System and method for bi-directional onboard battery charging function in separately excited motor drive

Abstract

Systems and methods are provided for bi-directional on-board battery charging functionality in separately excited motor drive. A separately excited motor (SEM) drive system, a method for manufacturing / using such a system, and a vehicle equipped with such a system are presented. A motor driving system includes: a rechargeable battery unit; and a multi-stage power factor correction (PFC) device interposed between the battery cell and the power source and electrically connecting the battery cell and the power source. The battery unit and the PFC device are electrically connected via a traction inverter module (TIM) device and a multi-stage power transfer circuit (PTC) device. The TIM includes a plurality of pairs of TIM switches, and the PTC device includes a plurality of PTC switches. The SEM unit includes a rotor assembly including a rotor core carrying rotor windings, and a stator assembly including a stator core carrying a plurality of stator windings electromagnetically paired with the rotor windings. Each stator winding is electrically connected to a respective pair of TIM switches, while the rotor winding is electrically connected to the PTC switches.

Description

[0001] introduction Technical Field

[0002] The present disclosure relates generally to electrical systems for charging batteries. More specifically, aspects of the present disclosure relate to an onboard high voltage electrical system for recharging batteries driven by a separately excited electric motor (SEM). Background Art

[0003] Current production motor vehicles (such as modern automobiles) are initially equipped with a drive train that operates to propel the vehicle and power the vehicle's onboard electronics. For example, in automotive applications, the vehicle drive train is typically represented by a prime mover that delivers drive torque to the vehicle's final drive system (e.g., differentials, half-shafts, corner modules, wheels, etc.) through an automatically or manually shifted electric transmission. Motor vehicles have historically been powered by reciprocating piston internal combustion engine (ICE) assemblies due to their ready availability, relatively light weight, and overall high efficiency. As some non-limiting examples, such engines include compression ignition (CI) diesel engines, spark ignition (SI) gasoline engines, two-stroke, four-stroke, and six-stroke architectures, and rotary engines. On the other hand, hybrid electric vehicles and all-electric vehicles (collectively referred to as "electrically driven vehicles") utilize alternative electric power sources to propel the vehicle and thereby minimize or eliminate reliance on fossil fuel-based engines for traction power.

[0004] A full electric vehicle (FEV) - colloquially known as an "electric vehicle" - is a type of electrically driven vehicle configuration that completely omits the internal combustion engine and associated peripheral components from the drivetrain, instead relying on a rechargeable energy storage system (RESS) and traction motors for vehicle propulsion. In a battery-based FEV, the engine assembly, fuel supply system, and exhaust system of an ICE-based vehicle are replaced with a single or multiple traction motors, a rechargeable battery subunit, and battery cooling and charging hardware. In contrast, a hybrid electric vehicle (HEV) drivetrain employs multiple traction power sources to propel the vehicle, most commonly operating an internal combustion engine assembly in conjunction with a battery-powered or fuel cell-powered traction motor. Because a hybrid electric drive vehicle is able to derive its electrical power from a source other than the engine, the HEV engine can be fully or partially shut down when the vehicle is propelled by the electric motor(s). Summary of the invention

[0005] The high voltage (HV) electrical system governs the transfer of power between the traction motors and the rechargeable battery cells that supply the necessary power to operate many hybrid electric and all-electric drivetrains. To provide the power capacity and energy density required to propel the vehicle at the desired speed and distance, contemporary traction battery packs group multiple battery cells (e.g., 8-16+ battery cells / battery pack) into individual battery modules (e.g., 10-40+ battery modules / battery pack) that are electrically interconnected to one another and mounted to the vehicle chassis, for example, via a battery pack housing or support tray. Located on the battery side of the HV power system is a front-end DC to DC power converter that is electrically connected to the battery pack(s) in order to increase the voltage level supplied to the main DC bus and power inverter module (PIM). Arranged across the positive and negative terminals of the main DC bus are high frequency bulk capacitors that provide electrical stability and store supplemental electrical energy. A dedicated electronic battery control module (EBCM) manages the operation of the battery pack(s) and traction motor(s) by operating in coordination with the powertrain control module (PCM) and the power electronics package of each electric motor.

[0006] As hybrid and electric vehicles become more common, infrastructure is being developed and deployed to make the daily use of such vehicles feasible and convenient. Electric vehicle supply equipment (EVSE) for recharging electric drive vehicles has many form factors, including residential electric vehicle charging stations (EVCS) purchased and operated by vehicle owners (e.g., installed in the owner's garage), publicly accessible EVCS provided by public utilities or private retailers (e.g., at municipal or commercial charging facilities), and advanced high-voltage fast charging stations (e.g., OEM multi-coupler 360+kW DCFC superchargers) used by manufacturers, dealers, and service stations. For example, plug-in hybrid and electric vehicles can be recharged by physically connecting the charging cable of the EVSE to the complementary charging port of the vehicle. In contrast, wireless AC charging systems use electromagnetic field (EMF) induction to provide vehicle charging capabilities without the need for charging cables and cable ports. In most countries, standardized conductive charger couplers are used to connect EVCS to the HV electrical system of the vehicle. The plug-in vehicle is equipped with a standardized charger inlet port for electrically mating with the charger coupler and locking the coupler in place to prevent inadvertent or unwanted uncoupling.

[0007] An electrical system for charging a battery driven by a separately excited electric motor (SEM), a method of manufacturing and operating such a system, and a vehicle equipped with such a system are presented herein. As an illustration and not limitation, the disclosed system and method employ a rechargeable battery pack to power a separately excited electric motor, a traction inverter module (TIM) for motor stator control, and a rotor excitation power transmission circuit (PTC) for motor rotor control. Unlike permanent magnet (PM) motor construction, separately excited electric motors are typically represented by rotor-carrying armature windings that electromagnetically cooperate with stator-carrying field windings to convert electrical energy into mechanical energy. The SEM drive system operates in conjunction with a front-end multi-level (2+, 3+, ... N+) power factor correction (PFC) converter to provide galvanically isolated high voltage (HV) battery charging features at reduced cost and increased efficiency. The TIM and rotor excitation PTC can each employ a variety of multi-level (2+, 3+, ... N+) form factors for scalability across different voltages (e.g., below and above 1 kV). In addition, the PTC can be implemented in a conductive power transfer configuration (e.g., a brush-based design) or a non-conductive power transfer configuration (e.g., an inductive, capacitive, and harmonic excitation design). Using this system architecture can help eliminate the mass, cost, and packaging space requirements of an onboard charging module (OBCM) for supporting AC charging of the system battery from the alternating current (AC) grid, thereby enabling bidirectional power flow to and from the grid.

