System and method for indirectly measuring angular position and / or rotational speed of wound rotor motor

Abstract

The present disclosure relates to systems and methods for indirectly measuring the angular position and / or rotational speed of a wound rotor motor. In accordance with various embodiments of the present disclosure, there is provided a system for indirectly measuring the angular position and / or rotational speed of an electric machine having a rotatable shaft, a wound rotor, and a stator having three or more phases. In some embodiments, the system includes a switching converter adapted to provide a current to the wound rotor, the current having a component detectable in the stator; current sensing circuitry adapted to detect a stator current; a filter circuitry adapted to extract a detectable component; and control circuitry for (i) transforming the extracted detectable components into two 90-degree displacement currents, (ii) demodulating the two 90-degree displacement currents to obtain an envelope waveform of the two 90-degree displacement currents, and (iii) analyzing the envelope waveform of the two 90-degree displacement currents to determine the angular position and / or rotational speed of the rotatable shaft.

Description

Technical Field

[0001] Example embodiments of the present disclosure relate generally to electric machines, such as motors, generators, and alternators, and more particularly to systems and methods for indirectly measuring the angular position and / or rotational speed of such electric machines. Background Art

[0002] In motor control applications, it is often necessary to know the angular position and / or speed of the motor's rotor. One method that has been used to determine the angular position and / or speed of the motor's rotor is to use a rotary transformer coupled to the motor. A rotary transformer is a device having a rotating winding that is excited using a high-frequency signal and two fixed windings positioned at 90 degrees to each other. Current flows through the rotating winding, which induces a current in the fixed two-phase winding. The two-phase windings positioned at 90 degrees to each other produce sine and cosine feedback currents. The relative amplitude of the two-phase voltage is measured and used to determine the angle of the rotor relative to the stator. The angular phase can be calculated using an "inverse tangent" function, a phase-locked loop, or other known techniques.

[0003] Applicants have identified numerous technical challenges and difficulties associated with measuring the angular position and / or rotational speed of an electric motor. Through effort, ingenuity, and innovation, Applicants have addressed the problems associated with measuring the angular position and / or rotational speed of an electric motor by developing the solutions embodied in the present disclosure, which are described in detail below. Summary of the Invention

[0004] Various embodiments described herein relate to systems and methods for indirectly measuring the angular position and / or rotational speed of electric machines, such as motors, generators, and alternators.

[0005] According to various embodiments of the present disclosure, a system is provided for indirectly measuring the angular position and / or rotational speed of an electric machine having a rotatable shaft, a wound rotor, and a stator having three or more phases. In some embodiments, the system includes a switching converter adapted to provide a current to the wound rotor, the current having a component detectable in the stator; a current sensing circuit system adapted to detect the stator current of each of three or more phases; a filtering circuit system adapted to extract the detectable component of the current provided to the wound rotor from the stator current of each of the three or more phases detected; and a control circuit system for (i) converting the detectable component of the current provided to the wound rotor extracted from the stator current of each of the three or more phases detected into two 90-degree-displaced currents, (ii) demodulating the two 90-degree-displaced currents to obtain an envelope waveform of each of the two 90-degree-displaced currents, and (iii) analyzing the envelope waveforms of the two 90-degree-displaced currents to determine the angular position and / or rotational speed of the rotatable shaft.

[0006] In some embodiments, the detectable component of the current provided to the wound rotor includes a ripple current of a switching current provided to the wound rotor.

[0007] In some embodiments, the detectable component of the current provided to the wound rotor comprises a sinusoidal signal having a lower frequency than the switching current provided to the wound rotor.

[0008] In some embodiments, the detectable component of the current provided to the wound rotor has a frequency that is adjustable and related to the rotational speed of the rotatable shaft.

[0009] In some embodiments, the filtering circuitry is adjustable to enable extraction of a detectable component of the current provided to the wound rotor having an adjustable frequency.

[0010] In some embodiments, the frequency of the detectable component of the current provided to the wound rotor is at least four times the frequency of the envelope waveforms of the two 90 degree displaced currents.

[0011] In some embodiments, the control circuitry uses a Clarke transform to transform a detectable component of the current provided to the wound rotor, extracted from the detected stator current of each of the three or more phases, into two 90 degree displaced currents.

[0012] In some embodiments, the control circuitry analyzes the envelope waveforms of the two 90 degree displacement currents to determine the angle and / or rotational speed of the rotatable shaft using a phase locked loop or an inverse tangent function.

[0013] In some embodiments, the electric machine comprises a motor, a generator, or an alternator.

[0014] In some embodiments, the electric machine comprises an electrically excited synchronous motor.

