FIELD OF THE DISCLOSURE

[0001] The present disclosure generally relates to electrical machines, and more particularly to techniques of using electrical machines for integrated onboard charging of electric vehicles.

BACKGROUND OF THE DISCLOSURE

[0002] Electrical machines are utilized in various applications including electric vehicles. For example, a drive system of an electric vehicle typically includes an alternating current (AC) electric motor driven by a direct current (DC) power source (e.g., a main battery). The AC electric motor is coupled to the DC power source via an inverter which performs switching functions to convert the DC power to AC power. The DC power source is a rechargeable energy storage device that needs to be replenished periodically. Typically, the DC power source is charged by connecting to a power grid using additional hardware, which results in increased cost and weight to the electric vehicle. Accordingly, there remains a need to develop techniques for charging electric vehicles by utilizing electrical machines for integrated onboard charging.

SUMMARY

[0003] According to some embodiments, the present disclosure provides a system for integrated onboard charging of an electric vehicle. The system includes an electrical machine disposed in the electric vehicle, and a controller coupled to the electrical machine. The electrical machine includes a first connector coupled to an energy source of the electric vehicle and a second connector couplable to an external device. The controller is configured to operate the electrical machine to charge the energy source from the external device via the second connector when operating in a battery charging mode. The controller is also configured to operate the electrical machine to energize the external device from the energy source via the second connector when operating in an equipment energization mode. Moreover, the controller is configured to operate the electrical machine to drive the electric vehicle by closing the second connector when operating in a vehicle operational mode. [0004] According to certain embodiments, the present disclosure provides a controller for integrated onboard charging of an electric vehicle. The controller includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the controller to operate an electrical machine disposed in the electric vehicle. The electrical machine includes a first connector coupled to an energy source of the electric vehicle and a second connector couplable to an external device. The instructions, when executed by the processor, also cause the controller to operate the electrical machine in a battery charging mode to charge the energy source from the external device via the second connector. The instructions, when executed by the processor, further cause the controller to operate the electrical machine in an equipment energization mode to energize the external device from the energy source via the second connector. Moreover, the instructions, when executed by the processor, cause the controller to operate the electrical machine in a vehicle operational mode to drive the electrical vehicle by closing the second connector.

[0005] According to some embodiments, the present disclosure provides a method for integrated onboard charging of an electric vehicle. The method includes operating an electrical machine disposed in the electric vehicle. The electrical machine includes a first connector coupled to an energy source of the electric vehicle and a second connector couplable to an external device. The method also includes operating the electrical machine in a battery charging mode to charge the energy source from the external device via the second connector. The method further includes operating the electrical machine in an equipment energization mode to energize the external device from the energy source via the second connector. Moreover, the method includes operating the electrical machine in a vehicle operational mode to drive the electrical vehicle by closing the second connector.

[0006] In certain embodiments, the second connector includes a charging socket and closing the second connector includes having a dummy plug connected to the charging socket when operating in the vehicle operational mode. The dummy plug is grounded and disposed in the electric vehicle. In some embodiments, the external device is an electric grid and the charging socket is disconnected from the dummy plug and connected to a plug associated with the electric grid when operating in battery charging mode to charge the energy source. In certain embodiments, the charging socket is disconnected from the dummy plug and connected to a plug associated with the external device when operating in the equipment energization mode to energize the external device. In some embodiments, closing the second connector includes activating a switch that connects the second connector to ground. In certain embodiments, the switch is activated to disconnect the second connector from ground when operating in the battery charging mode or the equipment energization mode.

[0007] In various embodiments, energy from the electric grid is filtered through one or more capacitors disposed in the electrical machine when operating in the battery charging mode to charge the energy source. In some embodiments, the electrical machine is as a six-phase machine.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. l is a block diagram illustrating a system for integrated onboard charging of an electric vehicle;

[0009] FIGS. 2-4 are schematic diagrams illustrating connections of the electric vehicle of FIG. 1 to an external device; and

[0010] FIG. 5 is a flow chart illustrating a method for integrated onboard charging of an electric vehicle.