[0008] Aspects of the present disclosure relate to a SEM drive system having TIM-based stator control and PTC-based rotor control with multi-level PFC for optimizing HV battery charging and enhancing OBCM functionality for both automotive and non-automotive applications. In an example, an adjustable speed motor drive system includes a multi-phase separately excited motor powered by a battery cell, such as a battery pack or battery module containing one or more rechargeable battery cells (e.g., prismatic, pouch, or cylindrical lithium-ion battery cells). A multi-level power factor correction device is electrically connected to an off-board power source (e.g., EVCS and utility grid); once connected, the PFC is inserted between the battery cell and the power source. A traction inverter module including multiple TIM switches is electrically connected to the battery cell and the PFC device, and is electrically connected to the battery cell or the PFC device. Similarly, a multi-level power transmission circuit including multiple PTC switches is electrically connected to the battery cell and the PFC device, and is electrically connected to the battery cell or the PFC device. The SEM unit comprises a rotor assembly including a rotor core carrying one or more rotor windings, adjacent to a complementary stator assembly including a stator core carrying a plurality of stator windings electromagnetically paired with the (one or more) rotor windings. Each stator winding is electrically connected to a corresponding pair of TIM switches, and each rotor winding is electrically connected to a PTC switch.

[0009] Additional aspects of the present disclosure relate to an electrically driven vehicle having a SEM-based drive train and an HV electrical system for charging the vehicle's resident battery. As used herein, the terms "vehicle" and "motor vehicle" may be used interchangeably and synonymously refer to any relevant vehicle platform, such as passenger vehicles (ICE, HEV, FEV, fuel cell, fully and partially autonomous, etc.), commercial vehicles, industrial vehicles, tracked vehicles, off-road and all-terrain vehicles, motorcycles, agricultural equipment, boats, aircraft, electric bicycles, etc. For non-motor vehicle applications, the disclosed concepts may be implemented for any logically related purposes, including pumping equipment, machine tools, appliances, etc. Although not limiting in themselves, the disclosed concepts may be particularly useful for use with DC SEMs and lithium (secondary) electric vehicle battery (EVB) units fed by three-phase inverters.

[0010] In an example, a motor vehicle includes a vehicle body having a passenger cabin, a plurality of wheels mounted to the vehicle body (e.g., via corner modules coupled to an integral or split-frame chassis), and other standard original equipment. For electric drive vehicle applications, the vehicle's electrified drivetrain employs one or more electric SEMs that operate alone (e.g., for an FEV drivetrain) or in conjunction with an internal combustion engine assembly (e.g., for an HEV drivetrain) to selectively drive one or more wheels and thereby propel the vehicle. Each SEM is operatively connected to a resident RESS that includes a battery assembly that may be in the nature of a chassis-mounted HV traction battery pack or an array of HV battery modules.

[0011] Continuing with the previous discussion, an onboard multi-stage PFC device, which is electrically connected to a battery assembly, is selectively electrically connected to an off-board power source and, once connected, is inserted between the vehicle battery assembly and the power source. An onboard TIM device comprising multiple pairs of TIM switches is electrically connected to the battery assembly and the PFC device. Similarly, an onboard multi-stage rotor PTC device comprising multiple pairs of PTC switches is electrically connected to the battery assembly, the TIM device, and the PFC device. Each SEM unit is fixed to the vehicle body and is electrically connected to the vehicle battery assembly, for example, via a TIM and / or PTC. The SEM unit includes a rotor assembly and a stator assembly, the rotor assembly including a rotatable rotor core carrying one or more electromagnetic rotor windings, the stator assembly including a fixed stator core carrying multiple electromagnetic stator windings electromagnetically paired with the rotor windings. Each stator winding is electrically connected to a corresponding pair of TIM switches (and is not connected to any PTC switch), while each rotor winding is electrically connected to a PTC switch (and is not connected to any TIM switch).

[0012] Aspects of the present disclosure also relate to manufacturing workflow processes, computer readable media, and control logic for manufacturing or using any of the disclosed HV electrical systems, SEM drive systems, and / or motor vehicles. In an example, a method for manufacturing an electric motor drive system is presented. The representative method includes, in any order and in any combination with any of the options and features disclosed above and below: receiving a battery cell comprising rechargeable battery cells; connecting a multi-stage PFC device to the battery cell, the PFC device being configured to be electrically connected to an electric power source and inserted between the battery cell and the electric power source, the PFC device comprising a plurality of PFC switches; connecting a traction inverter module device to the battery cell and the PFC device, the TIM device comprising a plurality of pairs of TIM switches; connecting a multi-stage power transmission circuit device to the battery cell and the PFC device, the PTC device comprising a plurality of PTC switches; receiving a separately excited motor unit having a rotor assembly and a stator assembly, the rotor assembly comprising a rotor core carrying a conductive rotor winding, and the stator assembly comprising a stator core carrying a plurality of conductive stator windings electromagnetically paired with the rotor windings; connecting each stator winding to a corresponding pair of TIM switches; and connecting the rotor windings to the PTC switches.

[0013] For any of the disclosed systems, methods, and vehicles, a TIM device may be electrically inserted between a stator assembly of a SEM unit and a battery unit or a PFC device. It may also be desirable that the TIM be characterized by a lack of direct current transfer connection to a rotor assembly of the SEM unit. Similarly, a PTC device may be electrically inserted between a rotor assembly of the SEM unit and a battery unit or a PFC device. In this example, it may also be desirable that the PTC device be characterized by a lack of direct current transfer connection to a stator assembly of the SEM unit.