[0015] According to various embodiments of the present disclosure, a method for indirectly measuring the angular position and / or rotational speed of an electric motor is provided, the electric motor having a rotatable shaft, a wound rotor, and a stator, the stator having three or more phases. In some embodiments, the method includes: providing a current to the wound rotor, the current having a component detectable in the stator; detecting the stator current of each of the three or more phases; extracting the detectable component of the current provided to the wound rotor from the stator current of each of the three or more phases detected; transforming the detectable component of the current provided to the wound rotor extracted from the stator current of each of the three or more phases detected into two 90-degree-displaced currents; demodulating the two 90-degree-displaced currents to obtain envelope waveforms of the two 90-degree-displaced currents; and analyzing the envelope waveforms of the two 90-degree-displaced currents to determine an estimate of the angular position and / or rotational speed of the rotatable shaft.

[0016] The above summary is provided merely to summarize some embodiments and provide a basic understanding of some aspects of the present disclosure. Therefore, it should be understood that the embodiments described above are merely examples and should not be construed as narrowing the scope or spirit of the present disclosure in any way. It should also be understood that the scope of the present disclosure encompasses many possible embodiments beyond those summarized herein, some of which are further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The description of the illustrative embodiments may be read in conjunction with the accompanying drawings. It should be appreciated that, for simplicity and clarity of illustration, the elements illustrated in the drawings are not necessarily drawn to scale unless otherwise noted. For example, the dimensions of some of the elements may be exaggerated relative to other elements unless otherwise noted. The various embodiments of the teachings of the present disclosure are shown and described with respect to the drawings presented herein, wherein

[0018] Figure 1 illustrates an example stator current waveform of an example system for indirectly measuring the angular position and / or rotational speed of an electric machine having a wound rotor according to some embodiments of the present disclosure;

[0019] Figure 2 illustrates an example transformed stator current waveform of an example system for indirectly measuring angular position and / or rotational speed of an electric machine having a wound rotor according to some embodiments of the present disclosure;

[0020] Figure 3illustrates an example demodulated stator current waveform of an example system for indirectly measuring angular position and / or rotational speed of an electric machine having a wound rotor according to some embodiments of the present disclosure;

[0021] Figure 4 is an example block diagram illustrating an example system for indirectly measuring the angular position and / or rotational speed of an electric machine having a wound rotor according to an example embodiment of the present disclosure;

[0022] Figure 5 is an example block diagram illustrating an example system for indirectly measuring the angular position and / or rotational speed of an electric machine having a wound rotor according to an alternative example embodiment of the present disclosure; and

[0023] Figure 6 is an example flow chart illustrating an example method for indirectly measuring the angular position and / or rotational speed of an electric machine having a wound rotor according to an example embodiment of the present disclosure. DETAILED DESCRIPTION

[0024] Some embodiments of the present disclosure will now be described more fully with reference to the accompanying drawings, which illustrate some, but not all, embodiments of the present disclosure. Indeed, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout.

[0025] As used herein, for purposes of explanation, terms such as "front," "back," "top," and the like are used in the examples provided below to describe the relative positions of certain components or portions of components. Furthermore, in light of this disclosure, the terms "substantially" and "approximately" indicate that the referenced element or associated description is accurate to within applicable engineering tolerances for those of ordinary skill in the art.

[0026] As used herein, the term "comprising" means including, but not limited to, and should be interpreted in the manner in which it is commonly used in a patent context. The use of broad terms such as including, comprising, and having should be understood to provide support for narrower terms such as consisting of, consisting substantially of, and consisting essentially of.

[0027] Phrases such as "in one embodiment," "according to one embodiment," and the like generally mean that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure, and may be included in more than one embodiment of the present disclosure (importantly, such phrases are not necessarily referring to the same embodiment).

[0028] The word “example” or “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations.

[0029] If the specification states that a component or feature "may", "could", "might", "should", "would", "preferably", "likely", "typically", "optionally", "for example", "often", or "might" (or other such language) is included or that a component or feature "may", "could", "might", "should", "would", "preferably", "likely", "typically", "optionally", "for example", "often", or "might" (or other such language) has a feature, then the particular component or feature is not required to include or have that feature. Such a component or feature may optionally be included in some embodiments, or it may be excluded.

[0030] Various embodiments of the present disclosure overcome the aforementioned technical challenges and difficulties and provide various technical improvements and advantages, based on, for example, but not limited to, providing example systems and methods for indirectly measuring the angular position and / or speed of an electric motor having a wound rotor without the use of a rotary transformer or other type of sensor. Various embodiments of the present disclosure provide example systems and methods for indirectly measuring the angular position and / or speed of electric motors such as motors, generators, and alternators. For simplicity, embodiments of the present disclosure are described herein only with respect to electric motors; however, embodiments of the present disclosure can also be used to indirectly measure the angular position and / or speed of generators and alternators. In various embodiments, the accuracy of the indirect measurement of the angular position and / or speed of the electric motor depends primarily on the accuracy of the current measurement, the interpolation method between measurements, and the variability of the speed associated with the mechanical parameters of the machine. The indirect measurement of the angular position and / or speed of the electric motor by various embodiments of the present disclosure is sufficient to implement field-oriented control of the electric motor in a manner equivalent to using a rotary transformer.

