Inductive sensor assembly, system and method

Abstract

This disclosure relates to inductive sensor assemblies, systems, and methods. An inductive sensor assembly is provided. The inductive sensor assembly includes a coil assembly and a movable conductive target. The coil assembly is discontinuously excited by a sequence of signal pulses. The coil assembly includes three coils coupled between three terminals in a predefined arrangement. The movable conductive target at least partially covers the coils during its movement. The inductive sensor assembly is configured to measure a corresponding current in the coil assembly at a predetermined time synchronized with the excitation of the coil assembly at the corresponding terminals to determine the displacement of the target.

Description

Technical Field

[0001] This disclosure generally relates to techniques related to inductive sensors, and more specifically to techniques related to self-inductance-based inductive sensing. Background Technology

[0002] Inductive position sensing (IPS) is a well-known technique used in various applications to measure the position or proximity of metallic objects. Generally, inductive position sensors typically employ non-magnetic technology, utilizing the physical principles of eddy currents or inductive coupling to detect the position of a target moving above at least one coil.

[0003] In some possible conventional implementations, inductive sensor operation is typically based on inductive coupling between a transmitting coil, a target, and at least one receiving coil. For example, in Figure 1 The paper describes an exemplary implementation of an inductor-based sensor that uses a single transmitting coil and two receiving coils, wherein the two receiving coils are arranged such that one receiving coil generates a sine signal and the other receiving coil generates a cosine signal for every 360° mechanical rotation of the target.

[0004] Coils are typically provided as copper traces on a printed circuit board (PCB). They can be arranged such that the transmitter coil induces a secondary voltage in both receiver coils, which depends on the position of a metal target above the coil. In some possible examples, the transmitter coil can be supplied with an alternating current (AC) signal via an oscillator. This, in turn, generates a high-frequency magnetic field through the transmitter coil, which is picked up by the receiver coils. Depending on the position of the metal target on the coil, the amplitude and phase of the secondary voltage picked up by the receiver coils may vary, allowing for the determination of the target's location by analyzing these effects.

[0005] However, displacement of a target can be detected based on a single coil because its inductance varies depending on how the target overlaps with the coil. While the operating principle relies on determining changes in impedance by measuring the current flowing through a single coil, in practice, a single measurement may not be sufficient. This is because such measurements are considered susceptible to external factors such as temperature and mechanical vibration, which can introduce errors into both the amplitude and offset of the measured current.

[0006] Therefore, there is a need for an improved design for IPS-based sensor implementation that can overcome some or all of the problems associated with conventional technologies and, more specifically, can objectively determine the position of a target on a coil, preferably improving energy efficiency and / or reducing complexity. Summary of the Invention

[0007] In view of some or all of the above-mentioned technical problems, this disclosure generally provides an inductive sensor assembly, system and corresponding method having the features of the respective independent claims.

[0008] According to one aspect of this disclosure, an inductive sensor assembly (sometimes referred to herein as a circuit / circuit system design, setup, implementation, etc.) is provided. The inductive sensor assembly may include a coil assembly discontinuously excited by a sequence of signal pulses. Specifically, the coil assembly may include at least three (or more) coils coupled between three terminals (or connections, ends, etc.) in a predefined arrangement. For example, in some possible examples, the coils in the coil assembly may be identical. The inductive sensor assembly may also include a movable conductive (e.g., copper, etc.) target that at least partially covers the coils during its movement. More specifically, the inductive sensor assembly may be configured to measure a corresponding current in the coil assembly at a predetermined time synchronized with the excitation of the coil assembly at the corresponding terminals to determine the (mechanical) displacement (e.g., (relative) position) of the target. According to various implementations, the predetermined time may be, for example, a predetermined (predefined) time after the end of the excitation pulse, or a predetermined (predefined) time during the excitation pulse. Furthermore, it will be clear from the following description that the proposed inductive sensor assembly can be configured to determine, for example, angular (rotational) or linear (or any other suitable) displacement, depending on various implementations and / or circumstances. This is not limited in this application. As used herein, the term "mechanical displacement" can be used collectively to refer to any suitable type of displacement, such as angular displacement, linear displacement, or any other more complex trajectory.

[0009] As described herein, this disclosure generally seeks to propose a more energy-efficient and less complex sensor design capable of measuring (determining, estimating, etc.) the (angular or linear) displacement of a target. Other advantages, not shown herein, will become apparent from the description below.

[0010] In some example embodiments, the inductive sensor assembly can be configured to determine the angular displacement of the target. In some possible examples, this angular displacement can be a (relative) angular position (e.g., an angle) relative to a reference angle. As described above, in some other possible implementations, the inductive sensor assembly can also be configured to determine the linear displacement of the target. In this case, those skilled in the art will understand and recognize that appropriate adaptation of the inductive sensor assembly may be required.

[0011] In some example embodiments, the predefined arrangement may include a triangular topology or a star topology, in which each coil is angularly displaced by a predetermined angle relative to a reference angle (e.g., a 0° reference angle). Of course, any other suitable arrangement of the coil assembly (e.g., a parallel arrangement) is possible depending on various implementations and / or circumstances. Furthermore, those skilled in the art will understand and recognize that, in the case of a determined linear position / displacement, the coil may be (linearly) displaced by a predetermined distance relative to a reference position.

