Rotor current prediction in electric motor drive with fixed side only compensation network

Abstract

Embodiments of the present disclosure provide an electric drive motor system including a stationary side, a rotating side, and a stationary side sensor system operable to detect current on the stationary side and to send current-based sensor readings to a controller. The fixed side further comprises a compensation network. The controller is operable to perform a rotor current prediction operation operable to predict a rotor current associated with the rotor on the rotating side based at least in part on the current-based sensor readings and a parameter of at least one component of the compensation network on the fixed side.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of the prior filing date of U.S. Provisional Application Serial No. 63 / 333,790, filed on April 22, 2022, the entire disclosure of which is incorporated herein by reference. Background Art

[0003] 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 of the machine. The stator usually has a multi-phase winding, and the rotor is made with field windings instead of permanent magnets. The rotor rotates in a magnetic field, and the magnetic field can be generated by windings or field coils. The field coil is an electromagnet that is used to generate a magnetic field in an electromagnetic machine, typically a rotating electrical machine such as a motor or generator. It consists of a coil of wire through which an electric current flows. In the case of a machine with a field coil, an electric current must flow in the coil to generate a magnetic field, otherwise no power is transferred to or from the rotor. The process of generating a magnetic field with the help of an electric current is called excitation. The field coil produces the most flexible form of flux regulation and deregulation, but at the expense of the flow of electric current.

[0004] Conventionally, the rotor windings of a WRSM can be powered or excited using a slip ring and brush assembly system. However, the slip ring and brush assembly system has disadvantages, including low efficiency at high speeds, frequent maintenance requirements, and overall loss, especially at high speeds due to the high contact resistance between the brushes and the slip rings.

[0005] In order to avoid the shortcomings of the slip ring and brush assembly excitation methods, wireless (or contactless) excitation or wireless power transfer systems or technologies have been developed. In general, wireless power transfer uses various technologies to transfer energy by means of an electromagnetic field (EMF) without the need for a physical link. In a wireless power transfer system, a transmitter device driven by power from a power source generates a time-varying EMF, which transmits power to a receiver device via mutual inductance (M) across space. The receiver device extracts power from the EMF using M and supplies the extracted power to an electrical load. Wireless power transfer provides power to electrical devices where interconnecting wires is inconvenient, dangerous or impossible. Wireless power technology is mainly divided into two categories, near field and far field. In near-field technology, time-varying EMF is generated using various technologies, including resonant inductive coupling. Resonant inductive coupling is a near-field wireless transfer of electrical energy between magnetically coupled coils, which are part of a resonant circuit and are tuned to resonate at the same frequency as the driving frequency.

[0006] Rotary transformer (RT) is a wireless power transfer system that can be used for controlled wireless excitation of WRSM rotor windings. RT performs the same general function as a conventional transformer, in that both transfer electrical energy from one circuit to another at the same frequency but different voltages. Conventional transformers work according to the principle of electromagnetic induction, that is, an electromotive force is induced in a closed circuit due to a variable magnetic field around it. RT is different from conventional transformers in that the RT geometry is arranged so that the primary winding and the secondary winding can rotate relative to each other, with negligible changes in electrical characteristics. In a known configuration, RT can be constructed by winding the primary winding and the secondary winding into two separate halves of a cup-shaped core. The concentric halves face each other, with each half mounted on one of the parts that rotate relative to each other. The magnetic flux provides coupling from one half of the cup-shaped core across the air gap to the other half, providing M that transfers energy from the primary winding of the RT to its secondary winding.

[0007] Known methods of using an RT system to provide excitation to a WRSM may include providing the RT system with a resonant tuning network, also referred to as a compensation network. The resonant tuning network may include circuit components (e.g., various combinations of resistors (R), inductors (L), and / or capacitors (C)) that enable an associated transformer to store oscillating electrical energy similar to a resonant circuit and thus act as a bandpass filter, allowing frequencies close to their resonant frequency to pass from the primary winding to the secondary winding, but blocking other frequencies. The amount 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 curve. Resonant circuits are often referred to as LC or LRC circuits because of the inductance, resistance, and capacitance components used to form the resonant circuit. In materials science, each material has its own natural frequency. If an external vibration is equal to the natural frequency, resonance occurs. In electrical science, the impedance of an inductor and a capacitor depends on frequency. The impedance of a capacitor is inversely proportional to the frequency, while the impedance of an inductor is directly proportional to the frequency. At a specific frequency, the two cancel each other out (or tune each other). Such a circuit is called a resonant circuit, and the specific frequency is the resonant frequency. Additionally, for an LC circuit, where the reactance of the L component is substantially the same as the reactance of the C component, the L and C components cancel each other, which means that the L and C components compensate or tune each other.

[0008] In conventional RT systems that provide resonant tuning or compensation (i.e., RT compensation systems), a resonant tuning network (or compensation network) is provided on both the stationary (or stator, or primary) side and the rotating (or rotor, or secondary) side of the WRSM. For the primary coil, the basic function of "compensation" is to minimize the input apparent power and / or minimize the voltage-ampere (VA) rating of the power supply. For the secondary coil, compensation cancels out the leakage inductance of the secondary coil in order to maximize the transfer capability.

[0009] RT compensation systems that provide resonant circuit components on both the stationary and rotating sides of a WRSM have disadvantages. For example, it is difficult to place a resonant tuning network or compensation network on the rotating side due to the very limited space and high temperature operating conditions of the rotating side, which exceeds the temperature ratings of commercially available resonant tuning components (such as capacitors). In addition, having a resonant tuning capacitor on the rotating side reduces the mechanical reliability of the rotating parts and increases the complexity, mechanical mass and inertia of the rotating parts, especially at high rotational speeds.

[0010] For a given torque and speed command in an electric motor, there is a target rotor excitation current that the electric motor drive system needs to inject into the rotor windings. In order to monitor and regulate this rotor winding current, a method of monitoring the actual rotor excitation current is needed so that the motor's current regulation system can confirm that the target rotor excitation current has been reached and maintained. A straightforward method of monitoring the actual rotor excitation current would be to place one or more current sensors at selected locations on the rotor and then configure the sensors with sufficient electronics (e.g., as an Internet of Things (IoT) device) to transmit the readings to the current regulation system on the fixed side of the motor. However, for many of the same reasons why it is difficult to place a resonant tuning network or compensation network on the rotating side of the motor, it is also difficult to place a current sensor on the rotating side of the motor and reliably obtain wired or wireless readings from the current sensor when it is rotating at the same rate (e.g., about 22,000 revolutions per minute (RPM)) and exposed to the same high temperatures as the rotor.

