figure 3 The topological schematic diagram of the AC charging and discharging system of the vehicle of the third embodiment of the present application is shown.

[0034] Figure 4 The topological schematic diagram of the AC charging and discharging system of the vehicle of the fourth embodiment of the present application is shown.

[0035] Figure 5 The waveform schematic diagram of the output voltage of the first inverter of an embodiment of the present application is shown.

[0036] Figure 6 The waveform schematic diagram of the output voltage of the first inverter of another embodiment of the present application is shown.

[0037] Figure 7 The corresponding relationship schematic diagram of the rotor position and the inductance size of a two-phase motor of an embodiment of the present application is shown.

[0038] Figure 8 The corresponding relationship schematic diagram of the rotor position and the inductance size of a two-phase motor of another embodiment of the present application is shown.

[0039] Figure 9A flowchart of an alternating current charging and discharging control method for a vehicle according to an embodiment of the present application. DETAILED DESCRIPTION

[0040] In order to further clarify the technical means and effects adopted by the present application to achieve the predetermined inventive objectives, the specific embodiments of the vehicle alternating current charging and discharging system and the alternating current charging and discharging control method according to the present application and their effects will be described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0041] Figures 1-4 A topological diagram of the vehicle alternating current charging and discharging system according to the present application is shown. As shown in the figure, Figures 1-4 The vehicle alternating current charging and discharging system includes a plurality of first windings of a first motor of a vehicle electric drive system, a plurality of first inverters of the vehicle electric drive system, a direct current bus, an active front-end rectifier, and a controller (not shown in the figure).

[0042] Each of the plurality of first windings is respectively connected to one of the plurality of first inverters, i.e., the first windings and the first inverters are one-to-one correspondingly connected.

[0043] Optionally, the first motor is an interior permanent magnet synchronous motor. The plurality of first windings of the first motor are electrically insulated and isolated, and the plurality of first inverters of the electric drive system are electrically isolated.

[0044] The plurality of first inverters are connected in parallel to the direct current bus, and a first disconnector 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.

[0045] The direct current bus includes two positive and negative buses, and the first disconnector is correspondingly arranged on each of the two positive and negative buses. When the first disconnector is closed, the first inverter and the corresponding first winding are connected in parallel with other first inverters and corresponding first windings, realizing torque output of the electric drive system. When the first disconnector is opened, the plurality of first inverters and the plurality of first windings are configured as a single isolation transformer connected to an alternating current output port of the first inverter, realizing DC / DC energy transmission and electrical insulation isolation function during alternating current charging and discharging of the first inverter and the first winding.

[0046] Optionally, the first inverter and the first winding are configured as a DAB (Dual Active Bridge) DC / DC converter, realizing DC / DC energy transmission 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 first inverter bus voltage.

[0047] Optionally, the first inverter at the energy delivery end of the plurality of first inverters is configured with a high-frequency pulse generator, the first inverter at the energy receiving end of the plurality of first inverters is configured as a non-controlled rectifier or a synchronous rectifier, the DC bus voltage of the first inverter at the energy receiving end is controlled through the active front-end rectifier, and energy is transmitted from the inverter at the high DC bus voltage end to the inverter at the low DC bus voltage end.

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

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

[0050] The AC charging and discharging system of the vehicle of the present application multiplexes the electrical drive system of the vehicle to realize the isolation AC charging and discharging function, so that the vehicle does not need to be separately configured with an OBC, thereby saving the production cost of the vehicle, reducing the space occupation of the vehicle, and reducing the weight of the vehicle. Moreover, by multiplexing the electrical drive system of the vehicle to realize the AC charging and discharging of the vehicle, the construction cost of the AC charging pile is greatly reduced. At the same time, by controlling the inverter of the electrical drive system of the vehicle to generate a high-frequency pulse voltage, the charging speed of the vehicle can be effectively improved.