[0031] Various embodiments of the present disclosure provide example systems and methods for indirectly measuring the angular position and / or rotational speed of a three-phase or multi-phase (i.e., more than three-phase) electric motor having a wound rotor (rather than a permanent magnet rotor), such as, but not limited to, an electrically excited synchronous motor (EESM) and an induction motor. A wound rotor motor (e.g., an EESM) has dedicated rotor windings that are used to provide a constant magnetic field when supplied with DC current (just like the permanent magnets in a permanent magnet synchronous motor). For simplicity, embodiments of the present disclosure are described herein only with respect to a three-phase electric motor; however, embodiments of the present disclosure can also be used to indirectly measure the angular position and / or rotational speed of a multi-phase electric motor.

[0032] Various embodiments of the present disclosure enable indirect measurement of the rotational position of the rotor at zero speed (stationary) and low speeds, thereby enabling the use of advanced motor control algorithms to generate nominal torque without torque ripple.

[0033] Various embodiments of the present disclosure do not require detailed information about the motor model, such as inductance curves and winding resistance, as may be required in other sensorless approaches that have been used.

[0034] Various embodiments of the present disclosure involve injecting a periodic signal into the rotor winding that introduces a small ripple in the field (i.e., rotor) current. The field current component affects the stator winding and can therefore be extracted from the stator current. In this respect, the rotor and stator of a wound-rotor motor itself function somewhat like a resolver, but with the windings displaced 120° instead of 90°.

[0035] In various embodiments of the present disclosure, the high-frequency harmonic components of the stator current contain position information and speed information. Thus, in various embodiments, a high-pass filter or a band-pass filter is used to extract the high-frequency response from the stator current.

[0036] Various embodiments of the present disclosure inject a sinusoidal signal into the field winding to generate a field current (I f ) to introduce a small ripple in the stator that is high enough to produce the desired effect without introducing undesirable torque ripple. In various embodiments, this is achieved by ensuring that the switching frequency (f SW ) (i.e., the frequency of the signal provided to the rotor winding (e.g., from a switching converter) to induce the desired magnetic field) is greater than the frequency of the injected signal (f HFI ) is high enough (e.g., at least about ten times higher) to achieve this. For example, in some embodiments, the frequency of the injected signal (f HFI ) is approximately 1.5 to 5 kilohertz (kHz), and the switching frequency (f SW ) is approximately 15 to 50kHz.

[0037] In various embodiments, the frequency of the injected signal should be several times greater than the rotational speed of the motor (e.g., 5 to 10 times). In some embodiments, the frequency of the injected signal can vary based on the speed of the motor (i.e., lower frequency at lower speeds and higher frequency at higher speeds). In such embodiments where the frequency of the injected signal varies based on the speed of the motor, an adjustable high-pass filter or band-pass filter (e.g., a high-pass filter or band-pass filter implemented in software where the passband frequency range can be adjusted as needed) is used to extract the high-frequency response from the stator current.

[0038] Various embodiments of the present disclosure may be implemented within a system or apparatus for controlling an electric motor, for example, which is often referred to as a drive system or motor controller.

[0039] Now, reference Figure 1 , illustrates an example stator current waveform 100 of an example system for indirectly measuring angular position and / or rotational speed of an electric machine having a wound rotor. Figure 1 The stator currents 102, 106, 110 (also labeled I U,HF , I V,HF , I W,HF ) in which high frequency components (i.e., signals injected with a frequency higher than the current provided to the stator windings to rotate the motor) are extracted for all three phases of a three-phase motor. Because this is for a three-phase motor, the stator currents are offset by 120 degrees from each other. In various embodiments, the example stator currents 102, 106, 110 are modulated according to the rotor position during rotation of the motor shaft. Figure 1 As shown, the stator current of each phase has an envelope waveform 104, 108, 112, which contains information about the rotor position and speed (in various embodiments, the envelope waveforms 104, 108, 112 are not obtained at this time, but are used for explanation purposes). Figure 1 is shown in ).

[0040] In various embodiments, the extracted high-frequency components of the three stator currents (if the motor is a three-phase motor) are transformed into two 90-degree offset currents using any method or technique suitable for such transformation, including but not limited to the Clarke transform. In this regard, the extracted high-frequency components can be used to determine the angular position and / or speed of the motor, similar to the output of the resolver.

[0041] Now, reference Figure 2 , illustrates an example transformed stator current waveform 200 of an example system for indirectly measuring angular position and / or rotational speed of an electric machine having a wound rotor. Figure 1 The transformed stator currents 202, 206 (also labeled I α,HF , I β,HF ).like Figure 2 As shown, each of the transformed stator currents has an envelope waveform 204, 208 that contains information about the rotor position and speed (in various embodiments, the envelope waveforms 204, 208 are not obtained at this time, but are provided for explanation purposes). Figure 2 is shown in ).