[0012] In some example embodiments, the coil assembly can be sequentially excited at corresponding terminals (to which the corresponding coil is coupled), and the corresponding current of the coil assembly can be continuously measured at the corresponding terminal at a predetermined time after the excitation of the corresponding terminal. It is worth noting that, as will be described in more detail below, this sequential excitation (stimulation) / continuous measurement method may be considered preferred in some possible cases, for example from the perspective of application-specific integrated circuit (ASIC) design, often due to the simplification of the internal structure by reusing the same excitation driver and sensing circuitry for each of the three terminals of the sensor. However, those skilled in the art will understand and recognize that any other suitable implementation (e.g., concurrent measurement) is also possible.

[0013] In some example embodiments, the coil assembly can be energized such that when any one of the three terminals is driven to a first predefined (e.g., 'high') potential, the other two terminals are placed to a second predefined (e.g., 'low') potential.

[0014] In some example embodiments, the target has a shape designed such that the inductance of the coil assembly (e.g., equivalent coil inductance) follows a predetermined mathematical function (formula) as a function of angular displacement. Those skilled in the art will understand and apply that, in practice, the shape of a target used to achieve a particular function / formula can be derived through various methods, such as finite element analysis, electromagnetic (EM) simulation, etc. This is not limited in this disclosure.

[0015] In some example embodiments, at the corresponding terminals i The corresponding current of the coil assembly measured at the location I i ( i =1, 2, 3) and the target φ The corresponding angular displacement follows: Where Am represents / indicates the modulation amplitude parameter, O Indicates / indicates static and displacement-independent offset parameters. φ i Indicates / indicates coupling to the corresponding terminal i The predetermined displacement angle of the corresponding coil relative to the reference angle.

[0016] In some example embodiments, the target φ The angular displacement can be determined by the following formula: ,in I i Indicates at the corresponding terminal i The corresponding current of the coil assembly measured at the location ( i =1, 2, 3), φ i Indicates coupling to the corresponding terminal. i The predetermined displacement angle of the corresponding coil relative to the reference angle. Of course, those skilled in the art will understand and recognize that determinations similar to or analogous to angular displacement can also be applied to any other suitable type of displacement, for example, through equivalent transformations of the corresponding coordinate system. For example, for linear displacement, the mathematical representation of such a transformation can be as follows: , where ΔX represents linear displacement and XR represents (predetermined) measurement range.

[0017] In some example embodiments, the predetermined time for measuring the current after coil excitation can be determined based on the LR time constant of the inductive sensor assembly and its driving circuitry system that generates the signal pulse sequence. More specifically, those skilled in the art will understand and recognize that, in practice, the 'R' factor can generally be understood to have two components: one component comes from the sensor coil (e.g., the resistance of copper on the PCB); and the other component comes from the equivalent resistance of the driving circuitry system on the ASIC side, which is configured to generate the signal pulse sequence for stimulating / exciting the coil assembly, and this is generally dominant.

[0018] According to another aspect of this disclosure, a system is also provided. Specifically, the system may include an inductive sensor assembly according to the foregoing aspects (and may also include exemplary embodiments). The system may also include a circuit system assembly (e.g., an ASIC, etc.) coupled to the inductive sensor assembly. More specifically, the circuit system assembly may be configured to discontinuously excite a coil assembly of the inductive sensor assembly with a sequence of signal pulses, and measure the current of the coil assembly at a predetermined time synchronized with the excitation of the coil assembly to determine a target displacement (e.g., angular or linear displacement) of the inductive sensor assembly.

[0019] In some example embodiments, circuit system components can be configured to sequentially excite coil components at corresponding terminals, and the corresponding current of the coil components can be continuously measured at the corresponding terminals at a predetermined time after the excitation of the corresponding terminals.

[0020] In some example embodiments, the circuit system components can be configured to excite the coil components such that when any one of the three terminals is driven to a first predefined (e.g., 'high') potential, the other two terminals of the three terminals are placed to a second predefined (e.g., 'low') potential.

[0021] In some example embodiments, the system may also be configured to support a self-diagnostic function involving determining the modulation amplitude parameters according to the following formula. Am : The static and displacement-independent offset parameters are determined according to the following formula. O : ; and based on the determined Am and O The system is determined to have defects based on its predetermined tolerance limits and corresponding parameters. Specifically, I i Indicates at the corresponding terminal i The corresponding current of the coil assembly measured at the location ( i =1, 2, 3), φ i Indicates coupling to the corresponding terminal. i The predetermined displacement angle of the corresponding coil relative to the reference angle. φ tan( represents the angular displacement of the target) φ Used to determine amplitude parameters Am offset parameter O Calculated as Therefore, continuous health / defect monitoring, or in other words, self-diagnostic capabilities, can be achieved. Specifically, this can be done without additional hardware. Instead, only some additional computation in the digital domain is required, but very high self-diagnostic coverage can be provided throughout the signal path, which is quite important for any safety-critical product.

[0022] Furthermore, according to another aspect of this disclosure, a method for using an inductive sensor assembly is provided. The inductive sensor assembly can be similar to the assembly described above. Specifically, the method may include providing a coil assembly discontinuously excited by a sequence of signal pulses and comprising three coils coupled between three terminals in a predefined arrangement. The method may further include providing a movable conductive target that at least partially covers the coils during its movement, thereby enabling measurement of a corresponding current in the coil assembly at a predetermined time synchronized with the excitation of the coil assembly at the respective terminals to determine the displacement of the target.