[0011] Therefore, there is a need in the art to provide an electric motor drive system having a compensation network and / or rotor current regulation functionality that provides the benefits of compensated RT functionality and / or rotor current sensing without the difficulties associated with providing compensation components and / or rotor current sensors on the rotating side of an electric motor (such as a WFSM). Summary of the invention

[0012] Embodiments of the present disclosure provide an electric drive motor system including a stationary side, a rotating side, and a stationary side sensor system operable to detect current on the stationary side and send a current-based sensor reading to a controller. The stationary side also includes a compensation network. The controller is operable to perform a rotor current prediction operation, which is operable to predict a rotor current associated with a rotor of the rotating side based at least in part on the current-based sensor reading and a parameter of at least one component of the compensation network of the stationary side.

[0013] Embodiments of the present disclosure provide a method of manufacturing an electric drive motor system, the method comprising forming a fixed side, a rotating side, and a fixed side sensor system, the fixed side sensor system being operable to detect current on the fixed side and send a sensor reading based on the current to a controller. The fixed side also includes a compensation network. The controller is operable to perform a rotor current prediction operation, which is operable to predict a rotor current associated with a rotor of the rotating side based at least in part on the current-based sensor reading and a parameter of at least one component of the compensation network of the fixed side. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a simplified block diagram illustrating a non-limiting example of an electric drive motor system having a rotor winding prediction module in an only-stationary-side compensation network according to aspects of the present disclosure;

[0015] Figure 2 The invention is a diagram showing an aspect of the present disclosure Figure 1 A simplified block diagram of a non-limiting example of how an electric motor drive system may be implemented is shown;

[0016] Figure 3 The invention is a diagram showing an aspect of the present disclosure Figure 1 A simplified block diagram of a non-limiting example of how a controller for an electric motor drive system may be implemented is shown;

[0017] Figure 4 It is shown Figure 1 and Figure 2 A simplified block diagram of an equivalent circuit representation of the electric drive motor system shown in;

[0018] Figure 5 It is shown Figure 1 and Figure 2 A simplified block diagram of another equivalent circuit representation of the electric drive motor system shown in ;

[0019] Figure 6 is a simplified flow chart illustrating a method according to aspects of the present disclosure;

[0020] Figure 7depicts various equations that may be used to perform a rotor winding prediction function in an electric motor drive system having a stationary-only compensation network according to aspects of the present disclosure;

[0021] Figure 8 depicts various equations that may be used to perform a rotor winding prediction function in an electric motor drive system having a stationary-only compensation network according to aspects of the present disclosure;

[0022] Fig. 9 depicts various equations that may be used to perform a rotor winding prediction function in an electric motor drive system having a stationary-only compensation network according to aspects of the present disclosure;

[0023] Fig.10 depicts various equations that may be used to perform a rotor winding prediction function in an electric motor drive system having a stationary-only compensation network according to aspects of the present disclosure;

[0024] Fig.11 is a simplified flow chart illustrating a method according to aspects of the present disclosure;

[0025] Fig.12 is a simplified flow chart illustrating a method according to aspects of the present disclosure;

[0026] Fig.13 It is shown Figure 1 and Figure 2 A simplified block diagram of an equivalent circuit representation of the electric drive motor system shown in;

[0027] Fig.14 It is shown Figure 1 and Figure 2 A simplified block diagram of another equivalent circuit representation of the electric drive motor system shown in ; and

[0028] Fig.15 It is shown Figure 1 and Figure 2 A simplified block diagram of another equivalent circuit representation of the electric drive motor system shown in FIG. DETAILED DESCRIPTION

[0029] Embodiments of the present disclosure provide a novel rotor winding current prediction technology that can be used in an electric motor drive system with an RT compensation system. In some embodiments of the present disclosure, the RT compensation system can be an RT with a novel fixed-side-only compensation network. The electric motor drive system may include an electric motor (e.g., WRSM) having a fixed side and a rotating side. The novel rotor winding current prediction technology and / or novel fixed-side-only compensation network disclosed herein solve the previously described difficulties associated with placing rotor winding current sensors and / or compensation networks on the rotating / secondary side. The novel rotor winding prediction technology is configured and arranged to eliminate the need for current sensing and sensor output communication on the rotating side, and the fixed-side-only compensation network is configured and arranged to eliminate the need for compensation components on the rotating side. In some embodiments of the present invention, for RT compensation system applications, the fixed-side-only compensation network can be implemented as a fixed-side-only resonant LCC (inductor-capacitor-capacitor) network, which is operable to provide tuning only on the fixed side (or primary side), and there is no compensation element (e.g., no one or more resonant tuning capacitor elements) on the rotating side (or secondary side). In the embodiments described herein, the term “stationary side only” is applied to a compensation network implemented in an electric drive motor system having a stationary side and a rotating side, meaning that no compensation components are provided on the rotating side.

[0030] In aspects of the present disclosure, the previously described electric motor drive system includes a resonant inverter operable to convert direct current (DC) (e.g., received from a vehicle battery) to high frequency (HF) AC and provide the HF AC to a fixed-side-only resonant LCC network to wirelessly provide excitation AC to a rotor excitation winding. A rotor rectifier converts the excitation AC to DC excitation and provides the DC excitation to the rotor windings of the electric motor. A novel rotor winding current prediction technique exploits features of the fixed-side-only resonant LCC to enable the rotor winding current to be estimated based at least in part on measurements and analysis of current generated by the resonant inverter. Embodiments of the present disclosure use a fixed-side sensor system (e.g., one or more IoT sensors) to provide a controller with measurements of the AC excitation current generated by the resonant inverter, the controller being operable to apply a novel winding current prediction technique based on a function of the AC excitation current (e.g., Figure 3 f(C1, C f1 , L f1 , L m , L s1 )) plus other parameters of the electric motor drive system to predict the rotor winding current.

[0031] The fixed-side-only resonant LCC is designed using a novel design method that includes calculating the "reflected" fixed-side coil impedance due to the impedance on the rotating-side coil of the electric motor. Generally speaking, the reflected impedance (or inductance) is the portion of the impedance of a circuit (e.g., circuit A) that is caused by the influence of another coupled circuit (e.g., circuit B). The novel design method also includes selecting the location and component values ​​of the fixed-side-only resonant LCC network so that the fixed-side-only resonant LCC network tunes the "reflected" fixed-side coil impedance due to the impedance on the rotating-side coil outside the fixed-side-only resonant LCC network. For example, with the appropriate location and size of the capacitive components of the fixed-side-only resonant LCC network, the capacitive components of the fixed-side-only resonant LCC network (e.g., Figure 2 The proper placement and size of the C1 capacitor (shown in Figure 1) tunes the rotating side winding of the electric motor from the stationary side.

