Voltage switching of electric motor

Abstract

A system for controlling a propulsion system of a vehicle includes a switching system including a first switching device connecting a battery system to a first set of windings of an electric motor, and a second switching device connecting the battery system to a second set of windings. The system also includes a controller configured to transition the propulsion system from an initial propulsion mode in which an initial voltage is applied to the electric motor to a target mode in which a target voltage is applied. The transitioning includes controlling the first switching device to provide current to the first set of windings at an initial voltage to produce torque, and then controlling the second switching device to cause the battery system to apply a target voltage to the second set of windings while providing current to the first set of windings at the initial voltage.

Description

Technical Field

[0001] The present disclosure relates to vehicles, and more particularly, to controlling voltage of an electric drive of a vehicle. Background Art

[0002] Vehicles, including gasoline and diesel powered vehicles, as well as electric and hybrid vehicles, have battery storage for purposes such as powering electric motors, electronic devices, and other vehicle subsystems. Some vehicles feature battery systems that can be operated to transition between different voltage levels. It is desirable to be able to operate such systems in a manner that reduces or minimizes voltage interruptions when transitioning between voltage levels applied to the electric motors to provide smooth transitions during vehicle operation. Summary of the invention

[0003] In one exemplary embodiment, a system for controlling a propulsion system of a vehicle includes a switch system connected to a battery system and a propulsion system, the battery system including a first battery assembly and a second battery assembly, the propulsion system including an electric motor having a first set of windings and a second set of windings, the switch system including a first switch device connecting the battery system to the first set of windings and a second switch device connecting the battery system to the second set of windings. The system also includes a controller configured to perform a transition of the propulsion system from an initial propulsion mode to a target mode during propulsion of the vehicle according to a commanded torque, in which an initial voltage is applied to the electric motor, and in which a target voltage is applied to the electric motor. The transition includes controlling the first switch device to provide current to the first set of windings at the initial voltage and operate the electric motor to generate torque for propelling the vehicle, and then controlling the second switch device to cause the battery system to apply the target voltage to the second set of windings, wherein current is provided to the first set of windings at the initial voltage while controlling the second switch device.

[0004] In addition to one or more features described herein, the transitioning also includes controlling the first switching device to cause the battery system to apply the target voltage to the first set of windings while the battery system applies the target voltage to the second set of windings.

[0005] In addition to one or more features described herein, the first switch device and the second switch device include mechanical switches or solid-state switches.

[0006] In addition to one or more features described herein, a first battery assembly is connected to a first inverter configured to supply alternating current (AC) to a first set of windings, and a second battery assembly is connected to a second inverter configured to supply AC current to a second set of windings.

[0007] In addition to one or more features described herein, the first battery assembly is selectively connected to a propulsion bus via a first switch, and the first switch device has a first switch position connecting the first inverter to a node between the first switch and the propulsion bus, and a second switch position connecting the first inverter to a node between the first switch and the first battery assembly. The second battery assembly is selectively connected to the propulsion bus via a second switch, and the second switch device has a first switch position connecting the second inverter to a node between the second switch and the propulsion bus, and a second switch position connecting the second inverter to a node between the second switch and the second battery assembly.

[0008] In addition to one or more features described herein, the first switching device and the second switching device are single pole double throw switches.

[0009] In addition to one or more of the features described herein, one of the initial voltage and the target voltage is a low voltage achieved by connecting the first battery assembly in parallel with the second battery assembly to a propulsion bus.

[0010] In addition to one or more of the features described herein, one of the initial voltage and the target voltage is a high voltage achieved by connecting the first battery assembly in series with the second battery assembly.

[0011] In another exemplary embodiment, a method of controlling a propulsion system of a vehicle includes receiving a request to convert the propulsion system from an initial voltage to a target voltage, the propulsion system including an electric motor having a first set of windings and a second set of windings, the electric motor being connected to a battery system including a first battery assembly and a second battery assembly, the propulsion system including a switch system having a first switch device connecting the battery system to the first set of windings and a second switch device connecting the battery system to the second set of windings. The method also includes, during propulsion of the vehicle according to a commanded torque, converting the propulsion system from an initial propulsion mode in which an initial voltage is applied to the electric motor to a target mode in which a target voltage is applied to the electric motor. The conversion includes controlling the first switch device to provide current to the first set of windings at the initial voltage and operating the electric motor to generate torque for propelling the vehicle, and then controlling the second switch device to cause the battery system to apply the target voltage to the second set of windings, wherein the second switch device is controlled while providing current to the first set of windings at the initial voltage.

[0012] In addition to one or more features described herein, the transitioning also includes controlling the first switching device to cause the battery system to apply the target voltage to the first set of windings while the battery system applies the target voltage to the second set of windings.

