Purely stationary-side compensation network

Abstract

Embodiments of the disclosure provide an electric drive motor system comprising a stationary side and a rotating side. The stationary side includes a purely stationary-side (OSS) compensation network. A first OSS compensation element of the OSS compensation network is operable to provide a compensation function for the rotating side.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of an earlier filing date from U.S. Provisional Application No. 63 / 333,790, filed April 22, 2022, the entire disclosure of which is incorporated herein by reference. GENERAL STATE OF THE ART

[0002] A wound rotor synchronous machine (WRSM) is an electric motor with a rotor and a stator. The stator is the fixed part of the machine, and the rotor is the rotating part. The stator typically has a multi-phase winding, and the rotor is constructed with a field winding instead of permanent magnets. The rotor rotates in a magnetic field, and the magnetic field can be produced by the windings or field coils. A field coil is an electromagnet used to generate a magnetic field in an electromagnetic machine, typically a rotating electrical machine such as a motor or generator. It contains a coil of wire through which a current flows. In a machine with field coils, a current must flow in the coils to generate the field; otherwise, no power is transferred to or from the rotor. The process of generating a magnetic field using an electric current is called excitation.Field coils provide the most flexible form of regulation and deregulation of magnetic flux, but at the expense of electrical current flow.

[0003] Typically, the rotor winding of a WRSM can be energized or excited using a slip-ring and brush assembly system. However, slip-ring and brush assembly systems have disadvantages, including inefficiency at high speeds, the frequent need for maintenance, and high overall losses, especially at high speeds due to the high contact resistance between the brush and slip ring.

[0004] To overcome the shortcomings of slip-ring and brush-array excitation methods, wireless (or contactless) excitation systems, or wireless power transmission systems, have been developed. In wireless power transmission, various technologies can generally be implemented to transmit power using electromagnetic fields (EMFs) without physical connection. In a wireless power transmission system, a transmitting device, driven by electrical power from a power source, generates a time-varying EMF that transfers power through space to a receiving device via mutual inductance (M). The receiving device uses M to extract power from the EMF and deliver the extracted power to an electrical load. Wireless power transmission provides power to electrical devices / loads where connecting wires are impractical, dangerous, or not possible.Wireless power technologies can be divided into two main categories: near-field and far-field. In near-field technologies, the time-varying EMF is generated using a variety of techniques, including resonant inductive coupling. Resonant inductive coupling is the wireless near-field transfer of electrical power between magnetically coupled coils that are part of a resonant circuit tuned to resonate at the same frequency as the drive frequency.

[0005] Rotary transformers (RTs) are a type of wireless power transfer system that can be used for the controlled wireless excitation of the rotor windings of a WRSM. An RT performs the same general function as a conventional transformer, as both transfer electrical power from one circuit to another at the same frequency but different voltages. A conventional transformer operates on the principle of electromagnetic induction, meaning the electromotive force is induced by the varying magnetic field in the closed circuit. An RT differs from a conventional transformer in that the RT geometry is arranged so that the primary and secondary windings can be rotated with respect to each other with negligible changes in electrical properties.In one known configuration, the RT can be constructed by winding the primary and secondary windings into separate halves of a cup core. The concentric halves face each other, with each half attached to one of the parts that rotates relative to each other. The magnetic flux provides the coupling from one half of the cup core to the other half across an air gap and provides the M that transfers power from the RT's primary windings to the secondary windings.

[0006] Known approaches for using RT systems to provide excitation for a WRSM may involve providing a resonant tuning network for the RT system, also known as a compensation network. A resonant tuning network may include circuit components (e.g., various combinations of resistors (R), inductors (L), and / or capacitors (C)) that allow the associated transformer to store oscillating electrical power similar to a resonant circuit, thus acting as a bandpass filter, passing frequencies near their resonant frequency from the primary to the secondary winding while blocking other frequencies. The magnitude of M between the primary and secondary windings, together with the quality factor (Q factor) of the circuit, determines the shape of the frequency response.Resonant circuits are often referred to as LC or LRC circuits due to the inductive, resistive, and capacitive components and are used to form the resonant circuit. In materials science, every material has its own natural frequency. When the external vibration is equal to the natural frequency, resonance occurs. In electrical engineering, the impedance of inductors and capacitors depends on frequency. Capacitive impedance is inversely proportional to frequency, while inductive impedance is directly proportional to frequency. At a certain frequency, the two cancel each other out (or cancel each other out). Such a circuit is called a resonant circuit, and this specific frequency is the resonant frequency. In LC circuits, where the reactance of the L component is essentially equal to the reactance of the C component, the L and C components cancel each other out, i.e.the L and C components compensate each other or cancel each other out.

[0007] In conventional RT systems that provide resonance tuning or compensation (i.e., an RT compensation system), the resonance tuning network (or compensation network) is present on both the stationary (or stator, or primary) side and the rotating (or rotating, or secondary) side of the WRSM. For the primary coil, a basic function of "compensation" is to minimize the input apparent power and / or to minimize the volt-amperes (VA) of the power supply. For the secondary coil, compensation cancels the secondary coil's stray inductance to maximize the transfer capability.

[0008] RT compensation systems that provide resonant circuit components on both the stationary and rotating sides of the WRSM have shortcomings. For example, it is difficult to place a resonant tuning network or compensation network on the rotating side due to very limited space and the high operating temperatures on the rotating side, which exceed the temperature tolerance of commercially available resonant tuning components, such as capacitors. Furthermore, the presence of a resonant tuning capacitor on the rotating side reduces the mechanical reliability of the rotating part and increases the complexity, mechanical mass, and inertia of the rotating part, especially at high rotation speeds.

[0009] Accordingly, there is a need in the art to provide a compensation network for use in an RT system that provides the advantages of wireless power transfer without the difficulties associated with providing compensation components on the rotating side of an electric motor, such as a WFSM. BRIEF DESCRIPTION OF THE INVENTION

[0010] Embodiments of the disclosure provide an electric drive motor system including a stationary side and a rotating side. The stationary side includes a purely stationary side (OSS) compensation network. A first OSS compensation element of the OSS compensation network is operable to provide a compensation function for the rotating side.