[0014] For any of the disclosed systems, methods, and vehicles, the PTC switches may include at least a first series of PTC switches electrically connected in parallel with a second series of PTC switches. In this example, each series of PTC switches may include at least two PTC switches electrically connected in series with each other. An optional brush slip ring (BSR) assembly may be inserted between the PTC device and the (one or more) electromagnetic rotor windings of the SEM unit and electrically connect the PTC device and the (one or more) electromagnetic rotor windings of the SEM unit. The BSR assembly may include a first BSR electrically connected to the first series of PTC switches and a second BSR electrically connected to the second series of PTC switches. The PTC device may also include a first capacitor electrically connected to the first series of PTC switches and a second capacitor electrically connected to the second series of PTC switches.

[0015] For any of the disclosed systems, methods, and vehicles, the PFC device may include a first series of PFC switches electrically connected in parallel with a second series of PFC switches. In this example, each series of PFC switches may include at least two PFC switches electrically connected in series with each other. The PFC device may also include a capacitor electrically connected in parallel with the first series of PFC switches and the second series of PFC switches. In addition, the PFC device may also include a first capacitor electrically connected to the first series of PFC switches and a second capacitor electrically connected to the second series of PFC switches.

[0016] For any of the disclosed systems, methods, and vehicles, the TIM device can include three pairs of solid-state TIM switches connected in series, and the stator assembly can carry three electromagnetic excitation windings. Each stator excitation winding can be electrically connected in series with a corresponding pair of solid-state TIM switches. As described above, the battery unit can take any logically related form factor, including a battery assembly, a battery pack, and / or a battery module, each of which can include a single or multiple rechargeable battery cells.

[0017] The present invention also includes the following scheme:

[0018] Solution 1. A motor drive system connectable to an electric power source, the motor drive system comprising:

[0019] A battery cell comprising a rechargeable battery cell;

[0020] a multi-stage power factor correction (PFC) device configured to be electrically connected to the power source and inserted between the battery unit and the power source;

[0021] a traction inverter module (TIM) device electrically connected to the battery unit and the PFC device, the TIM device including a plurality of pairs of TIM switches;

[0022] a multi-level power transmission circuit (PTC) device electrically connected to the battery cell and the PFC device, the PTC device including a plurality of PTC switches; and

[0023] A separately excited electric motor (SEM) unit having a rotor assembly and a stator assembly, the rotor assembly including a rotor core carrying a rotor winding, and the stator assembly including a stator core carrying a plurality of stator windings electromagnetically paired with the rotor winding, wherein each stator winding is electrically connected to a corresponding pair of TIM switches, and the rotor winding is electrically connected to the PTC switch.

[0024] Option 2. The electric motor drive system according to Option 1, wherein the TIM device is electrically inserted between the stator assembly of the SEM unit and the battery unit or the PFC device.

[0025] Option 3. The electric motor drive system according to Option 1, wherein the PTC device is electrically inserted between the rotor assembly of the SEM unit and the battery unit or the PFC device.

[0026] Option 4. The motor drive system of Option 1, wherein the PTC switches include a first series of PTC switches electrically connected in parallel with a second series of PTC switches.

[0027] Option 5. The motor drive system according to Option 4 further includes a brush slip ring (BSR) assembly inserted between the PTC device and the rotor winding of the SEM unit and electrically connecting the PTC device and the rotor winding of the SEM unit, the BSR assembly including a first BSR electrically connected to the first series of PTC switches and a second BSR electrically connected to the second series of PTC switches.

[0028] Embodiment 6. The motor drive system according to Embodiment 5, wherein the PTC device further comprises a first capacitor electrically connected to the first series of PTC switches and a second capacitor electrically connected to the second series of PTC switches.

[0029] Embodiment 7. The motor drive system according to Embodiment 6, wherein the first series of PTC switches and the second series of PTC switches each include at least two PTC switches electrically connected in series with each other.

[0030] Embodiment 8. The motor drive system of Embodiment 1, wherein the PFC device comprises a first series of PFC switches electrically connected in parallel with a second series of PFC switches.

[0031] Option 9. The motor drive system of Option 8, wherein the PFC device further comprises a capacitor electrically connected in parallel with the first series of PFC switches and the second series of PFC switches.

[0032] Embodiment 10. The motor drive system of Embodiment 9, wherein the first series of PFC switches and the second series of PFC switches each include at least two PFC switches electrically connected in series with each other.

[0033] Option 11. An electric motor drive system according to Option 1, wherein the multiple pairs of TIM switches include first, second and third pairs of solid-state TIM switches, and wherein the stator winding includes first, second and third excitation windings, each of which is electrically connected in series with a corresponding pair of solid-state TIM switches.

[0034] Option 12. An electric motor drive system according to Option 1, wherein the battery unit includes a battery pack and / or a plurality of battery modules including a plurality of rechargeable battery cells.

[0035] Solution 13. A motor vehicle, comprising:

[0036] Vehicle body;

[0037] a plurality of wheels attached to the vehicle body; and

[0038] a rechargeable energy storage system attached to the vehicle body and comprising a battery assembly including a plurality of rechargeable battery cells;

[0039] a multi-stage power factor correction (PFC) device electrically connected to the battery assembly and configured to be electrically connected to an off-board power source and, once connected, to be interposed between the battery assembly and the power source;

[0040] a traction inverter module (TIM) device electrically connected to the battery assembly or the PFC device, the TIM device comprising a plurality of pairs of TIM switches;

[0041] a multi-stage rotor power transfer circuit (PTC) device electrically connected to the battery assembly, the TIM device, and the PFC device, the rotor PTC device including a plurality of pairs of PTC switches; and

[0042] A separately excited electric motor (SEM) unit is attached to the vehicle body and is operable to drive one or more wheels to propel the motor vehicle, the SEM unit including a rotor assembly and a stator assembly, the rotor assembly including a rotor core carrying an electromagnetic rotor winding, and the stator assembly including a stator core carrying a plurality of electromagnetic stator windings electromagnetically paired with the rotor windings, wherein each stator winding is electrically connected to a corresponding pair of TIM switches, and the rotor winding is electrically connected to the PTC switch.