[0013] In addition to one or more features described herein, the first switch device and the second switch device include mechanical switches or solid-state switches.

[0014] In addition to one or more features described herein, the first battery assembly is connected to a first inverter configured to supply AC current to the first set of windings, and the second battery assembly is connected to a second inverter configured to supply AC current to the second set of windings.

[0015] In addition to one or more features described herein, the first battery assembly is selectively connected to a propulsion bus via a first switch, and the first switch device has a first switch position connecting the first inverter to a node between the first switch and the propulsion bus, and a second switch position connecting the first inverter to a node between the first switch and the first battery assembly. The second battery assembly is selectively connected to the propulsion bus via a second switch, and the second switch device has a first switch position connecting the second inverter to a node between the second switch and the propulsion bus, and a second switch position connecting the second inverter to a node between the second switch and the second battery assembly.

[0016] In addition to one or more features described herein, the first switching device and the second switching device are single pole double throw switches.

[0017] In addition to one or more of the features described herein, one of the initial voltage and the target voltage is a low voltage achieved by connecting the first battery assembly in parallel with the second battery assembly to a propulsion bus.

[0018] In addition to one or more of the features described herein, one of the initial voltage and the target voltage is a high voltage achieved by connecting the first battery assembly in series with the second battery assembly.

[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 to transition a propulsion system from an initial voltage to a target voltage, the propulsion system including an electric motor having a first set of windings and a second set of windings, the electric motor being connected to a battery system including a first battery assembly and a second battery assembly, the propulsion system including a switch system having a first switch device connecting the battery system to the first set of windings and a second switch device connecting the battery system to the second set of windings. The method also includes, during propulsion of the vehicle according to a commanded torque, transitioning the propulsion system from an initial propulsion mode in which an initial voltage is applied to the electric motor to a target mode in which a target voltage is applied to the electric motor. The transition includes controlling the first switching device to provide current to the first group of windings at the initial voltage and operate the electric motor to generate torque for propelling the vehicle, and then controlling the second switching device to cause the battery system to apply the target voltage to the second group of windings, wherein current is provided to the first group of windings at the initial voltage while controlling the second switching device.

[0020] In addition to one or more features described herein, the transitioning also includes controlling the first switching device to cause the battery system to apply the target voltage to the first set of windings while the battery system applies the target voltage to the second set of windings.

[0021] In addition to one or more of the features described herein, one of the initial voltage and the target voltage is a low voltage achieved by connecting the first battery assembly in parallel with the second battery assembly to a propulsion bus.

[0022] In addition to one or more of the features described herein, one of the initial voltage and the target voltage is a high voltage achieved by connecting the first battery assembly in series with the second battery assembly.

[0023] The above features and advantages and other features and advantages of the present disclosure are 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, from 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 propulsion system and a switch system for controlling voltage according to an exemplary embodiment;

[0026] Figure 2 Depicted is a battery system having two separate battery packs or two halves of a single battery pack, a propulsion system including a drive unit having a dual-winding electric motor, and various switches for varying the voltage output of the battery system according to an exemplary embodiment;

[0027] Figure 3 depicts components of a vehicle according to an exemplary embodiment, the components including a battery system having two separate battery packs or two halves of a single battery pack, a propulsion system including a drive unit having a dual-winding electric motor, and a switch system for facilitating conversion between voltages applied to the electric motor to propel the vehicle;

[0028] Figure 4 Depicts a low voltage operating state according to an exemplary embodiment. Figure 3 Propulsion system;

[0029] Figure 5 Depicts an intermediate operating state according to an exemplary embodiment. Figure 3 A propulsion system of claim 1, wherein a first set of windings of the electric motor is powered at a high voltage and a second set of windings of the electric motor is powered at a low voltage;

[0030] Figure 6 Depicts an intermediate operating state according to an exemplary embodiment. Figure 3 A propulsion system of claim 1, wherein a first set of windings of the electric motor is powered at a low voltage and a second set of windings of the electric motor is powered at a high voltage;

[0031] Figure 7 Depicts a high voltage operating state according to an exemplary embodiment Figure 3 Propulsion system;

[0032] Figure 8 depicts components of a vehicle according to an exemplary embodiment, the components including a battery system having two separate battery packs or two halves of a single battery pack, a propulsion system including a drive unit having a dual-winding electric motor, and a switch system for facilitating conversion between voltages applied to the electric motor to propel the vehicle;

[0033] Fig. 9 is a flow chart depicting aspects of a method of controlling a propulsion system of a vehicle according to an exemplary embodiment; and

[0034] Fig.10 A computer system according to an exemplary embodiment is depicted. DETAILED DESCRIPTION

[0035] 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.

