Power transfer using multi-winding motor

Abstract

An energy transfer system of a vehicle includes a multi-winding motor, a first inverter connected to a first set of windings, and a second inverter connected to a second set of windings. The system includes a controller configured to control the first inverter and the second inverter to control a charging current through the multi-winding motor at a desired power when the multi-winding motor is in a zero torque state. The controller is configured to control a charging current through the first inverter and the second inverter such that a first current vector associated with the first set of windings and a second current vector associated with the second set of windings are symmetric about a d-axis, and the multi-winding motor acts as a transformer, control of the first inverter and the second inverter provides power transfer between the first set of windings and the second set of windings.

Description

Technical Field

[0001] The present invention relates to power transfer to and / or from an energy storage system, such as a vehicle battery system, and more particularly to controlling power or energy transfer using a multi-winding electric machine. Background Art

[0002] Vehicles, including gasoline and diesel powered vehicles, as well as electric and hybrid electric vehicles, have battery storage devices for use, such as powering electric motors, electronic devices, and other vehicle subsystems. Electric and hybrid vehicles (e.g., cars, trucks, construction equipment, automated factory equipment, farm equipment, etc.) are charged by an external power source (e.g., charging station, power grid, etc.). Charging can include alternating current (AC) charging (e.g., a Level 1 or Level 2 outlet connected to the power grid) or direct current (DC) charging (e.g., DC fast charging (DCFC)). In addition, the current can flow in the reverse direction to allow the vehicle to supply power to an external energy storage system (e.g., the power grid, another vehicle, etc.). Typically, charging is handled by a vehicle charger, such as an on-board charging module (OBCM), which includes a conversion device for performing functions such as voltage control and AC-DC power conversion. Summary of the invention

[0003] In an exemplary embodiment, an energy transmission system for a vehicle includes a multi-winding motor, the multi-winding motor including a first set of windings and a second set of windings, the multi-winding motor connected to a battery system, a first inverter connected to the first set of windings, and a second inverter connected to the second set of windings. The system also includes a controller configured to receive a request for energy transmission, place the multi-winding motor in a charging mode, and when the multi-winding motor is in a zero torque state, control the first inverter and the second inverter to control the charging current through the multi-winding motor at a desired power, wherein the controller is configured to control the charging current through the first inverter and the second inverter so that a first current vector associated with the first set of windings and a second current vector associated with the second set of windings are symmetrical about a d-axis, and the multi-winding motor acts as a transformer. Control of the first inverter and the second inverter provides power transmission between the first set of windings and the second set of windings.

[0004] In addition to one or more features described herein, the controller is configured to control the charging current based on a reference charging current value, which is derived from a calibration of an optimal value of the d-axis current and an optimal value of the q-axis current, which optimal value is determined based on the power transmission capability of the multi-winding motor.

[0005] In addition to one or more features described herein, the reference charging current value is the minimum magnitude of charging current that can be applied to achieve a desired charging power.

[0006] In addition to one or more features described herein, the power transfer capability is estimated based on an energy relationship representing energy E as a function of the d-axis current and the q-axis current.

[0007] In addition to one or more features described herein, the power delivery capability is used to determine the maximum power per ampere (MPPA) for a given motor speed.

[0008] In addition to one or more features described herein, the MPPA specifies a minimum charging current at a given motor speed, the minimum charging current being determined based on an optimal value of the d-axis current and an optimal value of the q-axis current.

[0009] In addition to one or more features described herein, the system also includes a switch configured to selectively connect the first inverter to the battery system, the switch configured to be closed when the vehicle is in the propulsion mode.

[0010] In addition to one or more features described herein, the charging current is an AC current, the switch is configured to open to place the multi-winding motor in a charging mode, and control of the first inverter and the second inverter includes operating the first set of windings and the second set of windings as an isolation transformer to transfer power between the first set of windings and the second set of windings.

[0011] In another exemplary embodiment, a method of transferring energy to or from a battery system of a vehicle includes receiving a request for energy transfer at a controller connected to a charging system of the vehicle, the charging system including a multi-winding motor including a first set of windings and a second set of windings, a first inverter connected to the first set of windings, and a second inverter connected to the second set of windings, wherein the multi-winding motor is connected to the battery system. The method also includes placing the multi-winding motor in a charging mode, and when the multi-winding motor is in a zero torque state, controlling the first inverter and the second inverter to control a charging current through the multi-winding motor at a desired power, wherein the charging current is controlled by the first inverter and the second inverter so that a first current vector associated with the first set of windings and a second current vector associated with the second set of windings are symmetrical about a d-axis, and the multi-winding motor acts as a transformer. Control of the first inverter and the second inverter provides power transfer between the first set of windings and the second set of windings.