[0032] With the fixed side only resonant LCC network configuration, the primary side coil acts as a constant current source that is load independent and coupling coefficient independent. With this property of the fixed side only resonant LCC network, the primary coil current does not depend on the rotor current or the relative position of the primary and secondary coils. As a result, the root mean square (RMS) value of the inverter output current (which will have both active and reactive components) is directly related to the output current of the fixed side only resonant LCC network. In the disclosed electric motor drive system configuration, no secondary side compensation network is used or required. By high coupling coefficient and large L rotor inductor, eliminating the need for a tuning network. The L2 inductor can be referenced to the primary side and the C1 capacitor ( Figure 2 With proper design and dimensioning of the secondary winding (shown in Figure 1), the secondary winding can be tuned from the primary side. This configuration of the electric motor drive system has a significant impact on the L rotor inductance( Figure 2 ) is also not sensitive because the rotor winding inductance is on the DC side of the electric motor (i.e., from Figure 2 ), and the inductor in steady state operates as a short circuit at DC voltage and current. Therefore, L rotorThe inductance introduces a time constant only when the current changes from one value to another. In addition to introducing a time constant (inertia of the current change), the inductance is not reflected to the rectifier input and the primary side. Therefore, the novel rotor winding current prediction technique is operable to predict the rotor current by deriving the rotor current as a function of other fixed-side system parameters and the inverter output current, which is easy to measure, easy to process, and easy to control from the fixed side. In addition, because the LCC tuning on the primary side is configured and arranged so that there is no compensation on the secondary side (e.g., there is no one or more resonant tuning capacitors), the tuning circuit on the secondary side is simplified (i.e., the only tuning element on the secondary side is the secondary winding), the need to identify and provide a high temperature rotating side capacitor is eliminated, the cost associated with the secondary side tuning components is eliminated, and the overall reliability of the wireless motor excitation system is improved.

[0033] Turning now to a more detailed description of embodiments of the present disclosure, Figure 1 A system 100 embodying aspects of the present disclosure is depicted. The system 100 includes an energy source 110 electronically coupled to an electric motor drive system 102. The electric motor drive system 102 includes a resonant inverter 120, a DC excitation motor 130, and a controller 150, configured and arranged as shown. According to aspects of the present disclosure, the DC excitation motor 130 includes a fixed-side only compensation network 140 and a network of one or more fixed-side sensors 170. Further according to aspects of the present disclosure, the controller 150 includes a rotor winding current prediction module 160. Although the resonant inverter 120, the DC excitation motor 130, the fixed-side only compensation network 140, and the controller 150 are depicted as separate components, it should be understood that the resonant inverter 120, the DC excitation motor 130, the fixed-side only compensation network 140, and the controller 150 can be configured and arranged in any suitable combination. For example, the controller 150 may be incorporated into the resonant inverter 120 ; the resonant inverter 120 may be incorporated into the DC excitation motor 130 ; and / or the resonant inverter 120 and the controller 150 may be incorporated into the DC excitation motor 130 .

[0034] The energy source 110 can be implemented in various forms (including, for example, as a battery). In some embodiments of the present disclosure, the battery can be a battery pack having a group of one or more individual battery cells connected in series or in 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 pack). For example, the BCM can monitor several battery pack level characteristics, such as the battery pack current, battery pack voltage, and battery pack temperature measured by a current sensor. The battery pack can be recharged by an external power source (not shown). The battery pack may include power conversion electronics that are operable to regulate power from an external power source to provide the battery pack with appropriate voltage and current levels. The individual battery cells within the battery pack may be composed of various chemical formulas. The battery pack chemical composition may include, but is not limited to, lead acid, nickel cadmium (NiCd), nickel metal hydride (NIMH), lithium ion, or lithium ion polymer.

[0035] The resonant inverter 120 is electrically coupled between the energy source 110 and the DC excitation motor 130 to transfer excitation energy from the energy source 110 to the DC excitation motor 130. More specifically, the resonant inverter 120 is operable to provide energy from the energy source 110 to the fixed-side compensation network 140 of the DC excitation motor 130 at a desired resonant frequency for the purpose of providing excitation to the DC excitation motor 130. In an embodiment of the present disclosure, the resonant inverter 120 is operable to convert the DC voltage from the energy source 110 into an AC current of a desired resonant frequency according to the requirements of the DC excitation motor 130 and the fixed-side compensation network 140 for motor excitation. In an embodiment of the present disclosure, the resonant inverter 120 may be a full-bridge resonant inverter having four switches organized into two "phase legs". Each phase leg may include two switches connected in series and connected between a positive DC rail and a negative DC rail. A phase node may be positioned between the two switches of each phase leg to provide a phase of an AC waveform output of a desired resonant frequency. In some embodiments of the present disclosure, the resonant inverter 120 generates HF AC. The controller 150 is electrically coupled to the phase leg switches to control the on / off state of the switches, thereby controlling the frequency and phase of the AC waveform generated by the resonant inverter 120. The controller 150 includes a computing device (with memory) including a computer, a microprocessor digital signal processor, and the like configured and operable to execute software commands and programs, and may include associated firmware so that the controller 150 is configured and operable to control the on / off switching operation of the resonant inverter 120.

[0036] The controller 150 is also configured to send various control commands to the DC-excited motor 130 to control, for example, the torque and / or speed of the motor 130. In order to provide accurate control commands, the controller 150 must be able to monitor the current (e.g., I rotor ) state. A straightforward approach to monitoring the actual rotor winding current would be to place one or more current sensors at selected locations on the rotor and then configure the sensors with sufficient electronics (e.g., as IoT devices) to transmit the readings to the current regulation system of the controller 150. However, for many of the same reasons why it is difficult to place a resonant tuning network or compensation network on the rotating side of the motor 130, it is also difficult to place current sensors on the rotating side of the motor 130 and reliably obtain wired or wireless readings from current sensors that rotate at the same rate (e.g., approximately 22,000 RPM) and are exposed to the same high temperatures as the rotor of the motor 130. To address this issue, embodiments of the present disclosure configure the controller 150 to include a rotor winding current prediction module 160. According to aspects of the present disclosure, the controller 150 receives inverter output current / voltage readings (e.g., Figure 2 I shown in inv_o 、V inv_o ), and uses this reading along with other parameters of the system 100 to predict the rotor winding current without having to directly measure the rotor winding current. Additional details of the controller 150 and the rotor winding current prediction module 160 are described in Figures 2 to 10 and described in more detail later in this document.

[0037] The DC excitation motor 130 can be any compromise motor design suitable for the work to be performed by the motor. In conventional automotive-based motor applications, examples of work that can be done by the motor include operating or moving power windows; power seats; fans for heaters and radiators; windshield wipers; and / or the engine of a vehicle with a hybrid electric vehicle configuration. Regardless of the type of DC excitation motor 130, it relies on electromagnetic and flipping magnetic fields to generate mechanical power. Conventional implementations of DC excitation motors 130 include five basic parts, namely a stator; a rotor; a solid shaft; a coil; and a so-called "squirrel cage". The windings of a DC excitation motor stator are rings of electromagnets that are paired in sequence and energized, which produces a rotating magnetic field. The rotor in a DC excitation motor does not have any direct connection to the power supply and has no brushes. Instead, it often uses the squirrel cage described previously. The squirrel cage in a DC excitation motor is a set of rotor bars connected to two rings, one at each end. The squirrel cage rotor goes inside the stator. When the excitation power is sent through the stator, it generates EMF. The bars in the squirrel cage rotor are conductors, so they react to the flipping of the stator's magnetic poles, which causes the rotor to spin and create its own magnetic field. The key to an induction motor (where the rotor's magnetic field is induced by the stator's magnetic field) is that the rotor is always trying to catch up. It's always seeking static equilibrium, so it's spinning to find that stable state. However, the EMF generated by the stator is always a little faster than the rotor's magnetic field. The rotation of the rotor creates the torque needed to produce the mechanical power to turn the wheels of a car or the blades of a fan. Some DC-excited motors use a wound rotor (such as a WRSM), which is wrapped with wire instead of a squirrel cage. In either case, there is only one moving part in a DC-excited motor, which means there are fewer things to replace or maintain.

