Compensation device and compensation method of eddy current torque angle sensor

Abstract

The invention discloses a compensation device and a compensation method for an eddy current torque angle sensor. The compensation device comprises a residual current detection unit, an electromagnetic force calculation unit, a compensation voltage signal generation unit, a driving unit and a compensation coil, the residual current detection unit is used for collecting a residual current signal in the excitation coil in real time and converting the residual current signal into a digital current signal to be output; the electromagnetic force calculation unit is used for calculating the magnitude of the electromagnetic force generated by the residual current signal according to a pre-stored mapping model; the processor is also used for determining the acting direction of the electromagnetic force according to the pre-stored winding direction parameters of the excitation coil and the direction of the residual current signal; the compensation voltage signal generation unit is used for generating a compensation voltage signal according to the magnitude and action direction of the electromagnetic force; the compensation coil is used for generating a compensation magnetic field for offsetting the electromagnetic force according to the compensation current. According to the invention, the angle and torque jitter when the sensor is static can be effectively inhibited, and the torque and angle measurement precision is improved.

Description

Technical Field

[0001] This invention relates to the field of sensor electronic control technology, and in particular to a compensation device and compensation method for an eddy current torque angle sensor. Background Technology

[0002] Eddy current torque and angle sensors are widely used in automotive powertrain systems and industrial precision transmissions due to their advantages such as non-contact detection and fast response speed. Their working principle involves the stator coils generating an alternating magnetic field, which is then cut by the upper and lower rotor blades to produce eddy currents. The interaction between these eddy currents and the magnetic field generates an induced electrical signal, and changes in this induced electrical signal reflect the torque and angle signals.

[0003] However, when the eddy current torque angle sensor is stationary, residual excitation current still exists in the stator coil, resulting in residual eddy currents on the upper and lower rotor blades. These residual eddy currents generate unbalanced electromagnetic forces in the stator magnetic field, ultimately causing angle jitter errors and torque jitter errors.

[0004] Currently, existing technologies mainly improve the aforementioned errors through two approaches. One is by optimizing the sensor's mechanical structure or adjusting the magnetic field distribution, but this method often increases manufacturing costs and has limited effectiveness in eliminating microscopic residual forces. The other approach is to use simple filtering circuits at the electronic level to post-process the output signal to suppress noise. However, this method can only passively filter out noise in the signal and cannot directly detect and cancel the physical root cause of the error, namely the electromagnetic force generated by residual eddy currents themselves. Therefore, it is not effective in compensating for stationary jitter errors. Summary of the Invention

[0005] This invention provides a compensation device and method for an eddy current torque angle sensor. By detecting the residual current of the excitation coil in real time and actively generating a reverse compensation magnetic field to counteract the electromagnetic force generated therefrom, the device effectively suppresses the angle and torque jitter when the sensor is stationary, thereby improving the accuracy of torque and angle measurements.

[0006] In a first aspect, embodiments of the present invention provide a compensation device for an eddy current torque angle sensor, comprising: a residual current detection unit, an electromagnetic force calculation unit, a compensation voltage signal generation unit, a driving unit, and a compensation coil; the input end of the residual current detection unit is connected to the excitation coil of the eddy current torque angle sensor, for real-time acquisition of the residual current signal in the excitation coil, and conversion of the residual current signal into a digital current signal for output; the input end of the electromagnetic force calculation unit is connected to the output end of the residual current detection unit, for calculating the magnitude of the electromagnetic force generated by the residual current signal according to a pre-stored mapping model; and for determining the direction of action of the electromagnetic force according to pre-stored excitation coil winding parameters and the direction of the residual current signal; the input end of the compensation voltage signal generation unit is connected to the output end of the electromagnetic force calculation unit, for generating a compensation voltage signal according to the magnitude and direction of action of the electromagnetic force; wherein, the magnitude of the compensation voltage signal corresponds to the magnitude of the electromagnetic force, and the direction of action of the compensation voltage signal is opposite to the direction of action of the electromagnetic force; the input end of the driving unit is connected to the output end of the compensation voltage signal generation unit, for converting the compensation voltage signal into a compensation current; the compensation coil is coaxially arranged with the excitation coil and connected to the output end of the driving unit, for generating a compensation magnetic field to counteract the electromagnetic force according to the compensation current.

[0007] Optionally, the electromagnetic force calculation unit includes a second resistor and a first chip; the first end of the second resistor serves as the input terminal of the electromagnetic force calculation unit, the second end of the second resistor is connected to the input pin of the first chip, and the output pin of the first chip serves as the output terminal of the electromagnetic force calculation unit.

[0008] Optionally, the mapping model is stored in the first chip in the form of a polynomial fitting function, which includes a first function and a second function; the first function is used to calculate the residual eddy current of the rotor based on the residual excitation current of the excitation coil, and its specific expression is: The second function is used to calculate the magnitude of the electromagnetic force generated by the residual eddy currents in the rotor, based on the residual eddy currents in the rotor. The specific expression is as follows: Where I represents the residual excitation current of the excitation coil, E represents the residual eddy current of the rotor, and F represents the electromagnetic force; , , , , , , and These are the fitting coefficients determined based on the sensor model and parameters.

[0009] Optionally, the residual current detection unit includes a first resistor, a current detection chip, a first capacitor, and an analog-to-digital converter chip; the first end of the first resistor is connected to the current output terminal of the excitation coil and serves as the input terminal of the residual current detection unit; the second end of the first resistor is connected to the input pin of the current detection chip, used to convert the residual current signal flowing through the excitation coil into a voltage signal; the output pin of the current detection chip is filtered by the first capacitor and then connected to the input pin of the analog-to-digital converter chip; the output pin of the analog-to-digital converter chip serves as the output terminal of the residual current detection unit, used to convert the voltage signal into a digital current signal and output it.