[0051] In an embodiment, the controller is configured to select at least two bridge arms as target bridge arms in the plurality of bridge arms of each first inverter based on the excitation inductance of the motor when the first isolation switch is opened, and control the on-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 selects bridge arms in the plurality of bridge arms of the first inverter, so that the selected bridge arms can generate a larger excitation inductance when outputting a pulse voltage, so as to reduce the motor iron loss and the magnet steel loss, reduce the working resistance of the motor, and reduce the copper loss of the motor.

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

[0054] Table 1

[0055]

[0056] Furthermore, 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 the maximum excitation inductance.

[0057] Figure 7 The diagram illustrates the correspondence between the rotor position and the inductance of a two-phase motor, as shown below. Figure 7 As shown, M1-M6 represent the maximum magnetizing inductance generated by the rotor of the first motor at multiple different target electrical angles. To further reduce motor losses, the controller controls the output torque of the first motor shaft, causing the rotor of the first motor to rotate to the operating angle that allows the first motor to generate the maximum magnetizing inductance, which is the target electrical angle. Figure 7 As shown, the target electrical angles of the motor rotor corresponding to the maximum excitation inductance generated by the first motor are 0 (360), 60, 120, 180, 240, and 300.

[0058] Optionally, when selecting three bridge arms from multiple bridge arms of the first inverter as target bridge arms, two of these target bridge arms are connected in series, and the remaining two are connected in parallel to output a high-frequency pulse voltage. Table 2 shows the correspondence between the three target bridge arms and the motor electrical angles. The motor electrical angles in Table 2 are the angles between the d-axis of the motor's rotor flux linkage and the A-axis of the stator flux linkage of phase A of the winding. The bridge arms of the first inverter shown in Table 2 include three bridge arms: A, B, and C.

[0059] Table 2

[0060]

[0061] Furthermore, 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 the maximum excitation inductance.

[0062] Based on the above control of the target bridge arm and in conjunction with the output torque of the motor shaft, the maximum excitation inductance can be obtained, thereby further reducing motor losses.

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

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

[0065] In an embodiment, the active front-end rectifier is a one-way AC / DC rectifier, or is configured as a two-way AC / DC rectifier, so as to simultaneously realize the charging and discharging functions of the AC charging and discharging system of the vehicle.

[0066] In an embodiment, the AC charging and discharging system of the vehicle further comprises a second inverter and the first motor comprises a second winding, the second winding is connected to the second inverter, and a second isolation 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 isolation switch, when the second isolation switch is closed, the first motor outputs torque, and when the second isolation switch is opened, the second inverter is configured as an active front-end rectifier.

[0067] In this embodiment, the AC charging and discharging system of the vehicle further comprises 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 through a second isolation 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 isolation switch to be closed and the first isolation switch to be closed, the second inverter and the second winding are connected, and the first inverter and the first winding are connected, at this time, the driving mode is realized, and the torque output of the first motor is realized. When the controller controls the second isolation switch to be opened and the first isolation switch to be opened, the second inverter and the second winding are disconnected, and the DC bus between the plurality of first inverters is disconnected, at this time, the AC charging and discharging mode is realized, and the second inverter is configured as an active front-end rectifier.

[0069] In an embodiment, the AC charging and discharging system of the vehicle further comprises a third inverter of the electric drive system and a third winding of the second motor, the third winding is connected to the third inverter, and a third disconnection 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 disconnection switch, when the third disconnection switch is closed, the first motor and / or the second motor outputs torque, and when the third disconnection switch is opened, the third inverter is configured as an active front-end rectifier.

[0070] In this embodiment, the AC charging and discharging system of the vehicle further comprises 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 through a third disconnection 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 disconnection switch to be closed and the first disconnection switch to be closed, the third inverter and the third winding are connected, and the first inverter and the first winding are connected, at this time, the driving mode is realized, and the first motor and / or the second motor outputs torque. When the controller controls the third disconnection switch to be opened and the first disconnection switch to be opened, the third inverter and the third winding are disconnected, and the DC bus between the plurality of first inverters is disconnected, at this time, the AC charging and discharging mode is realized, and the second inverter is configured as an active front-end rectifier.

[0072] In an embodiment, the system further comprises a fourth inverter of the 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 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 short-circuit switch is closed, the neutral point of the fourth winding is short-circuited, the first motor and / or the third motor outputs torque, and when the short-circuit switch 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 of the active front-end rectifier or an AC output filter inductor.