[0038] In some embodiments of the present disclosure, the DC excitation motor 130 may be a WRSM. A WRSM is a rotary electric motor having 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 made with an excitation winding instead of a permanent magnet. The rotor rotates in a magnetic field, and the magnetic field may be generated by windings or excitation coils. In the case of a machine with an excitation coil, an excitation current must flow in the coil to generate a magnetic field, otherwise no power is transferred to or from the rotor. The excitation coil produces the most flexible form of flux regulation and deregulation, but at the expense of the flow of current. Conventionally, the rotor windings of a WRSM can be powered or excited with a slip ring and brush assembly. However, the slip ring and brush system has disadvantages, including low efficiency at high speeds, frequent maintenance requirements, and overall losses, especially at high speeds due to the high contact resistance between the brush and slip ring system.

[0039] In order to avoid the disadvantages of the slip ring and brush assembly excitation method, only the fixed side compensation network 140 is incorporated into the RT compensation system (not shown separately from the motor 130), which is operable to provide a wireless excitation or wireless power transfer from the stator side of the motor 130 to the rotor side of the motor 130. In an embodiment of the present disclosure, only the fixed side compensation network 140 can be implemented as a specially designed fixed side only RT compensation system. In general, RT is a circuit and method for wireless power transfer to the rotor winding of the WRSM for controlled excitation. RT is basically the same as a conventional transformer because it transfers electrical energy from one circuit to another at the same frequency but different voltages. In general, a conventional transformer works according to the principle of electromagnetic induction, that is, an electromotive force is induced in a closed circuit due to a variable magnetic field around it. RT differs from a conventional transformer in that the geometry of the RT is arranged so that the primary winding and the secondary winding can rotate relative to each other, with negligible changes in electrical characteristics. In a known configuration, the RT can be constructed by winding the primary winding and the secondary winding into separate halves of a cup-shaped core. The concentric halves face each other with each half mounted on one of the parts that rotate relative to each other. Magnetic flux provides coupling from one half of the cup core across the air gap to the other half, providing M that couples energy from the primary winding of the RT to its secondary winding.

[0040] In conventional RT designs that provide resonant tuning or compensation (i.e., RT compensation systems), the resonant tuning network (or compensation network) is provided on both the stationary (or primary) side and the rotating (or secondary) side 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, due to very limited rotor space and high temperature rotor operating conditions that exceed the temperature ratings of commercially available compact capacitors, it is difficult to place a resonant tuning network or compensation circuit on the secondary side in practice. In addition, having a resonant tuning capacitor on the secondary side increases the complexity of the rotating parts, increases mechanical mass, increases inertia, and reduces mechanical reliability, especially at high rotational speeds.

[0041] The fixed-side-only compensation network 140 solves the difficulties associated with going beyond on-paper design and computer simulation and actually implementing (i.e., building and using) conventional RT compensation system designs including fixed-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). More specifically, the fixed-side-only compensation network 140 is operable to facilitate wireless delivery of rotor excitation current from the fixed side to the rotating rotor, thereby eliminating brush and slip ring maintenance issues, as well as the inefficiencies, manufacturing challenges, and design drawbacks associated with brush and slip ring systems.

[0042] In aspects of the present disclosure, the fixed-side-only compensation network 140 takes into account the absence of a resonant tuning capacitor on the secondary side by providing an additional resonant tuning capacitor on the primary side (i.e., one of the resonant tuning capacitors of the LCC network embodiment of the fixed-side-only compensation network 140) and adjusting the two primary-side resonant tuning capacitors so that the uncompensated secondary side does not impose inefficiencies or other disadvantages on the network 140. In an embodiment of the present disclosure, a fixed-side-only LCC design method is provided, the method including reflecting the impedance and / or inductance of the secondary side to the primary side, and the secondary coil (e.g., Figure 2 The leakage inductance of L2) shown in Figure 1 is tuned on the primary side. In general, reflected impedance (or inductance) is the portion of the impedance of a circuit (e.g., circuit A) that is caused by affecting another coupled circuit (e.g., circuit B). In an embodiment of the present disclosure, this can be achieved by deriving an equivalent circuit model of system 100 and an overall impedance model of system 100, which allows the calculation of the reflected impedance from the secondary to the primary. Further simplifications are applied to the derived equivalent circuit model so that the total impedance seen by the resonant inverter 120 can be calculated. In order to tune this total impedance to unity power factor, the tuning capacitor of the LCC design (e.g., Figure 2 Thus, the fixed side only compensation network 140 eliminates the need for capacitor tuning on the secondary side, as well as the need for one or more secondary side resonant tuning capacitors and their tuning, by providing additional primary side tuning components (e.g., one or more resonant tuning capacitors) and adjusting the values ​​of the tuning components on the primary side. Additional details of the fixed side only LCC design and its associated design methods according to aspects of the present disclosure are provided in Figure 2 and Figures 11 to 15 is shown in and subsequently described herein.

[0043] Figure 2 A system 100A is depicted having a DC link capacitor (C dc ) is electronically coupled to a vehicle battery 110A of an electric motor drive system 102A. The system 100A is a system 100 ( Figure 1 ) is a non-limiting example embodiment; the vehicle battery 110A is the energy source 110 ( Figure 1 ) is a non-limiting example embodiment; and the electric motor drive system 102A is an electric motor drive system 102 ( Figure 1 1 and 1 . The electric motor drive system 102A may be implemented as a resonant inverter 120A electronically coupled to a controller 150 and a simplified representation of an electric machine 130A. The resonant inverter 120A is an inverter 120 ( Figure 11. The controller 150 is operable to include a rotor winding current prediction module 160. The motor 130A is a DC excitation motor 130 ( Figure 1 The motor 130A includes a novel stationary-side resonant LCC 140A, a network of one or more sensors 170 (e.g., IoT devices), a stationary-side excitation winding L1, a rotating-side excitation winding L2, a rectifier 210, and a rotor inductance L rotor and rotor resistance R rotor The novel fixed-side-only resonant LCC 140A is a novel fixed-side-only compensation network 140 ( Figure 1 1 and 10. The system 100A includes a fixed side (e.g., a stator side) 220 and a rotating side (e.g., a rotor side) 230. In general, the fixed side 220 includes the stator winding L1 and circuit elements on its left side, and the rotating side 230 includes the stator winding L2 and circuit elements on its right side. Although the resonant inverter 120A, the motor 130A, and the controller 150 are depicted as separate components, it should be understood that the resonant inverter 120A, the motor 130A, and the controller 150 can be configured and arranged in any suitable combination of components. For example, the controller 150 can be incorporated into the resonant inverter 120A; the resonant inverter 120A can be incorporated into the motor 130A; and / or the resonant inverter 120A and the controller 150 can be incorporated into the motor 130A.