[0010] Optionally, the compensation voltage signal generation unit includes a second chip, a driver, a third resistor, a digital-to-analog converter chip, a fourth resistor, a fifth resistor, an operational amplifier, and a second capacitor. The input pin of the second chip serves as the input terminal of the compensation voltage signal generation unit. The second chip is used to receive the magnitude and direction of the electromagnetic force and generate corresponding digital control signals. The input terminal of the driver is connected to the output pin of the second chip, and the output terminal of the driver is connected to the first terminal of the third resistor for buffering and driving the digital control signals. The input pin of the digital-to-analog converter chip is connected to the second terminal of the third resistor, and the output pin of the digital-to-analog converter chip is connected to the first terminal of the fourth resistor for converting the digital control signals into analog voltage signals. The first input terminal of the operational amplifier is connected to the second terminal of the fourth resistor, the second input terminal of the operational amplifier is connected to the first terminal of the fifth resistor, and the output terminal of the operational amplifier is connected to the first terminal of the second capacitor, serving as the output terminal of the compensation voltage signal generation unit. The operational amplifier is used to condition and amplify the analog voltage signals and output the compensation voltage signal. The second terminal of the fifth resistor and the second terminal of the second capacitor are both grounded.

[0011] Optionally, the driving unit includes a sixth resistor, a power amplifier, and a seventh resistor; the first end of the sixth resistor serves as the input terminal of the driving unit, and the second end of the sixth resistor is connected to the input terminal of the power amplifier; the first end of the seventh resistor is connected to the output terminal of the power amplifier, and the second end of the seventh resistor serves as the output terminal of the driving unit.

[0012] Optionally, the compensation device of the eddy current torque angle sensor also includes a protection unit connected between the output terminal of the compensation coil and ground, for dissipating the reverse induced electromotive force generated by the compensation coil.

[0013] Secondly, embodiments of the present invention provide a compensation method for an eddy current torque angle sensor, comprising: a residual current detection unit acquiring the residual current signal in the excitation coil of the eddy current torque angle sensor in real time, and converting the residual current signal into a digital current signal; an electromagnetic force calculation unit calculating the magnitude of the electromagnetic force generated by the residual current signal based on the digital current signal and a pre-stored mapping model, and determining the direction of action of the electromagnetic force based on the pre-stored excitation coil winding parameters and the direction of the residual current signal; a compensation voltage signal generation unit generating a compensation voltage signal based on the magnitude and direction of action of the electromagnetic force; wherein the magnitude of the compensation voltage signal corresponds to the magnitude of the electromagnetic force, and the direction of action of the compensation voltage signal is opposite to the direction of action of the electromagnetic force; a driving unit converting the compensation voltage signal into a compensation current; and driving a compensation coil with the compensation current to generate a compensation magnetic field that cancels the electromagnetic force; wherein the compensation coil and the excitation coil are arranged coaxially.

[0014] Optionally, the step of determining the direction of the electromagnetic force based on the pre-stored winding parameters of the excitation coil and the direction of the residual current signal includes: determining the direction of the magnetic field polarity based on the pre-stored winding parameters of the excitation coil and the direction of the residual current signal; determining the direction of the eddy current based on the direction of the residual current; and determining the direction of the electromagnetic force based on the direction of the magnetic field polarity and the direction of the eddy current.

[0015] Optionally, the step of determining the direction of electromagnetic force based on the direction of magnetic field polarity and the direction of eddy current includes: when the direction of magnetic field polarity and the direction of eddy current are the same, outputting a first force direction; when the direction of magnetic field polarity and the direction of eddy current are opposite, outputting a second force direction opposite to the first force direction.