[0011] Embodiments of the disclosure provide a method for manufacturing an electric drive motor system including a stationary side and a rotating side. The stationary side includes an OSS compensation network. A first OSS compensation element of the OSS compensation network is operable to provide a compensation function for the rotating side. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a simplified block diagram illustrating a non-limiting example of an electric drive motor system with a purely stationary-side compensation network in accordance with aspects of the disclosure; Fig. Figure 2 is a simplified block diagram illustrating a non-limiting example of how an electric motor drive system as shown in Fig. 1, may be implemented according to aspects of the disclosure; Fig. 3 is a simplified flow diagram illustrating a methodology according to aspects of the disclosure; Fig. 4 is a simplified flow diagram illustrating a methodology according to aspects of the disclosure; Fig. Figure 5 is a simplified block diagram illustrating an equivalent circuit representation for the electric drive motor systems used in Fig. 1 and Fig. 2 are shown; Fig. Figure 6 is a simplified block diagram further illustrating an equivalent circuit representation for the electric drive motor systems shown in Fig. 1 and Fig. 2 are shown; Fig. Figure 7 is a simplified block diagram further illustrating an equivalent circuit representation for the electric drive motor systems shown in Fig. 1 and Fig. 2 are shown; Fig. 8 illustrates various equations that may be used in constructing a purely stationary-side compensation network according to aspects of the disclosure; Fig. 9 illustrates various equations that may be used in constructing a purely stationary-side compensation network according to aspects of the disclosure; Fig. 10 illustrates various equations that may be used in constructing a purely stationary-side compensation network according to aspects of the disclosure; Fig. 11 illustrates various equations that may be used in constructing a purely stationary-side compensation network according to aspects of the disclosure; Fig. 12 illustrates various equations that may be used in constructing a purely stationary-side compensation network according to aspects of the disclosure; Fig. 13 illustrates various equations that may be used in constructing a purely stationary-side compensation network according to aspects of the disclosure; Fig. 14 illustrates various equations that may be used in constructing a purely stationary-side compensation network according to aspects of the disclosure; and Fig. 15 illustrates various equations that may be used in constructing a purely stationary-side compensation network according to aspects of the disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Embodiments of the disclosure provide an RT compensation system with a novel, purely stationary-side compensation network. In embodiments of the disclosure, the novel purely stationary-side compensation network can be integrated within an electric motor drive system with an electric motor (e.g., a WRSM) operable to include a stationary side and a rotating side. The novel purely stationary-side compensation network disclosed herein addresses the previously described difficulties associated with placing a resonant tuning network or compensation circuit on the rotating / secondary side by implementing the purely stationary-side compensation network as a purely stationary-side resonant LCC (inductor-capacitor-capacitor) network operable to provide tuning only on the stationary side (or primary side) without compensation elements (e.g.,, no resonant tuning capacitor element(s) are provided on the rotating side (or secondary side) for RT compensation system applications. In the embodiments described herein, the term "stationary-side only" for a compensation network implemented in an electric drive motor system having a stationary side and a rotating side means that no compensation components are provided on the rotating side. In embodiments of the disclosure, the need for compensation elements on the rotating side is eliminated by configuring the stationary-side only LCC network to perform a rotating-side compensation function, wherein the rotating-side compensation is provided by one or more compensation elements of the stationary-side only LCC network.For example, in some embodiments of the disclosure, the rotating side compensation function includes determining one or more values ​​of the one or more compensation elements of the stationary-side-only LCC network such that the one or more compensation elements on the stationary side provide the rotating side compensation function.

[0013] In aspects of the disclosure, the above-described electric motor drive system includes a resonant inverter operable to convert direct current (DC) power (e.g., from a vehicle battery) to high-frequency (RF) alternating current and provide the RF alternating current to the stationary-side only resonant LCC network. The stationary-side only resonant LCC network is configured to enable the stationary-side only resonant LCC network to perform the rotating-side compensation function in addition to providing stationary-side compensation. The rotating-side compensation function includes a novel design methodology that involves calculating the "reflected" impedance of the stationary-side coil, which is due to the impedance of the rotating-side coil of the electric motor. In general, a reflected impedance (or inductance) is the portion of the impedance of a circuit (e.g.,Circuit A), which is due to the influence of another coupled circuit (e.g., Circuit B). The novel design methodology further involves selecting the position and component values ​​of the purely stationary-side resonant LCC network such that the purely stationary-side resonant LCC network tunes the "reflected" stationary-side coil impedance, which is due to the impedance of the rotating-side coil, from the purely stationary-side resonant LCC network. With appropriate positioning and sizing of a capacitive component (e.g., a capacitive element in series with the primary windings / coils) of the purely stationary-side resonant LCC network, for example, the rotating-side windings of the electric motor can be controlled from the stationary side by appropriate positioning and sizing of the capacitive component (e.g., the C1 capacitor, shown in . Fig. 2) the purely stationary-side resonant LCC tuning network. The LCC tuning on the primary side is configured and arranged to achieve constant current source behavior on the primary-side coil, independent of the load current or coupling factor. Accordingly, the resonant inverter output current is directly related to a rectifier output current fed into the rotor windings on the secondary side. With no compensation (e.g., no resonant tuning capacitor(s)) on the secondary side, the tuning circuit on the secondary side is simplified, the need to identify and provide a high-temperature capacitor on the rotating side is eliminated, the costs associated with the secondary-side tuning components are eliminated, and the overall reliability of the wireless motor excitation system is improved.

