Electric drive system with static pulsed power transfer

Abstract

An electric drive system includes an electric machine having a stator assembly and a rotor assembly. The stator assembly has a plurality of multi-phase stator windings including a first stator winding and a second stator winding. The first inverter is adapted to feed power to the first stator winding. The second inverter is adapted to feed power to the second stator winding. The rotor assembly includes a rotor winding having a single phase. The controller is configured to selectively command excitation of the rotor windings with a pulsed field current such that a direct-axis (d-axis) stator flux linkage is generated. A d-axis stator voltage is induced in the first stator winding and the second stator winding through the d-axis stator flux linkage. Pulse power transfer is achieved by interaction of the d-axis stator voltage and the respective d-axis winding current of the first and second stator windings.

Description

Technical Field

[0001] The present disclosure generally relates to an electric drive system having an electric machine, and more particularly to an electric drive system having static pulsed power transmission between two stator windings. Background Art

[0002] An electric motor typically consists of a stator with multiple stator windings and a rotor that rotates within the stator. In generator mode, the rotation of the rotor induces a voltage in the stator windings, which powers an external load. Alternatively, if current is passed through the stator windings, the energized windings cause the rotor to rotate, and the motor will operate as a motor. In a synchronous motor, the stator and rotor magnetic fields are locked together and rotate at the same speed. The power transmission topology of the motor typically uses DC excitation on the rotor, which can be achieved, for example, using permanent magnets or single-phase field windings. Maintaining synchronization between the rotor and stator fields requires that the rotor rotate during power transmission. In addition, a mechanical clutch is required to decouple the motor from the shaft during power transmission. Summary of the Invention

[0003] Disclosed herein is an electric drive system having an electric motor with a stator assembly and a rotor assembly. The stator assembly has a plurality of multi-phase stator windings, including a first stator winding and a second stator winding. A first inverter is adapted to feed power to the first stator winding. A second inverter is adapted to feed power to the second stator winding. The rotor assembly includes a rotor winding having a single phase. A controller is in communication with the electric motor and includes a processor and tangible, non-transitory memory having instructions recorded thereon. The controller is configured to selectively command excitation of the rotor winding with a pulsed field current to generate a direct-axis (d-axis) stator flux. The d-axis stator flux induces a d-axis stator voltage in the first stator winding and the second stator winding. Pulsed power transmission is achieved through the interaction of the d-axis stator voltage with corresponding d-axis winding currents in the first stator winding and the second stator winding.

[0004] The controller can be adapted to selectively command excitation of the first and second stator windings with an alternating d-axis current having the same frequency as the pulsed field current to generate corresponding d-axis winding currents. The d-axis stator flux is in phase with the pulsed field current, and the d-axis stator voltage is 90 degrees ahead of the d-axis stator flux. When positive power is commanded, the corresponding d-axis winding current has a phase angle of zero degrees with the d-axis stator voltage, and when negative power is requested, the phase angle is 180 degrees.

[0005] The controller may be adapted to regulate the position of the rotor assembly via a closed-loop strategy, including regulating the position of the rotor assembly via the controller by applying a reluctance torque and / or an electromagnetic torque to the rotor assembly. The reluctance torque is induced by generating an error angle in a virtual reference frame of the rotor assembly, and the electromagnetic torque is induced by injecting a q-axis current component.

[0006] In some embodiments, a vehicle battery is selectively electrically coupled to the first stator winding, the battery providing power to the first stator winding during a propulsion mode of the vehicle. An external energy source is selectively electrically coupled to the second stator winding, the external energy source comprising at least one of a vehicle-to-load connection, a vehicle-to-property connection, and a vehicle-to-grid connection. During a charging mode of the vehicle, the second stator winding is adapted to consume energy from the external energy source, pulsed power transfer occurs from the second stator winding to the first stator winding, and the first stator winding is adapted to provide power to the vehicle battery.