[0016] The eddy current torque angle compensation device provided in this invention includes a residual current detection unit, an electromagnetic force calculation unit, a compensation voltage signal generation unit, a driving unit, and a compensation coil. The residual current detection unit is used to acquire the residual current signal in the sensor's excitation coil in real time and convert the residual current signal into a digital current signal. The electromagnetic force calculation unit, connected to the residual current detection unit, is used to calculate the magnitude of the electromagnetic force generated by the residual current signal according to a pre-stored mapping model, and to determine the direction of the electromagnetic force based on pre-stored structural parameters and the real-time acquired residual current direction. The compensation voltage signal generation unit, connected to the electromagnetic force calculation unit, is used to generate a corresponding compensation voltage signal based on the magnitude and direction of the electromagnetic force. The driving unit, connected to the compensation voltage signal generation unit, is used to convert the compensation voltage signal into a compensation current. The compensation coil is used to generate a compensation magnetic field to counteract the electromagnetic force based on the compensation current. That is, by real-time detection of the residual current in the excitation coil, calculating the magnitude and direction of the generated electromagnetic force, and then actively generating a reverse compensation magnetic field to directly counteract the unbalanced electromagnetic force, the problem of angle and torque jitter error in the static state of the eddy current torque angle sensor is solved. Compared to traditional mechanical structure optimization or back-end signal filtering methods, this approach more directly and effectively combats static jitter errors, thereby significantly reducing the angle and torque jitter of the eddy current torque angle sensor and improving measurement accuracy and stability. Furthermore, it eliminates the need for major modifications to the mechanical structure of the eddy current torque angle sensor. The components used in the compensation device are all highly versatile, resulting in lower costs than traditional mechanical optimization schemes. The overall unit size can be miniaturized, facilitating integration into the sensor housing or externally. It is widely adaptable to different models and specifications of eddy current torque angle sensors. Only the fitting formula of the mapping model and the relevant parameters of the compensation coil need to be adjusted according to the specific parameters of different eddy current torque angle sensors; there is no need to redesign the hardware structure of the compensation device, demonstrating strong practicality and versatility.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a compensation device for an eddy current torque angle sensor provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the results of an electromagnetic force calculation unit provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a residual current detection unit provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a compensation voltage signal generation unit provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a driving unit provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a compensation device for an eddy current torque angle sensor provided in an embodiment of the present invention; Figure 7 This is a flowchart of a compensation method for an eddy current torque angle sensor provided in an embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0022] Figure 1 This is a schematic diagram of the structure of a compensation device for an eddy current torque angle sensor provided in an embodiment of the present invention. Figure 1 As shown, the compensation device includes: a residual current detection unit 11, an electromagnetic force calculation unit 12, a compensation voltage signal generation unit 13, a driving unit 14, and a compensation coil L1; The input terminal of the residual current detection unit 11 is connected to the excitation coil of the eddy current torque angle sensor, which is used to collect the residual current signal in the excitation coil in real time and convert the residual current signal into a digital current signal for output. The input terminal of the electromagnetic force calculation unit 12 is connected to the output terminal of the residual current detection unit 11. It is used to calculate the magnitude of the electromagnetic force generated by the residual current signal according to the pre-stored mapping model. It is also used to determine the direction of the electromagnetic force according to the pre-stored excitation coil winding parameters and the direction of the residual current signal. The input terminal of the compensation voltage signal generation unit 13 is connected to the output terminal of the electromagnetic force calculation unit 12, and is used to generate a compensation voltage signal according to the magnitude and direction of the electromagnetic force; wherein, the magnitude of the compensation voltage signal corresponds to the magnitude of the electromagnetic force, and the direction of the compensation voltage signal is opposite to the direction of the electromagnetic force. The input terminal of the driving unit 13 is connected to the output terminal of the compensation voltage signal generation unit 12, and is used to convert the compensation voltage signal into a compensation current. The compensation coil L1 is arranged coaxially with the excitation coil and connected to the output terminal of the drive unit 13, and is used to generate a compensation magnetic field to counteract the electromagnetic force according to the compensation current.

[0023] In a preferred embodiment, the residual current signal may include a high-precision current sensor chip (e.g., a linear current sensor of model ACS723), a filter capacitor, and an analog-to-digital converter chip. The operation is as follows: the sampling resistor converts the residual current signal flowing through the excitation coil into a weak voltage signal; the current sensor chip amplifies and pre-conditions this voltage signal; subsequently, the signal passes through a filter capacitor to remove high-frequency noise; finally, the analog-to-digital converter chip converts the analog voltage signal into a high-resolution digital current signal (i.e., digital current signal I and its direction indicator I_Dir) for output.

[0024] The electromagnetic force calculation unit 12 may include a processing chip, such as a field-programmable gate array (FPGA) or microprocessor (e.g., an XC7K325T FPGA chip). It internally stores two types of key information: first, a mapping model of "residual current-eddy current-electromagnetic force," which can be a polynomial function fitted using experimental data, used to calculate the magnitude F of the electromagnetic force based on the input digital current value I; second, preset sensor structural parameters, such as the winding direction of the excitation coil (clockwise CW or counterclockwise CCW). After receiving the digital current signal, the electromagnetic force calculation unit 12 calculates the magnitude of the electromagnetic force using the mapping model, and then, combining the pre-stored coil winding parameters and the real-time current direction I_Dir, calculates the specific direction of the electromagnetic force according to the logic embedded in the laws of electromagnetism (such as the right-hand screw rule and the left-hand rule). The electromagnetic force calculation unit 12 ultimately outputs a complete vector containing information on the magnitude and direction of the electromagnetic force.

[0025] The function of the compensation voltage signal generation unit 13 is to convert the calculated abstract force command into a specific, executable voltage command. This unit may include a control chip (such as a microcontroller), a digital-to-analog converter (DAC), and a signal conditioning circuit. For example, the DAC may be a high-precision DAC chip (such as AD5791), and the signal conditioning circuit may be composed of an operational amplifier. The workflow is as follows: the control chip receives the electromagnetic force vector and generates corresponding digital control code based on a preset force-to-voltage conversion coefficient; this code is converted into an analog voltage signal by the DAC; this initial voltage signal is then proportionally amplified and offset adjusted by the conditioning circuit composed of the operational amplifier, ultimately generating a compensation voltage signal whose amplitude is proportional to the magnitude of the electromagnetic force and whose polarity is opposite to the direction of the electromagnetic force.

[0026] The function of the driving unit 14 is to provide sufficient driving capability to generate an effective compensation magnetic field. This unit may include a power amplifier (e.g., a power operational amplifier of model OPA548). It amplifies the low-power voltage signal output from the compensation voltage signal generation unit 13 and converts it into a compensation current capable of driving the compensation coil L1.

[0027] The compensation coil L1 is the final actuator for the compensation action. It is arranged coaxially with the original excitation coil of the eddy current torque angle sensor to ensure that the generated compensation magnetic field can cover the rotor blade area. When the drive current flows through the compensation coil, it generates a compensation magnetic field in the opposite direction to the previously calculated electromagnetic force, thereby directly canceling the unbalanced force on the rotor blades.