[0014] A more detailed description of embodiments of the disclosure will now be given below, wherein Fig. 1 illustrates a system 100 embodying aspects of the disclosure. System 100 includes a power source 110 electronically coupled to an electric motor drive system 102. Electronic motor drive system 102 includes a resonant inverter 120, a DC-excited motor 130, and an inverter controller 150 configured and arranged as shown. According to aspects of the disclosure, the DC-excited motor 130 includes a purely stationary-side compensation network 140. Although the resonant inverter 120, the DC-excited motor 130, the purely stationary-side compensation network 140, and the inverter controller 150 are illustrated as separate components, it should be understood that the resonant inverter 120, the DC-excited motor 130, the purely stationary-side compensation network 140, and the inverter controller 150 may be configured and arranged in any suitable combination.For example, the inverter controller 150 may be integrated within the resonant inverter 120; the resonant inverter 120 may be integrated within the DC-excited motor 130; and / or the resonant inverter 120 and the inverter controller 150 may be integrated within the DC-excited motor 130.

[0015] The power source 110 can be implemented in a variety of forms, for example, as a battery. In some embodiments of the disclosure, the battery can be a rechargeable battery comprising a set of one or more individual battery cells connected in series or parallel and operating under the control of one or more controllers, such as a battery control module (BCM), that monitors and controls the performance of the battery. The BCM can monitor various characteristics of the battery values, such as the battery current, measured, for example, by a current sensor, the battery voltage, and the battery temperature. The battery can be charged via an external power source (not shown). The battery can include power conversion electronics operable to condition the power from the external power source to provide the battery with the correct voltage and current values.The individual battery cells within a battery pack can be composed of a variety of chemical compositions. Battery chemistries include, but are not limited to, lead acid, nickel cadmium (NiCd), nickel metal hydride (NIMH), lithium-ion, or lithium-ion polymer.

[0016] Resonant inverter 120 is electrically coupled between power source 110 and DC-excited motor 130 to transfer excitation power from power source 110 to DC-excited motor 130. Specifically, resonant inverter 120 is operable to provide power from power source 110 to the pure stationary-side compensation network 140 of DC-excited motor 130 at a desired resonant frequency to excite DC-excited motor 130. In embodiments of the disclosure, resonant inverter 120 is operable to convert the DC voltage from power source 110 to AC power at the desired resonant frequency required by DC-excited motor 130 and pure stationary-side compensation network 140 for motor excitation.In embodiments of the disclosure, resonant inverter 120 may be a full-bridge resonant inverter with four switches organized as two "phase legs." Each phase leg may include two series-connected switches located between a positive and a negative DC rail. A phase node may be positioned between the two switches of each phase leg to provide the phases of an AC waveform output at a desired resonant frequency. In some embodiments of the disclosure, resonant inverter 120 generates RF AC power. Inverter controller 150 is electronically coupled to the phase leg switches to control the on and off states of the switches, thus controlling the frequency and phase of the AC waveform generated by resonant inverter 120.The inverter controller 150 includes a computing device (with memory) that includes a computer, a microprocessor, a digital signal processor, and the like, that is configured and operable to execute software instructions and programs, and that may include associated firmware, such that the controller 150 is configured and operable to control the switching on / off operations of the resonant inverter 120.

[0017] The DC motor 130 can be any eclectic motor design suitable for the work the motor is intended to perform. Examples of work that can be performed by motors in conventional automotive-based motor applications include operating or moving power windows, power seats, heater and radiator fans, windshield wipers, and / or the engine of a vehicle with a hybrid electric vehicle configuration. Regardless of the type of DC motor 130, it relies on electromagnetism and the reversing of magnetic fields to generate mechanical power. A conventional design of the DC motor 130 includes five basic parts: a stator, a rotor, a solid axle, coils, and a squirrel cage.The stator winding in a DC motor is a ring of paired electromagnets that are energized one after the other, creating the rotating magnetic field. The rotor of a DC motor has no direct connection to a power source and has no brushes. Instead, the previously described squirrel cage rotor is often used. The squirrel cage rotor in a DC motor is formed from a set of rotor bars connected to two rings, one at each end. The squirrel cage rotor is located inside the stator. When excitation power is sent through the stator, it generates an EMF. The bars of the squirrel cage rotor are conductors and therefore respond to the reversing of the stator poles, causing the rotor to rotate and generate its own magnetic field.The key point of an induction motor, where the rotor field is induced by the stator field, is that the rotor is constantly trying to catch up. It's always searching for stasis, so it rotates to find that steady state. However, the EMF generated by the stator will always be slightly faster than the rotor field. The rotation of the rotor creates the torque needed to generate mechanical power to turn a car's wheels or a fan's blades. Some DC motors use a wound rotor (such as a WRSM) wrapped with wire instead of a squirrel-cage rotor. In any case, there is only one moving part in a DC motor, meaning fewer things to replace or maintain.

[0018] In some embodiments of the disclosure, the DC-excited motor 130 may be a WRSM. A WRSM is a rotating electric motor with a rotor and a stator. The stator is the fixed part of the machine, and the rotor is the rotating part of the machine. The stator typically has a multi-phase winding, and the rotor is formed with a field winding instead of permanent magnets. The rotor rotates in a magnetic field, and the magnetic field can be produced by the windings or field coils. In a machine with field coils, an excitation current must flow in the coils to generate the field; otherwise, no power is transferred to or from the rotor. Field coils provide the most flexible form of regulation and deregulation of magnetic flux, but at the expense of electrical current flow. Typically, the rotor winding of a WRSM can be energized or excited via a slip ring and brush assembly system.However, slip ring and brush systems have disadvantages, including inefficiency at high speeds, the frequent need for maintenance, and overall high losses, especially at high speeds due to the high contact resistance between brush and slip ring systems.

[0019] To avoid the shortcomings of slip-ring and brush-array excitation methods, the stationary-side-only compensation network 140 is integrated within an RT compensation system (not shown separately from the motor 130) operable to provide compensated wireless excitation or wireless power transfer from a stator side of the motor 130 to a rotor side of the motor 130. In embodiments of the disclosure, the stationary-side-only compensation network 140 may be implemented as part of a specially designed stationary-side-only RT compensation system. Generally, the RT is a circuit and method for wirelessly transferring power to the rotor windings of a WRSM for controlled excitation.An RT is essentially the same as a conventional transformer in that it transfers electrical power from one circuit to another at the same frequency but different voltage. Generally, a conventional transformer operates on the principle of electromagnetic induction, meaning the electromotive force is induced by the varying magnetic field in the closed circuit. An RT differs from a conventional transformer in that the RT geometry is arranged so that the primary and secondary windings can be rotated with respect to each other with negligible changes in electrical properties. In one common configuration, the RT can be constructed by winding the primary and secondary windings in separate halves of a cup core.The concentric halves face each other, with each half attached to one of the parts that rotates relative to each other. The magnetic flux couples one half of the cup core to the other half across an air gap and provides the magnetic field that couples the power from the primary windings of the RT to the secondary windings.