[0007] In some embodiments, a power supply can be selectively coupled to the motor, the power supply being adapted to transmit a direct current (DC) signal. The power converter is adapted to receive a DC signal. A high-frequency rotary transformer is electrically coupled to the power converter, the high-frequency rotary transformer having a stationary portion and a rotating portion, such that an alternating current (AC) in the stationary portion induces an AC voltage in the rotating portion. The rectifier is adapted to receive an AC voltage from the rotating portion of the high-frequency rotary transformer, the rectifier being adapted to convert the AC voltage into a DC voltage. The DC bus is adapted to store the DC voltage from the rectifier. The electric drive system may include an inverter adapted to receive a DC voltage from the DC bus, the DC voltage being converted into an AC current in the inverter. The rotor winding includes a phase coil adapted to receive an AC current from the inverter to generate a rotor field.

[0008] In some embodiments, a power source is selectively coupled to the electric motor, the power source being adapted to transmit a DC signal. A DC-AC inverter is adapted to receive the DC signal for conversion to AC current. The electric drive system may include a slip ring arrangement adapted to receive AC current from the DC-AC inverter, the electric motor having a stationary side and a rotating side. The slip ring arrangement is positioned such that AC current flows from the stationary side to the rotating side, and a single-phase rotor winding is adapted to receive the AC current to generate a rotor field. Operation of the vehicle is controlled based in part on the power generated.

[0009] Disclosed herein is a method for pulsed power transmission in an electric drive system in a vehicle, the electric drive system comprising a controller having a processor and tangible, non-transitory memory, and an electric machine having a stator assembly and a rotor assembly. The method includes incorporating a plurality of multi-phase stator windings, including a first stator winding and a second stator winding, into the stator assembly, and a rotor assembly including a rotor winding having a single phase. The method includes adapting a first inverter to feed the first stator winding and adapting a second inverter to feed the second stator winding. The method includes selectively exciting the rotor windings with pulsed field currents via controller commands, such that a direct-axis (d-axis) stator flux is generated, and a d-axis stator voltage is induced in the first and second stator windings by the d-axis stator flux. Pulsed power transmission is achieved through the interaction of the d-axis stator voltage with corresponding d-axis winding currents in the first and second stator windings.

[0010] A vehicle having an electric motor is disclosed herein. The electric motor includes a stator assembly having a plurality of multi-phase stator windings, including a first stator winding and a second stator winding, and a rotor assembly including a rotor winding having a single phase. A controller is in communication with the electric motor and includes a processor and tangible, non-transitory memory having instructions recorded thereon. The controller is configured to selectively command excitation of the rotor winding with a pulsed field current to generate a direct-axis (d-axis) stator flux. The d-axis stator flux induces a d-axis stator voltage in the first stator winding and the second stator winding. Pulsed power transmission is achieved through the interaction of the d-axis stator voltage with corresponding d-axis winding currents in the first stator winding and the second stator winding.

[0011] The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description of the best modes for carrying out the disclosure when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic partial block diagram of an electric drive system having a motor and a controller;

[0013] Figure 2 It passes through Figure 1 A schematic partial cross-sectional view of a motor;

[0014] Figure 3 Can be Figure 1 A schematic flow chart of a method performed by a controller;

[0015] Figure 4 According to the first embodiment Figure 1 A schematic partial diagram of an electric drive system;

[0016] Figure 5 According to the second embodiment Figure 1 A schematic partial diagram of an electric drive system;

[0017] Figure 6 is a schematic diagram showing various motor parameters varying with time;

[0018] Figure 7 is a schematic graph showing active power generated by an electric machine over time; and

[0019] Figure 8 yes Figure 1 Simplified illustration of the rotor assembly within an electric drive system.