[0023] Similarly, another aspect of this disclosure also provides a method of using the system. This system may be similar to or analogous to the system described above. For example, the system may include an inductive sensor assembly comprising: a coil assembly including three (e.g., identical) coils coupled between three terminals in a predefined arrangement; and a (rotational or linear) movable conductive target that at least partially covers the coils during its movement. The system may also include a circuit system assembly coupled to the inductive sensor assembly. More specifically, the method may include: discontinuously exciting the coil assembly of the inductive sensor assembly by the circuit system assembly via a sequence of signal pulses; measuring a corresponding current in the coil assembly by the circuit assembly at a predetermined time synchronized with the excitation of the coil assembly at the corresponding terminals; and determining, by the circuit assembly, the displacement (angular or linear displacement) of the target of the inductive sensor assembly based on the measured current.

[0024] Those skilled in the art will understand that the details of the disclosed methods can be implemented as systems (e.g., in the form of circuit systems, circuit system components, etc.) suitable for performing some or all of the steps of the methods, and vice versa. In particular, it should be understood that the methods according to this disclosure relate to methods for operating systems (or circuit systems) according to the above embodiments and variations thereof, and the corresponding statements made with respect to the systems (or circuit systems) also apply to the corresponding methods, and vice versa.

[0025] It should also be understood that, in this disclosure, the terms "coupled" or "coupled" refer to elements communicating electrically with each other, whether directly connected, for example via wires, or in some other way (e.g., indirectly connected). It is worth noting that an example of coupling is a connection. Attached Figure Description

[0026] The following explanation of exemplary embodiments of this disclosure is based on the accompanying drawings, wherein the same reference numerals denote the same or similar elements, and in the drawings:

[0027] Figure 1 An example of a possible implementation of a conventional inductance-based sensor is illustrated schematically;

[0028] Figure 2 An example illustrating the functional relationship between target displacement and coil inductance is shown schematically by appropriately shaping the target;

[0029] Figure 3 The diagram illustrates, illustratively, an example of a graph showing a possible relationship between current and the angular displacement of a target when a coil assembly is excited by a pulse signal, according to some embodiments of the present disclosure.

[0030] Figure 4An example of a possible arrangement of the coils of an inductive sensor assembly according to some embodiments of the present disclosure is illustrated schematically;

[0031] Figure 5A and Figure 5B Examples of possible arrangements of coils according to some embodiments of the present disclosure are illustrated schematically;

[0032] Figure 6A and Figure 6B Examples of possible implementations of coil excitation schemes according to some embodiments of this disclosure are illustrated schematically;

[0033] Figure 7 Examples of possible systems according to some embodiments of the present disclosure are illustrated schematically, including an inductive sensor assembly and an application-specific integrated circuit (ASIC) used with the inductive sensor assembly.

[0034] Figure 8 Examples of possible implementations of determining the linear displacement of a target through equivalent transformations of the corresponding coordinate systems, according to some embodiments of the present disclosure, are illustrated schematically.

[0035] Figure 9 Another example of a possible implementation for determining the linear displacement of a target according to some embodiments of this disclosure is illustrated schematically;

[0036] Figure 10 This is a flowchart illustrating examples of methods for using an inductive sensor assembly according to some embodiments of this disclosure; and

[0037] Figure 11 This is a flowchart illustrating examples of methods for using the system according to some embodiments of this disclosure. Detailed Implementation

[0038] As stated above, unless otherwise specified, the same or similar reference numerals in this disclosure may denote the same or similar elements, and thus their repeated descriptions may be omitted for the sake of brevity. Furthermore, it should be noted that unless otherwise specified, the symbols used in the figures are for illustrative purposes only and should not be construed as constituting any form of limitation.

[0039] As stated above, in a broad sense, this disclosure relates generally to the field of inductive sensors (or sometimes referred to as inductance-based sensors), and more specifically to techniques related to self-inductance-based inductive sensing.

[0040] As mentioned earlier, typical conventional sensor implementations (e.g., Figure 1The sensor implementation illustrated herein can be configured to perform positioning, typically based on the variable mutual inductance between the transmitter coil and the receiver coil.

[0041] Conversely, more broadly, the techniques proposed in this disclosure are based on the self-inductance of (multiple) sensor coils and their dependence on the target position. In some possible cases, the displacement of the target can be detected based on only a single coil, since its inductance varies depending on how the target overlaps with the coil.

[0042] However, as mentioned above, although the operating principle relies on determining the change in impedance by measuring the current flowing through a single coil, in practice, a single measurement may not be sufficient. This is mainly because such measurements are considered susceptible to external factors such as temperature and mechanical vibration, which can introduce errors into both the (modulation) amplitude of the measured current (sometimes called the signal dynamic range) and the static and displacement-independent offset (sometimes called the DC offset).