[0042] In various embodiments, Figure 2The two 90° shifted sinusoidal phase currents shown are demodulated to extract the envelope waveforms. As discussed above, these envelope waveforms contain information about the rotor position and speed. Now, refer to Figure 3 , illustrates an example envelope waveform 300 of an example system for indirectly measuring angular position and / or rotational speed of an electric machine having a wound rotor. Figure 3 The extracted transformed stator currents 202, 206 (also labeled I α,demod , I β,demod )'s envelope waveforms 304, 308.

[0043] In various embodiments, Figure 3 The extracted envelope waveform shown may be used to determine rotor position and / or speed using an inverse tangent function, a phase locked loop, or other known techniques in a manner similar to that used with a resolver.

[0044] Various embodiments of the present disclosure enable angular position (phase) information to be obtained at any motor speed, including zero. As the motor's rotational speed decreases, the frequency of the extracted envelope waveform decreases and the wavelength increases, until, at zero speed, the extracted envelope waveform is essentially a horizontal line from which the motor's angular position can be determined.

[0045] In various embodiments of the present disclosure, the process of indirectly measuring the angular position and / or speed of an electric machine having a wound rotor can be repeated as needed. For example, in various embodiments, the process can be repeated for each cycle of stator current control (which is typically performed, for example, but not limited to, every 10 microseconds to 1 millisecond).

[0046] Now, reference Figure 4 , illustrates an example block diagram of an example system 400 for indirectly measuring the angular position and / or rotational speed of an electric machine having a wound rotor according to an embodiment of the present disclosure. Figure 4 As shown, a wound rotor motor 402 (eg, an EESM) has three-phase stator windings 404 and rotor windings 406. A switching converter 414 has a DC supply voltage (V DC ) and provides field current (I f ), thereby generating a field voltage (V f ) to induce an electromagnetic field in the rotor winding 406. The rotor is coupled to the motor shaft (not shown). The field oriented control (FOC) unit 410 receives the torque command (T e,ref ) and provides a control output to the three-phase switching inverter 408. The torque command may occur, for example, in the case of a traction motor of an electric vehicle, where the torque reference is given directly by the user using the vehicle accelerator. The three-phase switching inverter 408 has a DC supply voltage (V DC), and applies a time-varying AC current to the stator winding 404 to generate a rotating magnetic field. The rotating magnetic field generated by the stator couples with the magnetic field of the rotor winding 406 and causes the motor shaft to rotate.

[0047] Field current (I f ) The control module 432 receives a field current reference signal (I ) indicating what field current should be provided to the switching converter 414. f,ref ) and outputs the corresponding field voltage reference signal (V f,ref In various embodiments, the field current reference signal comes from a separate controller (not shown) that adjusts the field current reference as needed based on the motor speed to produce the desired torque. The field current control module 432 also receives a field current feedback signal (I f,fdbk ) so that the field current control module 432 can adjust its output as needed to ensure that the switching converter 414 is providing the desired field current to the rotor winding 406. In a conventional wound-rotor motor arrangement, a field current reference signal may be provided to the switching converter. Figure 4 In the example system of FIG. 4 , a field voltage reference signal is provided to a mixer 434 , where the field voltage reference signal is mixed with a signal to be injected (described further below).

[0048] exist Figure 4 In the example system of FIG. 4 , the control circuit system 420 includes a switching frequency control circuit system 422, a conversion circuit system 424, a filtering circuit system 426, a demodulation circuit system 428, and a position / speed determination circuit system 430. The switching frequency control circuit system 422 receives a signal (I f,inj,ampl ), the signal (I f,inj,ampl ) indicates the desired frequency and amplitude of the sinusoidal signal to be injected into the rotor winding. In various embodiments, I f,inj,ampl The signal may be a fixed parameter set by the user or may be controlled by a controller (not shown) based on specific conditions and / or other measurements. As described above, in some embodiments, the frequency of the injected signal may vary based on the speed of the motor, and this will be reflected in the indication (I f,inj,ampl ). Based on the received signal (I f,inj,ampl ), the switching frequency control circuit system 422 outputs a sinusoidal signal (V f,hf ), the sinusoidal signal (V f,hf ) has a signal as received (I f,inj,ampl ) is the desired frequency and amplitude indicated in . A sinusoidal signal (V f,hf ), where the sinusoidal signal (V f,hf ) and the field voltage reference signal (V f,ref) is mixed. Mixer 434 provides a combined signal (V f,sum ).

[0049] The stator current (including the high-frequency component injected into the rotor winding) is detected by current sensing circuitry 412. The detected stator current is provided to FOC unit 410, which uses the detected stator current as feedback for torque control. In the illustrated embodiment, the detected stator current is also provided by current sensing circuitry 412 to control circuitry 420.