[0020] In conventional RT designs that provide resonance tuning or compensation (i.e., the RT compensation system), a resonance tuning network (or compensation network) is present on both the stationary (or primary) and rotating (or secondary) sides of the WRSM. RT designs that have resonant circuit components on both the stationary and rotating sides of the WRSM are difficult to implement. For example, in practice, it is difficult to place a resonance tuning network or compensation circuit on the secondary side due to very limited space on the rotor and the high operating conditions of the rotor, which exceed the temperature capability of commercially available compact capacitors.In addition, a resonant tuning capacitor on the secondary side increases the complexity of the rotating part, increases the mechanical mass, increases inertia and reduces mechanical reliability, especially at high speeds.

[0021] The purely stationary-side compensation network 140 overcomes the difficulties associated with translating paper designs and computer simulations into practice (i.e., building and using) conventional RT compensation system designs that incorporate stationary-side and rotating-side compensation networks by providing the benefits of compensated RT functionality without the difficulties associated with providing compensation circuitry on the rotating side of a DC-excited motor 130 (e.g., a WFSM).In particular, the purely stationary-side compensation network 140 may be operable to support the wireless transfer of rotor excitation current from the stationary side to the rotating rotor, thereby eliminating the problems of brush and slip ring maintenance, as well as the inefficiencies, manufacturing issues, and design disadvantages associated with brush and slip ring systems.

[0022] In aspects of the disclosure, the purely stationary-side compensation network 140 takes into account that there is no resonance tuning capacitor on the secondary side by placing an additional resonance tuning capacitor (i.e., one of the resonance tuning capacitors of an LCC network implementation of the purely stationary-side compensation network 140) on the primary side and adjusting the two primary-side resonance tuning capacitors such that the uncompensated secondary side on the network 140 does not introduce any inefficiencies or other disadvantages. In embodiments of the disclosure, a purely stationary-side LCC design methodology is provided that includes reflecting the impedance and / or inductance of the secondary side to the primary side, and the leakage inductance of this secondary coil (e.g., L2 shown in Fig. 2) is tuned to the primary side. In general, a reflected impedance (or inductance) is the portion of the impedance of a circuit (e.g., circuit A) that is due to the influence of another coupled circuit (e.g., circuit B). In embodiments of the disclosure, this can be achieved by deriving the equivalent circuit models of the system 100 as well as the total impedance model of the system 100, which allows calculating the reflection impedance from the secondary side to the primary side. A further simplification is applied to the derived equivalent circuit models so that the total impedance of the resonant inverter 120 can be calculated. To tune this total impedance to a unity power factor, a tuning capacitor (e.g., C1 shown in Fig. 2) of the LCC design. Thus, the purely stationary-side compensation network 140 eliminates the need for capacitor tuning on the secondary side and the need for a secondary-side resonant tuning capacitor(s) and its tuning by providing additional primary-side tuning components (e.g., a resonant tuning capacitor(s)) and adjusting the values ​​of the tuning components on the primary side. Further details of the purely stationary-side LCC design and the associated design methodology according to aspects of the disclosure are described in the Fig. 3-15 and are described below.

[0023] Fig. 2 shows a system 100A with a vehicle battery 110A connected via an intermediate circuit capacitor (C dc) is electronically coupled to an electric motor drive system 102A. System 100A is a non-limiting example implementation of system 100 (shown in Fig. 1); the vehicle battery 110A is a non-limiting example implementation of the power source 110 (shown in Fig. 1); and the electric motor drive system 102A is a non-limiting example implementation of the electric motor drive system 102 (shown in Fig. 1). The electric motor drive system 102A may be implemented as a resonant inverter 120A electronically coupled to the inverter controller 150, and a simplified representation of an electric machine 130A. The resonant inverter 120A is a non-limiting example implementation of the inverter 120 (shown in Fig. 1). The electric machine 130A is an example implementation of the DC-excited motor 130 (shown in Fig. 1). The electric machine 130A includes a novel purely stationary-side resonant LCC 140A, a rectifier 210 and a rotor element which is driven by a rotor inductance L rotor and a rotor resistance R rotor The novel purely stationary-side resonant LCC 140A is a non-limiting example implementation of the novel purely stationary-side wireless power transmission network 140 (shown in Fig. 1). The system 100A includes a stationary side (e.g., the stator side) 220 and a rotating side (e.g., the rotor side) 230. Generally, the stationary side 220 includes the stator windings L1 and the circuit elements to the left thereof, and the rotating side 230 includes the stator windings L2 and the circuit elements to the right thereof. Although the resonant inverter 120A, the electric machine 130A, and the inverter controller 150 are illustrated as separate components, it should be understood that the resonant inverter 120A, the electric machine 130A, and the inverter controller 150 can be configured and arranged in any suitable combination of components.For example, the inverter controller 150 may be installed within the resonant inverter 120A; the resonant inverter 120A may be installed within the electric machine 130A; and / or the resonant inverter 120A and the inverter controller 150 may be installed within the electric machine 130A.