[0043] In view of this, generally speaking, one of the main technical objectives of this disclosure is to find an improved design for IPS-based sensor implementations that overcomes some or all of the problems associated with conventional techniques, and more specifically, is able to objectively determine the position of a target on a coil, preferably improving energy efficiency and / or reducing complexity. In doing so, in a broad (and not limiting) sense, this disclosure generally proposes providing three (e.g., identical) coils (or collectively referred to as a coil assembly) connected / coupled with a fixed and known angular offset, arranged to be supplied with voltage pulses and to sample the current at fixed intervals after the start of a (non-periodic) charging / discharging process.

[0044] Generally, pulse-based driving schemes can be considered to offer several advantages, including (but not limited to): simplicity of the coil driving circuitry; lower spectral density and average level of emitted electromagnetic (EM) interference; higher energy efficiency; control over pulse width and period to easily adapt to various inductive sensors and specific application requirements (e.g., in terms of speed, current consumption, EMC, etc.); and so on. Of course, any other applicable implementations, objectives, and / or advantages of this disclosure will become apparent from the detailed description below.

[0045] It is worth noting that although many of the examples described below appear to involve or focus on some possible implementations for determining the angular displacement of a (rotatably or angularly movable) target, those skilled in the art will understand and recognize that the techniques presented herein can also be suitably applied to determining the linear (or any other suitable mechanical) displacement of a (linearly movable) target. In any case, for illustrative purposes, some possible example implementations for suitably determining the linear displacement of a target will be described in more detail below.

[0046] First, the sensor section will be described.

[0047] In particular, when a conductive (e.g., copper, etc.) plate (or sometimes referred to as the target) covers the total cross-section (S) of the coil... o Part of (S) c When the eddy currents induced on the plate and their related effects on the magnetic field passing through the coil are applied, the coil (L) e The equivalent inductance of (L) may become the original inductance (L) o It is a small part of the equivalent inductance. In some possible examples, the equivalent inductance can be reduced according to the following formula / equation (1): (1)

[0048] Therefore, by appropriately shaping the target, the relationship between (mechanical) displacement (e.g., Δφ in terms of angular displacement or Δx in terms of linear displacement) and coil inductance can be appropriately made to follow any mathematical function that is differentiable within the measurement range (e.g., expressed as...). F s ( Δφ (For example, see) Figure 2 (The figure is shown illustratively in the text). Therefore, the above formula (1) can be expressed as follows: (2)

[0049] As mentioned above, by appropriately shaping the target, the sensor modulation function can be controlled according to system requirements. Here, for angle (or similarly for linear) measurement, the appropriately shaped target could be one that causes L... e Any target expressed in any suitable mathematical notation, such as: (3)

[0050] Specifically, the parameter K typically defines a relative sampling instance with respect to the LR time constant of the coil. In some possible cases, sampling instances can be, but are certainly not limited to, those that can be. This can be understood as corresponding to the maximum sensitivity. Generally, it can be understood that the predetermined time T0 for measuring the current after coil excitation can be determined based on the LR time constant of the inductive sensor assembly and the driving circuitry system that generates the signal pulse sequence. In particular, the "R" factor typically has two components: one component comes from the sensor coil (e.g., the resistance of copper on the PCB), and the other component comes from the equivalent resistance of the driving circuitry system in the ASIC, which can usually dominate.

[0051] Furthermore, parameter M can be considered as the selected modulation index of the sensor, i.e., the equivalent inductance. L e ( φ How much will it change due to the target displacement φ? (or simply) ).

[0052] As will be understood and recognized by those skilled in the art, in practice, L can be generated according to the above formula (3) depending on various implementations and / or circumstances. e The shape of the target can be obtained by any suitable method, such as finite element analysis, EM simulation, etc.

[0053] For a single coil, it can be shown that the current in the coil can depend on the displacement of the target on the coil. For an angular displacement φ, at a predetermined sampling time T0, the current will be: (4) in L e ( φ ) is the equivalent coil inductance of displacement φ, and R is the resistance connected in series with the coil.

[0054] Therefore, in some possible implementations, if a rectangular voltage pulse is supplied to the coil, theoretically, measuring the current after T0 (e.g., after the excitation pulse ends or during the excitation pulse) will allow the determination of the (relative) position of the target.

[0055] In some possible implementations, such as for sensors configured to measure angular displacement, when equation (3) is substituted into the above generalized equation (4), it can be further simplified to: (5) The parameter Am can be considered as typically representing the signal (modulation) amplitude (which usually corresponds to...). Figure 3 The dynamic range is illustrated in the diagram. The parameter O can be considered as typically representing static and displacement-independent offset (which is usually related to...). Figure 3 (The DC offset is illustrated in the diagram).

[0056] If both parameters Am and O are known, then the current I T0 A single measurement of (φ) is sufficient to calculate the position φ. However, as mentioned above, one of the problems here could be that both parameters Am and O are affected by various external factors, such as temperature, mechanical vibration, air gap changes, etc., and therefore can be considered as unknown.

[0057] In other words, although in theory a sensor with a single coil could allow determining that a target has moved and potentially how much it has rotated, the accuracy and repeatability of such a sensor arrangement are very low.

[0058] Therefore, in order to solve this problem and determine the actual angular position of the target in an objective manner, it may be necessary to be able to determine all the unknowns in the above equation (5), that is, all parameters Am, φ And O. More broadly, this further requires obtaining two additional data points and solving the following problem regarding angular displacement. φ The system of equations: (6)

[0059] It is worth noting that the letters A, B, and C used in this document are for illustrative purposes only. Those skilled in the art will understand and recognize that they essentially correspond to the respective currents measurable according to the above formula (5), and therefore can be readily replaced with… I i ,in i =1, 2, 3.