[0044] Still reference Figure 2 The fixed side 220 is configured to transfer power to the rotating side 230 using inductive power transfer, and the rotating side 230 is configured to receive power from the fixed side 220 via inductive power transfer. The fixed side 220 includes a DC vehicle battery 110A, a DC link capacitor C dc, resonant inverter 120A, only fixed side resonant LCC 140A and stator side coil L1. The resonant inverter 120A receives a DC input signal from a vehicle battery 110A and converts the DC input signal into an AC output signal of a desired resonant frequency. In some embodiments of the present disclosure, the resonant inverter 120A is a full-bridge inverter circuit, which is operable to include four power electronic switching devices T1, T2, T3, T4, configured and arranged as shown. The switching devices T1, T2, T3, T4 can be implemented in any suitable format, including but not limited to metal oxide semiconductor field effect transistors (metal oxide semiconductor field effect transistors, MOSFET), BJT, FET, IGBT, IGFET and the like. The 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 controller 150 turns on and off the switching devices T1, T2, T3, T4 to generate an AC output signal V at a desired resonant frequency. inv_out The controller 150 comprises a computing device (with memory) including a computer, microprocessor, digital signal processor, and the like configured and operable to execute software commands and programs, and may include associated firmware such that the controller is configured and operable to control the on / off switching operation of the resonant inverter 120A.

[0045] The controller 150 is also configured to send various control commands to the DC excitation motor 130A to control, for example, the torque and / or speed of the motor 130A. In order to provide accurate control commands, the controller must be able to monitor the rotor winding L entering the motor 130A. rotor Monitor the current entering the rotor winding L rotor A straightforward approach to measuring the actual current would be to place one or more current sensors at selected locations on the rotor and then configure the sensors with sufficient electronics (e.g., as IoT devices) to transmit the readings to the current regulation system of the controller 150. However, for many of the same reasons why it is difficult to place a resonant tuning network or compensation network on the rotating side 230 of the motor 130A, it is also difficult to place current sensors on the rotating side 230 of the motor 130A and reliably obtain wired or wireless readings from current sensors that rotate at the same rate (e.g., approximately 22,000 RPM) and are exposed to the same high temperatures as the rotor of the motor 130A. To address this issue, the controller 150 is operable to include a rotor winding current prediction module 160. According to aspects of the present disclosure, the controller 150 receives the inverter output current / voltage readings (I inv_out 、V inv_out), and uses this reading along with other parameters of the system 100A to predict the rotor winding current I rotor , without having to directly measure the rotor winding current I rotor Additional details of the controller 150 and the rotor winding current prediction module 160 are provided in Figures 3 to 10 and described in more detail later in this document.

[0046] Only the stationary-side resonant LCC 140A interconnects the resonant inverter 120A with the stator-side coil L1. Figure 2 In the non-limiting example embodiment of the present disclosure depicted in FIG. 1 , only the stationary-side resonant LCC 140A is configured to include a stator-side inductor L f1 , stator side series capacitor C1 (connected in series with stator side coil L1) and stator side parallel capacitor C f1 (With stator side inductor L f1 The stator-side series capacitor C1 is coupled in series to the positive terminal of the stator-side coil L1, and the stator-side parallel capacitor C f1 Coupled in parallel with the stator side coil L1.

[0047] The rotating side 230 includes a rotor side coil L2 electrically coupled to a rectifier 210. The rotor side coil L2 is close enough to the stator side coil L1 to be within the EMF generated by the stator side coil L1, so that M is between the stator side coil L1 and the rotor side coil L2. The rotor side coil L2 uses M to generate AC current, and the rectifier 210 converts the AC current to DC current (Irotor). In some embodiments of the present disclosure, the rectifier 210 is a bridge rectifier circuit including four diodes D1, D2, D3, and D4. The DC current is provided to the rotor of the motor 130A. The rotor is Figure 2 is represented as a resistor R rotor The series inductor L rotor .

[0048] Energy is transferred between the stator side coil L1 and the rotor side coil L2 via M, and any L1 / L2 leakage inductance does not contribute directly to the active power transfer. Leakage inductance can also be undesirable because it causes the voltage to change with load. In a conventional method of reducing leakage inductance and increasing M, a rotor side compensation circuit (e.g., a rotor side capacitance circuit / element) is provided on the rotating side 230. However, for applications such as systems 100, 100A, where the rotor side rotates relative to the stator side, it is extremely difficult to manufacture a rotor with a rotor side compensation circuit. Embodiments of the present disclosure avoid the need for rotor side compensation circuits / elements by configuring and arranging a fixed side resonant LCC 140A only so that the compensation provided by the rotor side compensation circuit / element on the rotating side 230 in a conventional RT compensation design is provided instead by the design and component value setting of the fixed side resonant LCC 140A only. Additional details of the fixed side resonant LCC 140A only design and its associated design methods according to aspects of the present disclosure are described in detail in the accompanying drawings. Figures 3 to 15 is shown in and subsequently described herein.

[0049] Figure 3 1 depicts additional details of how the controller 150 may be implemented as a current / voltage controller 150A having a rotor winding current prediction module 160A and a current / voltage regulation module 320. The controller 150A is also configured to send various control commands to the DC-excited motor 130A to control, for example, the torque and / or speed of the motor 130A. In order to provide accurate control commands, the controller must be able to monitor the rotor winding L entering the motor 130A. rotor The current I rotor state. To avoid the difficulties associated with placing a current sensor on the rotating side of the motor 130A and reliably obtaining wired or wireless readings from a current sensor that rotates at the same rate (e.g., about 22,000 RPM) and is exposed to the same high temperature as the rotor of the motor 130A, the controller 150A is operable to include a rotor winding current prediction module 160A. According to aspects of the present disclosure, the controller 150A receives the inverter output current / voltage readings from one or more fixed-side sensors 170 and uses the readings along with other parameters of the system 100A (f(C1, C f1 , L f1 , L m , L s1 )310) is used to predict the rotor winding current without having to directly measure the rotor winding current.