[0028] Continue to refer to Figure 1 The working process of this compensation device is as follows: After the compensation device is powered on, the residual current detection unit 11 continuously monitors the current of the excitation coil; the electromagnetic force calculation unit 12 processes this information in real time and quickly identifies the electromagnetic force causing the jitter; the compensation voltage signal generation unit 13 and the drive unit 14 then work together to generate and apply a compensation current to the compensation coil L1. The compensation coil L1, as the actuator of this device, is arranged coaxially with the excitation coil of the eddy current torque angle sensor. This arrangement ensures the effectiveness of magnetic field cancellation. After receiving the compensation current output by the drive unit 14, it generates a compensation magnetic field opposite to the magnetic field generated by the residual current. This compensation magnetic field cancels out the original magnetic field generated by the residual current, thereby eliminating the unbalanced electromagnetic force caused by the residual eddy current.

[0029] The eddy current torque angle compensation device provided in this invention includes a residual current detection unit, an electromagnetic force calculation unit, a compensation voltage signal generation unit, a driving unit, and a compensation coil. The residual current detection unit is used to acquire the residual current signal in the sensor's excitation coil in real time and convert the residual current signal into a digital current signal. The electromagnetic force calculation unit, connected to the residual current detection unit, is used to calculate the magnitude of the electromagnetic force generated by the residual current signal according to a pre-stored mapping model, and to determine the direction of the electromagnetic force based on pre-stored structural parameters and the real-time acquired residual current direction. The compensation voltage signal generation unit, connected to the electromagnetic force calculation unit, is used to generate a corresponding compensation voltage signal based on the magnitude and direction of the electromagnetic force. The driving unit, connected to the compensation voltage signal generation unit, is used to convert the compensation voltage signal into a compensation current. The compensation coil is used to generate a compensation magnetic field to counteract the electromagnetic force based on the compensation current. That is, by real-time detection of the residual current in the excitation coil, calculating the magnitude and direction of the generated electromagnetic force, and then actively generating a reverse compensation magnetic field to directly counteract the unbalanced electromagnetic force, the problem of angle and torque jitter error in the static state of the eddy current torque angle sensor is solved. Compared to traditional mechanical structure optimization or back-end signal filtering methods, this approach more directly and effectively combats static jitter errors, thereby significantly reducing the angle and torque jitter of the eddy current torque angle sensor and improving measurement accuracy and stability. Furthermore, it eliminates the need for major modifications to the mechanical structure of the eddy current torque angle sensor. The components used in the compensation device are all highly versatile, resulting in lower costs than traditional mechanical optimization schemes. The overall unit size can be miniaturized, facilitating integration into the sensor housing or externally. It is widely adaptable to different models and specifications of eddy current torque angle sensors. Only the fitting formula of the mapping model and the relevant parameters of the compensation coil need to be adjusted according to the specific parameters of different eddy current torque angle sensors; there is no need to redesign the hardware structure of the compensation device, demonstrating strong practicality and versatility.

[0030] Figure 2 This is a schematic diagram of the results from an electromagnetic force calculation unit provided in an embodiment of the present invention. Figure 2 As shown, the electromagnetic force calculation unit 12 includes a first chip U1 and a second resistor R2; The first end of the second resistor R2 serves as the input terminal of the electromagnetic force calculation unit 12, the second end of the second resistor R2 is connected to the input pin of the first chip U1, and the output pin of the first chip U1 serves as the output terminal of the electromagnetic force calculation unit 12.

[0031] Specifically, the second resistor R2 is a current-limiting resistor to ensure the stability and integrity of the input signal and prevent overshoot or interference from directly impacting the first chip U1.

[0032] The first chip U1 is the core computing and control device of the electromagnetic force calculation unit 12. In a preferred embodiment, the first chip U1 is an integrated circuit with high-speed computing capabilities and programmable logic, such as a field-programmable gate array (FPGA), a digital signal processor (DSP), or a microcontroller unit (MCU). For example, the model of the first chip U1 is XC7K325T.

[0033] The first chip U1 contains the program and data for executing the compensation algorithm of this invention, including a pre-stored "residual current-eddy current-electromagnetic force" mapping model (such as a polynomial fitting function) and the structural parameters of the sensor (such as the coil winding direction).

[0034] Continue to refer to Figure 2 The electromagnetic force calculation unit 12 works as follows: It receives a digital signal conditioned by a second resistor R2 through the input pin of the first chip U1. The processor inside the first chip U1 calls the mapping model in real time to perform mathematical calculations, accurately calculating the magnitude of the electromagnetic force. Simultaneously, combining pre-stored structural parameters and direction information from the residual current signal, it determines the vector direction of the electromagnetic force through a fixed logical judgment process (such as truth table lookup or algorithms based on the right-hand screw rule and left-hand rule). Finally, the calculated magnitude and direction information are combined into a complete control command, which is transmitted to the subsequent compensation voltage signal generation unit 13 through the output pin of the first chip U1. This embodiment achieves complex calculation functions with only a core chip and a resistor in a minimally simplistic peripheral circuit, significantly reducing the number of components and board area, lowering hardware complexity and failure rate, and improving system integration and reliability. Furthermore, the implementation based on a programmable chip (such as an FPGA) allows the core mapping model and judgment logic to be configured and updated via software or firmware. This means that the same hardware platform can easily adapt to sensors of different models and parameters. Only the mapping model coefficients and the structural parameters of the sensor need to be adjusted, which has strong versatility and flexibility.

[0035] In some embodiments, the mapping model is stored in the non-volatile memory of the first chip U1 in the form of a polynomial fitting function, which includes a first function and a second function.