[0012] In addition to one or more features described herein, control of the charging current is based on a reference charging current value derived from calibration of an optimal value of the d-axis current and an optimal value of the q-axis current determined based on the power transmission capability of the multi-winding motor.

[0013] In addition to one or more features described herein, the reference charging current value is the minimum magnitude of charging current that can be applied to achieve a desired charging power.

[0014] In addition to one or more features described herein, the power transfer capability is estimated based on an energy relationship representing energy E as a function of the d-axis current and the q-axis current.

[0015] In addition to one or more features described herein, the energy relationship is derived through at least one of simulation and experimentation.

[0016] In addition to one or more features described herein, the power transfer capability is used to determine the maximum power per ampere (MPPA) at a given motor speed, and the MPPA specifies the minimum charging current at a given motor speed, and the minimum charging current is determined based on an optimal value of the d-axis current and an optimal value of the q-axis current.

[0017] In addition to one or more features described herein, the charging system includes a switch configured to selectively connect the first inverter to the battery system, the switch configured to be closed when the vehicle is in the propulsion mode.

[0018] The method of claim 16, wherein the charging current is an AC current, and placing the multi-winding motor in a charging mode includes opening a switch, and controlling the first inverter and the second inverter includes operating the first set of windings and the second set of windings as an isolation transformer to transfer power therebetween.

[0019] In yet another exemplary embodiment, a vehicle system includes a memory having computer-readable instructions and a processing device for executing the computer-readable instructions, the computer-readable instructions controlling the processing device to perform a method. The method includes receiving a request for energy transfer at a controller connected to a vehicle charging system, the charging system including a multi-winding motor, the multi-winding motor including a first set of windings and a second set of windings, a first inverter connected to the first set of windings, and a second inverter connected to the second set of windings, the multi-winding motor connected to a battery system. The method also includes placing the multi-winding motor in a charging mode, and when the multi-winding motor is in a zero torque state, controlling the first inverter and the second inverter to control the charging current through the multi-winding motor at a desired power, wherein the charging current is controlled by the first inverter and the second inverter so that a first current vector associated with the first set of windings and a second current vector associated with the second set of windings are symmetrical about a d-axis, and the multi-winding motor acts as a transformer. Control of the first inverter and the second inverter provides power transfer between the first set of windings and the second set of windings.

[0020] In addition to one or more features described herein, control of the charging current is based on a reference charging current value derived from calibration of an optimal value for the d-axis current and an optimal value for the q-axis current, the optimal values ​​being determined based on power transfer capabilities of the multi-winding electric motor, wherein the reference charging current value is a minimum magnitude of the charging current that can be applied to achieve a desired charging power.

[0021] In addition to one or more features described herein, the power transfer capability is estimated based on an energy relationship representing energy E as a function of the d-axis current and the q-axis current.

[0022] In addition to one or more features described herein, the power transfer capability is used to determine the maximum power per ampere (MPPA) at a given motor speed, and the MPPA specifies the minimum charging current at a given motor speed, and the minimum charging current is determined based on an optimal value of the d-axis current and an optimal value of the q-axis current.

[0023] The above features and advantages and other features and advantages of the present disclosure will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, advantages and details appear, by way of example only, in the following detailed description, which refers to the accompanying drawings, in which:

[0025] Figure 1 is a top view of a motor vehicle including a battery assembly or system and a multi-drive system according to an exemplary embodiment;

[0026] Figure 2 Depicted is a charging system according to an exemplary embodiment that includes components of a vehicle propulsion system having a dual-winding electric machine;

[0027] Figure 3 depicts a portion of a dual-winding or multi-winding electric machine according to an exemplary embodiment and shows characteristics of a current vector;

[0028] Figure 4 is a flow chart describing aspects of a method of controlling a vehicle charging system and / or charging an energy storage system according to an exemplary embodiment;

[0029] Figure 5A and 5B Depicted showing Figure 4 Contour plots of aspects of examples of methods including estimating optimal d-axis and q-axis currents for applying a charging current to a vehicle battery system; and

[0030] Figure 6 A computer system according to an exemplary embodiment is depicted. DETAILED DESCRIPTION

[0031] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.

[0032] According to exemplary embodiments, methods, devices, and systems are provided for supplying power from a battery system of a vehicle (e.g., an electric or hybrid vehicle) to an energy storage system (e.g., a battery of another vehicle). Embodiments may also be used to receive power from a power source (e.g., a charging station) to provide charging to the battery system.