[0050] The rotor winding current prediction module 160 uses the characteristics of the fixed-side resonant LCC 140A to make the rotor winding current I rotor can be based at least in part on the current I generated by the resonant inverter inv_outThe measurement and analysis of is estimated. With the configuration of only the fixed-side resonant LCC network 140A, the primary-side coil L1 acts as a constant current source that is load-independent and coupling coefficient-independent. With this property of only the fixed-side resonant LCC network 140A, the primary coil current does not depend on the rotor current or the relative positions of the primary and secondary coils L1, L2. As a result, the inverter output current I inv_out The RMS value of (which will have both active and reactive components) is directly related to the output current of the fixed-side resonant LCC network 140A alone. In the disclosed configuration of the electric motor drive system 100, 100A, no secondary-side compensation network is used or required. By high coupling coefficients and large L rotor inductor, eliminating the need for a tuning network. The L2 inductor can be referenced to the primary side, and with proper design and sizing of the C1 capacitor, the secondary winding can be tuned from the fixed (or primary) side 220. This configuration of the electric motor drive system 102A has a significant impact on the L rotor Inductance is also insensitive because the rotor winding inductance is on the DC side of the electric motor 130A, and the inductor in steady state operates as a short circuit at DC voltage and current. Therefore, the inductor (L rotor ) introduces a time constant only when the current changes from one value to another. In addition to introducing a time constant (the inertia of the current change), this inductance is not reflected to the rectifier input and primary side. Therefore, the novel rotor winding current prediction module 160, 160A is operable to derive the rotor current L rotor As other system parameters and inverter output current I inv_out The function used to predict the rotor current L rotor , the inverter output current is easy to measure from the fixed side, easy to process and easy to control.

[0051] A non-limiting example of how the functions of the controller 150A and the rotor winding current prediction module 160A may be implemented is described in Figures 4 to 10 and described in more detail later herein. Figures 4 to 10 The diagrams and equations depicted in are provided as non-limiting implementation examples. Therefore, for the sake of brevity, some well-known details associated with the equations are briefly mentioned or not provided. First, turn to Figure 4 , in order to analyze Figure 2 In the circuit of the system 100A in FIG. 1 , the coupled inductor model 100B of the primary and secondary windings L1, L2 can be used together with the self-inductance and leakage inductance of each side 220, 230 and the coupling coefficient. The parameters of the coupled inductor model 100B of the rotor transformer windings L1, L2 are defined as follows: L1: primary side self-inductance; L m : Mutual inductance; L s1 : primary side leakage inductance; L2: secondary side self-inductance; L s2: Secondary leakage inductance; L s ′ 2: secondary leakage inductance referred to the primary side; and n: number of turns, n1 / n2. For each side of the transformer, the self-inductance is equal to the leakage inductance plus the magnetizing inductance. Therefore, we can write Figure 7 The rectifier output resistance (or rotor winding resistance) can be referenced to (or reflected to) the resistance given by Equation-1 to Equation-8. Figure 8 The equivalent load resistance R L rectifier input. When the resistor R L When used with the coupled inductor model 100B, the turns ratio between turns should be considered, as given by Equation-10 ( Figure 8 ) as depicted, where R L is the load resistance referenced to (or reflected to) the rectifier input; and R' L is the equivalent load resistance referenced to (or reflected to) the fixed (or primary) side 220 .

[0052] Using the above definitions of inductance and load resistance, the circuit diagram of system 100A (i.e., electric motor drive system 102A) can now be redrawn as Figure 5 The system 100C shown. Figure 5 As shown, the rotor current I' RL is the difference between the two branch currents, as given by Equation-11 ( Figure 8 As shown in the figure, Cf1 =U Cf1 x f1 , and I m =U m / (jωL m ), so then the rotor current can be rewritten as Equation-12 ( Figure 8 Here, U m will be equal to U Cf1 voltage plus including C1 and L S1 The voltage drop across the branch of . Therefore, equation-13 and equation-14 can be generated ( Figure 8 Here, I Cf1 You can use U cf1 x f1 Substituting, to generate Equation-15( Figure 8 ).

[0053] like Figure 5 As shown, U Cf1 The voltage can be written as the inverter output voltage minus the tuning inductor L f1 The voltage drop across the terminals is given by Equation-16 ( Fig. 9By this replacement, U m It can be obtained from equation-17( Fig. 9 As shown in the figure, U is required for the magnetization branch. m / jωL m , so we can generate equation-18( Fig. 9 In the generated U m / jωL m In the case of , the rotor current can be rewritten as shown in Equation-19 ( Fig. 9 ). m / jωL m and U CF1 =V inv0 –I inv0 xj m It can be expressed as Equation-20, Equation-21 and Equation-22 ( Fig.10 Finally, the rotor current is given by Equation-23 ( Fig.10 ) and / or Equation-24 ( Fig.10 ) are given.

[0054] from Figures 4 to 10 In the example depicted, it can be seen that is represented as and other parameters. In the disclosed representation, the prediction of the rotor current has no dependency on the rotor winding resistance or inductance, and has no dependency on the output voltage. Although there is a dependency on the inverter output voltage (which will change with the inverter duty cycle or the inverter input voltage), the increase or decrease of the rotor current and the inverter output current are linearly proportional. Therefore, the disclosed rotor current prediction is insensitive to the inverter input or output voltage, and it is insensitive to changes in the inverter duty cycle. Control can be performed from the input side of the resonant network (inverter output). and The relationship between is linear. Therefore, can be approximated as a linear equation that uses the inverter output voltage to predict the rotor current. Because the rotating (or rotor) side 230 is an equivalent resistive-inductive load, the rotor current prediction algorithm uses compensation calculations to improve accuracy. Figures 1 to 10 The equations depicted in use the first harmonic approximation of the inverter output voltage and current. Embodiments of the present disclosure also encompass implementing compensation methods to account for voltage and current harmonics at the inverter output voltage and current.

[0055] Figure 6A more general method 600 is depicted showing how the functionality of the controller 150A and the rotor winding current prediction module 160A may be implemented in accordance with an embodiment of the present disclosure. The method 600 begins at block 602, where the rotor current is equal to the inverter output current minus the parallel tuning capacitor current minus the magnetizing branch current. At block 604, the parallel tuning capacitor is written as a function of the branch voltage; and the magnetizing current is written as a function of the branch voltage. In block 606, the magnetizing branch voltage is set equal to the parallel tuning capacitor voltage plus the voltage drop across the series tuning capacitor plus the voltage drop across the primary leakage inductance. At block 608, the parallel tuning capacitor current is replaced by its voltage equation. At block 610, the parallel tuning capacitor voltage is made equal to the inverter output voltage minus the voltage drop across the series tuning inductor. At block 612, the equation obtained by converting the series tuning inductor current is converted. At block 604, the series tuning inductor current is converted based on the inverter output current and other parameters / values ​​(e.g., f(C1, C2)). f1 , L f1 , L m , L s1 ))Extract the rotor current.

[0056] Fig.11 Depicted is a diagram showing that a system 100, 100A ( Figure 1 and Figure 2 110A). In some embodiments of the present invention, portions of method 1100 (e.g., blocks 1112, 1114) may optionally be performed by a computer aided design (CAD) system running on a processor (e.g., having the same processor functionality as controller 150), the processor being operable to perform calculations, circuit modeling, and circuit simulation operations that may optionally be used to select compensation component values ​​for only the fixed side resonant LCC 140A. According to aspects of the present disclosure, the previously described CAD system may be implemented using a CAD software application that is operable to optionally perform Figures 11 to 15 Although the description of method 1100 refers to components of system 100A, the description is equally applicable to one or more corresponding elements of system 100.