[0060] In some possible examples, a simple way to achieve this is to add two additional measuring probes (coils) to the sensor assembly, which are displaced relative to a 0° reference angle by a fixed (e.g., predetermined) angle (φ2 and φ3). Therefore, Figure 4 The diagram illustratively illustrates an example where the angular displacement of the target results in three currents with three different phases. As mentioned above, in some possible cases, these three coils can also be collectively referred to as a coil assembly. It is worth noting that in... Figure 4 In the example, the coil appears to be uniformly displaced (120°) within the circle, but this is not always the case. For example, in some possible examples, for some possible applications, only a small portion / part of the entire measurement range (corresponding to the entire circle) may be of interest, so the coil may be appropriately positioned accordingly, for example, at different angles within the circle.

[0061] In this way, it can be proven that when solving equation (6) for a system with respect to φ, the angular displacement φ can be determined mathematically: (7)

[0062] As mentioned above, A, B, and C are typically used to represent... Figure 5A and Figure 5B The three currents measured at the three corresponding pins / terminals A, B, and C shown, φ1, φ2, and φ3, are (predetermined) constants as described above, defined by the proper arrangement of the three coils in the sensor assembly.

[0063] It is worth noting that in some possible implementations, the angle φ calculated based on the above equation (7) can be based on subtracting the (current) values ​​of A, B, and C, which can be easily implemented in the analog domain. In particular, this eliminates any common DC offset and allows the use of the full range of analog-to-digital converters (ADCs) in the signal path, as will be described in more detail below regarding ASIC design.

[0064] Depending on the implementation and / or requirements, the coils can be arranged in any suitable configuration. For example, in some possible implementations, the coils can be configured in a delta topology ( Figure 5A ) or star topology ( Figure 5B In this case, measurements on each pin / terminal can be performed continuously.

[0065] In some possible examples, the star topology can also be converted to a parallel topology, for example, if the center of the star is coupled to a predetermined reference potential / node (e.g., ground). In this case, the currents on pins A, B, and C can also be measured concurrently. That is, with all other considerations remaining constant, the sensor coils dedicated to each channel driver / sensing circuit can be stimulated / measured simultaneously. This configuration can be considered suitable for certain specific situations, such as applications requiring high precision for rapidly moving targets.

[0066] On the other hand, although it is at least theoretically possible to measure the currents at A, B, and C in parallel (e.g., where... Figure 5B The star topology is center-grounded (as described above), but in some other specific cases, this particular arrangement can be considered less desirable compared to using a star or delta topology and continuously measuring the current at A, B, and C as previously stated. One of the main reasons for this can be understood as the need to implement three identical driver / sensor circuits operating in parallel in order to concurrently excite and measure the current at A, B, and C. In contrast, continuous measurement schemes typically require a single ASIC, thus reducing size, cost, and complexity.

[0067] To measure the current at terminals A, B, and C, any suitable method can be used depending on the implementation and / or situation. For example, in the case of a delta topology / arrangement, the following excitation sequence can be used to generate current in the coil, such as... Figure 6A As illustrated.

[0068] Specifically, the coil can be passed through Figure 6A The corresponding pulses shown sequentially excite / stimulate (indicated as 'charging') the corresponding terminals A, B, and C, thereby allowing continuous measurement of the corresponding current in the coil at a predetermined time T0 after the excitation of the corresponding terminals. Specifically, as... Figure 6A As illustrated, the coil can be energized such that when any one of the three terminals A, B, and C is driven to a first predefined potential (e.g., 'high'), the other two terminals are placed / set to a second predefined potential (e.g., 'low'). In other words, there are no floating nodes / terminals / pins at any time during the energization of the coil.

[0069] Those skilled in the art will understand and recognize that the above-described stimulus / incentive sequence is also applicable to star topologies.

[0070] For the sake of completeness, it is worth mentioning that alternative stimulus / excitation methods for star topologies can also be used in some other possible examples, such as... Figure 6B As illustrated. Of course, those skilled in the art will understand and recognize that such excitation / stimulation can also be appropriately applied to triangular (or any other suitable) topology.

[0071] Specifically, such as Figure 6B As shown, one of the pins A, B, and C is always in a floating state (indicated as 'Z state'). However, it should be noted that in some possible cases, if one of A, B, or C remains floating after current has flowed through it, undesirable electromagnetic field (EMF) spikes may be generated. Therefore, in the preferred embodiment, the node should never be kept floating, as described above. In other words, regardless of which of the two topologies is chosen, in the preferred embodiment, terminals A, B, and C are driven such that one of A, B, and C is 'high' (or any other suitable reference potential), and the other two are 'low' (or any other suitable reference potential).

[0072] It can be seen that the above driving scheme results in the simultaneous measurement of two sensor coils. This is why, for this configuration, the above formula (3) should apply to the total equivalent inductance L of the coil assembly. e This is one of the reasons why, rather than a single coil, the system may, in some possible cases, become more sensitive to asymmetry in the three drive channels. However, as those skilled in the art will understand and recognize, it remains worth noting that, from a practical implementation perspective, the proposed technique is preferred.