[0036] According to exemplary embodiments, methods, apparatus and systems are provided for controlling vehicle propulsion, including varying a voltage level applied to an electric motor during vehicle propulsion. Embodiments provide for switching between voltage levels for driving a motor without interrupting torque applied to the vehicle.

[0037] In an embodiment, a vehicle includes a propulsion system having an electric motor and a battery system controllable to provide various output voltages. In an embodiment, the battery system includes a first battery assembly and a second battery assembly. For example, the first battery assembly can be a first battery pack, and the second battery assembly can be a second battery pack. In another example, if the battery system includes a single battery pack (e.g., a single battery pack having two halves), the first battery assembly and the second battery assembly can each be a part of the battery pack (e.g., one of the two halves).

[0038] In an embodiment, the electric motor is a three-phase or multi-phase dual-winding electric motor. The dual-winding motor includes a first set of windings and a second set of windings, wherein each phase winding in one set is connected in parallel to a corresponding phase winding in the other set. The dual-winding motor is controllable during vehicle propulsion to facilitate conversion between voltage levels (e.g., connecting battery assemblies in series to provide a relatively high voltage, and connecting battery assemblies in parallel to provide a relatively low voltage).

[0039] In an embodiment, a propulsion system includes a switching system having independently controllable switching devices that can be operated in conjunction with a dual winding motor to change the voltage level applied to a drive unit. The embodiment also includes a method for switching between voltage levels by sequentially operating the switching devices to change the voltage without generating an interruption in the torque applied to the vehicle to ensure smooth transitions and drivability.

[0040] The embodiments described herein present many advantages and technical effects. For example, existing variable voltage battery systems cannot change the voltage level applied to a single motor without some interruption in the output torque because switching between voltages involves a momentary disconnection that creates a torque hole (torque interruption provided to the vehicle) that may impair driving performance. Therefore, current systems with a single drive unit require that the vehicle be in a no-drive or no-load condition (i.e., zero torque applied by the drive unit) when switching between voltage levels. The embodiments described herein provide a solution to these limitations by allowing voltage switching or adjustment of the voltage applied to a single motor or drive unit without causing any torque holes. Therefore, the embodiments improve propulsion systems, including single drive systems, by allowing voltage changes and operating at an optimal voltage level for different torque and speed conditions in a smooth manner.

[0041] Embodiments are not limited to use with any particular vehicle and may be applicable in a variety of contexts. For example, embodiments may be used with automobiles, trucks, aircraft, construction equipment, agricultural equipment, automated factory equipment, and / or any other device or system including multiple drives and / or multiple conversion devices.

[0042] 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 for supporting 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.

[0043] The vehicle 10 may be an electric vehicle (EV), a hybrid vehicle, or any other vehicle including an electric motor. In one embodiment, the vehicle 10 includes a propulsion system 16 having a drive unit 20. The drive unit 20 includes an electric motor 22 that is configured to receive power from a battery system 40. The battery system 40 may also provide power to other components such as a cooling system 24.

[0044] In an embodiment, the electric motor 22 is a dual winding motor having at least two sets of windings. The first set of windings includes a phase winding for each phase of the motor, and the second set of windings includes a phase winding for each phase. The drive unit 20 also includes an inverter connected to each set of windings. For example, Figure 1 As shown, the drive unit 20 includes a first inverter 26 connected to one of the winding groups, and a second inverter 28 connected to the other winding group. Each inverter converts DC (direct current) power from the battery system 40 into multi-phase (e.g., two-phase, three-phase, six-phase, etc.) AC (alternating current) power to drive the motor 22.

[0045] like Figure 1 As shown, the vehicle 10 includes one motor. However, the embodiment is not limited thereto. For example, the vehicle 10 may include at least one additional electric motor. The additional electric motor may be a dual winding motor, which will have its own set of inverters.

[0046] exist Figure 1 In the embodiment of the present invention, the motor 22 is a three-phase dual-winding motor, but is not limited thereto. For example, the motor 22 may have more than two sets of windings, and each set may have an inverter. Therefore, the embodiments described herein are applicable to any multi-winding motor with any number of phases.

[0047] In the propulsion system 16, the drive unit 20 and the electric motor 22 are connected to a battery system 40. The battery system 40 may also be electrically connected to other components, such as vehicle electronics (e.g., via an auxiliary power module or APM 30). The battery system 40 may be configured as a rechargeable energy storage system (RESS).

[0048] In an embodiment, the battery system 40 includes a plurality of individual battery assemblies, each of which can be used in various configurations to provide different voltage levels. For example, the battery system 40 includes a first battery assembly, such as a first battery pack 44 and a second battery pack 46. The battery pack 44 includes a plurality of battery modules 48, and the battery pack 46 includes a plurality of battery modules 50. Each module 48, 50 includes a plurality of individual batteries (not shown). Although only two battery assemblies are shown, embodiments may include any number of battery assemblies (e.g., more than two battery packs).