[0050] The filter circuitry 426 of the control circuitry 420 extracts the current (I f,ref ) high-frequency components. As described above, Figure 1 An example of such high frequency components being extracted is illustrated.In such embodiments where the frequency of the injected signal varies based on the speed of the motor, the passband frequency of the filtering circuitry 426 is adjustable.

[0051] The filter circuit system 426 provides the extracted high frequency components to the conversion circuit system 424, which converts the extracted high frequency components of the three phases into two 90-degree displacement currents. As described above, Figure 2 An example of such a transformed stator current is shown. The transformation circuit system 424 provides the transformed stator current to the demodulation circuit system 428, which demodulates the two 90-degree displacement currents to extract the envelope waveform. As described above, Figure 3 An example of such an extracted envelope waveform is illustrated.

[0052] The demodulation circuitry 428 provides the extracted envelope waveform to the position / speed determination circuitry 430 which uses the extracted envelope waveform to determine the rotor angle θ using an inverse tangent function, a phase-locked loop, or other known techniques. r and / or speed ω r As is known to all, the determined speed ω r and the determined rotation angle θ r is used to calculate the electrical quality ω which is provided to the FOC unit 410 for torque control el and θ e l.

[0053] Now, reference Figure 5 , illustrates an example block diagram of an example system 500 for indirectly measuring the angular position and / or rotational speed of an electric machine having a wound rotor according to an alternative embodiment of the present disclosure. In various alternative embodiments, Figure 5The system uses the field current ripple at the switching frequency of the switching converter 514. These alternative embodiments use the switching frequency of the switching converter to generate an appropriate ripple level that is high enough to generate the desired effect in the stator without introducing undesirable torque ripple. Using this strategy, the injection frequency and the switching frequency coincide.

[0054] like Figure 5 As shown, a wound rotor motor 502 (eg, an EESM) has three-phase stator windings 504 and rotor windings 506. A switching converter 514 has a DC supply voltage (V DC ) and provides field current (I f ), thereby generating a field voltage (V f ) to induce an electromagnetic field in the rotor winding 506. The rotor is coupled to the motor shaft (not shown). The field oriented control (FOC) unit 510 receives the torque command (T e,ref ) and provides a control output to the three-phase switching inverter 508. The three-phase switching inverter 508 has a DC power supply voltage (V DC ) and applies a time-varying AC current to the stator winding 504 to generate a rotating magnetic field. The rotating magnetic field generated by the stator couples with the magnetic field of the rotor winding 506 and causes the motor shaft to rotate.

[0055] Field current (I f ) The control module 532 receives a field current reference signal (I ) indicating what field current should be provided to the switching converter 514. f,ref ) and outputs the corresponding field voltage reference signal (V f,ref The field current control module 532 also receives a field current feedback signal (I f,fdbk ) so that the field current control module 532 can adjust its output as needed to ensure that the switching converter 514 is providing the desired field current to the rotor winding 506. The field voltage reference signal (V f,ref ).

[0056] exist Figure 5 In the example system of FIG. 5 , the control circuit system 520 includes a switching frequency control circuit system 522, a conversion circuit system 524, a filtering circuit system 526, a demodulation circuit system 528, and a position / speed determination circuit system 530. The switching frequency control circuit system 522 receives a signal (I f,ampl,ref ), the signal (I f,ampl,ref ) indicates the desired frequency and amplitude of the sinusoidal signal to be injected into the rotor winding. In various embodiments, the signal I f,ampl,refIt can be a fixed parameter set by the user or can be controlled by a controller (not shown) based on specific conditions and / or other measurements. As described above, in some embodiments, the frequency of the injected signal can vary depending on the speed of the motor, and this will be reflected in the indicator (I f,ampl,ref ). Based on the received signal (I f,ampl,ref ), the switching frequency control circuit system 522 outputs a signal (f sw ) to indicate the desired switching frequency, which will affect the field current (I f,ref ) results in a desired ripple current. In various embodiments, the ripple current in the field current (I f,ref ) can have a "shark tooth" shape or a "saw tooth" shape, e.g. Figure 5 Field current (I f,ref ) as illustrated by the waveform above.

[0057] The stator current, which includes high-frequency components injected into the rotor winding, is detected by current sensing circuitry 512. The detected stator current is provided to FOC unit 510, which uses the detected stator current as feedback for torque control. In the illustrated embodiment, the detected stator current is also provided by current sensing circuitry 512 to control circuitry 520.

[0058] The filter circuitry 526 of the control circuitry 520 extracts the current (I f,ref In embodiments where the frequency of the injected signal varies based on the speed of the motor, the passband frequency of the filtering circuitry 526 is adjustable.

[0059] The filter circuit system 526 provides the extracted high-frequency components to the conversion circuit system 524, which converts the extracted high-frequency components of the three phases into two 90-degree offset currents. The conversion circuit system 524 provides the converted stator currents to the demodulation circuit system 528, which demodulates the two 90-degree offset currents to extract the envelope waveform.