[0020] Representative embodiments of the present disclosure are shown in the accompanying drawings by way of non-limiting example and are described in further detail below. However, it should be understood that the novel aspects of the present invention are not limited to the specific forms illustrated in the drawings listed above. On the contrary, the present disclosure is intended to cover modifications, equivalents, combinations, sub-combinations, permutations, groupings, and alternatives that fall within the scope of the present disclosure, such as those encompassed by the appended claims. DETAILED DESCRIPTION

[0021] Referring to the drawings, wherein like reference numerals refer to like parts, Figure 1 1 is a schematic partial view of an electric drive system 10, which may be part of a vehicle 12. Vehicle 12 may be a mobile platform such as, but not limited to, a passenger car, a sport utility vehicle, a light truck, a heavy vehicle, an ATV, a minivan, a bus, a transportation vehicle, a bicycle, a robot, an agricultural implement, sports-related equipment, a boat, an airplane, a train, or other device. Vehicle 12 may be partially or fully electric. Vehicle 12 may take many different forms and include multiple and / or alternative components and features.

[0022] The electric drive system 10 includes a motor / generator (referred to herein as an electric machine 14 ) configured to generate torque and a plurality of power converters 15 . Figure 1 , electric machine 14 includes a stator assembly 16 positioned at least partially around a rotor assembly 18 having a rotor shaft 20. Electric machine 14 is a wound rotor electric machine.

[0023] Figure 2 is a schematic partial cross-sectional view through the motor 14. Figure 2 , the stator assembly 16 and the rotor assembly 18 are separated by an air gap G. Figure 2 The stator assembly 16 has corresponding conductors 22 that extend through stator slots 24 and are arranged into grouped windings. The stator assembly 16 has two multi-phase stator windings, including a first stator winding 26 and a second stator winding 28, as shown in FIG. Figure 1-2 In other words, the stator assembly 16 has two grouped windings, each grouped winding having at least three phases. Figure 2 The electric machine 14 has a rotor assembly 18, which may be a salient pole rotor assembly 18. The rotor assembly 18 includes rotor poles 30 having wire wound thereon to form a single-phase rotor winding 34.

[0024] Motor-based power transmission strategies using synchronous motors typically require rotor rotation to synchronize the rotor magnetic field with the stator magnetic field. A mechanical clutch is required to decouple the motor from the vehicle's shaft during power transfer. As described below, the electric drive system 10 enables bidirectional pulsed power transmission techniques without the need for rotor rotation. The motor 14 can use current flow in the single-phase rotor winding 34 for rotor flux control. Additionally, the electric drive system 10 eliminates the need for a mechanical clutch.

[0025] refer to Figure 1 The electric drive system 10 includes a controller C having a processor P and a tangible non-transitory memory M (or a computer-readable storage medium) on which are recorded instructions for a method 50 for controlling the operation of the electric drive system 10 based on a torque demand. The method 50 is Figure 3 shown in and referenced below Figure 3 Description. Two embodiments of the electric drive system 10 are Figure 4-5 As shown in and below about Figure 4-5 describe.

[0026] The motor 14 operates as a transformer such that alternating current ("AC") in the rotor winding 34 excites an AC voltage in the first stator winding 26 and the second stator winding 28. With appropriate current control in the first stator winding 26 and the second stator winding 28, bidirectional power flow occurs between the two stator windings, thereby enabling static pulsed power transfer applications. Static power transfer herein refers to power transfer that does not require rotation of the rotor assembly 18. In other words, the motor 14 operates as a static transformer, with the stator windings 26, 28 and the rotor winding 34 being considered the primary and secondary windings in the transformer, respectively. The current, voltage, resistance, and inductance on the rotor side can be calculated using the turns ratio (N s / N f ) refers to the stator side.

[0027] refer to Figure 1-2 , the two sets of segmented multi-phase windings in the stator assembly 16 are fed by separate inverters for independent current control. Figure 1 , the first stator winding 26 and the second stator winding 28 are fed by a first inverter 40 and a second inverter 42, respectively. The first stator winding 26 and the second stator winding 28 are galvanically isolated. During power transfer, the first stator winding 26 and the second stator winding 28 can be electrically coupled to a power converter at an onboard energy storage system (e.g., a vehicle battery 44) and a power converter at an external energy source 46 (or grid 46), respectively. The external energy source 46 can be a vehicle-to-load connection (V2L), a vehicle-to-house (V2H) connection, or a vehicle-to-grid (V2G) connection.