[0033] Embodiments of the charging system utilize a dual winding motor, such as a segmented winding electric motor / generator. In an embodiment, the electric machine is part of a propulsion system for a vehicle, such as an electric or hybrid vehicle. For example, the electric machine is a three-phase (or multi-phase) motor having two sets of three-phase (or multi-phase) windings. The sets of windings are electrically isolated from each other, and each set of windings is connected to a corresponding inverter. For vehicle propulsion, one or both inverters are operated to provide alternating current (AC) to each phase of one or both sets of windings.

[0034] The charging system and the propulsion system can be placed in various charging modes for charging the vehicle battery system or providing charge to an external energy storage system (e.g., another vehicle or a power grid). An embodiment of the charging method includes determining a desired or optimal combination of q-axis and d-axis currents based on a motor model and a power transfer index. The power transfer index is calculated based on an active power parameter of the motor and corresponds to a machine energy that is independent of the machine speed. The energy is a function of the d-axis and q-axis currents. In an embodiment, the optimal d-axis and q-axis currents are calibrated by determining a maximum power per ampere (MPPA), and a charging current is applied to a set of windings based on the optimal d-axis and q-axis currents.

[0035] The embodiments described herein present many advantages and technical effects. These embodiments provide efficient charging and discharging capabilities by operating a dual-winding machine in an optimal manner to increase efficiency. For example, this increase is achieved by minimizing or reducing the current magnitude required to affect a desired charging parameter (e.g., charging power). In addition, the embodiments are applicable to a wide variety of charging and discharging operations.

[0036] Furthermore, embodiments may utilize already existing components and may simplify vehicle systems, thereby reducing the number of components and the complexity of such systems. For example, embodiments may eliminate the need for components such as an on-board charging module (OBCM) and a vehicle load module and allow for a reduction in the size of a device for heating a vehicle battery system. An OBCM may be eliminated because it has been found that charging efficiency using embodiments is at least as high as charging efficiency using existing OBCMs.

[0037] Embodiments are not limited to use with any particular vehicle and may be applicable in a variety of environments. For example, embodiments may be used in automobiles, trucks, aircraft, construction equipment, farm equipment, automated factory equipment, and / or any other equipment or system including multiple drives and / or multiple conversion devices.

[0038] Figure 1 An embodiment of a motor vehicle 10 is shown that includes a body 12 that at least partially defines an occupant compartment 14. The body 12 also supports various vehicle subsystems, including a propulsion system 16 and other subsystems to support the functions of the propulsion system 16 and other vehicle components, such as a braking subsystem, a suspension system, a steering subsystem, and if the vehicle is a hybrid electric vehicle, a fuel injection subsystem, an exhaust subsystem, etc.

[0039] The vehicle 10 may be an electric vehicle (EV), a hybrid vehicle, or any other vehicle having multiple electric motors or drive systems. In an embodiment, the vehicle 10 is an electric vehicle including multiple motors and / or drive systems. For example, the propulsion system 16 is a multi-drive system including a first drive system 20 and a second drive system 30. The first drive system 20 includes a first electric motor 22 and a first inverter module 24, as well as other components such as a cooling system 26. The second drive system 30 includes a second electric motor 32 and a second inverter 34 module, as well as other components such as a cooling system 36. The inverter modules 24 and 34 (e.g., traction power inverter units or TPIMs) each convert direct current (DC) power from a high voltage (HV) battery pack 44 into multi-phase (e.g., two-phase, three-phase, six-phase, etc.) alternating current (AC) power to drive motors 22 and 32.

[0040] like Figure 1 As shown, the drive system is configured such that the first electric motor 22 drives the front wheels (not shown) and the second electric motor 32 drives the rear wheels (not shown). However, embodiments are not limited in this regard, as there may be any number of drive systems and / or motors in different locations (e.g., a motor driving each wheel, dual motors per axle, etc.). Furthermore, embodiments are not limited to dual drive systems, as embodiments may be used in vehicles having any number of motors and / or power inverters.

[0041] In an embodiment, the motor 20 and / or the motor 30 is a multi-winding or dual-winding motor. For example, the motor 20 and the motor 30 are segmented winding machines having at least two sets of electrically isolated windings. Each inverter module 24 and 34 includes at least two inverter circuits (inverters), so that each inverter can control the current through the corresponding set of windings.

[0042] Drive system 20 and drive system 30 are electrically connected to battery system 40 and may also be electrically connected to other components, such as vehicle electronics (eg, via auxiliary power module or APM 42). Battery system 40 may be configured as a rechargeable energy storage system (RESS).

