An eddy current position sensor test bench calibration compensation test method

Abstract

This invention relates to the field of eddy current position sensor testing technology, and particularly to a calibration and compensation testing method for an eddy current position sensor test bench. The method comprises: S1, acquiring and preprocessing the output signal of the eddy current sensor; S2, performing calibration and compensation processing on the sine and cosine voltage signals to be compensated, obtaining calibrated compensated sine and cosine voltage signals; the sine and cosine voltage signal compensation processing includes at least one of the following: offset compensation and amplitude correction; S3, calculating and determining the angular position information of the eddy current position sensor; and S4, performing harmonic analysis on the signal using Fourier transform to obtain higher-order harmonic models under four conditions: initial position of the rotor relative to the stator, axial offset, radial offset, and tilt angle change. This invention significantly improves the accuracy of test results when testing eddy current sensor products by using offset compensation of the sine and cosine analog voltage signals, amplitude correction of the sine and cosine analog voltage signals, and rapid positioning through harmonic analysis.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of eddy current position sensor test, and particularly relates to a calibration compensation test method for an eddy current position sensor test bench. BACKGROUND

[0002] When the eddy current position sensor is tested on the test bench, the sensor is affected by the outside and the test bench itself, thereby affecting the analog signal output by the sensor, so that the test data of the eddy current position sensor test bench cannot accurately reflect the accuracy of the eddy current sensor.

[0003] Therefore, the present application provides a calibration compensation test method for an eddy current position sensor test bench to solve the above problems. SUMMARY

[0004] The present application aims at solving the problems in the prior art and provides a calibration compensation test method for an eddy current position sensor test bench.

[0005] The calibration compensation test method for the eddy current position sensor test bench comprises the following steps:

[0006] S1, obtaining and preprocessing the output signal of the eddy current sensor; the test bench drives the rotor of the eddy current sensor to rotate by a certain angle, and four analog voltage signals output by the stator of the eddy current position sensor at this time are obtained; the four analog voltage signals are differentially processed to obtain a to-be-compensated sine voltage signal and a to-be-compensated cosine voltage signal;

[0007] S2, performing calibration compensation processing on the obtained to-be-compensated sine and cosine voltage signals to obtain calibrated and compensated sine and cosine voltage signals;

[0008] The compensation processing of the sine and cosine voltage signals comprises at least one of bias compensation and amplitude correction.

[0009] S3, according to the calibrated and compensated sine and cosine voltage signals, the angle position information of the eddy current position sensor is calculated and determined; the angle position information calculated from the sine and cosine voltage signals of the eddy current sensor is subtracted from the angle position information of the mechanical rotation of the test bench to obtain the accuracy level of the position sensor.

[0010] S4, the signal is analyzed by Fourier transform to obtain a high-order harmonic model under four conditions of the initial position, axial offset, radial offset and inclination change of the rotor and the stator; when a problem occurs at the application end, the problem point can be quickly located and solved.

[0011] Preferably, in S1, the four analog voltage signals output by the sensor are in two modes: differential mode and single-ended mode.

[0012] Preferably, when the test bench drives the rotor to rotate one revolution and samples at n positions, the voltage signal output by the sensor stator has the following four values ​​at each position: at the initial point (i.e., zero position, 0°), 360 / n°, 2*360 / n°...(n-1)*360 / n°, and each value has n values:

[0013] SIN / SINP / SIN+: Positive sinusoidal voltage signal;

[0014] SINN / SIN-: Negative sinusoidal voltage signal (VDD / 2 in single-ended mode);

[0015] COS / COSP / COS+: Positive cosine voltage signal;

[0016] COSN / COS-: Negative cosine voltage signal (VDD / 2 in single-ended mode).

[0017] Preferably, the differential processing is as follows: the difference between SIN+ and SIN- is used to obtain n sinusoidal voltage signals SIN, i.e., SIN=(SIN+)-(SIN-); the difference between COS+ and COS- is used to obtain n cosine voltage signals COS, i.e., COS=(COS+)-(COS-).

[0018] Preferably, in S2, the bias compensation is as follows: the average of n sinusoidal voltage signals is taken to obtain the SIN OFFSET; the average of n cosine voltage signals is taken to obtain the COS OFFSET.