[0024] With further reference to Fig. 2, the stationary side 220 is configured to transmit power to the rotating side 230 by means of inductive power transfer, and the rotating side 230 is configured to receive power from the stationary side 220 by means of inductive power transfer. The stationary side 220 includes a DC vehicle battery 110A, a DC link capacitor C dc, a resonant inverter 120A, the single purely stationary-side resonant LCC 140A, and the stator-side coil L1. The resonant inverter 120A receives a DC input signal from the vehicle battery 110A and converts the DC input signal into an AC output signal having a desired resonant frequency. In some embodiments of the disclosure, the resonant inverter 120A is a full-bridge inverter circuit operable to include four power electronic switching devices T1, T2, T3, T4 configured and arranged as shown. The switching devices T1, T2, T3, T4 may be implemented in any suitable format, including, but not limited to, metal-oxide-semiconductor field-effect transistors (MOSFETs), BJTs, FETs, IGBTs, IGFETs, and the like.The inverter controller 150 is electrically coupled to each of the switching devices T1, T2, T3, T4 to control the switching operation of the resonant inverter 120A. The inverter controller 150 switches the switching devices T1, T2, T3, T4 on and off to generate the AC output signal V. inv_0 at the desired resonant frequency. The inverter controller 150 includes a computing device (with memory) that includes a computer, a microprocessor, a digital signal processor, and the like, operable to execute software instructions and programs, and may include associated firmware such that the controller 150 is configured and operable to control the on / off operations of the resonant inverter 122A.

[0025] The purely stationary-side resonant LCC 140A connects the resonant inverter 120A to the stator-side coil L1. In the non-limiting embodiment of the disclosure, illustrated in Fig. 2, the purely stationary-side resonant LCC 140A is configured to have a stator-side coil L f1 , a stator-side series capacitor C1 (in series with the stator-side coil L1), and a stator-side parallel capacitor C f1 (parallel to the stator-side coil L f1 ). The stator-side series capacitor C1 is coupled in series with a positive terminal of the stator-side coil L1 and the stator-side parallel capacitor C f1 is connected in parallel to the stator-side coil L1.

[0026] The rotating side 230 includes a rotor-side coil L2 that is electrically coupled to a rectifier 210. The rotor-side coil L2 is sufficiently close to the stator-side coil L1 to be within an EMF generated by the stator-side coil L1, so that M lies between the stator-side coil L1 and the rotor-side coil L2. The rotor-side coil L2 uses M to generate an alternating current, and the rectifier 210 converts the alternating current to a direct current (I rotor ). In some embodiments of the disclosure, the rectifier 210 is a bridge rectifier circuit with four diodes D1, D2, D3, D4. The direct current is provided to a rotor of the electric machine 130A. The rotor is in Fig. 2 as inductance L rotor in series with resistor R rotor shown.

[0027] Power is transferred through the M between the stator-side coil L1 and the rotor-side coil L2, but the leakage inductance L1 / L2 does not directly contribute to active real power transfer. Furthermore, the leakage inductance can be undesirable because it causes the voltage to change with load. In conventional approaches to reducing leakage inductance and increasing M, a rotor-side compensation circuit (e.g., a rotor-side compensation circuit / element) is provided on the rotating side 230. However, for applications such as system 100, 100A, where the rotor side rotates with respect to the stator side, it is extremely difficult to fabricate a rotor with a rotor-side compensation circuit.Embodiments of the disclosure avoid the need for the rotor-side compensation circuit / element by configuring and arranging the purely stationary-side resonant LCC 140A such that the compensation that would be provided by a rotor-side compensation circuit / element on the rotating side 230 in conventional RT compensation designs is instead provided by the design and component value settings of the purely stationary-side resonant LCC 140A. Further details of the purely stationary-side resonant LCC 140A design and associated design methodology according to aspects of the disclosure are described in FIGS. Fig. 3-15 and are described below.

[0028] Fig. 3 is a flowchart illustrating a methodology 300 implemented by the system 100, 100A (shown in Fig. 1 and Fig. 2). In some embodiments of the invention, portions of the methodology 300 (e.g., blocks 312, 314) may optionally be performed by a computer-aided design (CAD) system running on a processor (e.g., having the same processor functionality as the controller 150) operable to perform calculations, circuit modeling, and circuit simulation operations that may optionally be used to select the compensation component values ​​of the purely stationary-side resonant LCC 140A. According to aspects of the disclosure, the previously described CAD system may be implemented with CAD software applications that may optionally perform the various calculations and algorithms described in the Fig. 4-15. Although the description of methodology 300 refers to the components of system 100A, the description applies equally to the corresponding element(s) of system 100.

[0029] As in Fig. 3, the methodology 300 begins at block 302 by generating alternating current. In embodiments of the disclosure, the alternating current may be an RF alternating current generated by using the resonant inverter 120A to convert the DC current received from the vehicle battery 110A to the RF alternating current. At block 304, the RF alternating current is received at the novel stationary-side only compensation / tuning network (e.g., the stationary-side only resonant LCC 140A) associated with the primary coils L1.

[0030] Blocks 312 and 314 are offline operations that can be used to construct the purely stationary-side tuning network (e.g., the purely stationary-side resonant LCC 140A) used in blocks 304 and 306. In block 312, the "reflected" stationary-side coil impedance is calculated, which is due to the impedance on the rotating-side coil. In some embodiments of the invention, the impedance associated with the rotating side or primary coils is reflected to the stationary side. In some embodiments of the invention, the impedances associated with the primary coils and the load (as in Fig. 2 by L rotor and R rotorshown), reflected to the station side. In block 314, the position and component values ​​of the purely stationary-side tuning network are selected so that the purely stationary-side tuning network tunes the "reflected" stationary-side coil impedance, which is due to the impedance of the rotating-side coil, from the purely stationary-side tuning network. With appropriate positioning and dimensioning of a capacitive component (e.g., the C1 capacitor) of the purely stationary-side tuning network, for example, the rotating-side winding (e.g., L2) of the electric motor can be tuned from the stationary side by appropriately positioning and dimensioning the capacitive component (e.g., the C1 capacitor) of the purely stationary-side tuning network. Additional details on how blocks 312 and 314 can be implemented are provided in the Fig. 4-15 and are described in more detail below.