[0043] Solution 14. A method for manufacturing a motor drive system, the method comprising:

[0044] receiving a battery unit including a rechargeable battery cell;

[0045] connecting a multi-stage power factor correction (PFC) device to the battery cell, the PFC device being configured to be electrically connected to an electric power source and inserted between the battery cell and the electric power source, the PFC device comprising a plurality of PFC switches;

[0046] connecting a traction inverter module (TIM) device to the battery unit and the PFC device, the TIM device comprising a plurality of pairs of TIM switches;

[0047] connecting a multi-stage power transmission circuit (PTC) device to the battery cell and the PFC device, the PTC device comprising a plurality of PTC switches;

[0048] receiving a separately excited electric motor (SEM) unit having a rotor assembly and a stator assembly, the rotor assembly including a rotor core carrying an electrically conductive rotor winding, and the stator assembly including a stator core carrying a plurality of electrically conductive stator windings electromagnetically paired with the rotor windings;

[0049] connecting each stator winding to a corresponding pair of TIM switches; and

[0050] The rotor winding is connected to the PTC switch.

[0051] Embodiment 15. The method according to embodiment 14, wherein the TIM device is electrically inserted between a stator assembly of the SEM unit and the battery unit or the PFC device.

[0052] Option 16. The method according to Option 14, wherein the PTC device is electrically inserted between the rotor assembly of the SEM unit and the battery cell or the PFC device.

[0053] Embodiment 17. The method according to embodiment 14, wherein the PTC switches include a first series of PTC switches electrically connected in parallel with a second group of PTC switches, and wherein the first series of PTC switches and the second series of PTC switches each include at least two PTC switches electrically connected in series with each other.

[0054] Option 18. The method according to Option 17 further includes connecting a brush slip ring (BSR) assembly to the PTC device and the rotor winding of the SEM unit so that the assembly is inserted between the PTC device and the rotor winding, and the BSR assembly includes a first BSR electrically connected to a first series of PTC switches and a second BSR electrically connected to a second series of PTC switches.

[0055] Embodiment 19. The method according to Embodiment 14, wherein the PFC device comprises a first series of PFC switches electrically connected in parallel with a second group of PFC switches, and wherein the first series of PFC switches and the second series of PFC switches each comprise at least two PFC switches electrically connected in series with each other.

[0056] Embodiment 20. The method of embodiment 19, wherein the PFC device further comprises a capacitor electrically connected in parallel with the first series of PFC switches and the second series of PFC switches.

[0057] The above summary of the invention does not represent every embodiment or every aspect of the present disclosure. On the contrary, the above summary of the invention only provides an overview of some novel concepts and features set forth herein. When understood in conjunction with the accompanying drawings and the appended claims, the above-mentioned features and advantages of the present disclosure and other features and attendant advantages will be readily apparent from the following specific embodiments of the illustrated examples and representative modes for practicing the present disclosure. In addition, the present disclosure expressly includes any and all combinations and sub-combinations of the elements and features presented above and below. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is a partially schematic side view illustration of a representative motor vehicle having a SEM-based electrified powertrain, a rechargeable battery, and a high voltage electrical system for smart charging of the battery cells in accordance with aspects of the present disclosure.

[0059] Figure 2 is a schematic single-line diagram illustrating a representative SEM drive system with a front-end PFC converter connecting the stator side of the circuit to an off-board power source in accordance with aspects of the present disclosure.

[0060] Figure 3 is a schematic single-line diagram illustrating a representative SEM drive system with a front-end PFC converter connecting the rotor side of the circuit to an off-board power source in accordance with aspects of the present disclosure.

[0061] Figure 4 is a schematic single line diagram illustrating a representative two-stage rotor PTC with a brush slip ring assembly according to aspects of the present disclosure.

[0062] Figure 5 is a schematic single line diagram illustrating a representative three-stage rotor PTC with a brush slip ring assembly according to aspects of the present disclosure.

[0063] Figure 6 is a schematic single-line diagram illustrating a representative single-phase two-stage PFC converter according to aspects of the present disclosure.

[0064] Figure 7 is a schematic single-line diagram illustrating a representative three-phase two-stage PFC converter according to aspects of the present disclosure.

[0065] The present disclosure is applicable to various modifications and alternative forms, and some representative embodiments of the present disclosure are shown in the drawings by way of example and will be described in detail herein. However, it should be understood that the novel aspects of the present disclosure are not limited to the specific forms illustrated in the drawings listed above. On the contrary, the present disclosure covers all modifications, equivalents, combinations, arrangements, groupings and alternatives that fall within the scope of the present disclosure, such as those covered by the appended claims. DETAILED DESCRIPTION

[0066] The present disclosure allows for embodiments in many different forms. Representative embodiments of the present disclosure are shown in the accompanying drawings and will be described in detail herein with the following understanding: These embodiments are provided as illustrations of the disclosed principles, rather than limitations on the broad aspects of the present disclosure. In this regard, elements and limitations that are described, for example, in the abstract, introduction, summary of the invention, illustrations, and detailed description of the embodiments, but not explicitly set forth in the claims, should not be incorporated into the claims individually or collectively by implication, inference, or otherwise. In addition, the recording of "first", "second", "third", etc. in the specification or claims is not itself used to establish serial or numerical limitations; unless otherwise specifically specified, these names may be used to facilitate reference to similar features in the specification and drawings, and to distinguish between similar elements in the claims.

[0067] For purposes of this Detailed Description, unless specifically stated otherwise: the singular includes the plural, and vice versa; the words "and" and "or" shall be both conjunctions and disjunctions; the words "any" and "all" shall both mean "any and all"; and the words "include," "contain," "includes," "including," "having," and the like shall each mean "including, but not limited to." In addition, approximate words such as "about," "almost," "substantially," "generally," "approximately," and the like may each be used herein to indicate, for example, "at, approximately, or nearly at," or "within 0-5% of," or "within acceptable manufacturing tolerances," or any logical combination thereof. Finally, directional adjectives and adverbs such as head, tail, inboard, outboard, starboard, port, vertical, horizontal, up, down, front, rear, left, right, and the like may be relative to the motor vehicle, such as the forward driving direction of the motor vehicle when the vehicle is operatively oriented on a level driving surface.