[0019] Amplitude correction: Take the maximum and minimum values ​​within n sinusoidal voltage signals, and half of the difference is the amplitude correction value, i.e., SIN AMPLITUDE = (SIN MAX - SIN MIN) / 2; Take the maximum and minimum values ​​within n cosine voltage signals, and half of the difference is the amplitude correction value, i.e., COS AMPLITUDE = (COS MAX - COS MIN) / 2;

[0020] The calibrated and compensated sinusoidal voltage signal is (SIN - SIN OFFSET) / SIN AMPLITUDE; the calibrated and compensated cosine voltage signal is (COS - COS OFFSET) / COS AMPLITUDE.

[0021] Preferably, in step S3, the angular position information calculation process of the eddy current position sensor is as follows:

[0022] Calibration compensation tangent voltage signal = Calibration compensation sine voltage signal / Calibration compensation cosine voltage signal;

[0023] The angular position information of the eddy current position sensor = ATAN (calibration compensation tangent voltage signal);

[0024] Right now ;

[0025] The accuracy level of the position sensor = the angular position information of the eddy current position sensor - the angular position information of the mechanical rotation of the test bench itself.

[0026] Preferably, in S4, harmonics of orders a, b, c, and d are mainly mixed in under four conditions: initial position, axial offset, radial offset, and tilt angle change, respectively.

[0027] When the application finds that the sensor cannot accurately reflect the current angle position information, an oscilloscope can be used to collect four voltage signal data. After differential, bias compensation, and amplitude correction, Fourier transform is used to obtain the main b-th harmonic of the data. The axial offset is also mainly mixed with the b-th harmonic. Feedback is given to the application so that it can be adjusted and resolved in time.

[0028] The beneficial effects of this invention are:

[0029] This invention significantly improves the accuracy of test results when testing eddy current sensor products by using bias compensation of sine and cosine analog voltage signals, amplitude correction of sine and cosine analog voltage signals, and rapid positioning through harmonic analysis. Attached Figure Description

[0030] Figure 1 The sensor output signal proposed in this invention is shown in the sine-cosine analog differential mode diagram.

[0031] Figure 2 The sensor output signal proposed in this invention is shown in the analog single-ended mode diagram of sine and cosine. Detailed Implementation

[0032] 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.

[0033] A calibration and compensation test method for an eddy current position sensor test bench includes the following steps:

[0034] S1. Acquisition and preprocessing of output signal from eddy current sensor;

[0035] The test bench drives the rotor of the eddy current sensor to rotate at a certain angle, acquiring four analog voltage signals output from the stator of the eddy current position sensor at that moment. The sensor output has two modes: differential mode and single-ended mode. Schematic diagrams of the two output modes are shown below. Figure 1 andFigure 2 .

[0036] Differential processing is performed on the four analog voltage signals to obtain the sinusoidal voltage signal and cosine voltage signal to be compensated.

[0037] S2. The above-mentioned sine and cosine voltage signals to be compensated are calibrated and compensated to obtain calibrated and compensated sine and cosine voltage signals. The above-mentioned sine and cosine voltage signal compensation process includes at least one of the following: bias compensation and amplitude correction.

[0038] Because the external environment is mostly conductive but not magnetic, eddy current sensors, which are sensitive to electrical signals, are more susceptible to external interference than resolver sensors, which are sensitive to magnetic fields. Furthermore, the PCBA design itself, including wiring and vias, can also affect eddy current sensors. The influence of external factors and the sensor itself on eddy current sensors can be weakened or even eliminated through three steps: differential correction, bias compensation, and amplitude correction. Therefore, both eddy current test benches and power electronic controllers need to undergo these three steps to demonstrate the actual accuracy level achievable by eddy current products, thereby significantly improving the accuracy of test results obtained when testing eddy current products.

[0039] S3. Based on the above-mentioned calibration and compensation sine and cosine voltage signals, calculate and determine the angular position information of the above-mentioned eddy current position sensor. Subtract the angular position information calculated from the sine and cosine voltage signals of the eddy current sensor from the angular position information of the mechanical rotation of the test bench itself to obtain the accuracy level of the position sensor.

[0040] S4. Using Fourier transform to perform harmonic analysis on the signal, we obtain high-order harmonic models under four conditions: initial position of rotor and stator relative to each other, axial offset, radial offset, and tilt angle change. When problems occur at the client end, the problem point can be quickly located and resolved.

[0041] In this embodiment, the steps include:

[0042] S1. The test bench drives the rotor of the eddy current sensor to rotate at a certain angle, and at this time, it obtains the sinusoidal voltage signal to be compensated output by the stator of the eddy current position sensor.