[0031] Following the operations in block 304, the methodology 300 proceeds to block 306. In block 306, the purely stationary-side tuning network design includes compensation components (e.g., two capacitive elements C1, C f1 ) and calculated compensation component values ​​that allow the purely stationary-side tuning network to act as a load and further act as an M-independent constant current source operable to use the alternating current received in block 304 to generate an alternating EMF. With this property of the purely stationary-side tuning network (e.g., the purely stationary-side resonant LCC 140A), the current of the stationary-side coil (e.g., L1) does not depend on the rotor current (I rotor) or the relative position of the stationary-side coils (e.g., L1) and the rotating-side coil (L2). As a result, the alternating current generated in block 302 (e.g., by the resonant inverter 120A) has a root mean square (RMS) output current (which would have active and reactive components) that is directly related to the output current of the purely stationary-side tuning network. The resulting high M value and large L Rotor-Inductance eliminates the need for a rotating-side tuning network. The inductance of the rotating-side inductor (L2) can be referenced or reflected to the stationary side, and with appropriate positioning and dimensioning of a capacitive component (e.g., the Cf1 capacitor) of the purely stationary-side tuning network, the rotating-side winding (e.g., L2) of the electric motor can, for example, be tuned from the stationary side by appropriate positioning and dimensioning of the capacitive component (e.g., the Cf1 capacitor) of the purely stationary-side tuning network. The resulting system 100, 100A is also insensitive to the L- Rotor -Inductance, since this inductance of the rotor winding is located on the DC side (ie downstream of the rectifier 210, shown in Fig. 2) and an inductance in the stable state operates as a short circuit at DC voltages and currents. Thus, the L- Rotor only introduce a time constant when the current changes from one value to another. Apart from introducing a time constant (inertia with respect to the current change), L rotor not reflected to the input of the rectifier input 210 and to the stationary side 220.

[0032] Following the operations in block 306, the methodology 300 proceeds to block 308. In block 308, the alternating EMF in the rotating-side coil (L2) generates M between L1 and L2, and the rotating-side coil (L2) uses M to generate AC charging current. In block 310, the AC charging current is converted to a DC current and supplied to the downstream motor components (e.g., a rotor, shown in Fig. 2 as L rotor and R rotor ) provided.

[0033] The Fig. 4-15 illustrate a more detailed example of a design methodology for determining the component values ​​of the purely stationary-side resonant LCC 140A for the system 100A, which eliminates the need for compensation circuits and / or compensation components on the rotating side 230. In particular, Fig. 4 illustrates a design methodology 400 according to embodiments of the disclosure; Fig. 5-7 illustrate equivalent circuits and circuit models (systems 100B, 100C, 100D) used in one or more design methodologies according to embodiments of the disclosure; and Fig. 8-15 illustrate various equations (Equations 1-43) used in one or more design methodologies according to embodiments of the disclosure.

[0034] With reference to Fig. 4, the methodology 400 is described with reference to some of the component element identifiers (e.g., L r1 , C1, C f1, L1, L2, etc.) used in the equivalent circuits and circuit models (Systems 100B, 100C, 100D) shown in the Fig. 5-7, as described in Fig. 4, the methodology 400 is operable to begin in parallel at blocks 402 and 412 and then traverse multiple paths to generate the outputs at blocks 432 (primary coil current, primary shunt tuning capacitor current, and the voltage across the primary tuning capacitor), 436 (output voltage and power), and 422 (construction of the primary compensation network corresponding to the value of the primary series tuning capacitor (C1)). In block 402, the methodology 400 calculates the primary coil current, the primary shunt tuning capacitor current, and the voltage across the primary tuning capacitor. In block 404, the methodology 400 writes Z in as the sum of Z 12and the inductive reactance of the primary-side resonant tuning inductance (L f1 ). In block 406, the methodology writes 400 Z 12 as the parallel equivalent impedance of Z cf1 and Z1. In embodiments of the disclosure, Z1 is the total equivalent impedance detected by the inverter. In block 408, the methodology 400 writes Z1 as the sum of Z L1 , Z c1 and Z ref (Equation-6 in Fig. 8) and then provides Z1 to block 410. Essentially, block 412 calculates, in parallel with the operations in blocks 402-408, the secondary-side (i.e., the rotating-side) reflected impedance Z ref and inserts it into the equation Z1 in block 410 (equation-6 in Fig. 8).

[0035] Block 412 also provides its output to block 414. In block 414, methodology 400 adds the secondary reflected impedance to the primary coil inductance and the series tuning capacitor impedance. In block 416, methodology 400 forms the equivalent impedance circuit of the T-network, calculates the branch impedances, and calculates the total equivalent impedance detected by the inverter. In block 418, methodology 400 calculates the inverter output current. In block 420, methodology 400 constructs the value of the primary series tuning capacitor so that the inverter output reactive power is largely eliminated. Alternatively, block 420 may mask out the imaginary part of the total equivalent impedance detected by the inverter. In block 422, the methodology 422 constructs the primary compensation network according to the value of the primary side series tuning capacitor (C1).

[0036] Returning to block 410 from block 410, methodology 400 proceeds to block 430 and calculates Z in , ie Z1 parallel to Z in The calculation performed in block 430 is provided to block 432 and block 434. In block 432, methodology 400 calculates the primary coil current, the primary-side shunt tuning capacitor current, and the voltage across the primary tuning capacitor. In block 434, methodology 400 calculates the secondary-side current using the voltage induced on the secondary side as well as the total equivalent impedance of the secondary side. The calculations performed in block 434 are provided to block 436, where methodology 400 calculates the output voltage and power.