[0036] The first function is used to calculate the residual eddy current in the rotor based on the residual excitation current of the excitation coil. The specific expression is as follows: ; The second function is used to calculate the magnitude of the electromagnetic force generated by the residual eddy currents in the rotor, and its specific expression is as follows: ; Where I represents the residual excitation current of the excitation coil, E represents the residual eddy current of the rotor, and F represents the electromagnetic force; , , , , , , and These are the fitting coefficients determined based on the sensor model and parameters.

[0037] Specifically, all fitting coefficients are not theoretically derived values, but rather obtained by conducting a series of standard experiments on the specific eddy current torque angle sensor to be compensated (such as measuring the equivalent interference force generated under known residual current), collecting a large number of data points, and then fitting the data using mathematical tools such as the least squares method. For example, for a specific eddy current torque angle sensor, the fitting coefficients are: , , , ; , , , ; These fitting coefficients are then permanently written into the first chip U1, making the compensation device specifically designed for this model of eddy current torque angle sensor. To visually demonstrate the calculation process of the model, the following is a calculation example based on the above example coefficients (as shown in Table 1): Table 1 Examples of electromagnetic force calculations based on example fitting coefficients The modeling method described in this embodiment transforms complex electromagnetic forces, which are difficult to measure directly, into a deterministic calculation problem of residual currents that can be measured directly. The mapping model parameters can be calibrated experimentally, enabling the same hardware design to be quickly adapted to sensors of different specifications, significantly improving the versatility and flexibility of this compensation device.

[0038] In some embodiments, the magnetic field polarity direction is determined based on the pre-stored excitation coil winding parameters and the direction of the residual current signal; the eddy current direction is determined based on the residual current direction; and the direction of the electromagnetic force is determined based on the magnetic field polarity direction and the eddy current direction.

[0039] Specifically, the coil winding direction parameters (e.g., clockwise CW encoded as 1, counterclockwise CCW encoded as 2) are determined based on the sensor's physical structure at the factory and pre-stored in the register or firmware of the first chip U1. The judgment logic is based on the right-hand screw rule: for a given excitation coil winding direction, the polarity direction of the magnetic field it generates has a fixed relationship with the direction of the current flowing through it. In a preferred embodiment, this relationship is solidified as follows: if the excitation coil winding direction is the first direction (e.g., clockwise CW), then the magnetic field polarity direction B_Dir is the same as the current direction I_Dir; if the excitation coil winding direction is the second direction opposite to the first direction (e.g., counterclockwise CCW), then the magnetic field polarity direction B_Dir is opposite to the current direction I_Dir. This logic can be implemented by looking up a pre-stored truth table or by directly executing conditional judgment statements.

[0040] According to the principle of electromagnetic induction, the direction of the residual eddy current generated in the rotor blades is related to the changing magnetic field that produces it. In a simplified and efficient model, the relationship between the direction of the eddy current and the direction of the excitation current can be directly established. Specifically, the direction of the eddy current, E_Dir, is determined to be opposite to the direction of the residual current, I_Dir. This relationship is directly encoded into the decision logic as a fixed physical law.

[0041] The direction of the electromagnetic force on a current-carrying conductor (equivalent to a rotor blade carrying eddy currents) placed in a magnetic field is determined by both the direction of the magnetic field and the direction of the current. Optionally, when the polarity direction of the magnetic field B_Dir is the same as the direction of the eddy current E_Dir, a first force direction is output (e.g., "positive" encoded as 0); when they are opposite, a second force direction opposite to the first force direction is output (e.g., "reverse" encoded as 1). This rule can also be implemented by embedding a truth table or logical operations (such as XOR operations).

[0042] To illustrate this more clearly, a specific example is provided below. Assume that the upper and lower excitation windings of a certain sensor are both wound clockwise (CW, corresponding to binary 00000001), and the direction of the residual current collected in real time is positive, I_Dir=0.

[0043] Determine the direction of magnetic field polarity B_Dir: According to the rule "clockwise downward, B_Dir=I_Dir", B_Dir=0 (positive magnetic field).

[0044] Determine the direction of the eddy current E_Dir: According to the rule "E_Dir is opposite to I_Dir", E_Dir=1 (reverse eddy current).

[0045] Determine the direction of the electromagnetic force F_Dir: At this time, the polarity direction of the magnetic field B_Dir is opposite to the direction of the eddy current E_Dir, and the second force direction should be output, so F_Dir=1 (reverse force).

[0046] Figure 3 This is a schematic diagram of the structure of a residual current detection unit provided in an embodiment of the present invention. Figure 3 As shown, the residual current detection unit 11 includes a first resistor R1, a current detection chip U2, a first capacitor C1, and an analog-to-digital converter chip U3; The first end of the first resistor R1 is connected to the current output terminal of the excitation coil and serves as the input terminal of the residual current detection unit 11. The second end of the first resistor R1 is connected to the input pin of the current detection chip U2 and is used to convert the residual current signal flowing through the excitation coil into a voltage signal. The output pin of the current detection chip U2 is filtered by the first capacitor C1 and then connected to the input pin of the analog-to-digital converter chip U3. The output pin of the analog-to-digital converter chip U3 serves as the output terminal of the residual current detection unit 11, used to convert the voltage signal into a digital current signal and output it.