[0073] In this embodiment, the AC charging and discharging system of the vehicle further comprises a fourth inverter of the electric drive system and a fourth winding of the third motor, the fourth inverter and the fourth winding are connected, the fourth winding is connected to the power grid or a load in a switchable manner through a short-circuit switch, and 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 be closed, the neutral point of the fourth winding is short-circuited, and the third motor operates in the driving mode, and when the controller controls the short-circuit switch to be opened, the fourth inverter is configured as an active front-end rectifier or a load output, and the fourth winding is configured as a grid-connected inductor of the active front-end rectifier or an AC output filter inductor.

[0075] In a specific embodiment, as shown inFigure 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, and winding 1 and winding 2 are respectively connected to inverter 1 and inverter 2. The first disconnector (K1, K2) is two, which is respectively arranged 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 disconnector (K1, K2) to be closed, the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2 operate in parallel, realizing the torque output of the electric drive system of the vehicle.

[0077] When the controller controls the first disconnector (K1, K2) to be opened, the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2 realize DC / DC energy transmission and electrical isolation, and through the configured unidirectional or bidirectional DA / AC converter, the charging and discharging function of the battery is realized.

[0078] Optionally, as shown in the figure, Figure 5 After the controller controls the first disconnector (K1, K2) to be opened, the controller controls the opening and closing of the power switch tube of inverter 1, 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 (wherein, 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 bridge arm (or single-phase bridge arm) of the same phase as the bridge arm outputting the high-frequency pulse voltage of inverter 1 outputs another group of high-frequency pulse voltage, +Vdc2, 0, -Vdc2 (wherein, Vdc2 is the DC bus voltage of inverter 2). That is, inverter 1 and inverter 2 are in the DAB (Dual Active Bridge, Dual Active Bridge) working mode of DC / DC converter, and the energy transmission is realized by relying on the amplitude difference or pulse width difference or / and phase difference of the output voltage of inverter 1 and inverter 2.

[0079] Optionally, as shown in the figure, Figure 6As shown, after the controller controls the first disconnectors (K1, K2) to be disconnected, the controller controls the opening and closing of the power switch tubes of the inverter 1, two-phase (or single-phase) bridge arms in the three-phase bridge arms of the inverter 1 output high-frequency pulse voltages, +Vdc1, 0, -Vdc1 (wherein Vdc1 is the DC bus voltage of the inverter 1); and the inverter 2 is in a diode rectification state (or a synchronous rectification state), and the two-phase (or single-phase) bridge arms of the inverter 2 and the inverter 1 output high-frequency pulse voltages in the same phase work to output +Vdc2, 0, -Vdc2 (Vdc2 is the DC bus voltage of the inverter 2). In this mode, Vdc1≥Vdc2 is required. When energy needs to be transmitted in reverse, the inverter 2 is switched, the inverter is rectified, and Vdc2≥Vdc1.

[0080] In a specific embodiment, as shown in Figure 2 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 respectively connected to inverter 1 and inverter 2. The first disconnectors (K1, K2) are two, which are respectively arranged on the positive and negative DC buses between the inverter 1 and the inverter 2. The second winding of the first motor includes winding 3, the second inverter includes inverter 3, winding 3 is connected to inverter 3, and the second disconnectors (K3, K4, K5) are arranged therebetween, Figure 2 The second disconnectors shown in are three, of course, according to the actual use requirement, the second disconnectors can also be arranged as two. The power grid or the load is connected between the second disconnectors (K3, K4, K5) and the inverter 3.

[0081] When the controller controls the first disconnectors (K1, K2) and the second disconnectors (K3, K4, K5) to be closed, 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, realizing the torque output of the electric drive system of the vehicle.

[0082] When the controller controls the first disconnectors (K1, K2) and the second disconnectors (K3, K4, K5) to be disconnected, the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2 realize DC / DC energy transmission and electrical isolation, and cooperate with the inverter 3 to realize the AC / DC conversion function of one-way or two-way DA / AC alternating current charging and discharging.