DETAILED DESCRIPTION

[0011] For the purposes of promoting an understanding of the principles of the present disclosure, reference is now made to the embodiments illustrated in the drawings, which are described below. The embodiments disclosed herein are not intended to be exhaustive or to limit the disclosure to the precise form disclosed in the following detailed description. Rather, these embodiments were chosen and described so that others skilled in the art may utilize their teachings.

[0012] The terms “couples,” “coupled,” and variations thereof are used to include both arrangements wherein two or more components are in direct physical contact and arrangements wherein the two or more components are not in direct contact with each other (e.g., the components are “coupled” via at least a third component), but yet still cooperate or interact with each other.

[0013] Throughout the present disclosure and in the claims, numeric terminology, such as first and second, is used in reference to various components or features. Such use is not intended to denote an ordering of the components or features. Rather, numeric terminology is used to assist the reader in identifying the component or features being referenced and should not be narrowly interpreted as providing a specific order of components or features.

[0014] One of ordinary skill in the art will realize that the embodiments provided can be implemented in hardware, software, firmware, and/or a combination thereof. Programming code according to the embodiments can be implemented in any viable programming language such as C, C++, HTML, XTML, JAVA or any other viable high-level programming language, or a combination of a high-level programming language and a lower level programming language.

[0015] Referring to FIG. 1, a block diagram of a system 100 for integrated onboard charging is shown including an electric vehicle 102 and an electric grid 104 (e.g., a 3-phase distribution grid, a microgrid, etc.) with an outlet 105 for vehicle-to-grid (V2G) charging. Unlike conventional approaches that utilize a separate onboard charger and a separate V2G system, system 100 implements an integrated onboard charging scheme that eliminates the need for additional hardware to interface with electric grid 104 when charging/recharging electric vehicle 102. This in turn provides significant cost savings and weight reductions to electric vehicle 102.

[0016] Electric vehicle 102 includes, among other things, an electrical machine 106, an inverter 108, and a battery bank 110. For ease of illustration, other components of electric vehicle 102 (e.g., transmission, brakes, wheels, etc.) are not shown, the operations of which are known to those skilled in the art. As used herein, the term “electric vehicle” refers to any vehicle that is partly or entirely operated based on stored electric power such as a pure electric vehicle, a hybrid electric vehicle, or the like. Such vehicles can include road vehicles (e.g., cars, trucks, buses, etc.), rail vehicles, underwater vessels, aircrafts, and other suitable vehicles. [0017] FIGS. 2-4 are schematic diagrams illustrating connections between electric vehicle 102 and an external device 200. According to various embodiments, electrical machine 106 is a traction motor that provides torque in electric vehicle 102. For example, electrical machine 106 is a six-phase AC machine. As used herein, the term “AC machine” refers to an AC powered device that converts electrical energy to mechanical energy or vice versa.

[0018] Electrical machine 106 includes a first connector 202 (e.g. a first set of terminals) coupled to battery bank 110 via inverter 108 and a second connector 204 (e.g., a second set of terminals) couplable to external device 200 (e.g., outlet 105 of electric grid 104). First connector 202 represents one end of windings 206A-206F, while second connector 204 represents another end of windings 206A-206F.

[0019] Each of windings 206A-206F is associated with a respective phase of electrical machine 106. Windings 206A-206F represent a stator of electrical machine 106. For ease of illustration, the stator and other components (e.g., rotor, shaft, etc.) of electrical machine 106 are not shown. Generally, the rotor is mounted to the shaft and the rotor is separated from the stator by an air gap. When utilized as a motor, the stator causes the rotor to rotate utilizing electrical energy thereby rotating the shaft to provide mechanical energy. On the other hand, when utilized as a generator, the shaft is rotated by an external mechanical force that causes the rotor to rotate thereby causing the stator to generate electrical energy.

[0020] A controller 208 operates electrical machine 106 via inverter 108. For example, controller 208 receives operating signals from electrical machine 106 and generates control signals to control the switching operations of inverter 108 to thereby control the outputs (e.g., currents) provided to windings 206A-206F. Controller 208 controls winding phase currents in electrical machine 106 such that no torque is generated inside electrical machine 106 during energy transfer operations.