[0043] When the test bench drives the rotor to rotate once and samples at n positions, the voltage signal output by the sensor stator is measured at the initial point (i.e., zero position, 0°), 360 / n°, 2*360 / n°...(n-1)*360 / n°. The sensor voltage signal measured at each position has the following four types, each with n values:

[0044] SIN / SINP / SIN+: Positive sinusoidal voltage signal;

[0045] SINN / SIN-: Negative sinusoidal voltage signal (VDD / 2 in single-ended mode);

[0046] COS / COSP / COS+: Positive cosine voltage signal;

[0047] COSN / COS-: Negative cosine voltage signal (VDD / 2 in single-ended mode).

[0048] Differential processing is performed on the four analog voltage signals to obtain the sinusoidal voltage signal and cosine voltage signal to be compensated.

[0049] Differential: Subtracting SIN+ from SIN- yields n sinusoidal voltage signals SIN, i.e., SIN=(SIN+)-(SIN-); Subtracting COS+ from COS- yields n cosine voltage signals COS, i.e., COS=(COS+)-(COS-).

[0050] S2. The above-mentioned sine and cosine voltage signals to be compensated are calibrated and compensated to obtain calibrated and compensated sine and cosine voltage signals. The above-mentioned sine and cosine voltage signal compensation process includes at least one of the following: bias compensation and amplitude compensation.

[0051] Bias compensation: Averaging n sinusoidal voltage signals yields SIN OFFSET; averaging n cosine voltage signals yields COS OFFSET. (During joint debugging with a power electronic controller, it was found that due to limitations in the controller's storage and computing capabilities, the bias compensation can be adjusted to SIN OFFSET = (SIN MAX + SIN MIN) / 2, COS OFFSET = (COS MAX + COS MIN) / 2. While this slightly reduces the accuracy of the compensation, it lowers the requirements on the controller chip.)

[0052] Amplitude correction: Take the maximum and minimum values ​​within n sinusoidal voltage signals, and half of the difference is the amplitude correction value, i.e., SIN AMPLITUDE = (SIN MAX - SIN MIN) / 2; Take the maximum and minimum values ​​within n cosine voltage signals, and half of the difference is the amplitude correction value, i.e., COS AMPLITUDE = (COS MAX - COS MIN) / 2.

[0053] The calibrated and compensated sinusoidal voltage signal is (SIN - SIN OFFSET) / SIN AMPLITUDE; the calibrated and compensated cosine voltage signal is (COS - COS OFFSET) / COS AMPLITUDE.

[0054] After differential, bias compensation, and amplitude correction, approximately standard sine and cosine signals are obtained (bias is 0, amplitude is 1), which facilitates subsequent angle calculation and improves the accuracy of the data when reflecting the sensor's precision level.

[0055] S3. Based on the above-mentioned calibration and compensation sine and cosine voltage signals, calculate and determine the angular position information of the above-mentioned eddy current position sensor. Subtract the angular position information calculated from the sine and cosine voltage signals of the eddy current sensor from the angular position information of the mechanical rotation of the test bench itself to obtain the accuracy level of the position sensor.

[0056] The calculation process of the angular position information of the eddy current position sensor:

[0057] Calibration compensation tangent voltage signal = Calibration compensation sine voltage signal / Calibration compensation cosine voltage signal;

[0058] The angular position information of the eddy current position sensor = ATAN (calibration compensation tangent voltage signal);

[0059] Right now

[0060] The accuracy level of the position sensor = the angular position information of the eddy current position sensor - the angular position information of the mechanical rotation of the test bench itself.

[0061] (4) Using Fourier transform to perform harmonic analysis on the signal, harmonic models are obtained for four cases: initial position of rotor and stator relative to each other, axial offset, radial offset, and tilt angle change. When problems occur at the application end, the problem point can be quickly located and solved.

[0062] Define the a, b, c, and d harmonics that are mainly mixed in under four conditions: initial position, axial offset, radial offset, and tilt angle change, respectively;

[0063] When the application finds that the sensor cannot accurately reflect the current angular position information, a voltage measurement tool (oscilloscope) can be used to collect four voltage signal data. After differential, bias compensation, and amplitude correction, Fourier transform is used to obtain the main b-th harmonic of the data. The axial offset is also mainly mixed with the b-th harmonic. At this time, it can be fed back to the application, which should indicate that there is an axial offset during installation. Adjust and resolve it in time.

[0064] This invention significantly improves the accuracy of test results when testing eddy current sensor products by using bias compensation of sine and cosine analog voltage signals, amplitude correction of sine and cosine analog voltage signals, and rapid positioning through harmonic analysis.