[0083] In an embodiment, as shown in Figure 3As shown in the first motor, the first winding 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 and inverter 1 and inverter 2 are connected respectively. The first disconnecting switch (K1, K2) is two, which is respectively set between the positive and negative DC bus of inverter 1 and inverter 2. The third winding of the second motor includes winding 3, and the third inverter includes inverter 3, winding 3 and inverter 3 are connected, and the third disconnecting switch (K3, K4, K5) is arranged between them, Figure 3 The third disconnecting switch shown in the middle is three, of course, according to the actual use demand, the third disconnecting switch can also be set to two. The power grid or load is connected between the third disconnecting switch (K3, K4, K5) and the inverter 3.

[0084] When the controller controls the first disconnecting switch (K1, K2) to be closed, the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2 operate in parallel between them, realizing the torque output of the first motor of the electric drive system of the vehicle.

[0085] When the controller controls the first disconnecting switch (K1, K2) and the second disconnecting switch (K3, K4, K5) to be closed, 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 between them, realizing the torque output of the first motor and / or the second motor of the electric drive system of the vehicle.

[0086] When the controller controls the first disconnecting switch (K1, K2) and the second disconnecting switch (K3, K4, K5) to be disconnected, the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2 realize DC / DC energy transmission and electrical isolation between them, and cooperate with inverter 3 to realize the AC / DC conversion function of one-way or two-way DA / AC alternating current charging and discharging.

[0087] In a specific embodiment, as Figure 4 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 and inverter 1 and inverter 2 are connected respectively. The first disconnecting switch (K1, K2) is two, which is respectively set between the positive and negative DC bus of inverter 1 and inverter 2. The third winding of the second motor includes winding 3, and the third inverter includes inverter 3, winding 3 and inverter 3 are connected, and the short-circuit switch (K3, K5) is arranged between the power grid or load and winding 3,

[0088] When the controller controls the first disconnecting switch (K1, K2) to be closed, the combination of winding 1 and inverter 1 and the combination of winding 2 and inverter 2 operate in parallel between them, realizing the torque output of the first motor of the electric drive system of the vehicle.

[0089] When the controller controls the first disconnecting switch (K1, K2) and the second disconnecting switch (K3, K5) to be closed, the combination of the winding 1 and the inverter 1, the combination of the winding 2 and the inverter 2, and the combination of the winding 3 and the inverter 3 are operated in parallel between each other, realizing the torque output of the first motor and / or the third motor of the electric drive system of the vehicle.

[0090] When the controller controls the first disconnecting switch (K1, K2) and the second disconnecting switch (K3, K5) to be closed, the combination of the winding 1 and the inverter 1, the combination of the winding 2 and the inverter 2, and the combination of the winding 3 and the inverter 3 are operated in parallel between each other, realizing the torque output of the first motor and / or the third motor of the electric drive system of the vehicle.

[0091] According to another embodiment of the present application, a control method for AC charging and discharging of a vehicle is provided, which is applied to the AC charging and discharging system of any of the above embodiments, as shown in FIG. 10, the method comprising: Figure 9

[0092] Step S10, when the vehicle is in the charging and discharging mode, controlling the first disconnecting switch arranged on the DC bus between the two adjacent first inverters to be closed, the same-phase two-phase (or single-phase) bridge arms of the bridge arms outputting high-frequency pulse voltage, and controlling at least two target bridge arms in the plurality of bridge arms of the first inverter to be high-frequency on-off, so as to generate high-frequency pulse voltage on the first winding. Wherein, the high frequency is at least KHZ order of magnitude.

[0093] Specifically, when the controller controls the first disconnecting switch to be closed and the plurality of first inverters and the plurality of first windings work in the DC / DC mode, the controller controls the target bridge arms of the first inverter to be high-frequency on-off, so as to output high-frequency pulse voltage, and the high-frequency pulse energy output by the first inverter is isolated via the first winding and realized periodically.