[0043] In an embodiment, the battery system 40 includes a battery assembly, such as a battery pack 44. The battery pack 44 includes a plurality of battery modules 46, wherein each battery module 46 includes a plurality of individual battery cells (not shown). The battery system 40 may also include a monitoring unit 48 configured to receive measurements from sensors 50. Each sensor 50 may be an assembly or system having one or more sensors for measuring various battery and environmental parameters, such as temperature, current, and voltage.

[0044] The vehicle 10 may include a charging system that may be used to charge the battery pack 44 and / or to supply power from the battery pack 44 to charge another energy storage system (e.g., V2V charging). The charging system includes at least one dual inverter and an associated multi-winding motor that may be selectively connected to the charging port 58. For example, the motor 20 and / or the motor 30 is a multi-winding motor, such as a segmented winding machine, and the inverter 24 and / or the inverter 34 is configured as a dual inverter or multi-inverter module.

[0045] The charging port 58 includes or is connected to a bidirectional charger that allows bidirectional transfer of energy. The charging system can be used to transfer power from the battery pack 44 to charge an external energy storage system (e.g., another vehicle, a portable energy storage system, a power grid, etc.). For example, the charging system is configured for vehicle-to-vehicle (V2V), vehicle-to-grid (V2G), and / or vehicle-to-everything (V2X) charging.

[0046] The charging system may be used to transfer power from an external energy storage system (e.g., a charging station, an electrical grid, a donor vehicle battery system) to charge the battery pack 44. For example, the charging system is configured for traditional or conventional charging, DC fast charging (DCFC), V2V charging, grid-to-vehicle (G2V) charging, and / or load-to-vehicle (L2V) charging. This power transfer may be referred to as a discharge operation or process.

[0047] Any of a variety of controllers may be used to control the functions of the charging system and / or other vehicle systems. The controller includes any suitable processing device or unit, and may use an existing controller, such as a battery system controller (e.g., a RESS or battery management system controller), and / or a controller in a drive system. For example, a controller 60 may be included to control charging operations as described herein.

[0048] The vehicle 10 also includes a computer system 62 that includes one or more processing devices 64 and a user interface 66. The computer system 62 can communicate with the charging system controller, for example to provide commands thereto in response to user input. The various processing devices, modules, and units can communicate with each other via a communication device or system, such as a controller area network (CAN) or transmission control protocol (TCP) bus.

[0049] Any switch described herein can be any suitable type of switch, such as a mechanical contactor, an electronic switch, or a solid-state switching device. Any suitable solid-state or electronic device can be used as a switch. For example, the switch can include a solid-state relay or a transistor, such as a silicon (Si) insulated gate bipolar transistor (IGBT) and a field effect transistor (FET). Examples of FETs include metal oxide semiconductor FETs (MOSFETs), Si MOSFETs, silicon carbide (Sic) MOSFETs, gallium nitride (GaN) high electron mobility transistors (HEMTs), and SiC junction gate FETs (JFETs). Other examples of switches that can be used include diamond, gallium oxide, and other power switching devices based on wide bandgap (WBG) semiconductors.

[0050] Figure 2 Components of the propulsion system and battery system that form part of the charging system are depicted. Although only the motor 20 and inverter module 24 are shown and discussed, it should be understood that the motor 30 and inverter 34 may be similarly configured (in addition to or in place of the motor 20 and inverter module 24).

[0051] In an embodiment, the electric motor 20 is a dual-winding motor including two sets of three-phase (or multi-phase) windings. For example, the motor 20 is a segmented winding machine having at least two sets of windings. Each set of windings includes a primary winding 70 having a first set of phase windings A1, B1, C1, and a secondary winding 72 having a second set of phase windings A2, B2, C2. The primary winding 70 is electrically isolated from the secondary winding 72, and the windings 70 and 72 have respective neutral points N1 and N2.

[0052] The inverter module 24 includes a first or primary inverter circuit (inverter) 74 electrically connected to the first winding 70, and a second or secondary inverter 76 electrically connected to the second winding 72. The inverter includes a switch group in a half-bridge configuration for driving the windings. The primary inverter 74 includes switches S1 and S2 connected to the phase winding A1, switches S3 and S4 connected to the phase winding B1, and switches S5 and S6 connected to the phase winding C1. The capacitor Cp is connected in parallel to the switch group in the inverter 76.

[0053] The secondary inverter 76 includes switches S7 and S8 connected to the phase winding A2, switches S9 and S10 connected to the phase winding B2, and switches S11 and S12 connected to the phase winding C2. A capacitor Cs is connected in parallel to the switch group in the inverter 76.

[0054] Capacitors Cp and Cs are used to stabilize voltage and limit current fluctuations and ripples. In an embodiment, inverters 74 and 76 share a common capacitor.