[0049] The charging system may be used to charge battery pack 44 and battery pack 46, and / or supply power from battery pack 44 and / or battery pack 46 to charge another energy storage system (e.g., vehicle-to-vehicle (V2V) and / or vehicle-to-everything (V2X) charging). The charging system includes an on-board charging module (OBCM) 52 electrically connected to a charging port 54 for charging an energy storage system such as a utility AC power source.

[0050] The battery system 40 and / or the propulsion system 16 include various switching devices for controlling the operation of the battery pack and selectively connecting the battery pack to the drive unit 20. Various switches can be used to adjust or change the output voltage for the drive motor 22. For example, one or more switches are controlled to change the voltage during vehicle propulsion in a manner that provides a smooth transition and reduces or minimizes any torque holes that may occur using existing control systems. The various switches and associated control devices and circuits are collectively referred to as a "switch system." Conversion between voltages is also referred to as "voltage switching."

[0051] In one embodiment, the switching system includes at least one switching device 60 (also referred to as a "battery switching device") for selectively connecting battery pack 44 in series to battery pack 46. Battery switching device 60 allows battery packs 44 and 46 to be connected in parallel or in series to provide various voltage levels.

[0052] In an embodiment, the switching system includes switch devices that allow for selective connection and disconnection of winding sets to facilitate voltage switching and maintain torque levels to propel the vehicle 10 during voltage switching, as further discussed herein. For example, switch device 62 selectively connects the battery system 40 to the inverter 26 and the first set of windings, and switch device 64 selectively connects the battery system to the inverter 28 and the second set of windings.

[0053] Any of a variety of controllers may be used to control the functions of the battery system 40, the switch system, and the drive unit 20. The controller includes any suitable processing device or unit, and an existing controller such as a drive system controller, a RESS controller, and / or a controller in a drive system may be used. For example, a controller 65 may be included to control the switching and drive control operations as discussed herein.

[0054] The vehicle 10 also includes a computer system 55 including one or more processing devices 56 and a user interface 58. The computer system 55 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 a transmission control protocol (TCP) bus.

[0055] Figure 2 An embodiment of the propulsion system 16 and the battery system 40 is depicted, and a circuit connecting the battery system 40 to the motor 22 is schematically represented. As shown, the motor 22 is a dual-winding motor that includes two sets of three-phase (or multi-phase) windings. For example, the motor 22 is a segmented winding machine having at least two sets of windings. The motor 22 can be a permanent magnet synchronous motor, but is not limited thereto, and can be any suitable type of motor (e.g., an induction motor).

[0056] The winding set includes a first set of windings 70 having a set of phase windings a1, b1, c1 and a second set of windings 72 having a set of phase windings a1, b1, c1. In this embodiment, windings a1 and a2 have the same phase (phase A), windings b1 and b2 have the same phase (phase B), and windings c1 and c2 have the same phase (phase C). Phases A, B, and C are separated by 120 degrees in the embodiment.

[0057] The first set of windings 70 is connected in parallel with the second set of windings in the motor 22. Specifically, the phase winding a1 is connected in parallel with the phase winding a2, the phase winding b1 is connected in parallel with the phase winding b2, and the phase winding c1 is connected in parallel with the phase winding c2.

[0058] As shown, the first set of windings 70 is connected to the inverter 26, and the second set of windings 72 is connected to the inverter 28. During normal propulsion (i.e., when the battery system supplies current to both sets of windings 70 and 72), the battery system 40 provides an output current that is converted into an alternating current by the inverters 26 and 28. For each phase, half of the total magnitude of the output current is provided by the inverter 26, and the other half is provided by the inverter 28.

[0059] Each inverter 26 and 28 has three phase branches (A, B, and C) for connecting to corresponding phase terminals in the motor 22. The inverter 26 includes three sets of switches 26a, 26b, and 26c in a half-bridge configuration for converting DC power to AC power by applying current to the first set of windings 70 to drive the motor 22. The inverter 26 and the first set of windings 70 define a first propulsion channel, referred to as "motor channel 1". Similarly, the inverter 28 includes three sets of switches 28a, 28b, and 28c in a half-bridge configuration for converting DC power to AC power and applying AC current to the second set of windings 72. The inverter 28 and the second set of windings 72 define a second propulsion channel, referred to as "motor channel 2".