[0094] In an embodiment, the control method for AC charging and discharging of the vehicle further comprises: when the first disconnecting switch is controlled to be closed, selecting at least two bridge arms as target bridge arms in the plurality of bridge arms of each first inverter based on the excitation inductance of the motor; and / or controlling the motor rotor to rotate to a target electrical angle, so that the motor generates the maximum excitation inductance.

[0095] In this embodiment, in order to enable the first motor to generate a larger excitation inductance, the controller selects among the plurality of bridge arms in the first inverter, so that the selected bridge arms can generate a larger excitation inductance when outputting pulse voltage, so as to reduce the working resistance of the motor while reducing the iron loss and magnetic steel loss of the motor, and reduce the copper loss of the motor.

[0096] ​Optionally, when two bridge arms of the plurality of bridge arms of the first inverter are selected as target bridge arms, the two target bridge arms are connected in series to output the high-frequency pulse voltage. As shown in Table 3, the correspondence between the three target bridge arms and the motor electrical angle is disclosed. The motor electrical angle in Table 3 is the angle between the d-axis of the rotor flux of the motor and the A-axis of the stator flux of the winding A. 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 the maximum excitation inductance.

[0100] Figure 7 The correspondence between the rotor position of the two-phase motor and the inductance is shown as Figure 7 As shown in M1-M6, the maximum excitation inductance generated by the motor rotor of the first motor at a plurality of different target electrical angles. In order to further reduce the loss of the motor, the controller controls the torque output of the first motor shaft, so that the rotor of the first motor rotates to the working angle at which the first motor generates the maximum excitation inductance, i.e. the target electrical angle, as shown in Figure 7 As shown in M1-M6, the maximum excitation inductance generated by the motor rotor of the first motor at a plurality of different target electrical angles. In order to further reduce the loss of the motor, the controller controls the torque output of the first motor shaft, so that the rotor of the first motor rotates to the working angle at which the first motor generates the maximum excitation inductance, i.e. the target electrical angle, as shown in

[0101] Optionally, when three bridge arms of the plurality of bridge arms of the first inverter are selected as target bridge arms, two target bridge arms of the three target bridge arms are connected in series, and the other target bridge arm is connected in parallel to output the high-frequency pulse voltage. As shown in Table 4, the correspondence between the three target bridge arms and the motor electrical angle is disclosed. The motor electrical angle in Table 4 is the angle between the d-axis of the rotor flux of the motor and the A-axis of the stator flux of the winding A. 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 the maximum excitation inductance.

[0105] According to the above control of the target bridge arms and 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 correspondence between the rotor position of the three-phase motor and the inductance size is shown as Figure 8 M1-M6 are the maximum excitation inductances generated by the motor rotor of the first motor at a plurality of different target electrical angles, as shown. In order to further reduce the loss of the motor, the controller controls the first motor shaft to output torque, 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, the target electrical angle, as shown Figure 8 When the maximum excitation inductance generated by the first motor is generated, the target electrical angle of the motor rotor corresponding to the maximum excitation inductance generated by the first motor is 30, 90, 150, 210, 270, 330.

[0107] Step S20, when the vehicle is in the driving mode, the first isolator is closed and the battery is powered to the first motor, so that the first motor generates torque.

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

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

[0110] According to another embodiment of the application, a vehicle is provided, which comprises the AC charging and discharging system of the vehicle of any of the above embodiments.

[0111] According to another embodiment of the application, a controller is provided, which comprises a memory and a processor, the memory stores a computer program, and the program can implement the steps of the AC charging and discharging control method of the vehicle in any of the above embodiments when executed by the processor.

[0112] According to another embodiment of the application, a readable storage medium is provided for storing a computer program, which implements the steps of the AC charging and discharging control method of the vehicle in any of the above embodiments when executed by a computer or a processor.

[0113] The application realizes AC charging of the vehicle by multiplexing the isolator and winding of the electric drive system of the vehicle, so that it is not necessary to separately configure an OBC 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, multiplexing the electric drive system of the vehicle to realize AC charging can greatly reduce the cost required for setting up a DC charging pile, and users can experience faster AC charging and lower charging cost.