[0057] like Fig.11 As shown, the method 1100 begins at block 1102 with generating AC. In an embodiment of the present disclosure, the AC may be HF AC generated by converting DC received from a vehicle battery 110A to HF AC using a resonant inverter 120A. At block 1104, the HF AC is received at a novel fixed-side only compensation / tuning network (e.g., fixed-side only resonant LCC 140A) associated with the primary coil L1.

[0058] Blocks 1112 and 1114 are off-line operations that can be used to design only the fixed side tuning network (e.g., only the fixed side resonant LCC 140A) used at blocks 1104, 1106. At block 1112, the "reflected" fixed side coil impedance due to the impedance on the rotating side coil is calculated. In some embodiments of the invention, the impedance associated with the rotating side or primary coil is reflected to the fixed side. In some embodiments of the invention, the impedance associated with the primary coil and the load (e.g., by Figure 2 L rotor and R rotor denoted) is reflected to the fixed side. At block 1114, the location and component values ​​of the fixed side only tuning network are selected so that the fixed side only tuning network tunes the "reflected" fixed side coil impedance due to the impedance on the rotating side coil outside the fixed side only tuning network. For example, with appropriate location and size of the capacitive components (e.g., C1 capacitor) of the fixed side only tuning network, the rotating side winding (e.g., L2) can be tuned from the fixed side by appropriate location and size of the capacitive components (e.g., C1 capacitor) of the fixed side only tuning network. Additional details of how blocks 1112 and 1114 may be implemented are described in Figures 12 to 15 and described in more detail later herein.

[0059] After the operation at block 1104, the method 1100 moves to block 1106. At block 1106, only the fixed side tuning network design has a compensation component (eg, including two capacitive elements C1, C f1 ), which enables the fixed-side-only tuned network to act as a load and further act as an M-independent constant current source that is operable to generate an alternating current EMF using the AC received at block 1104. Utilizing this property of the fixed-side-only tuned network (e.g., the fixed-side-only resonant LCC 140A), the fixed-side coil (e.g., L1) current does not depend on the rotor current (Irotor) or the relative positions of the fixed-side coil (e.g., L1) and the rotating-side coil (L2). As a result, the AC generated at block 1102 (e.g., generated by the resonant inverter 120A) has an output current root mean square (RMS) value (which will have both active and reactive components) that is directly related to the output current of the fixed-side-only tuned network. The resulting high M value and large L rotor The inductor eliminates the need for a tuning network on the rotating side. The inductance of the rotating side inductor (L2) can be referenced or reflected to the fixed side and the capacitive components (e.g., C f1 capacitors), can be tuned from the fixed side (e.g., by tuning only the capacitive components of the network on the fixed side (e.g., C f1The resulting system 100, 100A tunes the rotating side winding (e.g., L2) by properly positioning and sizing the capacitor. rotor Inductance is also not sensitive because the rotor winding inductance is on the DC side (i.e., from Figure 2 rectifier 210 shown), and the inductor in steady state operates as a short circuit at DC voltage and current. Therefore, L rotor The time constant is introduced only when the current changes from one value to another. In addition to introducing the time constant (the inertia of the current change), L rotor It is not reflected to the input of the rectifier input 210 and the fixed side 220 .

[0060] After the operation at block 1106, the method 1100 moves to block 1108. At block 1108, the AC EMF generated 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. At block 1110, the AC charging current is converted to DC current and provided to downstream motor components (e.g., the rotor, Figure 2 Indicated as L rotor and R rotor ).

[0061] Figures 12 to 15 A more detailed example of a design method for determining component values ​​for a stationary-side-only resonant LCC 140A of a system 100A that eliminates the need for compensation circuits and / or compensation components on the rotating side 230 is depicted. More specifically, Fig.12 depicts a design method 1200 according to an embodiment of the present disclosure; and Figures 13 to 15 Depicted are equivalent circuits and circuit models (systems 100B, 100C, 100D) used in one or more design methods according to embodiments of the present disclosure.

[0062] Go to Fig.12 , will refer to Figures 13 to 15 Some component element labels (e.g., L f1 , C1, C f1 , L1, L2, etc.) to describe method 1200. Fig.12As shown, method 1200 is operable to start in parallel at blocks 1202 and 1212, and then move through multiple paths to generate outputs at blocks 1232 (primary coil current, primary side shunt tuning capacitor current, and voltage across the primary tuning capacitor), 1236 (output voltage and power), and 1222 (primary compensation network design based on the value of the primary side series tuning capacitor (C1) value). At block 1202, method 1200 calculates the primary coil current, the primary side shunt tuning capacitor current, and the voltage across the primary tuning capacitor. At block 1204, method 1200 converts Z in Written as Z 12 and the primary side resonant tuning inductor (L f1 ) is the sum of the inductive reactances of the Z 12 Written as Z cf1 and Z1 in parallel. In the disclosed embodiment, Z1 is the total equivalent impedance seen by the inverter. At block 1208, method 1200 writes Z1 as Z L1 , Z c1 and Z ref sum( Figure 8 =Equation 6 in ( ) and then provides Z1 to block 1210. Substantially in parallel with the operations at blocks 1202-1208, block 1212 calculates the secondary side (ie, rotating side) reflected impedance Z ref , and substitute it into the Z1 equation at block 1210 ( Figure 8 =Equation-6 in the above table.

[0063] Block 1212 also provides its output to block 1214. At block 1214, method 1200 adds the reflected impedance of the secondary side to the impedance of the primary side coil inductance and the series tuning capacitor. At block 1216, method 1200 forms a T network equivalent impedance circuit, calculates the branch impedance and the total equivalent impedance seen by the inverter. At block 1218, method 1200 calculates the inverter output current. At block 1220, method 1200 designs the primary side series tuning capacitor value so that the inverter output reactive power is greatly eliminated. Alternatively, block 1220 can tune off the imaginary part of the total equivalent impedance seen by the inverter. At block 1222, method 1222 designs the primary compensation network according to the value of the primary side series tuning capacitor (C1) value.

[0064] Returning to block 1210, method 1200 moves from block 1210 to block 1230 and calculates whether Z1 and Z in Parallel Z inThe calculations performed in block 1230 are provided to blocks 1232 and 1234. At block 1232, the method 1200 calculates the primary coil current, the primary side shunt tuning capacitor current, and the voltage across the primary tuning capacitor. At block 1234, the method 1200 calculates the secondary side current using the voltage induced on the secondary side along with the total equivalent impedance of the secondary side. The calculations performed at block 1234 are provided to block 1236, where the method 1200 calculates the output voltage and power.