[0060] As shown, the first inverter 26 and the second inverter 28 are connected to the propulsion DC bus 74. The battery switching device 60 includes at least one switch that can be operated to connect and disconnect the battery packs to each other. The battery switching device 60 may include two switches 76 (SE1) and 78 (SE2) as shown, or may include a single switch. The battery pack 44 is connected to the propulsion bus 74 through switches 80 (SA1) and 82 (SA2), and the battery pack 46 is connected to the propulsion bus 74 through switches 84 (SB1) and 86 (SB2).

[0061] The switch can be operated in various configurations to control which battery packs supply power to which inverters and to change the voltage applied to one or more inverters. In an embodiment, the battery packs 44 and 46 have the same nominal voltage (e.g., 400V), and one or more switches can be controlled to connect the battery packs 44 and 46 in parallel to supply a low voltage (the voltage is the same as the battery pack voltage, and the total current is the sum of the currents through the battery packs 44 and 46). One or more switches can be controlled to connect the battery packs in series to provide a high voltage (the voltage is the sum of the individual voltages of the battery packs 44 and 46). For example, each battery pack 44 and 46 has a voltage of 400V, and can be configured to output a low voltage (400V in this example) by connecting the battery packs 44 and 46 in parallel, and is configured to output a high voltage (800V in this example) by connecting the battery packs 44 and 46 in series. The terms "low voltage" and "high voltage" are relative terms and are not intended to limit any particular voltage level.

[0062] Note that there may be more than two battery packs with at least one switch between adjacent battery packs; in this case, the battery packs may be connected to each other in various ways to provide more than two voltages. In addition, there may be a single battery pack with multiple sections (e.g., a single battery with switches separating parallel strings of batteries); in this case, the switch system may be used to apply different voltages by connecting the strings in various ways.

[0063] Figure 3 An embodiment of a propulsion system 16 , a battery system 40 , and a switch system including a switchgear 60 is depicted. The embodiment also includes an exemplary configuration of switchgear 62 and 64 .

[0064] The switch device 62 ("first switch device") and the switch device 64 ("second switch device") may be single pole double throw switches (or other types of switches) and may be operable to selectively connect the inverter and drive unit to the propulsion bus 74. The switch devices 62 and 64 provide flexibility in the voltage level applied to the motor 22 and allow the motor 22 to operate at different bus voltage levels. The switch devices 62 and 64 may be operated during driving conditions and controlled to change the voltage level without any interruption, thereby avoiding torque holes (zero torque during switching) and ensuring smooth transitions and drivability.

[0065] In an embodiment, the switch device 62 is configured as a three-way switch device that connects the first inverter 26 to two switches or switch branches. The switch device 62 is schematically shown as being connected to the inverter 26 via a node C1. The switch device 62 includes a first switch 62a (or a first switch branch) that selectively connects the node C1 to a node A1 on the DC bus 74. The second switch 62b (or a second switch branch) selectively connects the node C1 to a node B1 and is connected in parallel with the switch 62a. Because both the switch 62a and the switch 62b are connected to the node C1 on one side, but are connected to different points in the circuit across the switch 82 (SA2), the switch device 62 can be considered as a single device called a single-pole double-throw (SPDT) switch.

[0066] In an embodiment, the switch device 64 is also configured as a three-way switch device that connects the second inverter to two switches or switch branches. The switch device 64 is schematically shown as being connected to the inverter 28 via node C2. The switch device 64 includes a third switch 64a that selectively connects node C2 to node A2 and a fourth switch 64b that selectively connects node C2 to node B2. The switch device 64 can also be considered a SPDT switch (switches 64a and 64b are both connected to node C2, but are connected to different points across the switch 84).

[0067] In an embodiment, the switch devices 62 and 64 include mechanical contactors. For illustrative purposes, the switch devices 62 and 64 are configured as single-pole double-throw (SPDT) switches, but may be any other suitable type of mechanical switch. Each switch device 62 and 64 may be integrated into the battery system circuit or included as a single device or removable module.

[0068] Figure 4-8 Various switching states of the switch system and corresponding operating modes of the propulsion system 16 are depicted. Figure 2 The control and switch states of the switch devices 60, 62 and 64 are discussed in the embodiment (mechanical contactor). However, solid-state switches (see Fig. 9 ) similarly controls the switch state.

[0069] To switch between switch states (and corresponding operating modes), the controller 65 (or other suitable processor or processing device) performs a sequential switching operation in which one set of windings drives the motor while voltage switching is performed on another set of windings.