[0055] The propulsion system including the motor 20 may enter a propulsion mode in which the primary inverter 74 and / or the secondary inverter 76 drives the motor 20. In an exemplary propulsion mode, the switch 78 is closed and both the inverters 74 and 76 drive the motor 20. In another propulsion mode, the switch 78 is open and the inverters 74 and 76 may be used independently to drive the motors.

[0056] The propulsion system can be placed in any of a variety of charging modes. When the system is in charging mode, the motor 20 is in a zero torque state and the switch 78 can be opened to disconnect the inverter 76 from the battery pack 44. During the charging of the battery pack 44, the inverter 74 and the inverter 76 are used to control the charging current. The windings 70 and 72 act as an isolation transformer for energy transfer. The amount of power provided when charging or discharging can be controlled based on the motor speed.

[0057] The charging mode includes, for example, a mode in which the battery pack 44 is charged by an external power source. The external power source may be a charging station, a portable charger, the grid, or a battery system of another vehicle (V2V charging). The charging system can provide a variety of charging modes, including traditional or conventional charging and DC fast charging (DCFC).

[0058] The charging mode may include one or more discharge modes, in which energy from the battery pack 44 is provided to charge an external energy storage system. Examples of discharge modes include V2G charging, vehicle to trailer charging, V2V charging, V2X charging, and the like.

[0059] The charging port 58 includes or is connected to a charger 80. In an embodiment, the charger 80 is a universal charger that includes the ability to transfer and control AC or DC current during charging and discharging.

[0060] For example, Figure 2 As shown, the charger 80 includes an AC charger 82 connected to a set of switches 84. The AC charger 82 includes components for controlling the amount of AC current passing through the charging port 58. The charger 80 also includes a DC charger 86 and a pair of switches 88.

[0061] The set of switches 84 enables bidirectional AC charging. By operating the appropriate switches, single-phase, two-phase or three-phase current can be applied via the AC charger 82. An auxiliary converter 90 can be included for controlling the AC current, and includes multiple sets of switches and capacitors Ca for each phase. The first set of switches S14 and S15 controls the first AC phase, the second set of switches S16 and S17 controls the second AC phase, and the third set of switches S18 and S19 controls the third AC phase. Each half bridge of the auxiliary converter 90 is connected to one of the sets of switches 84.

[0062] In an embodiment, a propulsion system is used to control energy transfer to and from a vehicle battery system by a control method, the control method is used to apply a charging current according to a reference current value. In an embodiment, the reference current value is a minimum charging current amplitude that can be applied to achieve or maintain a desired charging power. The method provides charging or discharging at a maximum or desired power while reducing or minimizing power loss or energy loss.

[0063] Combination Figure 2 as well as Figure 3 An example of a model of the motor 20 is shown to describe aspects of the method.

[0064] Figure 3 Depicted are a portion of a stator 100, a segment of a primary winding 70, and a segment of a secondary winding 72. Also shown is a tertiary winding 102 segment, which may be included, for example, to reduce imbalance in the primary winding 70 and redistribute the flow of fault current. Figure 3 Also depicted is a portion of a rotor 104 including a set of permanent magnets 106 .

[0065] Figure 3 Also depicted are current vectors associated with windings 70 and 72. The current vectors include a vector i2 representing the current through secondary winding 72 and a vector i1 representing the current through primary winding 70. Each vector has a q-axis component (q-axis current) and a d-axis component (d-axis current). The primary current vector i1 has a d-axis current i2. d1 and q-axis current i q1 , the secondary current vector i2 has a d-axis current i d2 and q-axis current i q2 The current vectors i1 and i2 are symmetrical about the d-axis. d1 and i d2 are all positive and have the same magnitude. The q-axis current i q1 and i q2 have the same magnitude but opposite sign.

[0066] During rotation, when the motor 20 is in a propulsion mode, the voltage and current of the primary winding 70 are in phase with the voltage and current of the secondary winding 72, and the motor 20 converts electrical energy into mechanical energy. The motor 20 can be placed in a regeneration mode, in which the motor 20 converts mechanical energy into electrical energy. When the motor 20 is in a charging mode, the voltages of the primary winding 70 and the secondary winding 72 are in phase, and the current of the primary winding 70 is out of phase (e.g., offset by 180 degrees) with the current of the secondary winding 72. In the charging mode, power flows from one winding to the other, and the motor 20 acts as a transformer.

[0067] During power transfer at zero torque, the motor 20 is in a charging mode and the current vectors i1 and i2 rotate at a synchronous speed as the rotor 104 rotates. The speed of the rotor 104 may vary based on power demand.