[0021] Inverter 108 includes, among other things, a plurality of switching devices 210 (e.g., insulated-gate bipolar transistors (IGBTs), diodes, etc.) to appropriately switch DC voltages and provide energization to windings 206A-206F as known to those skilled in the art. For example, inverter 108 is a single six-phase inverter that controls windings 206A-206F. In certain embodiments, controller 208 is part of inverter 108. [0022] Inverter 108 is coupled to battery bank 110 (e.g., lithium-ion battery packs). In some embodiments, inverter 108 is connected to battery bank 110 via a DC bus which includes one or more DC bus capacitors. Battery bank 110 acts as an energy source of electric vehicle 102 that needs to be replenished periodically. For example, controller 208 receives an input from a user (e.g., an operator of electric vehicle 102) indicating that battery bank 110 needs to be charged. As an example, a monitoring device in electric vehicle 102 (e.g., a battery management system (BMS)) sends a signal to controller 208 indicating that the state-of-charge of battery bank 110 is low and thus battery bank 110 needs recharging.

[0023] According to some embodiments, controller 208 includes a non-transitory memory having instructions that, in response to execution by a processor, cause the processor to perform the functions of controller 208 as described herein. The processor, non-transitory memory and controller 208 are not particularly limited and can, for example, be physically separate.

[0024] In certain embodiments, controller 208 forms a portion of a processing subsystem including one or more computing devices having memory, processing, and communication hardware. For example, controller 208 can be a single device or a distributed device, and functions of controller 208 can be performed by hardware and/or as computer instructions on a non-transient computer readable storage medium, such as the non-transitory memory.

[0025] In some embodiments, controller 208 includes one or more interpreters, determiners, evaluators, regulators, and/or processors that functionally execute the operations of controller 208. Interpreters, determiners, evaluators, regulators, and processors can be implemented in hardware and/or as computer instructions on a non-transient computer readable storage medium and can be distributed across various hardware or computer-based components.

[0026] To charge and recharge battery bank 110, controller 208 operates electrical machine 106 in a battery charging mode where electric vehicle 102 is connected to external device 200. In this case, external device 200 is electric grid 104. For example, electrical vehicle 102 is connected to outlet 105 to allow energy (e.g., electricity) to flow between electric vehicle 102 and electric grid 104. To facilitate this, second connector 204 in electrical machine 106 includes a charging socket 212 (e.g., AC socket) configured to receive a charging plug 214 (e.g., V2G plug) associated with outlet 105 of electric grid 104. Once charging plug 214 is connected to charging socket 212, the energy from electric grid 104 is provided to battery bank 110 to charge/recharge battery bank 110.

[0027] Electrical machine 106 also includes a plurality of capacitors 216 that form star points with respective windings 206A-206F. Capacitors 216 operate as low-pass filters during charging/recharging to filter the energy from electric grid 104 (e.g., remove higher order harmonics).

[0028] To prevent any sudden rush of current (e.g., inrush current protection) when first plugged into outlet 105, second connector 204 in electrical machine 106 includes a plurality of relays 218 (e.g., solid-state relays coupled with inrush current limiters) coupled to respective windings 206A-206F. Relays 218 are normally closed. When charging plug 214 is initially detected (e.g., via an information pin) in charging socket 212, controller 208 sends a control signal 220 to open relays 218 to ensure that electrical machine 106 does not experience any surge of input currents. In some embodiments, controller 208 also commands the BMS to pre-charge DC bus capacitors to avoid any potential connection inrush current. Once charging plug 214 is fully plugged into charging socket 212, controller 208 sends control signal 220 to close relays 218 again so that charging can take place. In various embodiments, controller 208 monitors and measures input current and/or voltage from outlet 105.