[0070] For example, Figure 4 shows an initial state where the vehicle 10 is operating at an initial voltage level, Figure 5 and Figure 6 shows an intermediate state, and Figure 7The target state of the vehicle 10 operating at the target voltage is shown. In this example, the switching is sequentially controlled to Figure 4 The initial state of the motor is changed to an intermediate state in which one set of windings drives the motor while the other set of windings undergoes voltage switching (the intermediate state can be Figure 5 or Figure 6 Then, the control switches sequentially to switch another set of windings with voltage (while one set of windings drives the motor) and puts the vehicle 10 in Figure 7 The target state is shown. Alternatively, the initial state can be Figure 7 state, and performs sequential switching operations to transition to Figure 4 In another alternative, the target state can be Figure 5 or Figure 6 In this way, the propulsion voltage can be varied while maintaining the torque level and avoiding torque holes.

[0071] Figure 4 The switch system is shown when the vehicle 10 is in a "low voltage" operating state. In this state, switches 76 (SE1) and 78 (SE2) are open (disconnected), and the battery packs 44 and 46 are connected in parallel to the DC bus 74. Switches 80 (SA1), 82 (SA2) are closed (on), and switches 84 (SB1) and 86 (SB2) are closed. The battery pack 44 uses the battery voltage (low voltage, such as 400V) to power the inverter 26 and the first set of windings 70 via the current i1, and the battery pack 46 powers the inverter 28 and the second set of windings 72 at a low voltage via the current i2.

[0072] Switch 62b is opened (OFF) and switch 62a is closed (ON) and connects node C1 to node A1. Switch 64a is closed and switch 64b is opened to connect node C2 to node A2. In this way, the inverter and two battery packs are connected to the DC bus 74 in parallel.

[0073] Figure 5 The switching system is shown when the vehicle 10 is in an intermediate operating state, with the inverter 26 supplying power at a low voltage and the inverter 28 supplying power at a high voltage. Switches 76 (SE1) and 78 (SE2) are closed to connect the battery packs 44 and 46 in series.

[0074] In this state, the switching device 62 connects only the node C1 to the battery pack 44 by closing the switch 62b and opening the switch 62a. The switch 80 (SA1) is closed and the switch 82 (SA2) is opened. The switch 84 (SB1) is opened and the switch 86 (SB2) is closed. The switch 64a is closed and the switch 64b is opened to connect the nodes C2 and A2. In order to switch from the low voltage state to this state, the switch 62 is first operated to keep the first group of windings 70 at a low voltage. Then the switch 64 is operated to switch the voltage applied to the second group of windings 72 while the first group of windings 70 is powered at a low voltage. This sequential operation can be performed to switch between any of the various states described herein (i.e., by first controlling the switch 62 and then controlling the switch 42, or vice versa).

[0075] When the vehicle 10 is switched from the low voltage state to the intermediate state, the battery pack 46 and the battery pack 44 are connected in series to the inverter 28, and the second set of windings 72 is powered by the current i2 at a high voltage. The battery pack 44 supplies power to the inverter 26 at a low voltage via the current i1. Therefore, the first set of windings 70 receives a low voltage and presents the full command torque.

[0076] Figure 6 The switching system is shown when vehicle 10 is in another intermediate operating state, where inverter 26 supplies power at a high voltage and inverter 28 supplies power at a low voltage. Switches 76 (SE1) and 78 (SE2) are closed to connect battery packs 44 and 46 in series.

[0077] Switching device 62 connects the series connected battery pack to inverter 26 (switch 62b is open and switch 62a is closed). Switch 80 (SA1) is closed and switch 82 (SA2) is open. Switch 84 (SB1) is open and switch 86 (SB2) is closed. Switching device 64 connects battery pack 46 to inverter 28 (switch 64a is open and switch 64b is closed to connect nodes A2 and C2). In this state, the second set of windings 72 exhibits full command torque, while the first set of windings 70 switches to a high voltage.

[0078] Figure 7 The switch system is shown when the vehicle 10 is in a "high voltage" operating mode. In this mode, switches 70 (SE1) and 72 (SE2) are closed to connect battery packs 44 and 46 in series. Both battery packs 44 and 46 supply power to inverter 26 and inverter 28 at a high voltage (the sum of the battery voltages, e.g., 800V).

[0079] Switching device 62 connects node C1 to battery packs 44 and 46 by opening switch 62b and closing switch 62a. Switch 80 (SA1) is closed and switch 82 (SA2) is open. Switch 84 (SB1) is open and switch 86 (SB2) is closed. Switch 64a is closed and switch 64b is open to connect inverter 28 to battery packs 44 and 46 via node C2. During operation, current i1 is supplied to inverter 26 at a high voltage, and current i2 is supplied to inverter 28 at a high voltage.

[0080] It should be noted that when transitioning from an initial high voltage state to a low voltage state, the motor windings providing propulsion may not provide full torque during the transition. For example, if the initial state is Figure 7 If the torque is high, then when one of the winding sets is switched to a low voltage state, the other set of windings provides propulsion at a low voltage (i.e., half of the initial torque). Even in this case, torque hollowing does not occur because torque is continuously applied during the transition.