[0065] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A calibration and compensation test method for an eddy current position sensor test bench, characterized in that, Includes the following steps: S1. Acquisition and preprocessing of output signals from eddy current sensor: The test bench drives the rotor of the eddy current sensor to rotate at a certain angle, and acquires the four analog voltage signals output by the stator of the eddy current position sensor at this time. The four analog voltage signals are differentially processed to obtain the sinusoidal voltage signal and cosine voltage signal to be compensated. The sensor outputs four analog voltage signals in two modes: differential mode and single-ended mode. When the test bench drives the rotor to rotate once and samples at n positions, the voltage signal output by the sensor stator is measured at the initial point (i.e., zero position, 0°), 360 / n°, 2*360 / n°...(n-1)*360 / n°. The sensor voltage signal measured at each position has the following four types, each with n values: SIN / SINP / SIN+: Positive sinusoidal voltage signal; SINN / SIN-: Negative sinusoidal voltage signal (VDD / 2 in single-ended mode); COS / COSP / COS+: Positive cosine voltage signal; COSN / COS-: Negative cosine voltage signal (VDD / 2 in single-ended mode); S2. Perform calibration compensation processing on the obtained sinusoidal voltage signals to be compensated to obtain calibrated compensated sinusoidal voltage signals. Sine and cosine voltage signal compensation processing includes at least one of the following: bias compensation, amplitude correction; S3. Based on the above calibration compensation sine and cosine voltage signals, calculate and determine the angular position information of the above eddy current position sensor. Subtract the angular position information calculated from the sine and cosine voltage signals of the eddy current sensor from the angular position information of the mechanical rotation of the test bench itself to obtain the accuracy level of the position sensor. S4. Using Fourier transform to perform harmonic analysis on the signal, high-order harmonic models are obtained under four conditions: initial position of rotor and stator relative to each other, axial offset, radial offset, and tilt angle change. When problems occur at the application end, the problem point can be quickly located and resolved.

2. The calibration and compensation test method for an eddy current position sensor test bench according to claim 1, characterized in that, Differential processing is as follows: the difference between SIN+ and SIN- is used to obtain n sinusoidal voltage signals SIN, i.e., SIN=(SIN+)-(SIN-); the difference between COS+ and COS- is used to obtain n cosine voltage signals COS, i.e., COS=(COS+)-(COS-).

3. The calibration and compensation test method for an eddy current position sensor test bench according to claim 1, characterized in that, In S2, the bias compensation is as follows: the average of n sinusoidal voltage signals is taken to obtain SIN OFFSET; the average of n cosine voltage signals is taken to obtain COS OFFSET. Amplitude correction: Take the maximum and minimum values ​​within n sinusoidal voltage signals, and half of the difference is the amplitude correction value, i.e., SIN AMPLITUDE = (SIN MAX - SIN MIN) / 2; Take the maximum and minimum values ​​within n cosine voltage signals, and half of the difference is the amplitude correction value, i.e., COS AMPLITUDE = (COS MAX - COS MIN) / 2; The calibrated and compensated sinusoidal voltage signal is (SIN - SIN OFFSET) / SIN AMPLITUDE; the calibrated and compensated cosine voltage signal is (COS - COS OFFSET) / COS AMPLITUDE.

4. The calibration and compensation test method for an eddy current position sensor test bench according to claim 1, characterized in that... In step S3, the calculation process of the angular position information of the eddy current position sensor is as follows: Calibration compensation tangent voltage signal = Calibration compensation sine voltage signal / Calibration compensation cosine voltage signal; The angular position information of the eddy current position sensor = ATAN (calibration compensation tangent voltage signal); Right now ; The accuracy level of the position sensor = the angular position information of the eddy current position sensor - the angular position information of the mechanical rotation of the test bench itself.

5. The calibration and compensation test method for an eddy current position sensor test bench according to claim 1, characterized in that... In S4, the initial position, axial offset, radial offset, and tilt angle change are defined as the four cases in which harmonics of the orders a, b, c, and d are mainly mixed, respectively, where a / b / c / d are all assumed values. When the application finds that the sensor cannot accurately reflect the current angular position information, an oscilloscope can be used to collect four voltage signal data. After differential, bias compensation, and amplitude correction, Fourier transform can be used to obtain the main b-th harmonic of the data. The axial offset is also mainly mixed with the b-th harmonic. This can determine that the cause of the problem at the application is "very likely that there is an axial offset between the stator and rotor after installation". Feedback can be given to the application for timely adjustment and resolution.

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