[0047] Specifically, the current sensing chip U2 (such as the linear Hall current sensor model ACS723) is a high-precision, isolated signal conditioner. Its functions include signal amplification, level conversion, and electrical isolation. Its working principle is as follows: it receives the voltage signal converted by the first resistor R1, and internally adjusts it to a suitable amplitude range (e.g., 0-3.3V) for subsequent circuit processing through a precision amplification circuit. Simultaneously, this chip provides isolation between power ground and signal ground, effectively blocking common-mode noise and interference in the power loop from being conducted to sensitive measurement circuits, greatly improving the system's anti-interference capability and safety. The first capacitor C1 is a filter element, its function being to filter out high-frequency noise.

[0048] The residual current detection unit 11 operates as follows: When current flows through the first resistor R1, a voltage signal proportional to it is generated across its terminals according to Ohm's law, thus completing the current-to-voltage conversion. This voltage signal is then sent to the current detection chip U2, which integrates a high-gain, low-drift amplifier circuit to amplify the weak voltage signal to a standardized voltage range suitable for subsequent processing. Its built-in electrical isolation effectively blocks power ground noise from interfering with the fragile signal chain. The amplified analog voltage signal may still contain high-frequency noise, so it is filtered by the first capacitor C1 to suppress out-of-band noise and improve signal quality. Finally, the clean analog voltage is sent to the input pin of the analog-to-digital converter chip U3. The analog-to-digital converter chip U3 instantaneously samples, holds, and quantizes the voltage at a preset sampling frequency and resolution (e.g., 16 bits), converting it into a digital code representing the magnitude and direction of the original residual current. This digital signal, as the final output of the residual current detection unit 11, is directly input to the electromagnetic force calculation unit 12 for real-time processing.

[0049] Figure 4 This is a schematic diagram of the structure of a compensation voltage signal generation unit provided in an embodiment of the present invention. Figure 4 As shown, the compensation voltage signal generation unit 13 includes a second chip U2, a driver Q1, a third resistor R3, a digital-to-analog converter chip U4, a fourth resistor R4, a fifth resistor R5, an operational amplifier Q2, and a second capacitor C2. The input pin of the second chip U2 serves as the input terminal of the compensation voltage signal generation unit 13. The second chip is used to receive the magnitude and direction of the electromagnetic force and generate corresponding digital control signals. The input terminal of driver Q1 is connected to the output pin of the second chip U2, and the output terminal of driver Q1 is connected to the first terminal of the third resistor R3, which is used to buffer and drive the digital control signal. The input pin of the digital-to-analog converter chip U4 is connected to the second end of the third resistor R3, and the output pin of the digital-to-analog converter chip U4 is connected to the first end of the fourth resistor R4, which is used to convert digital control signals into analog voltage signals. The first input terminal of operational amplifier Q2 is connected to the second terminal of the fourth resistor R4, the second input terminal of operational amplifier Q2 is connected to the first terminal of the fifth resistor R5, and the output terminal of operational amplifier Q2 is connected to the first terminal of the second capacitor C2, serving as the output terminal of the compensation voltage signal generation unit 13. Operational amplifier Q2 is used to condition and amplify the analog voltage signal and output a compensation voltage signal; the second terminal of the fifth resistor R5 and the second terminal of the second capacitor C2 are both grounded.

[0050] Specifically, assume that the first chip U1 calculates the electromagnetic force that needs to be compensated based on the mapping model and outputs a 16-bit digital value Force_Digital, for example, Force_Digital=20000 (range 0~65535, corresponding to a force of 0~5N).

[0051] Direction Inversion and Digital Mapping: The second chip U2 in the compensation voltage signal generation unit 13 receives the electromagnetic force digital quantity Force_Digital and its direction flag. Based on the direction flag, it determines whether the output of the digital-to-analog converter chip U4 should be a positive or negative voltage (i.e., the sign).

[0052] The second chip U2 calculates the digital code DAC_Code that should be input to the digital-to-analog converter chip U4 based on the preset force-to-voltage conversion coefficient K. The formula is: DAC_Code = Force_Digital K (K is an adjustable coefficient) Assuming K=1.6, then DAC_Code=20000 1.6 = 32000.

[0053] The digital-to-analog converter chip U4 (such as AD5791) receives DAC_Code=32000. When this chip operates in ±5V bipolar mode, the conversion relationship between its output Vout and the input digital code DAC_Code (0~65535) is as follows: Vout=(DAC_Code / 65535) 10V-5V; Substitute into the calculation: Vout=(32000 / 65535) 10-5≈(0.488) 10⁻⁵ = 4.88 - 5 = -0.12 V; At this point, the digital-to-analog converter chip U4 has output an initial compensation voltage (-0.12V) that corresponds to the magnitude of the electromagnetic force but has the opposite polarity.

[0054] The initial voltage of -0.12V is proportionally amplified by a conditioning circuit consisting of operational amplifier Q2. Assuming the amplification factor G = 10, the final output compensation voltage V_comp is: V_comp=Vout G=-0.12V 10 = -1.2V; This is the compensation voltage signal received at the input terminal of the drive unit 14, whose amplitude is proportional to the electromagnetic force and whose direction is opposite to it.

[0055] Figure 5 This is a schematic diagram of the structure of a driving unit provided in an embodiment of the present invention. Figure 5 As shown, the drive unit 14 includes a sixth resistor R6, a power amplifier Q3, and a seventh resistor R7; The first end of the sixth resistor R6 serves as the input terminal of the drive unit 14, and the second end of the sixth resistor R6 is connected to the input terminal of the power amplifier Q3; the first end of the seventh resistor R7 is connected to the output terminal of the power amplifier Q3, and the second end of the seventh resistor R7 serves as the output terminal of the drive unit 14.