[0060] The demodulation circuitry 528 provides the extracted envelope waveform to the position / speed determination circuitry 530 which uses the extracted envelope waveform to determine the rotor angle θ using an inverse tangent function, a phase-locked loop, or other known techniques. r and / or speed ω r As is known to all, the determined speed ω r and the determined rotation angle θ ris used to calculate the electrical quality ω which is provided to the FOC unit 510 for torque control el and θ e l.

[0061] Although components are described with respect to functional limitations, it should be understood that specific implementations necessarily include the use of specific computing hardware. It should also be understood that in some embodiments, some of the components described herein include similar or common hardware. For example, in some embodiments, two sets of circuit systems utilize the same processor(s), memory(s), circuit system(s), and / or the like to perform their related functions, such that each set of circuit systems does not require duplicate hardware.

[0062] Now, reference Figure 6 , Figure 6 Flowcharts are provided that illustrate example steps, processes, procedures, and / or operations according to various embodiments of the present disclosure. Figure 6 The various methods described herein of the illustrated example methods may provide various technical benefits and improvements. It should be noted that each block of the flowcharts and combinations of blocks in the flowcharts may be implemented by various components such as hardware, firmware, circuit systems, and / or other devices associated with the implementation of software (including one or more computer program instructions). For example, Figure 6 One or more of the procedures described in the flowchart may be embodied by computer program instructions, which may be stored in a non-transitory memory of an apparatus employing an embodiment of the present disclosure and executed by a processor in the apparatus. These computer program instructions may instruct a computer or other programmable device to operate in a specific manner, such that the instructions stored in the computer-readable storage memory produce an article of manufacture, the implementation of which implements the functions specified in the flowchart block(s).

[0063] As described above and should be appreciated, based on this disclosure, embodiments of the present disclosure can be configured as methods, devices, back-end network devices, etc. Thus, each embodiment may include various components comprising any combination of entire hardware or software and hardware. Furthermore, each embodiment may take the form of a computer program product on at least one non-transient computer-readable storage medium, in which computer-readable program instructions (e.g., computer software) are embodied. Similarly, each embodiment may take the form of a computer program code stored on at least one non-transient computer-readable storage medium. Any suitable computer-readable storage medium may be utilized, including a non-transient hard disk, CD-ROM, flash memory, optical storage device, or magnetic storage device.

[0064] Having described example systems, devices, computing environments, and user interfaces associated with embodiments of the present disclosure, example flowcharts including various operations performed by the circuit systems, devices, systems, and / or devices described herein will now be discussed. It should be appreciated that each of the flowcharts depicts an example process that can be performed, for example, by one or more of the circuits, devices, systems, and / or devices described herein using one or more of its components. The blocks indicating the operations of each process can be arranged in any of several ways, as depicted and described herein. In some such embodiments, one or more blocks of any process in the processes described herein occur simultaneously rather than sequentially. In some such embodiments, one or more blocks of any process in the processes described herein appear between one or more blocks of another process, before one or more blocks of another process, and / or operate as a sub-process of a second process. Additionally or alternatively, any process in the process can include some or all of the steps described and / or depicted, and in some embodiments, include one or more optional operation blocks. With respect to the flowchart(s) below, in some or all embodiments of the present disclosure, one or more blocks in the depicted blocks may be optional. Optional boxes are indicated using broken lines (or "dashed lines"). Also, it should be appreciated that one or more of the operations of each flow chart may be combined, substituted, reordered, and / or otherwise modified as described herein.

[0065] Now, reference Figure 6 , illustrates an example flow chart of an example method 600 for indirectly measuring the angular position and / or rotational speed of a motor having a wound rotor according to some embodiments of the present disclosure. In some embodiments, the example method 600 can be implemented by the example system described herein, including but not limited to the above-mentioned example system in combination with Figure 4 The example system 400 described and / or above in combination Figure 5 An example system 500 is described.

[0066] exist Figure 6 In the example method shown, the example method 600 begins at step / operation 602. At step / operation 604, one or more components of the system (such as, but not limited to, the switching frequency control circuit system 422 of the control circuit system 420 and the above-mentioned components) are connected to the control circuit system 420. Figure 4 The switching converter 414 used in conjunction with the mixer 434 described above provides a current to the wound rotor that has a component detectable in the stator. As described above, in various embodiments, a periodic signal can be injected into the rotor winding to introduce a small ripple in the rotor current. Alternatively, in various alternative embodiments, the switching frequency can be selected to induce a desired ripple current.

[0067] At step / operation 606, one or more components of the system (such as but not limited to those in combination with the above) Figure 4 The depicted control circuitry 420 , used in conjunction with the current sensing circuitry 412 , detects stator current from each of the three phases of the stator windings 404 of the EESM 402 .