[0028] refer to Figure 1 , the vehicle battery 44 provides power to the first stator winding 26 during the propulsion mode of the vehicle 12. During the charging mode, the first stator winding 26 (on the battery side) provides power to the battery 44. During the charging mode, the second stator winding 28 (on the grid side) consumes power from the grid 46; power is drawn from the grid-side stator winding ( Figure 1 The second stator winding 28 in the battery side is transferred to the stator winding ( Figure 1 The first stator winding 26 in FIG. Figure 1 , the torque generated by the electric drive system 10 is then transferred to the wheels 48 of the vehicle 12 .

[0029] Now refer to Figure 3 , which shows that Figure 1 Flowchart of method 50 executed by controller C. Method 50 does not need to be applied in the specific order described herein, and some blocks may be omitted. Memory M may store controller-executable instruction sets, and processor P may execute the controller-executable instruction sets stored in memory M.

[0030] according to Figure 3 At block 52, method 50 includes applying an alternating current i _field (e.g., sinusoidal, sawtooth) to excite the rotor winding 34. Figure 6 Shown in FIG. 3 is a pulsed field current 310 . Figure 6 3 is a schematic diagram of various motor parameters 300, wherein the horizontal axis 302 depicts time and the vertical axis 304 depicts amplitude. As will be understood by those skilled in the art, in geometric terms, the direct axis (d-axis) and the quadrature axis (q-axis) are single-phase representations of the flux contributions of separate sinusoidal phase quantities occurring at the same angular velocity. The d-axis is specifically aligned / in phase with the magnetic field (north pole) of the rotor assembly 18. When controlling the flux and torque settings of the motor 14, the d-axis and q-axis commands in the motor control can be used as adjustable set points (or control handles) accessible to the controller C. For the purpose of generating flux, the d-axis voltage command can be used to manipulate the d-axis current.

[0031] according to Figure 3 In block 54 of FIG. 5 , the single-phase rotor winding 34 acts as an “exciter”, thereby generating alternating d-axis stator flux linkages 312 in the first stator winding 26 and the second stator winding 28. d-axis stator flux 312 (see Figure 6 ) is in phase with the pulsed field current 310. Due to the d-axis stator flux 312, an alternating d-axis stator voltage 314 (v_d) is induced in the first stator winding 26 and the second stator winding 28. The d-axis stator voltage 314 leads the d-axis stator flux 312 by 90 degrees because the induced voltage is the derivative of the flux.

[0032] according to Figure 3 At block 56, the controller C is configured to selectively command the first stator winding 26 and the second stator winding 28 to be excited with an alternating d-axis current (e.g., sinusoidal, sawtooth, etc.) having the same frequency as the pulsed field current 310 to generate respective d-axis winding currents 316, 318 in the first stator winding 26 and the second stator winding 28. The respective d-axis winding currents 316, 318 interact with the d-axis stator voltage 314 to produce power. In other words, power is generated by the motor 14 via the induced d-axis stator voltage 314 (see Figure 6 ) is generated by the interaction of the d-axis stator voltage 314 and the corresponding d-axis winding currents 316, 318 in the first stator winding 26 and the second stator winding 28. If the d-axis stator voltage 314 and the corresponding d-axis winding currents 316, 318 are in phase, active power and unity power factor can be achieved. The generated active power can be expressed as:

[0033]

[0034] Depending on the direction of power flow, the corresponding d-axis winding current can be in phase with the d-axis stator voltage 314 (zero degree phase angle) when positive power is required, or out of phase with the d-axis stator voltage 314 (180 degree phase angle) when negative power is required.

[0035] The first stator winding 26 and the second stator winding 28 consume and deliver power, i.e., bidirectional power. The corresponding d-axis winding currents 316, 318 can define the same amplitude but opposite polarity, so that the corresponding flux linkages due to the stator winding currents cancel, and the d-axis stator flux linkage 312 simply depends on the pulsed field current 310. The reactive power (wasted) generated is approximately zero.