[0073] Now, referring to the ASIC side. Specifically, Figure 7The diagram illustratively illustrates a possible (not limiting) implementation of an example topology for the ASIC 720 used in conjunction with the sensor 710 described above. Generally, the ASIC 720 provides a voltage pulse (e.g., a rectangular pulse) on one of A, B, or C, and measures the sample at a predetermined time after the start of the charging and discharging process of the coil. Therefore, the ASIC 720, particularly when used in conjunction with the sensor 710 described above, allows the necessary information to be transferred to the digital domain to solve the above equation (7), while fully utilizing the dynamic range of the ADC 725, as described above.

[0074] Specifically, the driver stage 721 can be configured to apply the aforementioned excitation / stimulation and measurement scheme to the three ends (A, B, and C) of the coil. It is worth noting that, although in conventional sensor implementations (such as...) Figure 1 As shown, coils are typically excited with AC current from an oscillator, but in this disclosure, the ASIC can supply pulses (e.g., square, rectangular, etc.) to the coil assembly to discontinuously excite the coil. Those skilled in the art will understand and recognize that exciting the transmitter coil with short (discontinuous) pulses can be considered to have at least the following effects. First, glitchy excitation signals (e.g., short rectangular pulses) typically have a fairly wide spectral bandwidth, allowing their energy to propagate over a wider frequency band. This results in a reduced spectral density of electromagnetic noise generated by such a system during operation, thereby improving its EMC performance. Furthermore, the power consumption of the sensor can be significantly reduced compared to conventional techniques based on AC current, since a continuous current supply to the coil is not required. Therefore, the ASIC can also be powered synchronously with the pulse sequence. Additionally, a rectifier is not required, as the current supplied to the coil and the induced current are already in a form suitable for further processing. Finally, the design of the excitation generator can also be greatly simplified. In some possible examples, the clock scheme used to generate the pulses can be randomized (e.g., by using an analog random generator, etc.). Therefore, electromagnetic interference that the coil might cause to adjacent circuits can be greatly reduced. Furthermore, using a random clock scheme may disrupt any potential correlation with, for example, external interference signals, thereby positively impacting the system's immunity to electromagnetic interference.

[0075] In addition, the current sensing stage 722 and the sample-and-hold stage 723 are typically able to sample the current of all three phases being measured, and with the help of the MUX stage 724, select and subtract the current at A, B, and C.

[0076] Therefore, it can be seen that the calculations of (BA), (AC), and (CB) in the above equation (7) can be performed in the analog domain, eliminating the DC offset of the signal, and thus fully utilizing the dynamic range of the ADC through the dynamic components of the information signal. The rest of the system / circuit system follows a known receiver path topology, and therefore will not be discussed in detail here for the sake of brevity.

[0077] Of course, those skilled in the art will understand and recognize that Figure 7 This exemplary implementation of ASIC 720 shown is provided merely as a possible example for illustrative purposes and should not be construed as constituting any form of limitation. Any other suitable implementation of the ASIC may be employed depending on various circumstances and / or requirements.

[0078] It is worth noting that the proposed ASIC architecture (especially when used in conjunction with the proposed sensor components) can also generally be considered to have many advantages, namely: The differential signal path proposed in this paper can be considered to be unaffected by common-mode and power supply interference. Information is carried by current rather than voltage potential, making it sensitive to voltage drops (e.g., I0). Insensitive to R-drop, parasitic coupling, etc. In a star topology, the equivalent inductance Le(φ) is always greater than the inductance of the individual coil. In this case, a higher inductance can be considered preferred for sensor sensitivity and ASIC electrical requirements, which helps in sensor miniaturization. • The current from the sensor can be sampled and subtracted in the analog domain, thereby eliminating the DC offset of the signal in advance. This, in turn, allows full utilization of the ADC's dynamic range through the dynamic components of the information signal. Finally, complex signal post-processing can be completely transferred to the digital domain.

[0079] It should also be noted that the entire system (i.e., the combination of the aforementioned sensors and ASIC) can be considered to derive further benefits from continuous health / defect monitoring.

[0080] More specifically, in the event that the sensor malfunctions in some way, the derived values ​​of parameters Am and O can be used to determine whether an error exists. Similar to equation (7) above, the other two unknowns (i.e., the amplitude parameter Am and the offset parameter O) can be determined according to the system of equation (6) using the following equations (8) and (9): (8) (9)

[0081] It is worth mentioning that in the above equations (8) and (9), the amplitude parameter is used to determine the amplitude parameter. Am and offset parameters O tan ( φ ) can be calculated according to equation (7): (10)

[0082] In the event of a defect or malfunction, the values ​​of these two parameters may exceed narrow tolerance limits (e.g., defined by natural but relatively small processes, voltage and temperature (PVT) variations, etc.), thereby triggering appropriate alarm signals, etc.

[0083] It is worth noting that the aforementioned self-diagnostic functions typically do not require additional hardware. Providing this benefit only requires additional computation in the digital domain, but can potentially offer very high self-diagnostic coverage across the entire signal path, which can be considered a fairly important requirement for any safety-critical product.