[0081] Figure 8 An embodiment is depicted in which the switch devices 62 and 64 are configured as solid-state switch devices. Any suitable solid-state or electronic device can be used as a switch. For example, the switch devices 62 and 64 can include solid-state relays and transistors, such as silicon (Si) insulated gate bipolar transistors (IGBTs) field effect transistors (FETs). Examples of FETs include metal oxide semiconductor FETs (MOSFETs) Si MOSFETs, silicon carbide (Sic) MOSFETs, gallium nitride (GaN) high electron mobility transistors (HEMTs) Sic junction gate FETs (JFETs). Other examples of switches that can be used include diamond, gallium oxide, and other wide bandgap (WBG) semiconductor-based power switching devices.

[0082] For example, switching device 62 includes two solid-state switches, such as IGBTs 92a and 92b, connected as a half-bridge to node C1. Switching device 64 includes IGBTs 94a and 94b (or two other solid-state switches) connected as a half-bridge to node C2.

[0083] Fig. 9 An embodiment of a method 100 for controlling a propulsion system of a vehicle, such as propulsion system 16, is shown. Aspects of method 100 may be performed by one or more processors disposed in the vehicle, such as controller 65. However, method 100 is not limited thereto, as the method may be performed by any suitable processing device or system or combination of processing devices.

[0084] Method 100 includes a number of steps or phases represented by blocks 101-104. Method 100 is not limited to the number or order of steps therein, as some steps represented by blocks 101-104 may be performed in a different order than described below, or fewer than all of the steps may be performed.

[0085] At box 101, during a driving or propulsion condition (i.e., a condition in which voltage is applied to the motor 22 according to a commanded torque), the controller 65 determines whether it is desired to change the voltage level applied to the motor from an initial voltage to a target voltage. This determination may be based on a request to change the operating mode of the vehicle 10 (e.g., via user interaction with the vehicle 10, such as a request to place the vehicle in a high-performance mode). Additionally or alternatively, this determination may be based on measurements of vehicle and / or driver conditions, such as vehicle speed, driver interaction with the accelerator pedal, etc.

[0086] For example, the vehicle 10 is in a normal mode, where the initial voltage is a low voltage (e.g., 400V). The switch devices 60 and 62 of the switch system are set to switch positions so that both sets of windings receive a low voltage (e.g., 400V). These switch positions correspond to a low voltage state of the switch system. The user may request a switch to a high performance mode, where a high voltage (e.g., 800V) will be applied to the motor 22. The user may request a switch to other modes, such as a mode in which a high voltage is applied to one drive unit and a low voltage is applied to another drive unit.

[0087] At box 102, the switch system is controlled so that the first set of windings receives an initial voltage. For example, the switch device 62 is controlled to connect only the battery pack 44 to the inverter 26 by opening the switch 62a and closing the switch 62b. The switch position of the switch device 62 is Figure 5 , and the first set of windings 70 is powered at an initial voltage.

[0088] At box 103, the switch system is then controlled to switch the voltage applied to the second set of windings from the initial voltage to the target voltage. The switching of the voltage applied to the second set of windings occurs when the vehicle is propelled by the torque generated by the first set of windings.

[0089] For example, when battery 44 provides current to first set of windings 70, switching device 64 is controlled to connect battery 44 and 46 in series and connect the series connected battery to set of windings 72. During this switching operation, the vehicle continues to be propelled by the torque generated by the first set of windings to avoid interruption.

[0090] At block 104 , vehicle propulsion is controlled at a target voltage.

[0091] The method 100 may also include controlling the switching device 62 to switch the voltage applied to the first set of windings to the target voltage. This control is performed when the second set of windings is powered at the target voltage. In this way, both sets of windings are voltage switched without any torque holes.

[0092] Fig.10 Aspects of an embodiment of a computer system 140 are shown that can perform various aspects of the embodiments described herein. The computer system 140 includes at least one processing device 142, which typically includes one or more processors for performing various aspects of the image acquisition and analysis methods described herein.

[0093] Components of computer system 140 include a processing device 142 (such as one or more processors or processing units), memory 144, and a bus 146 that couples various system components including system memory 144 to processing device 142. System memory 144 may be a non-transitory computer-readable medium and may include various computer system-readable media. Such media may be any available media that is accessible to processing device 142 and includes both volatile and non-volatile media and removable and non-removable media.

[0094] For example, system memory 144 includes nonvolatile memory 148, such as a hard drive, and may also include volatile memory 150, such as random access memory (RAM) and / or cache memory. Computer system 140 may also include other removable / non-removable, volatile / nonvolatile computer system storage media.