[0036] The electric drive system 10 can employ different current waveforms (harmonic injection) in both the first and second stator windings 26, 28, and the rotor winding 34 to increase the robustness of current control, minimize vibration, and improve power transfer. The number of turns of the rotor winding 34 is selected so that it is compatible with the DC voltage, the desired power level, the fundamental frequency during power transfer, and meets the field winding magnetomotive force requirements and the field winding rated current during the propulsion mode of the vehicle 12.

[0037] The electric drive system 10 may be controlled so that the torque fluctuation during static power transmission is below a predetermined threshold to improve the performance of other components (eg Figure 1 In one example, the predefined threshold value may be set between approximately 1 nm (Newton meter) and 2 nm (Newton meter). Additionally, the rotor assembly 18 may be moved to an intermediate portion of the gear play with appropriate inverter control prior to power transmission (e.g., 15 degrees) to achieve clearance for possible vibrations of the rotor assembly 18.

[0038] according to Figure 3 At block 58 , the method 50 includes controlling vehicle operation via the active power generated in the electric drive system 10 . The torque demand of the vehicle 12 is modulated by the electric drive system 10 . Figure 7 is a schematic graph where the horizontal axis 352 depicts time and the vertical axis 354 depicts power (kW). Trace 350 shows the active power produced by the motor 14. Figure 7 , trace 360 ​​shows positive power 360 (power consumed from external energy source 46 ). Trace 362 shows negative power 362 generated (power delivered to vehicle battery 44 ).

[0039] according to Figure 3 At block 60, the controller C may be adapted to regulate the rotor position via a closed loop strategy to ensure that no main rotor moves during the static pulse power transmission. Figure 8 , a simplified schematic diagram of a rotor assembly 418 as an electromagnet is shown. The electromagnet 418 defines a south pole (S) and a north pole (N). Although the magnetic torque component will average to zero when the alternating stator flux is injected according to the above-described method 50, the alternating stator flux may have a non-zero component of reluctance torque.

[0040] The controller C can employ this reluctance torque in a controlled manner to maintain the desired angular position of the rotor assembly 418. The amplitude of the d-axis current command used as part of the method 50 can also be slowly increased to allow the closed-loop position control of the rotor assembly 418 to react while producing less torque. As will be appreciated by those skilled in the art, this closed-loop strategy can be implemented in a rotating or stationary reference frame using the αβ or ABC voltage signals. Due to slot harmonics, some rotor positions may be less affected by torque ripples than other rotor positions during the injection of alternating stator flux. For example, Figure 1 The rotor assembly 18 can be selectively positioned to a predetermined optimal angular position when the vehicle 12 is shut off. The following equation for determining torque (T) can be used to control the position of the rotor assembly 418 using reluctance torque: Here, P is the number of poles of the motor 14, 、 as well as are the field current, q-axis current, and d-axis current. as well as are the field inductance, q-axis inductance, and d-axis inductance of the motor 14 .

[0041] Here, the weight decreases to zero because when the field current 310 is injected, the q-axis current (i qHowever, in some embodiments, the controller C can command the injection of a component on the q axis to The q-axis and d-axis currents can be expressed as follows: ;as well as .

[0042] In the above equation, the error angle 430 is the angular difference between the real dq-axis reference frame aligned with the north pole N of the rotor assembly 418 and the virtual reference frame.

[0043] refer to Figure 8 , axis 410 and axis 420 ) are the corresponding d-axis and q-axis current components on the real reference frame. Axis 412 ( and axis 422( ) are the corresponding d-axis and q-axis current components in the virtual reference frame of controller C. These expressions, when multiplied together (assuming Expressed as: ; Similarly, P is the number of poles of the motor 14, as well as are the d-axis inductance and q-axis inductance of the motor 14 .