[0068] Figure 4 An embodiment of a method 200 of controlling energy transfer is shown. Energy transfer may be performed to charge a battery system in a vehicle by controlling a charging current provided by an external power source, and / or by controlling a charging current provided by a battery system to an external energy storage system.

[0069] Aspects of method 200 may be performed by a processor or a combination of processors. For example, if the method is used to power a load from multiple battery systems in a vehicle, one or more controllers in the vehicle may be used. In other examples, such as charging one or more vehicles from a charging station, the method may be performed by a controller in the charging station and / or a controller in a connected vehicle.

[0070] Note that method 200 is not limited in this regard and may be performed by any suitable processing device or system or combination of processing devices.

[0071] Method 200 includes a number of steps or phases represented by blocks 201 - 205. Method 200 is not limited to the number or order of steps therein, as some steps represented by blocks 201 - 205 may be performed in a different order than described below, or less than all steps may be performed in an order.

[0072] In the following, for the purpose of illustration, Figure 2 and 3 Method 200 is discussed with reference to motor 20, propulsion system, and battery system 40 shown in FIG. Method 200 may be similarly performed in conjunction with motor 30. Furthermore, method 200 may be performed with any suitable system having a multi-winding electric machine and an energy storage device, and is therefore not limited to the systems described herein.

[0073] At block 201 , the controller 60 (and / or other processing device, such as a RESS controller, a battery management system (BMS) controller, etc.) receives a request for power transfer between the battery system 40 and an external energy source or energy storage system.

[0074] The request may be a request to provide power to an external energy storage system, such as another vehicle for V2V charging. In other embodiments, the request is to charge the battery system 40 from a charging station or other energy source.

[0075] At block 202 , the controller 60 receives or determines power transfer or charging parameters, such as a desired charging voltage or maximum voltage, a desired charging power, and motor parameters (eg, winding characteristics, such as the number of turns in each set of windings 70 and 72 ).

[0076] At block 203 , when the motor 20 is in the charging (power transfer) mode, the controller 60 evaluates the power transfer capability of the motor 20 . The evaluation is based on an expression for the active power of the motor 20 .

[0077] The power transfer capability may be determined by obtaining or calculating a power transfer index. In an embodiment, the power transfer index is the energy E (ie, the amount of energy converted as a function of electrical angle), which is a function of the d-axis and q-axis currents.

[0078] In an embodiment, the energy E is derived from the following active power (P) equation:

[0079] or

[0080]

[0081] Among them, ω re is the speed of the motor 20. d2 is the d-axis flux linkage of the secondary winding 72, λ q2 is the q-axis flux of the secondary winding 72, λ pm is the flux linkage of the permanent magnet 106. md is the d-axis mutual inductance between the two windings, L mq is the q-axis mutual inductance between the two windings, L d is the d-axis winding inductance, L q is the q-axis winding inductance.

[0082] E can be derived from the above equation as follows:

[0083] or

[0084]

[0085] The energy E can be calibrated, for example, by experiments and / or by operating the motor 20 in simulation. A model of the motor 20, such as a dq model (aspects of which are described in Figure 3 ), for simulating operation and determining or calibrating the optimal values ​​of the d-axis current and the q-axis current for various energy transfer levels. The optimal values ​​can be stored as a lookup table or other data structure for calibrating the optimal charging current to obtain the desired power.

[0086] The index is used to determine the best combination of d-axis and q-axis currents. In an embodiment, the best combination refers to the d-axis and q-axis currents that provide the desired power to be transmitted with minimum current usage.

[0087] At block 204, the motor 20 is placed in charging mode by electrically connecting the charger 80 to an external power source or storage system. For DC power transfer, the pair of switches 88 are closed and all switches in the set of switches 84 are open. For AC power transfer, the pair of switches 88 are open and at least one switch in the set of switches 84 is closed.

[0088] At block 205 , energy transfer (charging or discharging) is initiated by receiving a charging current (if the energy transfer is for charging the battery pack 44 ) or generating a charging current (if the energy transfer is for charging an external energy storage system).

[0089] Energy transfer is controlled by adjusting or controlling the magnitude of the charging current based on a maximum power per ampere (MPPA) control method to apply the charging current based on a minimum value. For example, the controller 60 periodically receives voltage and current measurements, determines actual d-axis and q-axis currents, and compares them to limit values ​​including minimum d-axis and q-axis currents required to produce a desired power level. Figure 5A and 5B An example of MPPA control is shown and will be discussed further herein.

[0090] Control of the charging current may be performed in real time. The comparison with the set point and control of the charging current may be performed in real time, for example by being performed continuously (eg generating current sensor and other sensor outputs at each sampling time).