[0068] At step / operation 608, one or more components of the system (such as but not limited to the above-mentioned components) Figure 4 The filter circuit system 426 of the control circuit system 420 described above extracts the high frequency component of the current provided to the wound rotor from the stator current of each of the three phases detected. As described above, Figure 1 An example of such extracted high-frequency components is illustrated.

[0069] At step / operation 610, one or more components of the system (such as, but not limited to, the above-mentioned components) Figure 4 The conversion circuit system 424 of the control circuit system 420 described above converts the extracted high-frequency components of the three phases into two 90-degree displacement currents. As described above, Figure 2 An example of such transformed stator current is illustrated.

[0070] At step / operation 612, one or more components of the system (such as, but not limited to, the above-mentioned components) Figure 4 The demodulation circuit system 428 of the control circuit system 420 described above demodulates the two 90-degree offset currents to extract the envelope waveform. As described above, Figure 3 An example of such an extracted envelope waveform is illustrated.

[0071] At step / operation 614, one or more components of the system (such as, but not limited to, the above-mentioned components) Figure 4 The position / speed determination circuitry 430 of the depicted control circuitry 420 uses the extracted envelope waveform to determine rotor position and / or speed using an inverse tangent function, a phase-locked loop, or other known techniques.

[0072] In some embodiments, Figure 6 The example method shown is repeated continuously.

[0073] Some or all of the functionality described herein may be implemented as part of an integrated circuit system (IC) to perform, for example, one or more of the functions described herein.

[0074] The processing elements described herein, such as control circuit systems, may include one or more processors, input / output circuit systems, data storage media, communication circuit systems, and / or other components configured to perform computing operations. In some embodiments, the data storage medium may be configured to store information, data, content, applications, instructions, etc., for enabling the processing elements described herein to perform various functions. Thus, in some embodiments, the processing elements described herein may be referred to as functional logic. The processing elements described herein may be implemented in several different ways. For example, in some embodiments, the processing elements described herein may include one or more processing devices configured to execute in an independent manner. Additionally or alternatively, in some embodiments, the processing elements described herein may include one or more processors (multiple) that are configured in series via a bus to enable independent implementation of instructions, pipeline processing, and / or multi-threaded processing. The use of the terms "controller," "processor," "control circuit system," and "processing circuit system" should be understood to include a single-core processor, a multi-core processor, multiple processors within the processing element described herein, and / or one or more remote or "cloud" processors (multiple) outside the processing element described herein.

[0075] In an example embodiment, the processing element described herein can be configured to implement instructions stored in a data storage medium or otherwise accessible to a processor. Alternatively or additionally, the processing element described herein in some embodiments is configured to implement hard-coded functionality. Thus, whether configured by hardware or software methods or by a combination thereof, the processing element described herein represents an entity (e.g., physically embodied in a circuit system) that can perform operations according to an embodiment of the present disclosure while being configured accordingly. Alternatively or additionally, as another example in some example embodiments, when the processing element described herein is embodied as an executor of software instructions, these instructions configure the processing element described herein in a particular manner to perform the algorithms embodied in the specific operations described herein when such instructions are implemented.

[0076] Thus, use of the term "circuitry" as used herein with respect to components of an apparatus should be understood to include specific hardware configured to perform the functions associated with the specific circuitry described herein. The term "circuitry" should be broadly interpreted to include hardware and, in some embodiments, software for configuring the hardware. For example, in some embodiments, "circuitry" may include processing circuitry, storage media, network interfaces, input / output devices, and the like.

[0077] in conclusion

[0078] Those skilled in the art to which these disclosures relate who have benefited from the teachings presented in the foregoing description and the associated drawings will recognize many adaptations and other embodiments of the disclosure set forth herein. Although these figures illustrate only certain components of the apparatus and systems described herein, it will be understood that various other components may be used in conjunction with the systems. Therefore, it will be understood that the present disclosure is not limited to the specific embodiments disclosed, and adaptations and other embodiments are intended to be included within the scope of the appended claims. Moreover, the steps in the method described above do not necessarily occur in the order depicted in the accompanying drawings, and in some cases, one or more of the depicted steps may occur substantially simultaneously or may involve additional steps. Although specific terms are employed herein, they are used in a general descriptive sense only and are not intended to be limiting.

[0079] Although various embodiments according to the principles disclosed herein have been shown and described above, they can be modified by those skilled in the art without departing from the spirit and teachings of the present disclosure. The embodiments described herein are representative only and are not intended to be limiting. Many variations, combinations, and adaptations are possible and are within the scope of the present disclosure. Alternative embodiments resulting from combining, integrating, and / or omitting features of the embodiment(s) are also within the scope of the present disclosure. Thus, the scope of protection is not limited by the description set forth above.

[0080] Additionally, the section headings used herein are intended to be consistent with the recommendations in 37 CFR 1.77 or to otherwise provide organizational cues. These headings should not limit or characterize the disclosure(s) set forth in any claims that may arise from this disclosure.