[0056] Specifically, the compensation voltage signal V_comp is input from the input terminal of the drive unit 14 and first passes through the sixth resistor R6. This resistor is used to limit the current flowing into the input terminal of the power amplifier Q3 to prevent overshoot signals from damaging the amplifier under abnormal conditions.

[0057] Power amplifier Q3 (e.g., model OPA548) is the core of this unit; it is a voltage-controlled current source. Its working principle is as follows: based on the compensation voltage signal V_comp received at its input, it automatically adjusts the voltage at its output through an internal high-gain error amplifier and a powerful output stage. This ensures that the current flowing through the load connected in the output circuit (here, a series combination of the compensation coil and the seventh resistor R7) is proportional to the input voltage. The proportionality coefficient is determined by the amplifier's transconductance or an external feedback network.

[0058] Figure 6 This is a structural schematic diagram of a compensation device for an eddy current torque angle sensor provided in an embodiment of the present invention. Figure 6 As shown, the compensation device also includes a protection unit 15, which is connected between the output terminal of the compensation coil L1 and the ground, and is used to discharge the reverse induced electromotive force generated by the compensation coil L1.

[0059] Optionally, the protection unit 15 includes a diode D1, the anode of which is connected to the output terminal of the compensation coil L1, and the cathode of which is grounded.

[0060] Specifically, the compensation coil L1, as an inductive element, cannot experience sudden changes in current. When the drive current output by the drive unit 14 changes rapidly or is suddenly turned off, according to Lenz's law, an induced electromotive force is generated across the compensation coil L1, its direction attempting to maintain the original current direction. Since the anode of diode D1 is positively connected to this output terminal, diode D1 will immediately conduct due to the forward bias voltage. After conduction, diode D1 provides a direct, low-impedance path to ground for the freewheeling current in the compensation coil L1. This process rapidly dissipates the energy stored in the magnetic field of the compensation coil L1 and clamps the voltage between the output terminal of the compensation coil L1 and ground at the forward voltage drop level of the diode (typically about 0.7V), thereby effectively preventing the occurrence of reverse high voltage spikes that could reach tens or even hundreds of volts. In other words, the protection unit 15 can effectively suppress the reverse voltage spike generated by the inductance characteristics of the compensation coil L1, preventing this high voltage from being directly applied to the output pin of the power amplifier Q3 of the drive unit 14, thus avoiding damage to the power amplifier Q3 due to overvoltage, and greatly improving the reliability and service life of the entire compensation device.

[0061] Based on the same inventive concept, this embodiment of the invention also provides a compensation method for an eddy current torque angle sensor, which can be applied to the compensation device provided in any embodiment of the invention. Figure 7 This is a flowchart illustrating a compensation method for an eddy current torque angle sensor provided in an embodiment of the present invention. Figure 7 As shown, the compensation method includes: S101, The residual current detection unit collects the residual current signal in the excitation coil of the eddy current torque angle sensor in real time and converts the residual current signal into a digital current signal. S102. The electromagnetic force calculation unit calculates the magnitude of the electromagnetic force generated by the residual current signal based on the digital current signal and the pre-stored mapping model, and determines the direction of the electromagnetic force based on the pre-stored excitation coil winding parameters and the direction of the residual current signal.

[0062] In some embodiments, the magnetic field polarity direction is determined based on the pre-stored excitation coil winding parameters and the direction of the residual current signal; the eddy current direction is determined based on the residual current direction; and the direction of the electromagnetic force is determined based on the magnetic field polarity direction and the eddy current direction.

[0063] When the polarity of the magnetic field is the same as the direction of the eddy current, the first force direction is output; when the polarity of the magnetic field is opposite to the direction of the eddy current, the second force direction is output, which is opposite to the first force direction.

[0064] S103, The compensation voltage signal generation unit generates a compensation voltage signal based on the magnitude and direction of the electromagnetic force.

[0065] Among them, the magnitude of the compensation voltage signal corresponds to the magnitude of the electromagnetic force, and the direction of the compensation voltage signal is opposite to the direction of the electromagnetic force. S104, The drive unit converts the compensation voltage signal into a compensation current; S105. A compensation coil is driven by a compensation current to generate a compensation magnetic field that cancels out the electromagnetic force; wherein the compensation coil and the excitation coil are arranged coaxially.

[0066] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0067] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A compensation device for an eddy current torque angle sensor, characterized in that, include: The system includes a residual current detection unit, an electromagnetic force calculation unit, a compensation voltage signal generation unit, a drive unit, and a compensation coil. The input terminal of the residual current detection unit is connected to the excitation coil of the eddy current torque angle sensor, and is used to collect the residual current signal in the excitation coil in real time and convert the residual current signal into a digital current signal for output. The input terminal of the electromagnetic force calculation unit is connected to the output terminal of the residual current detection unit, and is used to calculate the magnitude of the electromagnetic force generated by the residual current signal according to the pre-stored mapping model. It is also used to determine the direction of the electromagnetic force based on the pre-stored excitation coil winding parameters and the direction of the residual current signal; The input terminal of the compensation voltage signal generation unit is connected to the output terminal of the electromagnetic force calculation unit, and is used to generate a compensation voltage signal according to the magnitude and direction of the electromagnetic force; wherein, the magnitude of the compensation voltage signal corresponds to the magnitude of the electromagnetic force, and the direction of the compensation voltage signal is opposite to the direction of the electromagnetic force. The input terminal of the driving unit is connected to the output terminal of the compensation voltage signal generation unit, and is used to convert the compensation voltage signal into a compensation current. The compensation coil is arranged coaxially with the excitation coil and connected to the output terminal of the drive unit, and is used to generate a compensation magnetic field to counteract the electromagnetic force according to the compensation current.