[0044] Therefore, reference Figure 8 , by creating a small error angle 430 in the virtual reference system , a small average amount of reluctance torque can be induced. This induced reluctance torque is then applied to the rotor assembly 18 to maintain the desired angular position of the rotor assembly 18. A control loop can be added around the torque generation method discussed above. Here, the controlled variable is the rotor position, and the control knob is the q-axis current or angle error. Various types of regulators available to those skilled in the art can be used, such as a proportional-integral (PI) control module, a proportional-integral-derivative (PID) control module, or a lead-lag compensator.

[0045] Now refer to Figure 4 , shows an electric drive system 110 according to a first embodiment. The electric drive system 110 includes an electric machine 114 having a stator assembly 116 and a rotor assembly 118 having a rotor shaft 120. The electric drive system 110 has a rotating side 122 and a stationary side 124 separated by an air gap G.

[0046] refer to Figure 4, a power source 126 (e.g., a high voltage battery) is selectively coupled to the electric drive system 110 and is adapted to transmit a direct current (DC) signal to a power converter, such as a DC-AC inverter 130. The DC to AC inverter 130 converts the DC signal into an AC signal for transmission to a stationary portion 132 of a rotary transformer T. The rotary transformer T is adapted to couple electrical signals between two portions that rotate relative to each other and may be a high frequency rotary transformer. In one embodiment, the high frequency rotary transformer has an operating frequency in excess of approximately 10 kilohertz. The AC excitation in the stationary portion 132 induces a voltage in a rotating portion 134 of the rotary transformer T, which is connected to a rectifier 136. The rectifier 136 converts the AC voltage and establishes a DC voltage in a DC bus 138.

[0047] refer to Figure 4 The DC voltage from the DC bus 138 is converted into AC current by the inverter 140 and supplied to the phase coil 142 in the rotor assembly 118, thereby generating a rotor field. The rotor magnetic field interacts with the stator magnetic field in the first stator winding 148 and the second stator winding 150. Figure 4 The first and second stator windings 148 and 150 are fed by first and second inverters 152 and 154, which are powered by an energy source 156. The interaction of the rotor magnetic field with the stator magnetic field results in the generation of torque, which is subsequently transferred to the wheels 48 of the vehicle 12. Figure 4 The example shown in includes a single wireless power transfer across an air gap G.

[0048] Now refer to Figure 5 , shows an electric drive system 210 according to a second embodiment. The electric drive system 210 includes an electric machine 214 having a stator assembly 216 and a rotor assembly 218 having a rotor shaft 220. The electric drive system 210 has a rotating side 222 and a stationary side 224 separated by an air gap G.

[0049] refer to Figure 5 , a power source 226 (e.g., a high voltage battery) is selectively coupled to the electric drive system 210 and is adapted to transmit a DC signal to an inverter 230, which converts the DC signal into an AC signal. The AC signal flows from the stationary side 224 to the rotating side 222 via mechanical contact power transmission in the form of a slip ring arrangement 232, which supplies the AC signal to a phase coil 234 in the rotor assembly 218. The slip ring arrangement 232 is used to transmit power or electrical signals between a stationary component and a rotating component, and may also be referred to as a rotating electrical joint, an electric rotary joint, and a slip ring. The slip ring arrangement 232 may include one or more rotating rings and stationary brushes. The configuration of the slip ring arrangement 232 may vary based on the application.

[0050] AC excitation in the phase coil 234 results in a rotor magnetic field that interacts with the stator magnetic field in the first stator winding 248 and the second stator winding 250. Figure 5 The first stator winding 248 and the second stator winding 250 are fed by a first inverter 252 and a second inverter 254, which are powered by an energy source 256. The interaction of the rotor magnetic field with the stator magnetic field results in the generation of torque, which is subsequently transferred to the wheels 48 of the vehicle 12.