[0037] The following is a more detailed discussion of the equivalent circuits and circuit models (Systems 100B, 100C, 100D) shown in the Fig. 5-7, together with the various equations (equations 1-43) presented in the Fig. 8-15, where Fig. 5 shows the equivalent circuit of the system 100, 100A with a first harmonic approximation (FHA), and Fig. 6 shows the mutually coupled circuit model of the system 100, 100A with serial equivalent internal resistances for circuit components. In Fig. 6, the self-inductances of the primary and secondary coils are used, while the magnetization branch uses current-dependent voltage sources to model the effect of mutual coupling between the primary and secondary windings. Since no resonance tuning circuit is implemented on the secondary side, the equivalent impedance of the secondary side can be calculated using Equation 1 (shown in Fig. 8) are reflected at the primary side. The input current on the primary side (i.e., the inverter output current) can be calculated by equation-2 (shown in Fig. 8), where the input impedance (Z in ) or the total impedance detected by the inverter by Equation-3 (shown in Fig. 8). The Z 12 -component of equation-3 is given by equation-4 (shown in Fig. 8) provided. Since L f1 with C f1 is hidden, this results in equation-5 (shown in Fig. 8). At the same time, the impedance Z1 is determined by equation-6 (shown in Fig. 8), where Z ref is the reflected impedance from the secondary side, which is given by Equation-7 (shown in Fig. 8) can be written.

[0038] The primary coil current can be calculated by equation-8 (shown in Fig. 9) and the current of the primary side parallel tuning capacitor (C f1 ) is given by equation-9 (shown in Fig. 9) and the voltage is given by equation-10 (shown in Fig. 9). The secondary coil current would be a function of the voltage induced on the secondary side and the total equivalent impedance of the secondary side, which is given by Equation-11 (shown in Fig. 9). The voltage across the output is calculated from equation 12 (shown in Fig. 9) and the output power can be calculated using equation-13 (shown in Fig. 9) can be calculated.

[0039] For the design of the purely stationary-side resonant LCC 140A, the equivalent internal series resistances can be assumed to be zero and the output load can be considered resistive, since the inductance of the rotor winding is on the DC side (i.e., downstream of the rectifier 210) and has no influence on the steady-state operation of the system. From these points of view, the secondary-side total equivalent impedance is determined from Equation 14 (shown in Fig. 10) and the reflected impedance from the secondary side to the primary side is calculated from Equation-15A, Equation-15B and Equation-16 (shown in Fig. 10).

[0040] When designing the parameters of the purely stationary-side resonant LCC 140A on the primary side, this reflected impedance from the secondary side should also be taken into account, since the inductance of the secondary coil is not masked on the secondary side. Therefore, the T-network of the purely stationary-side resonant LCC 140A can be designed with all equivalent impedances, including the reflected impedance Z ref from the secondary side. Accordingly, the equivalent T-circuit model of the purely stationary-side resonant LCC 140A can be illustrated as the system 100D, which in Fig. 7. For the system 100D, the impedance j Zb and j Za each by equation-17 (shown in Fig. 11) and Equation-18 (shown in Fig. 11). As a result, the input current i Lf1 using Equation-19 (shown in Fig. 11) and the component Z 12 of Equation-19 is calculated using Equation-20 (shown in Fig. 11) and Equation-21 (shown in Fig. 11). As a result, the input impedance (as detected by the inverter 120A) of the purely stationary-side resonant LCC 140A is determined to be Z in as in Equation-22 (shown in Fig. 11). As a result, the input current i Lf1 expressed by equation-23 (shown in Fig. 11). The primary coil current i1 is given by equation-24 (shown in Fig. 12) and the input current can be calculated using equation-25 (shown in Fig. 12). The primary compensation capacitor must eliminate the reactive power so that Equation-26 (shown in Fig. 12), Equation-27 (shown in Fig. 12), Equation-28 (shown in Fig. 12) and Equation-29 (shown in Fig. 13). Accordingly, the value of the purely stationary-side tuning capacitor C1 is determined by equation-30 (shown in Fig. 30). It is also noted that the value of C1 cannot be negative. Therefore, the expression for the capacitor C1 should satisfy the condition specified in Equation-31 (shown in Fig. 13) and / or the condition specified in Equation-32 (shown in Fig. 13). Consequently, the values ​​of self-inductances L1 and L2 can be constructed from the DC gain given by Equation-33 (shown in Fig. 13). To determine the input inductance of L f1 To construct the circuit, the output power can first be calculated by equation-34 (shown in Fig. 14), Equation-35 (shown in Fig. 14) and Equation-36 (shown in Fig. 14). Solving Equation-36 (shown in Fig. 14) for L f1can be calculated using equation-37 (shown in Fig. 15) to Equation-42 (shown in Fig. 15) to get Equation-43 (shown in Fig. 15).

[0041] Accordingly, from the above description of Fig. 3-15, it can be seen that the purely stationary-side resonant LCC 140A provides technical effects and advantages. Although C1 is located on the stationary side 230, C1 performs a compensation function for the rotating side, which is operable to provide compensation for the L2 windings on the rotating side. This compensation function for the rotating side can be implemented by reflecting the L2 impedance to the stationary side 220, in which case the various calculations shown in the Fig. 8-15, to use the reflected impedance as part of the process for developing the value for C1. In some embodiments of the invention, the impedances associated with the primary coils and the load (as in Fig. 2 by L rotor and R rotor shown), is reflected to the station side and used to develop the values ​​for C1. In some embodiments of the disclosure, in addition to compensating the L2 windings from the stationary side 220, a portion of L1 or the difference between L1 and L f1 compensated together. Thus, in some embodiments of the disclosure, the value of C1 depends on L2, L1 and L f1 off. C f1 becomes a “hide” of L f1 which provides at least a portion of the compensation for the L1 windings on the stationary side 220.

[0042] The various components / modules of the systems shown herein are shown separately for convenience and explanation. In embodiments of the disclosure, the functions performed by the various components / modules / models may be distributed differently than shown without affecting the scope of the various embodiments of the disclosure described herein, unless expressly stated otherwise.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the," are intended to include the plural forms unless the context clearly precludes them. It is further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of certain features, integers, steps, acts, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, acts, element components, and / or groups thereof.

[0044] The diagrams presented herein are illustrative. Many variations of the diagram or the steps (or operations) described therein may exist without departing from the spirit of the disclosure. For example, the actions may be performed in a different order, or actions may be added, deleted, or modified. Furthermore, the term "coupled" describes the presence of a signal path between two elements and does not imply a direct connection between the elements without intervening elements / connections. All such variations are considered part of the present disclosure.