2. The compensation device for the eddy current torque angle sensor according to claim 1, characterized in that, The electromagnetic force calculation unit includes a second resistor and a first chip; The first end of the second resistor serves as the input terminal of the electromagnetic force calculation unit, the second end of the second resistor is connected to the input pin of the first chip, and the output pin of the first chip serves as the output terminal of the electromagnetic force calculation unit.

3. The compensation device for the eddy current torque angle sensor according to claim 2, characterized in that, The mapping model is stored in the first chip in the form of a polynomial fitting function, which includes a first function and a second function. The first function is used to calculate the residual eddy current in the rotor based on the residual excitation current of the excitation coil. The specific expression is as follows: ; The second function is used to calculate the magnitude of the electromagnetic force generated by the residual eddy currents in the rotor based on the residual eddy currents in the rotor. The specific expression is as follows: ; Where I represents the residual excitation current of the excitation coil, E represents the residual eddy current of the rotor, and F represents the electromagnetic force; , , , , , , and These are the fitting coefficients determined based on the sensor model and parameters.

4. The compensation device for the eddy current torque angle sensor according to claim 1, characterized in that, The residual current detection unit includes a first resistor, a current detection chip, a first capacitor, and an analog-to-digital converter chip; The first end of the first resistor is connected to the current output terminal of the excitation coil and serves as the input terminal of the residual current detection unit. The second end of the first resistor is connected to the input pin of the current detection chip and is used to convert the residual current signal flowing through the excitation coil into a voltage signal. The output pin of the current detection chip is filtered by the first capacitor and then connected to the input pin of the analog-to-digital converter chip. The output pin of the analog-to-digital converter chip serves as the output terminal of the residual current detection unit, used to convert the voltage signal into a digital current signal and output it.

5. The compensation device for the eddy current torque angle sensor according to claim 1, characterized in that, The compensation voltage signal generation unit includes a second chip, a driver, a third resistor, a digital-to-analog converter chip, a fourth resistor, a fifth resistor, an operational amplifier, and a second capacitor; The input pin of the second chip serves as the input terminal of the compensation voltage signal generation unit. The second chip is used to receive the magnitude and direction of the electromagnetic force and generate corresponding digital control signals. The input terminal of the driver is connected to the output pin of the second chip, and the output terminal of the driver is connected to the first terminal of the third resistor, for buffering and driving the digital control signal; The input pin of the digital-to-analog converter chip is connected to the second end of the third resistor, and the output pin of the digital-to-analog converter chip is connected to the first end of the fourth resistor, for converting the digital control signal into an analog voltage signal; The first input terminal of the operational amplifier is connected to the second terminal of the fourth resistor, the second input terminal of the operational amplifier is connected to the first terminal of the fifth resistor, the output terminal of the operational amplifier is connected to the first terminal of the second capacitor, and serves as the output terminal of the compensation voltage signal generation unit. The operational amplifier is used to condition and amplify the analog voltage signal and output the compensation voltage signal. The second terminal of the fifth resistor and the second terminal of the second capacitor are both grounded.

6. The compensation device for the eddy current torque angle sensor according to claim 1, characterized in that, The driving unit includes a sixth resistor, a power amplifier, and a seventh resistor; The first end of the sixth resistor serves as the input terminal of the driving unit, and the second end of the sixth resistor is connected to the input terminal of the power amplifier. The first end of the seventh resistor is connected to the output end of the power amplifier, and the second end of the seventh resistor serves as the output end of the driving unit.

7. The compensation device for the eddy current torque angle sensor according to claim 6, characterized in that, It also includes a protection unit connected between the output terminal of the compensation coil and ground, used to discharge the reverse induced electromotive force generated by the compensation coil.

8. A compensation method for an eddy current torque angle sensor, characterized in that, include: The residual current detection unit acquires the residual current signal in the excitation coil of the eddy current torque angle sensor in real time and converts the residual current signal into a digital current signal. The electromagnetic force calculation unit calculates the magnitude of the electromagnetic force generated by the residual current signal based on the digital current signal and the pre-stored mapping model, and determines the direction of the electromagnetic force based on the pre-stored excitation coil winding parameters and the direction of the residual current signal. The compensation voltage signal generation unit generates a compensation voltage signal based on the magnitude and direction of the electromagnetic force; wherein the magnitude of the compensation voltage signal corresponds to the magnitude of the electromagnetic force, and the direction of the compensation voltage signal is opposite to the direction of the electromagnetic force. The driving unit converts the compensation voltage signal into a compensation current; A compensation coil is driven by the compensation current to generate a compensation magnetic field that counteracts the electromagnetic force; wherein the compensation coil and the excitation coil are arranged coaxially.

9. The compensation method for the eddy current torque angle sensor according to claim 8, characterized in that, The step of determining the direction of the electromagnetic force based on the pre-stored excitation coil winding parameters and the direction of the residual current signal includes: The direction of magnetic field polarity is determined based on the pre-stored excitation coil winding parameters and the direction of the residual current signal. The direction of the eddy current is determined based on the direction of the residual current; The direction of the electromagnetic force is determined based on the polarity of the magnetic field and the direction of the eddy current.

10. The compensation method for the eddy current torque angle sensor according to claim 9, characterized in that, The step of determining the direction of electromagnetic force based on the polarity of the magnetic field and the direction of the eddy current includes: When the polarity of the magnetic field is the same as the direction of the eddy current, a first force direction is output; when the polarity of the magnetic field is opposite to the direction of the eddy current, a second force direction opposite to the first force direction is output.

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