[0065] Therefore, it can be obtained from Figures 11 to 15 As can be seen from the foregoing description, only the fixed side resonant LCC 140A provides technical effects and technical benefits. Although C1 is on the fixed side 230, C1 performs a rotating side compensation function, which is operable to provide compensation for the L2 winding on the rotating side. This rotating side compensation function can be achieved by reflecting the L2 impedance to the fixed side 220 and then using Figures 8 to 15 The various calculations shown in FIG. 1 are implemented to use the reflected impedance as part of the process to develop the value of C1. In some embodiments of the present invention, the impedance associated with the primary coil L2 and the load (as represented by Figure 2 L rotor and R rotor ) is reflected to the fixed side and used to develop the value of C1. In some embodiments of the present disclosure, in addition to compensating the L2 winding from the fixed side 220, C1 also jointly compensates a portion of L1 or L1 and L f1 Therefore, in some embodiments of the present disclosure, the value of C1 depends on L2, L1 and L f1 . C f1 Used to "tune out" L f1 , which provides at least a portion of compensation for the L1 winding on the fixed side 220. In an embodiment of the present invention, the rotor winding current prediction module 160 estimates the rotor current without relying on the L f1 , C f1 and any parameter value of C1.

[0066] For ease of illustration and explanation, the various components / modules of the system shown herein are depicted separately. In embodiments of the present disclosure, the functions performed by the various components / modules / models may be distributed differently than shown without departing from the scope of the various embodiments of the present disclosure described herein, unless otherwise explicitly stated.

[0067] The terms used herein are for the purpose of describing specific embodiments only and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements parts and / or groups thereof.

[0068] The figures described herein are illustrative. There may be many variations of the figures or the steps (or operations) described therein without departing from the spirit of the present disclosure. For example, actions may be performed in different orders, or actions may be added, deleted or modified. In addition, the term "coupling" describes having a signal path between two elements, and does not imply a direct connection between elements, without intermediate elements / connections therebetween. All of these variations are considered to be a part of the present disclosure.

[0069] The following definitions and abbreviations will be used in the interpretation of the claims and specification. As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," "contains," or "containing" or any other variation thereof are intended to cover a non-exclusive inclusion. For example, a composition, mixture, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, mixture, process, method, article, or apparatus.

[0070] Additionally, the term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The terms "at least one" and "one or more" are understood to include any integer greater than or equal to one, i.e., one, two, three, four, etc. The term "plurality" is understood to include any integer greater than or equal to two, i.e., two, three, four, five, etc. The term "connected" may include both indirect "connections" and direct "connections."

[0071] The terms "about," "substantially," "approximately," and variations thereof are intended to include the degree of error associated with measurement of a particular quantity based on the equipment available at the time the application was filed. For example, "about" may include a range of ±8% or 5% or 2% of a given value.

[0072] The flowcharts and block diagrams in the figures illustrate the architecture, functions and operations of possible implementations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, segment or portion of an instruction, which includes one or more executable instructions for implementing one or more specified logical functions. In some alternative embodiments, the functions indicated in the blocks may appear outside the order indicated in the figure. For example, two blocks shown in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order, depending on the functions involved. It will also be noted that each block illustrated in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs a specified function or action or performs a combination of dedicated hardware and computer instructions.

[0073] Although the present disclosure has been described with reference to one or more exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from the scope of the present invention. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the present disclosure without departing from its essential scope. Therefore, it is intended that the present invention is not limited to the specific embodiments disclosed as the best mode contemplated for carrying out the present invention, but that the present invention will include all embodiments falling within the scope of the claims.

Claims

1. An electric drive motor system, comprising: Fixed side; Rotating side; as well as a fixed-side sensor system operable to sense current on the fixed-side and send sensor readings based on the current to a controller; wherein the fixed side includes a compensation network; and Wherein, the controller is operable to perform a rotor current prediction operation, the rotor current prediction operation comprising predicting a rotor current associated with the rotor on the rotating side based at least in part on the current-based sensor reading and a parameter of at least one component of the compensation network on the stationary side.

2. The electric drive motor system according to claim 1, wherein: The stationary side also includes an inverter operable to convert direct current (DC) received from an energy source into alternating current (AC).

3. The electric drive motor system according to claim 2, wherein: The current detected by the fixed-side sensor system comprises the AC.

4. The electric drive motor system according to claim 1, wherein: At least one component of the compensation network on the stationary side comprises a capacitive element.

5. The electric drive motor system according to claim 1, wherein: At least one component of the compensation network on the fixed side includes an inductive element.

6. The electric drive motor system according to claim 5, wherein: At least one component of the compensation network on the fixed side further comprises a capacitive element.

7. The electric drive motor system of claim 1, wherein: The fixed-side compensation network comprises a fixed-side only (OSS) compensation network; and The at least one component of the fixed-side compensation network comprises a first OSS compensation element of the OSS compensation network.

8. The electric drive motor system according to claim 7, wherein: The first OSS compensation element is operable to provide a rotating side compensation function.

9. The electric drive motor system according to claim 8, wherein: The value of the first OSS compensation element is selected to provide the rotating side compensation function.

10. The electric drive motor system of claim 1, wherein: The fixed side includes a stator having a fixed side winding; The rotating side includes a rotor having a rotating side winding; and The stationary side winding is operable to wirelessly transmit an alternating current (AC) excitation signal to the rotating side winding.

11. A method of manufacturing an electric drive motor system, comprising: forming a fixed side; forming a rotating side; as well as forming a fixed-side sensor system operable to detect current on the fixed side and send sensor readings based on the current to a controller; wherein the fixed side includes a compensation network; and Wherein, the controller is operable to perform a rotor current prediction operation, the rotor current prediction operation comprising predicting a rotor current associated with the rotor on the rotating side based at least in part on the current-based sensor reading and a parameter of at least one component of the compensation network on the stationary side.

12. The method according to claim 11, wherein: The stationary side also includes an inverter operable to convert direct current (DC) received from an energy source into alternating current (AC).

13. The method according to claim 12, wherein: The current detected by the fixed-side sensor system comprises the AC.

14. The method according to claim 11, wherein: At least one component of the compensation network on the stationary side comprises a capacitive element.

15. The method according to claim 11, wherein: At least one component of the compensation network on the fixed side includes an inductive element.

16. The method according to claim 15, wherein: At least one component of the compensation network on the fixed side further comprises a capacitive element.

17. The method of claim 11, wherein: The fixed-side compensation network comprises a fixed-side only (OSS) compensation network; and The at least one component of the fixed-side compensation network comprises a first OSS compensation element of the OSS compensation network.

18. The method according to claim 17, wherein: The first OSS compensation element is operable to provide a rotating side compensation function.

19. The method according to claim 18, wherein: The value of the first OSS compensation element is selected to provide the rotating side compensation function.

20. The method of claim 11, wherein: The fixed side includes a stator having a fixed side winding; The rotating side includes a rotor having a rotating side winding; and The stationary side winding is operable to wirelessly transmit an alternating current (AC) excitation signal to the rotating side winding.

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