[0114] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the technical solution of the present application, can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, as long as it does not deviate from the technical solution of the present application, shall still fall within the scope of the technical solution of the present application.

Claims

1. An alternating current charging and discharging system for a vehicle, characterized by, The system comprises a plurality of first windings of a first motor of a vehicle electric drive system, a plurality of first inverters of the electric drive system, a DC bus, an active front-end rectifier and a controller; Each of the plurality of first windings is connected to one of the plurality of first inverters respectively; The plurality of first inverters are connected in parallel to the DC bus, and a first disconnector is arranged 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 disconnector and the first inverters, and is configured to control the opening and closing of the first disconnector, to control the first motor to output torque when the first disconnector is closed, to control the plurality of first windings and the plurality of first inverters to realize AC charging and discharging, DC / DC energy transmission and electrical insulation isolation when the first disconnector is opened, and to control the bridge arm end of the first inverter to generate a high-frequency pulse voltage after the first disconnector is opened. The controller is configured to select at least two bridge arms as target bridge arms from the plurality of bridge arms of each first inverter based on the excitation inductance of the first motor when the first disconnector is opened, and to control the on-off of the target bridge arms to generate the high-frequency pulse voltage.

2. The AC charging and discharging system of a vehicle according to claim 1, characterized by, 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 the maximum excitation inductance.

3. The AC charging and discharging system of a vehicle according to claim 2, characterized by, The active front-end rectifier is a unidirectional AC / DC rectifier, or is configured as a bidirectional AC / DC rectifier.

4. The AC charging and discharging system of a vehicle according to claim 1, characterized by, The system further comprises a second inverter and a second winding of the first motor, the second winding is connected to the second inverter, a second disconnector is arranged between the second winding and the second inverter, and the second inverter is connected to the DC bus; 5. The AC charging and discharging system of a vehicle according to claim 1, characterized by, The controller is configured to control the opening and closing of the second disconnector, to control the first motor to output torque when the second disconnector is closed, and to configure the second inverter as the active front-end rectifier when the second disconnector is opened. The system further comprises a third inverter of the vehicle electric drive system and a third winding of a second motor, the third winding is connected to the third inverter, a third disconnector is arranged between the third winding and the third inverter, and the third inverter is connected to the DC bus; 6. The AC charging and discharging system of a vehicle according to claim 1, characterized by, The controller is configured to control the opening and closing of the third disconnector, to control the first motor and / or the second motor to output torque when the third disconnector is closed, and to configure the third inverter as the active front-end rectifier when the third disconnector is opened. The system further comprises a fourth inverter of the vehicle electric drive system and a fourth winding of a 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 arranged between the neutral point of the fourth winding and the power grid; 7. The AC charging and discharging system of a vehicle according to claim 1, characterized by, ​ The controller is configured to control the opening and closing of the short-circuit switch, when the short-circuit switch is closed, the neutral point of the fourth winding is short-circuited, and the first motor and / or the third motor outputs torque, when the short-circuit switch is opened, the fourth inverter is configured to output the active front-end rectifier or an alternating current load, and the fourth winding is configured to be a grid-connected inductor of the active front-end rectifier or an alternating current output filter inductor.

8. An alternating current charge-discharge control method for a vehicle, characterized by, The method is applied to the alternating current charging and discharging system of the vehicle of any one of claims 1-7, and the method comprises: When the vehicle is in a charging and discharging mode, a first isolation switch provided on the direct current bus between two adjacent first inverters is controlled to be opened, and at least two target bridge arms in a plurality of bridge arms of the first inverter are controlled to be turned on and off, so as to generate a high-frequency pulse voltage at the 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 alternating current charging and discharging control method of a vehicle according to claim 8, characterized by, The method further comprises: When the first isolation switch is controlled to be opened, at least two bridge arms in a plurality of bridge arms of each first inverter are selected as the target bridge arms based on the excitation inductance of the motor; and / or The motor rotor is controlled to rotate to a target electrical angle, so that the motor generates maximum excitation inductance.

10. A vehicle characterized by comprising: The alternating current charging and discharging system of the vehicle of any one of claims 1-7.

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