[0051] In summary, the electric drive system 10 enables bidirectional pulsed power transfer to and from the vehicle 12. The electric machine 14 may be a wound-field synchronous motor having a single-phase rotor winding 34 and dual three-phase stator windings. The rotor winding 34 is excited with a single-phase pulsed field current 310, which induces an alternating d-axis stator flux 312 in the first and second stator windings 26, 28. The d-axis stator flux 312 is in phase with the excitation current 310. The d-axis stator flux 312 induces an alternating d-axis stator voltage 314 in the first and second stator windings 26, 28, which is 90 degrees ahead of the d-axis stator flux 312. During the power transfer mode, the rotor speed is maintained at approximately 0 rpm. The inductance of the single-phase rotor winding 34 can limit the maximum frequency during charging. A relatively low number of turns and low inductance of the rotor winding 34 can be used to achieve optimal power levels and efficiency.

[0052] Figure 1 The controller C includes a computer-readable medium (also called a processor-readable medium), including non-transitory (e.g., tangible) media that participates in providing data (e.g., instructions) that can be read by a computer (e.g., by a processor of a computer). Such media can take many forms, including but not limited to non-volatile media and volatile media. Non-volatile media can include, for example, optical or magnetic disks and other persistent memories. Volatile media can include, for example, dynamic random access memory (DRAM), which can constitute main memory. Such instructions can be transmitted by one or more transmission media, including coaxial cables, copper wires, and optical fibers, including wires that include a system bus connected to a processor of a computer. Some forms of computer-readable media include, for example, floppy disks, flexible disks, hard disks, magnetic tapes, other magnetic media, CD-ROMs, DVDs, other optical media, physical media, RAM, PROMs, EPROMs, FLASH-EEPROMs, other memory chips or cassettes, or other media from which a computer can read.

[0053] The lookup table, database, data repository or other data storage repository described herein can include various mechanisms for storing, accessing and retrieving various data, including a set of files in a hierarchical database, a file storage system, an application database in a proprietary format, a relational database management system (RDBMS), etc. Each such data storage can be included in a computing device that employs a computer operating system such as one of those mentioned above and can be accessed via a network in various ways. The file system can be accessed from the computer operating system and can include files stored in various formats. In addition to the language (such as the above-mentioned PL / SQL language) for creating, storing, editing and executing stored procedures, RDBMS can also adopt structured query language (SQL).

[0054] The numerical values ​​of the parameters (e.g., quantities or conditions) in this specification (including the appended claims) should be understood as being modified by the term "about" in each corresponding instance, regardless of whether "about" actually appears before the numerical value. "About" means that the numerical value allows some slight imprecision (close to the accuracy of the value to a certain extent; approximately or reasonably close to the value; close). If the imprecision provided by "about" is not otherwise understood in this art with this ordinary meaning, then "about" as used herein at least represents the variation that may be caused by the common methods of measuring and using these parameters. In addition, the disclosure of the range includes the disclosure of each value and the further divided range within the entire range. Each value within the range and the endpoints of the range are disclosed as separate embodiments herein.

[0055] The detailed description and the accompanying drawings or figures support and describe the present disclosure, but the scope of the present disclosure is limited only by the claims. Although some best modes and other embodiments for carrying out the claimed disclosure have been described in detail, there are various alternative designs and embodiments for practicing the disclosure defined in the appended claims. In addition, the embodiments shown in the drawings or the features of the various embodiments mentioned in this specification are not necessarily to be understood as embodiments that are independent of each other. On the contrary, it is possible that each feature described in one of the examples of the embodiment can be combined with one or more other desired features from other embodiments, resulting in other embodiments not being described in words or with reference to the drawings. Therefore, such other embodiments fall within the framework of the scope of the appended claims.

Claims

1. An electric drive system for a vehicle, comprising: An electric motor having a stator assembly and a rotor assembly, the stator assembly having a plurality of multi-phase stator windings including a first stator winding and a second stator winding, the rotor assembly including a rotor winding having a single phase; a first inverter adapted to feed power to the first stator winding; a second inverter adapted to feed power to the second stator winding; a controller in communication with the motor, the controller having a processor and tangible, non-transitory memory on which instructions for a pulsed power transfer method are statically recorded; wherein the controller is configured to selectively command excitation of the rotor winding with a pulsed field current so as to generate a direct-axis (d-axis) stator flux linkage, and induce a d-axis stator voltage in the first stator winding and the second stator winding via the d-axis stator flux linkage; and The pulse power transmission is achieved through interaction between the d-axis stator voltage and corresponding d-axis winding currents in the first stator winding and the second stator winding.