[0045] The following definitions and abbreviations are to be used in interpreting the claims and the description. The terms "comprises", "comprising", "include", "containing", "has", "comprising", "has", "containing", "contains" or "containing" or any other variation thereof, are intended to cover non-exclusive inclusion. For example, a composition, mixture, process, method, article, or device that includes a list of elements is not necessarily limited to those elements, but may also include other elements not expressly listed or pertaining to that composition, mixture, process, method, article, or device.

[0046] Furthermore, the term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or construction described herein as "exemplary" is not necessarily preferred or advantageous over other embodiments or constructions. The terms "at least one" and "one or more" include any integer greater than or equal to one, i.e., one, two, three, four, etc. The term "a plurality" includes any integer greater than or equal to two, i.e., two, three, four, five, etc. The term "connection" can include both an indirect "connection" and a direct "connection."

[0047] The terms "about," "substantially," "approximately," and variations thereof are intended to encompass the degree of error associated with the measurement of the particular quantity using the equipment available at the time of filing. For example, "about" may imply a range of ± 8%, 5%, or 2% of a particular value.

[0048] Each flowchart and block diagram in the figures illustrates the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or section of instructions that includes one or more executable instructions to implement the specified logical function(s). In some alternative implementations, the functions listed in the blocks may occur in a different order than shown in the figures. For example, two blocks shown in succession may actually execute substantially concurrently, or the blocks may execute partially in reverse order depending on the respective functionality.It is also to be understood that each block of the block diagram and / or flowchart illustrations, and combinations of blocks in the block diagram and / or flowchart illustrations, may be implemented by special purpose hardware-based systems that perform the specified functions or acts, or that implement combinations of special purpose hardware and computer instructions.

[0049] Although the disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. Moreover, many changes may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its essential scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but the invention is intended to include all embodiments falling within the scope of the claims. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 333,790

[0001]

Claims

[1] Electric drive motor system comprising: a stationary side; and a rotating page; wherein the stationary side comprises a purely stationary side (OSS) compensation network; and wherein a first OSS compensation element of the OSS compensation network is operable to provide a compensation function for the rotating side. [2] The system of claim 1, wherein a value of the first OSS compensation element is selected such that the value of the first OSS compensation element contributes to the rotating side compensation function. [3] The system of claim 2, wherein a second OSS compensation element of the OSS compensation network is operable to provide a compensation function for the stationary side. [4] The system of claim 3, wherein a value of the second OSS compensation element is selected such that the value of the second OSS compensation element contributes to the stationary side compensation function. [5] The system of claim 4, wherein a third OSS compensation element of the OSS compensation network is operable to further contribute to the stationary side compensation function. [6] The system of claim 5, wherein a value of the third OSS compensation element is selected such that the value of the third OSS compensation element contributes to the stationary side compensation function. [7] The system of claim 2, wherein the first OSS compensation element comprises a first capacitive OSS compensation element. [8] System according to claim 4, wherein: the first OSS compensation element comprises a first capacitive OSS compensation element; and the second OSS compensation element comprises a second capacitive OSS compensation element. [9] System according to claim 6, wherein: the first OSS compensation element comprises a first capacitive OSS compensation element; the second OSS compensation element comprises a second capacitive OSS compensation element; and the third OSS compensation element comprises an inductive OSS compensation element. [10] The system of claim 1, wherein: the stationary side comprises a stator with stationary-side windings; the rotating side comprises a rotor with rotating-side windings; the stationary-side windings are operable to wirelessly transmit alternating current (AC) excitation signals to the rotating-side windings; the OSS compensation network is operable to provide excitation signals to the stationary-side windings; the rotating side compensation function is applied to the wireless transmission of the AC excitation signals to the rotating side windings; the first OSS compensation element comprises a first capacitive OSS compensation element; the OSS compensation network further comprises an inductive element coupled via a node leading to a capacitive element and the first capacitive OSS compensation element; and the first capacitive OSS compensation element is serially coupled to the stationary-side windings. [11] A method of manufacturing an electric drive motor system, the method comprising: Forming a stationary side; and Forming a rotating side; wherein the stationary side comprises a purely stationary side (OSS) compensation network; and wherein a first OSS compensation element of the OSS compensation network is operable to provide a compensation function for the rotating side. [12] The method of claim 11, wherein a value of the first OSS compensation element is selected such that the value of the first OSS compensation element contributes to the rotating side compensation function. [13] The method of claim 12, wherein a second OSS compensation element of the OSS compensation network is operable to provide a compensation function for the stationary side. [14] The method of claim 13, wherein a value of the second OSS compensation element is selected such that the value of the second OSS compensation element contributes to the compensation function for the stationary side. [15] The method of claim 14, wherein a third OSS compensation element of the OSS compensation network is operable to further contribute to the stationary side compensation function. [16] The method of claim 15, wherein a value of the third OSS compensation element is selected such that the value of the third OSS compensation element contributes to the stationary side compensation function. [17] The method of claim 12, wherein the first OSS compensation element comprises a first capacitive OSS compensation element. [18] The method of claim 14, wherein: the first OSS compensation element comprises a first capacitive OSS compensation element; and the second OSS compensation element comprises a second capacitive OSS compensation element. [19] The method of claim 16, wherein: the first OSS compensation element comprises a first capacitive OSS compensation element; the second OSS compensation element comprises a second capacitive OSS compensation element; and the third OSS compensation element comprises an inductive OSS compensation element. [20] The method of claim 11, wherein: the stationary side comprises a stator with stationary-side windings; the rotating side comprises a rotor with rotating-side windings; the stationary-side windings are operable to wirelessly transmit alternating current (AC) excitation signals to the rotating-side windings; the OSS compensation network is operable to provide excitation signals to the stationary-side windings; the rotating side compensation function is applied to the wireless transmission of the AC excitation signals to the rotating side windings; the first OSS compensation element comprises a first capacitive OSS compensation element; the OSS compensation network further comprises an inductive element coupled via a node leading to a capacitive element and the first capacitive OSS compensation element; and the first capacitive OSS compensation element is serially coupled to the stationary-side windings.

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