[0068] Referring now to the drawings, wherein like reference numerals refer to like features throughout the several views, Figure 1A representative motor vehicle is shown in the drawings, which is generally indicated at 10 and is depicted herein as a sedan-style electric drive motor vehicle for the purpose of discussion. The illustrated motor vehicle 10 - also referred to herein as simply a "motor vehicle" or "vehicle" - is merely an exemplary application in which various aspects of the present disclosure may be practiced. Similarly, incorporating the present concept into a FEV drivetrain powered by a single set of RESS should be understood as a non-limiting implementation of the disclosed features. As such, it will be understood that various aspects and features of the present disclosure may be applied to other drivetrains and RESS architectures, incorporated into any logically related type of motor vehicle, and equally used for both motor vehicle applications and non-motor vehicle applications. In addition, only selected components of the motor vehicle, SEM drive, and HV electrical system are shown and described herein in additional detail. However, the vehicle, SEM, and electrical system discussed below may include many additional and alternative features, as well as other available peripheral components, for implementing the various methods and functions of the present disclosure.

[0069] Figure 1 The representative vehicle 10 is initially equipped with a center stack telecommunications and information ("telematics") unit 14 that communicates with a remotely located cloud computing host service 24 (e.g., ) wireless communications. As a non-limiting example, Figure 1 Other in-vehicle hardware components 16 shown in the figure include an electronic video display device 18, a microphone 28, an audio speaker 30, and various user input controls 32 (e.g., buttons, knobs, switches, touch screens, etc.). These hardware components 16 serve as a human / machine interface (HMI) that enables a user to communicate with the telematics unit 14 and other components that reside both in the vehicle 10 and remote from the vehicle 10. For example, the microphone 28 provides a means for the occupant to enter verbal commands. In contrast, the speaker 30 provides auditory output to the vehicle occupants and can be a separate speaker dedicated for use with the telematics unit 14, or can be part of the audio system 22. The audio system 22 is operatively connected to the network connection interface 34 and the audio bus 20 to receive analog information and present it as sound via one or more speaker components.

[0070] Communicatively coupled to the telematics unit 14 is a network connection interface 34, suitable examples of which include twisted pair / fiber optic Ethernet switches, parallel / serial communication buses, local area network (LAN) interfaces, controller area network (CAN) interfaces, and the like. The network connection interface 34 enables the vehicle hardware 16 to send and receive signals with each other and with systems and subsystems both onboard and offboard of the vehicle body 12. This allows the vehicle 10 to perform various vehicle functions, such as modulating the powertrain output, activating the vehicle braking system, controlling the vehicle steering, regulating the charging and discharging of the vehicle battery, and other automated functions. For example, the telematics unit 14 can receive and transmit signals to / from a powertrain control module (PCM) 52, an onboard charging module (OBCM) 54, an electronic battery control module (EBCM) 56, a steering control module (SCM) 58, a brake system control module (BSCM) 60, and various other vehicle ECUs.

[0071] Continue to refer Figure 1 , the telematics unit 14 is an onboard computing device that provides hybrid services both individually and through its communication with other networked devices. The telematics unit 14 is typically comprised of one or more processors 40, each of which may be embodied as a discrete microprocessor, an application specific integrated circuit (ASIC), or a dedicated control module. The vehicle 10 may provide centralized vehicle control via a central processing unit (CPU) 36, which is operatively coupled to an IC real time clock (RTC) 42 and one or more electronic memory devices 38, each of which may take the form of a CD-ROM, solid state drive (SSD) memory, hard disk drive (HDD) memory, semiconductor memory, or the like.

[0072] Long range communications (LRC) capabilities with off-board devices may be provided via cellular communications components, navigation and location components (e.g., a global positioning system (GPS) transceiver), or a wireless modem (all of which are collectively indicated at 44). Short range communications (SRC) may be provided via short range wireless communications devices 46 (e.g., The communication devices described above may provide data exchange as part of a periodic broadcast in a vehicle-to-vehicle (V2V) communication system or a vehicle-to-everything (V2X) communication system.

[0073] The CPU 36 receives sensor data from one or more sensing devices that use, for example, light detection, radar, laser, ultrasound, optics, infrared, or other suitable technologies (including short-range communication technologies (e.g., DSRC) or ultra-wideband (UWB) radio technologies), for example, to perform automated vehicle operations or vehicle navigation services. According to the illustrated example, the motor vehicle 10 can be equipped with one or more digital cameras 62, one or more distance sensors 64, one or more vehicle speed sensors 66, one or more vehicle dynamic sensors 68, and any necessary filtering, classification, fusion and analysis hardware and software for processing the raw sensor data. The type, placement, number and interoperability of the distributed array of sensors on the vehicle can be adapted individually or collectively to a given vehicle platform to achieve a desired level of autonomous vehicle operation.

[0074] To propel the motor vehicle 10, the electrified powertrain is operable to generate tractive torque and deliver it to one or more of the vehicle's drive wheels 26. Figure 1 , represented by an electric traction motor 78 connected to a rechargeable energy storage system (RESS) which may be in the nature of a traction battery pack 70 mounted on the chassis. The battery pack 70 may include one or more battery modules 72, each housing a group of electrochemical battery cells 74, such as lithium-ion or lithium-polymer battery cells of the pouch, can, or prismatic type. One or more electric machines, such as adjustable speed multi-phase SEM motor / generator (M) units 78, draw power from one or more rechargeable battery cells, such as the traction battery pack 70, and optionally deliver power to one or more rechargeable battery cells, such as the traction battery pack 70. The HV electrical system having a power inverter 80 electrically connects the battery pack 70 to the (one or more) motor / generator units 78 and modulates the current transfer between them. The battery pack 70 may be configured such that module management, cell sensing, and module-to-host communication functionality is integrated directly into each module 72 and performed wirelessly via a wireless-enabled cell monitoring unit (CMU) 76 .

[0075] Discussed below is a separately excited electric motor (SEM) drive system and method that uses a stator-side power inverter for SEM stator control and a rotor-side excitation circuit for SEM rotor control. A multi-level front-end power factor correction (PFC) converter selectively connects the SEM drive circuit to the grid, thereby providing galvanically isolated HV battery charging at reduced cost and increased efficiency. The power inverter and the rotor excitation circuit can each adopt various multi-level (2+, 3+, ... N+) form factors, for example, for scalability across different voltages (e.g., above and below 1 kilovolt (kV)). In addition, the PTC can adopt a conductive power transmission configuration (e.g., a brush-based design) or a non-conductive power transmission configuration (e.g., an inductive, capacitive, and asymmetric design). The TIM can also adopt different form factors, including a three-phase two-stage inverter, a three-level neutral point clamped (NPC) inverter, a three-level T-type inverter, a three-level flying capacitor inverter, and the like. Use of this system architecture may help minimize the mass, cost, and packaging space requirements of an onboard charging module to support AC-fed fast charging of the battery from the grid while also enabling bidirectional power flow to and from the grid.