[0081] While this detailed description has presented some embodiments of the present disclosure, the appended claims encompass other embodiments of the present disclosure that differ from the described embodiments according to various adaptations and modifications. For example, the appended claims may encompass any form of system, apparatus, integrated circuit system, or method for estimating the angular position and / or speed of a three-phase or multi-phase electric motor with a wound rotor by injecting a signal into the rotor windings to introduce a small ripple in the field current, which can be extracted from the stator current and analyzed.

[0082] In the following claims, unless the specific terms "means for" or "step for" are used in a given claim, it is not intended that the claim be interpreted under 35 USC 112, paragraph 6.

Claims

1. A system for indirectly measuring the angular position and / or rotational speed of an electric machine having a rotatable shaft, a wound rotor, and a stator, the stator having three or more phases, the system comprising: a switching converter adapted to provide a current to the wound rotor, the current having a component detectable in the stator; current sensing circuitry adapted to detect a stator current for each of the three or more phases; filtering circuitry adapted to extract the detectable component of the current provided to the wound rotor from the detected stator current of each of the three or more phases; as well as control circuitry for (i) converting the detectable component of the current provided to the wound rotor, extracted from the detected stator current of each of the three or more phases, into two 90-degree-displaced currents, (ii) demodulating the two 90-degree-displaced currents to obtain an envelope waveform of each of the two 90-degree-displaced currents, and (iii) analyzing the envelope waveforms of the two 90-degree-displaced currents to determine the angular position and / or rotational speed of the rotatable shaft. 2 . The system of claim 1 , wherein the detectable component of the current provided to the wound rotor comprises a ripple current of a switching current provided to the wound rotor. 3 . The system of claim 1 , wherein the detectable component of the current provided to the wound rotor comprises a sinusoidal signal having a lower frequency than a switching current provided to the wound rotor.

4. The system of claim 1 , wherein the detectable component of the current provided to the wound rotor has a frequency that is adjustable and related to the rotational speed of the rotatable shaft.

5. The system of claim 4, wherein the filtering circuitry is adjustable to enable extraction of the detectable component of the current provided to the wound rotor having an adjustable frequency.

6. The system of claim 4, wherein the frequency of the detectable component of the current provided to the wound rotor is at least four times the frequency of the envelope waveform of the two 90 degree displaced currents.

7. The system of claim 1 , wherein the control circuitry transforms the detectable component of the current provided to the wound rotor extracted from the detected stator current of each of the three or more phases into two 90-degree displaced currents using a Clarke transform.

8. The system of claim 1, wherein the control circuitry uses a phase-locked loop or an inverse tangent function to analyze the envelope waveforms of the two 90-degree displacement currents to determine the angle and / or rotational speed of the rotatable shaft.

9. The system of claim 1, wherein the electric machine comprises a motor, a generator, or an alternator.

10. The system of claim 1, wherein the electric machine comprises an electrically excited synchronous motor.

11. A method for indirectly measuring the angular position and / or rotational speed of an electric machine having a rotatable shaft, a wound rotor, and a stator, the stator having three or more phases, the method comprising: providing a current to the wound rotor, the current having a component detectable in the stator; detecting a stator current of each of the three or more phases; extracting the detectable component of the current supplied to the wound rotor from the detected stator current of each of the three or more phases; converting the detectable component of the current supplied to the wound rotor, extracted from the detected stator current of each of the three or more phases, into two 90-degree displaced currents; Demodulating the two 90-degree displacement currents to obtain an envelope waveform of each of the two 90-degree displacement currents; as well as The envelope waveforms of the two 90-degree displacement currents are analyzed to determine the angular position and / or rotational speed of the rotatable shaft. 12 . The method of claim 11 , wherein the detectable component of the current provided to the wound rotor comprises a ripple current of a switching current provided to the wound rotor.

13. The method of claim 11, wherein the detectable component of the current provided to the wound rotor comprises a sinusoidal signal having a lower frequency than a switching current provided to the wound rotor.

14. The method of claim 11, wherein the detectable component of the current provided to the wound rotor has a frequency that is adjustable and related to the rotational speed of the rotatable shaft.

15. The method of claim 14, wherein the frequency of the detectable component of the current provided to the wound rotor is at least four times the frequency of the envelope waveform of the two 90 degree displaced currents.

16. The method of claim 11, wherein the detectable component of the current provided to the wound rotor extracted from the detected stator current of each of the three or more phases is transformed into two 90-degree displaced currents using a Clarke transform.

17. The method of claim 11, wherein the envelope waveforms of the two 90-degree displacement currents are analyzed using a phase-locked loop or an arc tangent function to determine the angle and / or rotational speed of the rotatable shaft.

18. The method of claim 11, wherein the electric machine comprises a motor, a generator, or an alternator.

19. The method of claim 11, wherein the electric machine comprises an electrically excited synchronous motor.

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