[0084] It is also worth mentioning that, in some cases, the system will allow for simplified and cost-effective calibration of potential inter-channel asymmetries. These asymmetries translate into angular errors and nonlinearities. Specifically, measurements taken at only three data points (target locations) during production testing after system manufacturing will be able to determine the individual φ for each channel (A, B, and C). i And amplitude, these data can be further stored as normalized data on the ASIC for use in calibrating the sensor accordingly.

[0085] Furthermore, as mentioned above, although many of the examples above seem to involve or concern the determination of the angular displacement of a (rotatably or angularly movable) target, the techniques presented herein can also be applied (e.g., through appropriate adaptation, etc.) to determine the linear displacement of a (linearly movable) target. For completeness, some possible (and not limiting) examples will be described with reference to the following figures, schematically illustrating some general principles regarding the determination of linear displacement.

[0086] Figure 8 The first example implementation shown can be considered relatively simple because it generally illustrates the possible transformation between the polar coordinate system used to determine angular displacement and the Cartesian coordinate system that can be used to determine linear displacement, and how the coil arrangement and target shape change when the linear displacement is determined.

[0087] For this simple sensor arrangement, the coil's PCB can be relatively small. However, as... Figure 8 As illustrated, in this example, the target length will be twice the measurement range, which could be considered unsuitable for some potential applications.

[0088] As a second possible example implementation for determining linear displacement. Figure 9 A linear position sensor with a parallel coil arrangement (topology) is schematically illustrated. This typically allows for smaller, simpler targets, which is thus considered a preferred embodiment for many industrial applications. More broadly, those skilled in the art will understand and recognize that, in this specific example, the required mathematical relationship / function between the target position and the coil's self-inductance can be achieved through appropriate shaping of the coil windings.

[0089] at last, Figure 10 and Figure 11 The diagram illustrates a flowchart of a possible example method according to some example embodiments of this disclosure.

[0090] Specifically, Figure 10 An example of a method 1000 using an inductive sensor assembly according to some embodiments of the present disclosure is illustrated schematically. The inductive sensor assembly may be similar to or analogous to the assembly described above with reference to the drawings, etc. Specifically, method 1000 may include providing a coil assembly at step S1010, the coil assembly being discontinuously excited by a sequence of signal pulses, and comprising three coils coupled between three terminals in a predefined arrangement. Method 1000 may further include providing a movable conductive target at step S1020, the movable conductive target at least partially covering the coils during its movement, thereby enabling the measurement of the corresponding current of the coil assembly at a predetermined time synchronized with the excitation of the coil assembly at the corresponding terminals to determine the displacement of the target.

[0091] Similarly, Figure 11 An example of method 1100 using a system according to some embodiments of the present disclosure is illustrated schematically. The system may be similar to or analogous to the system described above with reference to the accompanying drawings, etc. For example, the system may include an inductive sensor assembly comprising: a coil assembly including three (e.g., identical) coils coupled between three terminals in a predefined arrangement; and a (rotational or linear) movable conductive target that at least partially covers the coils during its movement. The system may also include a circuit system assembly coupled to the inductive sensor assembly. More specifically, method 1100 may include, at step S1110, the circuit system assembly discontinuously stimulating the coil assembly of the inductive sensor assembly with a sequence of signal pulses. Method 1100 may also include, at step S1120, the circuit assembly measuring a corresponding current in the coil assembly at a predetermined time synchronized with the stimulation of the coil assembly at the corresponding terminals. Finally, method 1100 may include, at step S1130, the circuit assembly determining the displacement (angular or linear displacement) of the target of the inductive sensor assembly based on the measured current.

[0092] The technology presented in this disclosure also offers several other advantages, including (but not limited to): high configurability, typically meaning that a single product can be configured to cover many application scenarios; no need for demanding analog components, thus making it relatively easy to implement; providing an easy-to-use, high-coverage self-diagnostic method for the entire signal path; readiness for higher Automotive Safety Integrity Levels (ASIL); high EMC robustness; low current consumption; low cost of goods sold (COGS); and minimizing the bill of materials (BOM) for external components.

[0093] It is important to note that the exemplary implementation of the coil shown in the figure, which may have a specific winding, arrangement, or placement, is for possible illustrative purposes only and should certainly not be construed as a limitation of any kind. Any other suitable arrangement, implementation, and / or application may be employed, as will be understood and recognized by those skilled in the art.

[0094] It should be noted that the circuit / system features described above correspond to various method features; however, for the sake of brevity, these method features may not be explicitly described. The disclosure of this document is also intended to extend to these method features. In particular, this disclosure is understood to also relate to methods of manufacturing and / or operating the aforementioned circuit system / system, and / or methods of providing and / or arranging the corresponding elements in the circuit system / system.

[0095] It should also be noted that, based on the fundamental technical field, the examples of embodiments of this disclosure are applicable to various applications or system configurations. In other words, the examples shown in the above-described drawings, which serve as the basis for the above examples, are merely illustrative and do not limit this disclosure in any way. That is, based on the defined principles, other existing and proposed new functionalities available in corresponding operating environments can be used in conjunction with the examples of embodiments of this disclosure.

[0096] Finally, it should be noted that the specification and accompanying drawings only illustrate the principles of the proposed circuits and methods. Those skilled in the art will be able to implement various arrangements, which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and embodiments outlined in this document are primarily for illustrative purposes to aid the reader in understanding the principles of the proposed methods. Moreover, all statements and specific examples herein used to provide the principles, aspects, and embodiments of the invention are intended to cover their equivalents.