[0076] Various aspects of the disclosed concept are directed to an intelligent integrated AC charging system that uses an active front-end PFC in combination with a separately excited motor drive. Current isolation can be achieved through the rotor and stator cores of the motor, where power is transferred through magnetic coupling of the rotor-carrying and stator-carrying electromagnetic coils of the SEM. A dedicated control scheme can be incorporated into the inverter controller for a DC-DC operating mode that delivers charging power to the battery with minimal losses. During battery charging operations, a mechanical disconnect can be used to isolate the motor shaft of the SEM, for example, to achieve optimal speed control of the SEM, and thereby maximize power transfer and efficiency. Multi-stage interleaved or non-interleaved front-end PFC stages (e.g., rated at least 20kW) can be used to provide a suitable intermediate HV DC feed to the segmented winding motor and the dual inverter-based DC-DC converter.

[0077] In some non-limiting examples, the multi-level power inverter can be configured as any one or more of a diode clamp, active clamp, T-type, flying capacitor, or cascaded H-bridge power inverter topology. The switches of any of the TIM, PFC, and PTC configurations described herein can be embodied as electromechanical contactors, or in optional embodiments, as solid-state switches, such as IGBTs, MOSFETs, or other switchable semiconductor-based components. As non-limiting examples, the inverter, power factor, and rotor excitation stage can use any one or combination of Si IGBTs + anti-parallel diodes, SiC MOSFETs, SiC Schottky diodes, GaN FETs, Ga2O3 switches / diodes, diamond-based power devices, etc. Isolated DC-DC power conversion can be achieved using three-phase dual active bridge operation combined with multi-stage / multi-level conversion circuits to interface with appropriate RESS voltages (e.g., 150V to 1kV and above).

[0078] Next go to Figure 2 and Figure 3 , wherein like reference numerals are used throughout the views to indicate the same or similar components, shows two non-limiting examples of SEM drive systems, indicated at 200 and 300, respectively, which are suitable for electrically connecting and disconnecting a high voltage power source (such as an AC utility grid 201) with a battery unit (such as a rechargeable battery assembly 202). Although different in appearance, it is contemplated that the above reference Figure 1 Any of the features and options described for the FEV drivetrain (e.g., electric traction motor 78) and vehicle RESS (e.g., traction battery pack 70) may be incorporated into the Figure 2 and Figure 3 For example, both SEM drive systems 200 and 300 may be generally represented by a rechargeable battery cell / assembly 202, a power factor correction (PFC) device 204, a traction inverter module (TIM) device 206, a power transfer circuit (PTC) device 208, and a separately excited electric motor (SEM) unit 210.

[0079] The rechargeable battery assembly 202 may employ any of the battery options described herein, including one or more battery packs or one or more battery modules, each of which contains one or more rechargeable battery cells 212 (e.g., prismatic, pouch, or cylindrical lithium-ion battery cells). In addition, each battery assembly may include a set of solid-state relay contactors / switches (not shown) that independently respond to signals from an appropriate controller / control module to manage the electrical output of the battery system. Although for simplicity of illustration, the Figure 2 and Figure 3Only one battery assembly 202 and one motor 210 are shown, but the SEM drive system 200, 300 may include any number of battery units, motor units, and associated electrical hardware without departing from the intended scope of the present disclosure.

[0080] A DC to AC and AC to DC power inverter 206, which may be part of a traction inverter module (TIM), is connected to the SEM unit 210 via multi-phase windings 214A, 214B, and 214C to transfer electrical energy between the SEM unit 210 and the battery assembly 202. Figure 2 In the embodiment of the present invention, the TIM device 206 (also referred to herein as an "inverter stage" or an "inverter sub-circuit") is directly electrically connected to the PFC device 204 and the SEM unit 210 and is inserted between the PFC device 204 and the SEM unit 210. In contrast, Figure 3 The TIM device 206 is directly electrically connected to the battery cell 202 and the SEM unit 210 and is inserted between the battery cell 202 and the SEM unit 210. In both examples shown, the TIM device 206 lacks a direct electrical connection to the rotor assembly 218 of the SEM unit 210. The DC battery output voltage is delivered from the battery 202 to the TIM 206 and the PTC 208 across the positive and negative voltage bus rails 220A and 220B, respectively, with an optional fixed DC bus capacitor 222 ( Figure 2 ) is placed across rails 220A and 220B.

[0081] A representative power inverter topology may incorporate multiple inverters and corresponding motor control modules operable to receive motor control commands and thereby control inverter states for providing motor drive or regeneration functionality. Figure 2 and Figure 3 The TIM device 206 may include one or more pairs of series-connected electromechanical or semiconductor switches (also referred to herein as "TIM switches") that cooperatively convert direct current (DC) power from one or more energy storage devices (e.g., battery assembly 202) into alternating current (AC) voltage for powering one or more motors (e.g., SEM unit 210) via high-frequency switching. According to the example shown, the TIM device 206 includes six semiconductor switches S I1 , S I2 , S I3 , S I4 , S I5 and S I6 , which are arranged into three pairs of solid-state TIM switches 224A, 224B and 224C connected in series. The three switch pairs 224A, 224B and 224C can be electrically connected in parallel with each other. Each switch S I1 -S I6It can be embodied as a voltage-controlled bipolar switching device in the form of an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a wideband GaN device (WBG), or other suitable switch having a corresponding gate to which a gate signal is applied to change the on / off state of a given switch.