2. The electric drive system according to claim 1, wherein: The controller is adapted to selectively command excitation of the first and second stator windings with an alternating d-axis current having the same frequency as the pulsed field current to generate respective d-axis winding currents. 3 . The electric drive system of claim 1 , wherein the d-axis stator flux is in phase with the pulsed field current, and the d-axis stator voltage is 90 degrees ahead of the d-axis stator flux.

4. The electric drive system according to claim 1, wherein: The controller is adapted to adjust the position of the rotor assembly via a closed-loop strategy comprising applying a reluctance torque and / or an electromagnetic torque to the rotor assembly, wherein the reluctance torque is induced by creating an error angle in a virtual reference frame of the rotor assembly and the electromagnetic torque is induced by injecting a q-axis current component.

5. The electric drive system according to claim 1, wherein: When positive power is commanded, the corresponding d-axis winding current has a phase angle of zero degrees with the d-axis stator voltage, and when negative power is required, the phase angle is 180 degrees.

6. The electric drive system according to claim 1, further comprising: a vehicle battery selectively electrically coupled to the first stator winding, the battery providing power to the first stator winding during a propulsion mode of the vehicle; an external energy source selectively electrically coupled to the second stator winding, the external energy source comprising at least one of a vehicle-to-load connection, a vehicle-to-property connection, and a vehicle-to-grid connection; as well as wherein, during a charging mode of the vehicle, the second stator winding is adapted to consume energy from the external energy source, the pulsed power transfer occurs from the second stator winding to the first stator winding, and the first stator winding is adapted to provide power to the vehicle battery.

7. The electric drive system according to claim 1, further comprising: a power supply selectively couplable to the motor, the power supply being adapted to transmit a direct current (DC) signal; a power converter adapted to receive the DC signal; a high-frequency rotary transformer electrically coupled to the power converter, the high-frequency rotary transformer having a stationary portion and a rotating portion such that an alternating current (AC) in the stationary portion induces an AC voltage in the rotating portion; a rectifier adapted to receive an AC voltage from a rotating portion of the high-frequency rotary transformer, the rectifier adapted to convert the AC voltage into a DC voltage; and A DC bus is adapted to store the DC voltage from the rectifier.

8. The electric drive system according to claim 7, further comprising: an inverter adapted to receive a DC voltage from the DC bus, the DC voltage being converted into an AC current in the inverter; as well as The rotor winding includes phase coils adapted to receive AC current from the inverter to generate a rotor field.

9. The electric drive system according to claim 1, further comprising: a power supply selectively connectable to the motor, the power supply being adapted to transmit a DC signal; a DC-AC inverter adapted to receive the DC signal for conversion into AC current; a slip ring device adapted to receive AC current from the DC-AC inverter, the electric machine having a stationary side and a rotating side; as well as The slip ring device is positioned such that the AC current flows from the stationary side to the rotating side, and the single-phase rotor winding is adapted to receive the AC current to generate a rotor field.

10. A method of pulsed power transmission in an electric drive system in a vehicle, the electric drive system having a controller and an electric motor, the controller having a processor and tangible, non-transitory memory, the electric motor having a stator assembly and a rotor assembly, the method comprising: Incorporating a plurality of multi-phase stator windings in the stator assembly, the plurality of multi-phase stator windings including a first stator winding and a second stator winding, the rotor assembly including a rotor winding having a single phase; adapting a first inverter to feed power to the first stator winding; adapting a second inverter to feed power to the second stator winding; selectively exciting the rotor windings with pulsed field currents via the controller command such that a direct-axis (d-axis) stator flux is generated, and a d-axis stator voltage is induced in the first stator winding and the second stator winding by the d-axis stator flux; and Pulsed power transmission is achieved through interaction of the d-axis stator voltage with corresponding d-axis winding currents in the first and second stator windings.

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