[0091] For example, to control AC charging (receiving AC power from the grid or other external source), AC current is received via the charger 82 and the charging current is regulated via the charger 82 according to a set point.

[0092] The charging current flows through the auxiliary converter 90, which can be controlled to adjust parameters such as phase and voltage. The charging current flows to the phase windings A2, B2 and / or C2 through the inverter 76, and the windings 70 and 72 act as an isolation transformer. The inverter 74 acts as a synchronous active pulse width modulation (PWM) rectifier to convert AC to DC to charge the battery pack and control power. The switches in the auxiliary converter 90 can also be used to perform power factor correction (PFC), which reduces harmonic distortion in the AC supplied to the inverter module 24 (i.e., shaping the line current to produce a current waveform close to a basic sine wave and aligning the phase with the voltage from an external source).

[0093] To control the power transfer (i.e., discharge) from the battery pack 44 to the external system, the DC current from the battery pack 44 is converted to AC current by the inverter 74, and the AC current is fed to the phase windings A1, B1, and / or C1. The windings 70 and 72 again act as a transformer (optionally stepping up or down the voltage), and the AC current flows through the inverter 76 and is output to provide charge to the external system.

[0094] To control DC charging (e.g., DCFC charging) or discharging (e.g., V2V), switches 84 are all open and switch pair 88 is closed. If the voltage of battery pack 44 is the same as the received voltage, switch 78 is closed and the received DC power is fed directly to battery pack 44.

[0095] If the voltages are different, switch 78 is open, the two sets of windings act as an isolation transformer, and both inverters 74 and 76 act as dual active bridge DC-DC converters to control power in either direction. For example, the voltage can be boosted by appropriately controlling the switches in inverters 74 and 76.

[0096] Figure 5A and 5B Aspects of an example of method 200 are depicted and show how to determine optimal d-axis and q-axis currents. Figure 5A is the d-axis current (i d2 ) (e.g., through one or more of phases A2, B2, and C2) and the q-axis current (i q2 ), as determined by modeling and / or calibration. The current is expressed in amperes (A) and the energy E is expressed in kilowatt-seconds / radian (kWs / rad).

[0097] These contours reflect the d2 and i q2 The E values ​​for various combinations of magnitudes are color coded as shown in legend 212. For example, contour line 214 represents the energy corresponding to 40 kW / sec. d2 and i q2 The contour line 216 represents the energy corresponding to 20 kW / sec. d2 and i q2 A combination of values.

[0098] Figure 5B An example of the results of the d-axis and q-axis current estimation is depicted in the contour plot 220. The contour plot 220 represents the power P as a function of the d-axis current (i d ) and q-axis current (i q2 ). Line 222 represents different current amplitudes.

[0099] The graph 220 also shows various power levels at different motor speeds. The graph 220 can be generated by converting energy E into power P based on the motor speed (ie, P = E * ω re ). This power limit may be a rated limit or a limit determined by modeling or experimentation. For example, for a motor speed (i.e., the mechanical speed of the rotor) of about 1000 RPM (revolutions per minute), curve 224 represents the power limit as i d and i q2 Curve 226 represents the power P for a motor speed of about 2000 RPM, curve 228 represents the power P for a motor speed of about 4000 RPM, and curve 230 represents the power P for a motor speed of about 6000 RPM.

[0100] Curve 232 represents the maximum power per ampere (MPPA) determined as part of the control method described above. In this example, the relationship shown by curve 232 is used by the controller to determine the amount of charging current to apply.

[0101] Figure 6 Aspects of an embodiment of a computer system 240 are shown, which can perform various aspects of the embodiments described herein. The computer system 240 includes at least one processing device 242, which typically includes one or more processors for performing various aspects of the image acquisition and analysis methods described herein.

[0102] Components of computer system 240 include a processing device 242 (such as one or more processors or processing units), a memory 244, and a bus 246 that couples various system components including system memory 244 to processing device 242. System memory 244 may be a non-transitory computer-readable medium and may include various computer system-readable media. Such media may be any available media that can be accessed by processing device 242, including volatile and non-volatile media, and removable and non-removable media.

[0103] For example, system memory 244 includes nonvolatile memory 248, such as a hard drive, and may also include volatile memory 250, such as random access memory (RAM) and / or cache memory. Computer system 240 may also include other removable / non-removable, volatile / nonvolatile computer system storage media.

[0104] The system memory 244 may include at least one program product having a set (i.e., at least one) of program modules configured to perform the functions of the embodiments described herein. For example, the system memory 244 stores various program modules that generally perform the functions and / or methods of the embodiments described herein. Module 252 may be included to perform functions related to acquiring signals and data, and module 254 may be included to perform functions related to energy transmission control discussed herein. The system 240 is not limited thereto because other modules may be included. As used herein, the term "module" refers to a processing circuit, which may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the functions.