[0082] Each pair of solid-state TIM switches 224A, 224B, and 224C may be electrically connected in series to a respective one of the stator-carrying field windings 214A, 214B, 214C of the SEM stator assembly 216. Figure 2 and Figure 3 The TIM device 206 of the battery cell 202 uses a fast controller automated switch control technique, such as a pulse width modulation (PWM) signal, to invert the DC power supplied during the discharge of the battery cell 202 into AC power suitable for driving the SEM unit 210. A pre-charge circuit (not shown) can be used to charge the DC link capacitor 226 within the TIM device 206 at a controlled rate to equalize the voltage across each pair of switches 224A-224C before closing the contactors / switches within the battery cell 202.

[0083] Continue to refer Figure 2 and Figure 3 The multi-stage PFC device 204 is selectively electrically connected to the power source 201 and, once connected, is inserted between the power source 201 and the rest of the SEM drive system 200, 300 (i.e., the battery cell 202, the TIM 206, the PTC 208, and the SEM 210). The PFC device 204 (also referred to as a "PFC stage" or a "PFC converter") provides power factor correction by shaping the input current, for example, to meet the current harmonic limits of the system 200, 300. Figure 2 In the embodiment, the PFC device 204 is directly electrically connected to the power source 201 and the TIM device 204 and is inserted between the power source 201 and the TIM device 204. In contrast, Figure 3 The PFC device 204 is directly electrically connected to the power source 201 and the PTC device 208 and inserted between the power source 201 and the PTC device 208. In both examples shown, the PFC device 204 is located on the stator side circuit or the rotor side circuit of the SEM drive system 200, 300, whichever side is opposite to the battery unit 202.

[0084] The PFC subcircuit can adopt various topologies, including single-phase and multi-phase PFC configurations, multi-level (two-level, three-level...N-level) PFC configurations, active and hybrid switching PFC configurations, etc. Figure 6 and Figure 7Two non-limiting examples of PFC devices are shown, respectively - a single-phase two-stage PFC converter 204A and a three-phase two-stage PFC converter 204B - which may be incorporated into Figure 2 and Figure 3 The multi-phase PFC may be applicable to SEM drive systems 200, 300. Figure 2 where the PFC is located on the stator side of the SEM, in line with the multi-phase windings of the motor. In contrast, single-phase PFC may be suitable for applications such as Figure 3 The application shown in , where the PFC is located on the rotor side of the SEM, in line with the DC armature winding of the motor.

[0085] Figure 6 and Figure 7 The PFC devices 204A and 204B may include one or more pairs of series-connected electromechanical or semiconductor switches (also referred to herein as "PFC switches") that cooperatively increase the power factor of the current drawn by the SEM drive system 200, 300, for example to improve the distribution efficiency when recharging the battery cell 202. According to the example shown, Figure 6 The PFC device 204A includes four semiconductor switches S W1 , S W2 , S W3 and S W4 , which are arranged as two pairs of series-connected solid-state switches 228A and 228B. The two switch pairs 228A-228B can be electrically connected in parallel to each other via PFC transmission rails 232A and 232B. Figure 6 In the embodiment, the first switch pair 228A can be electrically connected to the positive induction coil terminal of the rotor-carrying armature winding 234, and the second switch pair 228B can be electrically connected to the negative induction coil terminal of the armature winding 234. In contrast, Figure 7 The PFC device 204B includes six semiconductor switches S W1 -S W6 , which are arranged into three pairs of series-connected solid-state switches 229A, 229B, and 229C. The three switch pairs 229A-229C can be electrically connected in parallel to each other via PFC transmission rails 232A, 232B. Figure 7 In the embodiment of the present invention, each switch pair 229A-229C can be electrically connected in series to a corresponding one of the stator-carrying excitation windings 214A, 214B, 214C.

[0086] The boost capacitor 230 can be arranged across the positive and negative transmission rails 232A and 232B of the PFC devices 204A, 204B, respectively, and thereby electrically connected in parallel with multiple pairs of series-connected switches. These transmission rails 232A, 232B also electrically connect the switch pairs 228A-228B and 229A-229C of the PFC devices 204A, 204B to the power source 201. For a three-level PFC configuration, including single-phase and multi-phase designs, each pair of series-connected switches can be expanded to include four switches (e.g., a total of eight switches in a single-phase PFC, or a total of twelve switches in a multi-phase PFC). In addition, a corresponding blocking capacitor (not shown) can be arranged across the circuit line connecting the four switches in each set of series-connected switches.

[0087] For both SEM drive systems 200, 300, a multi-stage PTC device 208 (also referred to as a "PTC stage" or "rotor excitation circuit") is electrically connected to the rotor side of the SEM unit 210 on its output side and to both the battery device 202 and the PFC device 204 on its input side. Figure 2 and Figure 3 The PTC device 208 can provide single-phase rotor excitation functionality to the rotor assembly 218 of the SEM, for example, to optimize motor control and system charging. Figure 2 In the embodiment, the PTC device 208 is directly electrically connected to the battery cell 202 and the SEM rotor assembly 218 and is inserted between the battery cell 202 and the SEM rotor assembly 218. In contrast, Figure 3 The PTC device 208 is directly electrically connected to and interposed between the PFC device 204 and the rotor assembly 218. In both examples shown, the PTC device 208 lacks a direct electrical connection to the stator assembly 216 of the SEM unit 210. While not limiting per se, the disclosed motor drive architecture can benefit from using an asymmetric bridge drive circuit to drive the rotor power transmission circuit.

[0088] The disclosed rotor excitation circuit can adopt a variety of different topologies, including 2+, 3+, ... N+ multi-level form factors and conductive, inductive and capacitive configurations. Figure 4 and Figure 5 Two non-limiting examples of PTC devices are illustrated, respectively - a two-stage conduction rotor excitation power transfer circuit (RPTC) 208A and a three-stage conduction RPTC 208B - which may be incorporated into Figure 2 and Figure 3 Each PTC device includes a plurality of sets of electromechanical or semiconductor switches (also referred to herein as "PTC switches") connected in series, which cooperatively manage the flow of power from the battery cell 202 to the SEM rotor assembly 218. According to the example shown, Figure 4 The rotor excitation PTC 208A contains four semiconductor switches S W1 -S W4 , which are arranged as two pairs of solid-state switches 236A and 236B connected in series. The two switch pairs 236A-236B can be electrically connected in parallel to each other via PTC transmission rails 238A and 238B. In comparison, Figure 5 The rotor excitation PTC 208B contains eight semiconductor switches S W1 -S W8 , which are arranged into two sets of solid-state switches 237A and 237B connected in series. The two switch sets 237A-237B can be electrically connected in parallel to each other via PTC transmission rails 238A, 238B. Figure 4 and Figure 5 In both, the input side of the RPTC 208A, 208B is electrically connected to the battery cell 202 , while the output side of the RPTC 208A, 208B is electrically connected to the SEM rotor assembly 218 .