[0095] The system memory 144 may include at least one program product having a set (e.g., at least one) of program modules that are configured to perform the functions of the embodiments described herein. For example, the system memory 144 stores various program modules that typically perform the functions and / or methods of the embodiments described herein. A module 152 for performing functions associated with monitoring a propulsion system may be included, and a module 154 for performing functions associated with switching may be included. The system 140 is not limited thereto, as 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 described functions.

[0096] Processing device 142 may also communicate with one or more external devices 156, such as a keyboard, pointing device, and / or any device that enables processing device 142 to communicate with one or more other computing devices (e.g., a network card, a modem, etc.). Communication with various devices may occur via input / output (I / O) interfaces 164 and 165.

[0097] The processing device 142 may also communicate with one or more networks 166, 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 168. It should be appreciated 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, among others.

[0098] The terms "one" and "an" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced item. Unless the context clearly indicates otherwise, the term "or" means "and / or". References to "aspects" throughout the specification mean that a particular element (e.g., a 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 the various aspects.

[0099] 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.

[0100] Unless otherwise indicated herein, all test standards are the most current standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0101] 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 invention belongs.

[0102] 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 its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic 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 system for controlling a propulsion system of a vehicle, comprising: a switch system connected to a battery system and the propulsion system, the battery system including a first battery assembly and a second battery assembly, the propulsion system including an electric motor having a first set of windings and a second set of windings, the switch system including a first switch device connecting the battery system to the first set of windings and a second switch device connecting the battery system to the second set of windings; as well as a controller configured to execute a transition of the propulsion system from an initial propulsion mode in which an initial voltage is applied to the electric motor to a target mode in which a target voltage is applied to the electric motor during propulsion of the vehicle according to a command torque, the transition comprising: controlling the first switching device to provide current to the first set of windings at the initial voltage and operating the electric motor to generate torque for propelling a vehicle; as well as The second switching device is then controlled to cause the battery system to apply the target voltage to the second group of windings, wherein the second switching device is controlled while supplying current to the first group of windings at the initial voltage.

2. The system of claim 1, wherein the transition further comprises controlling the first switching device to cause the battery system to apply the target voltage to the first set of windings while the battery system applies the target voltage to the second set of windings.

3. The system of claim 1, wherein the first switching device and the second switching device comprise mechanical switches or solid-state switches.

4. The system of claim 1, wherein the first battery assembly is connected to a first inverter configured to supply alternating current (AC) to the first set of windings, and the second battery assembly is connected to a second inverter configured to supply AC current to the second set of windings.

5. The system of claim 4, wherein the first battery assembly is selectively connected to a propulsion bus via a first switch, and the first switch device has a first switch position that connects the first inverter to a node between the first switch and the propulsion bus, and a second switch position that connects the first inverter to a node between the first switch and the first battery assembly; and The second battery assembly is selectively connected to the propulsion bus via a second switch, and the second switch device has a first switch position and a second switch position, wherein the first switch position connects the second inverter to a node between the second switch and the propulsion bus, and the second switch position connects the second inverter to a node between the second switch and the second battery assembly.

6. The system of claim 5, wherein the first switching device and the second switching device are single-pole double-throw switches.

7. The system of claim 1, wherein one of the initial voltage and the target voltage is a low voltage achieved by connecting the first battery assembly and the second battery assembly in parallel to a propulsion bus.

8. The system according to claim 7, wherein: One of the initial voltage and the target voltage is a high voltage achieved by connecting the first battery assembly and the second battery assembly in series.

9. A method of controlling a propulsion system of a vehicle, comprising: receiving a request to transition the propulsion system from an initial voltage to a target voltage, the propulsion system comprising an electric motor having a first set of windings and a second set of windings, the electric motor connected to a battery system comprising a first battery assembly and a second battery assembly, the propulsion system comprising a switch system having a first switch device connecting the battery system to the first set of windings and a second switch device connecting the battery system to the second set of windings; as well as transitioning the propulsion system from an initial propulsion mode in which the initial voltage is applied to the electric motor to a target mode in which the target voltage is applied to the electric motor while the vehicle is propelled according to a command torque, the transition comprising: controlling the first switching device to provide current to the first set of windings at the initial voltage and operating the electric motor to generate torque for propelling a vehicle; as well as The second switching device is then controlled to cause the battery system to apply the target voltage to the second group of windings, wherein the second switching device is controlled while supplying current to the first group of windings at the initial voltage.

10. The method of claim 9, wherein the transitioning further comprises controlling the first switching device to cause the battery system to apply the target voltage to the first set of windings while the battery system applies the target voltage to the second set of windings.

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