Claims

1. An inductive sensor assembly, comprising: A coil assembly, discontinuously excited by a sequence of signal pulses, wherein the coil assembly comprises three coils coupled between three terminals in a predefined arrangement; as well as A movable conductive target that at least partially covers the coil during its movement. The inductive sensor assembly is configured to measure the corresponding current of the coil assembly at a predetermined time to determine the displacement of the target, the predetermined time being synchronized with the excitation of the coil assembly at a corresponding terminal.

2. The inductive sensor assembly of claim 1, wherein the inductive sensor assembly is configured to determine the angular displacement of the target.

3. The inductive sensor assembly according to claim 2, wherein... The predefined arrangement includes a triangular topology or a star topology, in which each of the coils is angularly displaced by a predetermined angle relative to a reference angle.

4. The inductive sensor assembly according to claim 2, wherein... The coil assembly is sequentially energized at corresponding terminals, and the corresponding current of the coil assembly is continuously measured at the corresponding terminal at the predetermined time following the energization of the corresponding terminal.

5. The inductive sensor assembly according to claim 2, wherein... The coil assembly is energized such that when any one of the three terminals is driven to a first predefined potential, the other two of the three terminals are placed at a second predefined potential.

6. The inductive sensor assembly according to claim 2, wherein... The target has the following shape: designed such that the inductance of the coil assembly, as a function of the angular displacement, follows a predetermined mathematical function.

7. The inductive sensor assembly according to claim 2, wherein... At the corresponding terminals i The corresponding current of the coil assembly measured at the location I i , i =1, 2, 3, and the target φ The corresponding angular displacement follows: I i = Am ∙sin ( φ + φ i )+ O ,in Am Indicates the modulation amplitude parameter. O This represents a static and displacement-independent offset parameter, and φ i Indicates coupling to the corresponding terminal i The predetermined displacement angle of the corresponding coil relative to the reference angle.

8. The inductive sensor assembly of claim 2, wherein the target φ The angular displacement is determined according to the following formula: ， in I i Indicates at the corresponding terminal i The corresponding current of the coil assembly measured at the location, i =1, 2, 3, and φ i Indicates coupling to the corresponding terminal i The predetermined displacement angle of the corresponding coil relative to the reference angle.

9. The inductive sensor assembly according to claim 2, wherein... The predetermined time for measuring the current after coil excitation is determined based on the following: the LR time constant of the inductive sensor assembly and the drive circuit system of the inductive sensor assembly that generates the signal pulse sequence.

10. A system comprising: The inductive sensor assembly according to claim 1; as well as The circuit system component is coupled to the inductive sensor component. The circuit system component is configured to: discontinuously excite the coil component of the inductive sensor component with a sequence of signal pulses, and measure the current of the coil component at a predetermined time synchronized with the excitation of the coil component, in order to determine the displacement of the target of the inductive sensor component.

11. The system of claim 10, wherein The circuit system components are configured to sequentially excite the coil assembly at corresponding terminals, and the corresponding current of the coil assembly is continuously measured at the corresponding terminal at the predetermined time following the excitation of the corresponding terminal.

12. The system according to claim 10, wherein The circuit system components are configured to excite the coil assembly such that when any one of the three terminals is driven to a first predefined potential, the other two of the three terminals are placed at a second predefined potential.

13. The system of claim 10, wherein the system is further configured to support a self-diagnostic function, the self-diagnostic function comprising: The modulation amplitude parameter is determined according to the following formula. Am : ； The static and displacement-independent offset parameters are determined according to the following formula. O : ； as well as Based on the determined Am and O The presence of defects in the system is determined by the system and its corresponding predetermined tolerance limits. in I i Indicates at the corresponding terminal i The corresponding current of the coil assembly measured at the location, i =1, 2, 3, φ i Indicates coupling to the corresponding terminal i The predetermined displacement angle of the corresponding coil relative to the reference angle. φ Let represent the angular displacement of the target, and tan( φ ) is used to determine the modulation amplitude parameters Am and the static and displacement-independent offset parameters O Calculated as .

14. A method of using an inductive sensor assembly, comprising: A coil assembly is provided, which is discontinuously excited by a sequence of signal pulses and includes three coils coupled between three terminals in a predefined arrangement; as well as A movable conductive target is provided, which at least partially covers the coil during movement of the movable conductive target. This allows for the measurement of the corresponding current in the coil assembly at a predetermined time to determine the displacement of the target, the predetermined time being synchronized with the excitation of the coil assembly at the corresponding terminal.

15. A method of using a system, the system comprising: Inductive sensor assembly, including: A coil assembly comprising three coils coupled between three terminals in a predefined arrangement; and A movable conductive target that at least partially covers the coil during movement of the movable conductive target; and The circuit system component is coupled to the inductive sensor component. The method includes: The coil assembly of the inductive sensor assembly is discontinuously excited by the circuit system components through a sequence of signal pulses; The circuit assembly measures the corresponding current of the coil assembly at a predetermined time, the predetermined time being synchronized with the excitation of the coil assembly at the corresponding terminal; and The displacement of the target by the inductive sensor assembly is determined by the circuit assembly based on the measured current.

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