[0089] For a conductive PTC configuration, a brush slip ring (BSR) assembly 240 may be inserted between and electrically connect the rotor excitation PTCs 208A, 208B of the SEM unit 210 and the rotor carrying armature windings 234. Figure 4 and Figure 5 In the example shown, the BSR assembly 240 includes two discrete electromechanical BSR connectors 242A and 242B, each of which may generally consist of one or more graphite / metal brushes contacting a rotating metal ring. The first BSR connector 242A is electrically connected to a first pair / group of series-connected PTC switches 236A, 237A, while the second BSR connector 242B is electrically connected to a second pair / group of series-connected PTC switches 236B. For the three-stage RPTC 208B, a first blocking capacitor 244A is electrically connected to the first PTC switch group 237A, and a second blocking capacitor 244B is electrically connected to the second PTC switch group 237B.

[0090] The separately excited motor unit 210 is inserted between the TIM 206 and the PTC 208 and is powered by the rechargeable battery assembly 202 to generate a motor output torque, such as a rotation Figure 112, and thereby propel the vehicle 10 or perform work in a non-motor vehicle SEM drive application. Unlike a multi-phase PM motor that relies on a rotor-carried permanent magnet, a synchronous wound-field SEM is typically represented by a rotor-carried armature winding that electromagnetically cooperates with a stator-carried field winding to convert electrical energy into mechanical energy. As shown, the SEM unit 210 includes a rotor assembly 218 that is coaxial with and rotatable relative to the stator assembly 216. For a radial flux motor configuration, the stator assembly 216 includes an annular stator core 246 that carries a plurality of electromagnetic stator "field" windings 214A-214C. In contrast, the rotor assembly 218 includes a cylindrical rotor core 248 that carries one or more electromagnetic rotor "armature" windings 234. In this example, the rotor core 248 is rotatably mounted within the hollow center of the stator core 246 so that the stator core assembly 216 surrounds the rotor assembly 218.

[0091] The field windings and armature windings 214A-214C and 234 are energized with power supplied by the battery assembly 202; once energized, the stator-carrying field windings 214A-214C are electromagnetically coupled with the rotor-carrying armature windings 234 and drive the rotor-carrying armature windings 234 (electromagnetic coupling at Figure 2 and Figure 3 216 and 218). The motor output member - which may be in the nature of a rigid rotor shaft (not shown) - may be fixedly attached to the rotor core 248 by splines, keys, bolts, or other means to rotate in unison therewith and output motor torque therefrom. Although not limiting in themselves, the stator core and rotor cores 246, 248 may be manufactured as laminated core constructions, each laminated core construction being comprised of a stack of iron or other iron-containing plates. Other components of the SEM unit 210, such as a protective motor housing, motor end covers, bearings, seals, electrical terminals, etc., are present but not shown. Although illustrated and described as a radial flux motor, the SEM unit 210 may employ axial flux architectures and transverse flux architectures within the scope of the present disclosure.

[0092] Various aspects of the present disclosure have been described in detail with reference to the illustrated embodiments; however, those skilled in the art will recognize that many modifications may be made thereto without departing from the scope of the present disclosure. The present disclosure is not limited to the precise configuration and composition disclosed herein; any and all modifications, changes and variations apparent from the foregoing description are within the scope of the present disclosure as defined by the appended claims. Furthermore, the present concept expressly includes any and all combinations and sub-combinations of the foregoing elements and features.

Claims

1. A motor drive system connectable to an electric power source, the motor drive system comprising: A battery cell comprising a rechargeable battery cell; a multi-stage power factor correction (PFC) device configured to be electrically connected to the power source and inserted between the battery unit and the power source; a traction inverter module (TIM) device electrically connected to the battery unit and the PFC device, the TIM device including a plurality of pairs of TIM switches; a multi-stage power transmission circuit (PTC) device electrically connected to the battery unit and the PFC device, the PTC device including a plurality of PTC switches; and A separately excited electric motor (SEM) unit having a rotor assembly and a stator assembly, the rotor assembly including a rotor core carrying a rotor winding, and the stator assembly including a stator core carrying a plurality of stator windings electromagnetically paired with the rotor winding, wherein each stator winding is electrically connected to a corresponding pair of TIM switches, and the rotor winding is electrically connected to the PTC switch. 2 . The motor drive system of claim 1 , wherein the TIM device is electrically inserted between a stator assembly of the SEM unit and the battery unit or the PFC device. 3 . The motor drive system of claim 1 , wherein the PTC device is electrically inserted between a rotor assembly of the SEM unit and the battery unit or the PFC device.

4. The motor drive system of claim 1 wherein the PTC switches include a first series of PTC switches electrically connected in parallel with a second series of PTC switches.

5. The motor drive system of claim 4, further comprising a brush slip ring (BSR) assembly inserted between the PTC device and the rotor winding of the SEM unit and electrically connecting the PTC device and the rotor winding of the SEM unit, the BSR assembly comprising a first BSR electrically connected to the first series of PTC switches and a second BSR electrically connected to the second series of PTC switches.

6. The motor drive system of claim 5, wherein the PTC device further comprises a first capacitor electrically connected to the first series of PTC switches and a second capacitor electrically connected to the second series of PTC switches.

7. The motor drive system of claim 6, wherein the first series of PTC switches and the second series of PTC switches each include at least two PTC switches electrically connected in series with each other.

8. The motor drive system of claim 1, wherein the PFC device comprises a first series of PFC switches electrically connected in parallel with a second series of PFC switches.

9. The motor drive system of claim 8, wherein the PFC device further comprises a capacitor electrically connected in parallel with the first series of PFC switches and the second series of PFC switches.

10. The motor drive system of claim 9, wherein the first series of PFC switches and the second series of PFC switches each include at least two PFC switches electrically connected in series with each other.

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