[0029] After charging/recharging is completed, charging plug 214 is disconnected from charging socket 212. Thus, when not charging/recharging, controller 208 operates electrical machine 106 in a vehicle operational mode. Here, electric vehicle 102 is in operation and charging socket 212 is connected to a dummy plug 222 disposed in electric vehicle 102 (e.g., in chassis of electric vehicle 102). Dummy plug 222 is grounded so that when plugged into charging socket 212, second connector 204 is closed. In other words, windings 206A-206F form a star point with all phases in electrical machine 106 being shorted as a result.

[0030] In FIG. 3, instead of dummy plug 222, a switch 302 is used. For example, second connector 204 is coupled to switch 302 which includes an interlock coil 304 and a plurality of switches 306 connected to respective windings 206A-206F before capacitors 216. During charging/recharging, controller 208 sends a control signal 320 to energize interlock coil 304 and open switches 306 so that electrical machine 106 can receive energy from outlet 105 via charging plug 214. After charging/recharging is completed, controller 208 sends control signal 320 to close switches 306 to thereby close second connector 204. In this manner, second connector 204 is grounded and windings 206A-206F in electrical machine 106 form a star point. In some embodiments, charging socket 212 includes a cover that is grounded. After charging/recharging is completed, the cover is placed over charging socket 212 so that second connector 204 can be closed.

[0031] When electric vehicle 102 is fully charged but not in operation, energy stored in electric vehicle 102 can be provided to power external device 200. In FIG. 4, controller 208 operates electrical machine 106 in an equipment energization mode that provides power to other machines or equipment (e.g., a second electric vehicle, a concrete mixer, etc.). For example, controller 208 receives an input from a user or operator of electric vehicle 102 indicating that electric vehicle 102 has capacity to share or contribute energy. As such, a socket 402 associated with external device 200 can be connected to charging socket 212 so that energy is transferred from electric vehicle 102 to external device 200.

[0032] Referring now to FIG. 5, a method 500 for integrated onboard charging of an electric vehicle (e.g., 102) is shown. For example, method 500 is performed by a controller (e.g., 208). At block 502, the controller operates an electrical machine (e.g., 106) disposed in the electric vehicle. The electrical machine includes a first connector (e.g., 202) coupled to an energy source (e.g., 110) of the electrical vehicle and a second connector (e.g., 204) couplable to an external device (e.g., 200). In some examples, the electrical machine is a six-phase machine.

[0033] At block 504, the controller operates the electrical machine in a battery charging mode to charge the energy source from the external device via the second connector. In this scenario, the external device is in the form of an electric grid (e.g., 104). In various embodiments, when operating the electrical machine in the battery charging mode to charge the energy source from the electric grid, energy from the electric grid is filtered through one or more capacitors disposed in the electrical machine.

[0034] At block 506, the controller operates the electrical machine in an equipment energization mode to energize the external device from the energy source via the second connector. In this scenario, the external device is in the form of another machine or equipment such as a concrete mixer.

[0035] At block 508, the controller operates the electrical machine in a vehicle operational mode to drive the electric vehicle by closing the second connector. In some embodiments, the second connector includes a charging socket (e.g., 212). As such, closing the second connector includes connecting a dummy plug (e.g., 214) to the charging socket. The dummy plug is grounded and disposed in the electric vehicle.

[0036] In certain embodiments, when operating in the battery charging mode, the charging socket is disconnected from the dummy plug and connected to a plug associated with the electric grid to charge the energy source. In some embodiments, when operating in the equipment energization mode, the charging socket is disconnected from the dummy plug and connected to a plug associated with the external device to energize or power the external device.

[0037] In some embodiments, closing the second connector includes activating a switch (e.g., 302) that connects the second connector to ground. In certain embodiments, when operating in the battery charging mode or the equipment energization mode, the switch is activated to disconnect the second connector from ground.

[0038] This application is intended to cover any variations, uses, or adaptations of the present disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which the present disclosure pertains and which fall within the limits of the appended claims.

[0039] Furthermore, the connecting lines shown in the various figures contained herein are intended to represent functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements. The scope is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.”

[0040] Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B or C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C.

[0041] Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic with the benefit of this disclosure in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments.

[0042] Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.