[0105] Processing device 242 may also communicate with one or more external devices 256, which may be keyboards, pointing devices, and / or any device that enables processing device 242 to communicate with one or more other computing devices (e.g., network cards, modems, etc.). Communications with various devices may occur through input / output (I / O) interfaces 264 and 265.

[0106] The processing device 242 may also communicate with one or more networks 266, such as a local area network (LAN), a general wide area network (WAN), a bus network, and / or a public network (e.g., the Internet) via a network adapter 268. It should be understood that, although not shown, other hardware and / or software components may be used in conjunction with the computer system 40. Examples include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, and data archival storage systems, etc.

[0107] The terms "one" and "an" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced items. The term "or" means "and / or", unless the context clearly indicates otherwise. References to "an aspect" throughout the specification mean that a particular element (e.g., feature, structure, step, or characteristic) described in conjunction with that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it should be understood that the described elements may be combined in any suitable manner in various aspects.

[0108] When an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

[0109] Unless otherwise indicated herein, all test standards are the most recent standards in effect as of the filing date of the present application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0110] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0111] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from the scope thereof. In addition, many modifications may be made to adapt specific situations or materials to the teachings of the disclosure without departing from the essential scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A vehicle energy transmission system, comprising: a multi-winding motor including a first set of windings and a second set of windings, the multi-winding motor connected to a battery system; a first inverter connected to the first set of windings; a second inverter connected to the second set of windings; as well as A controller configured to receive a request for energy transfer, place the multi-winding motor in a charging mode, and when the multi-winding motor is in a zero torque state, control the first inverter and the second inverter to control the charging current through the multi-winding motor at a desired power, wherein the controller is configured to control the charging current through the first inverter and the second inverter so that a first current vector associated with the first group of windings and a second current vector associated with the second group of windings are symmetrical about the d-axis, and the multi-winding motor acts as a transformer, and the control of the first inverter and the second inverter provides power transfer between the first group of windings and the second group of windings.

2. The system according to claim 1, wherein: The controller is configured to control the charging current based on a reference charging current value derived from calibration of an optimal value of a d-axis current and an optimal value of a q-axis current, the optimal value being determined based on a power transmission capability of the multi-winding motor.

3. The system according to claim 2, wherein: The reference charging current value is the minimum magnitude of the charging current that can be applied to achieve a desired charging power.

4. The system according to claim 2, wherein: The power transfer capability is estimated based on an energy relationship representing energy E as a function of the d-axis current and the q-axis current.

5. The system according to claim 4, wherein: The power transfer capability is used to determine the maximum power per ampere (MPPA) for a given motor speed.

6. The system according to claim 5, wherein: The MPPA specifies a minimum charging current at a given motor speed, the minimum charging current being determined based on an optimal value of the d-axis current and an optimal value of the q-axis current. 7 . The system of claim 1 , further comprising a switch configured to selectively connect the first inverter to the battery system, the switch configured to be closed when the vehicle is in a propulsion mode.

8. The system according to claim 7, wherein: The charging current is an AC current, the switch is configured to open to place the multi-winding motor in the charging mode, and control of the first inverter and the second inverter includes operating the first set of windings and the second set of windings as an isolation transformer to transfer power between the first set of windings and the second set of windings.

9. A method of transferring energy to or from a battery system of a vehicle, comprising: receiving a request for energy transfer at a controller connected to a vehicle charging system, the charging system including a multi-winding motor including a first set of windings and a second set of windings, a first inverter connected to the first set of windings, and a second inverter connected to the second set of windings, wherein the multi-winding motor is connected to a battery system; Put the multi-winding motor into charging mode; and When the multi-winding motor is in a zero torque state, the first inverter and the second inverter are controlled to control the charging current through the multi-winding motor with a desired power, wherein the charging current is controlled by the first inverter and the second inverter so that a first current vector associated with the first group of windings and a second current vector associated with the second group of windings are symmetrical about the d-axis, and the multi-winding motor is used as a transformer, and control of the first inverter and the second inverter provides power transmission between the first group of windings and the second group of windings.

10. The method according to claim 9, wherein: The control of the charging current is based on a reference charging current value, which is derived from calibration of an optimal value of the d-axis current and an optimal value of the q-axis current, the optimal value being determined based on the power transmission capability of the multi-winding motor, and the reference charging current value being the minimum amplitude of the charging current that can be applied to achieve the desired charging power.

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