CN-121977627-A - Rotary transformer envelope signal correction decoding method and system

CN121977627ACN 121977627 ACN121977627 ACN 121977627ACN-121977627-A

Abstract

The invention belongs to the technical field of rotary transformer signal processing, and particularly relates to a rotary transformer envelope signal correction decoding method and system, wherein the method comprises the steps of demodulating an output signal of a rotary transformer by using frequency shift to obtain a sine envelope signal and a cosine envelope signal; based on preset sampling frequency, acquiring sine envelope signals and cosine envelope signals, performing off-line parameter estimation, estimating an envelope angular frequency estimated value of the envelope signals, then estimating an amplitude estimated value, a phase offset estimated value and a direct current offset estimated value of the envelope signals by using the envelope angular frequency estimated value, acquiring the sine envelope signals and the cosine envelope signals, and performing on-line non-ideal envelope signal correction and angular position decoding. According to the rotary transformer envelope signal correction decoding method and system, the influence of harmonic wave items in an envelope signal is fully considered by adopting the angular frequency off-line estimation method based on the self-adaptive notch filter and system identification.

Inventors

YU LIHONG
Shao Huiyang

Assignees

中国民航大学

Dates

Publication Date: 20260505
Application Date: 20260121

Claims (10)

1. A rotary transformer envelope signal correction decoding method, comprising: Generating a sinusoidal excitation signal and injecting the sinusoidal excitation signal into an excitation winding of the rotary transformer; demodulating the output signal of the rotary transformer by using the frequency shift to obtain a sine envelope signal and a cosine envelope signal; Based on a preset sampling frequency, acquiring the sine envelope signal and the cosine envelope signal, performing off-line parameter estimation, estimating an envelope angular frequency estimated value of the envelope signal, and then estimating an amplitude estimated value, a phase offset estimated value and a direct current offset estimated value of the envelope signal by using the envelope angular frequency estimated value; and acquiring the sine envelope signal and the cosine envelope signal, and carrying out on-line non-ideal envelope signal correction and angular position decoding by using an amplitude estimation value, a phase offset estimation value and a direct current offset estimation value.
2. The method for correcting and decoding the envelope signal of the rotary transformer according to claim 1, wherein the steps of collecting the sinusoidal envelope signal and the cosine envelope signal based on a preset sampling frequency and performing offline parameter estimation, estimating an envelope angular frequency estimated value of the envelope signal, and then estimating an amplitude estimated value, a phase offset estimated value and a dc offset estimated value of the envelope signal by using the envelope angular frequency estimated value include: Applying an adaptive notch filter to the sine envelope signal and the cosine envelope signal, and minimizing a prediction error in the iterative identification process of the transfer function of the adaptive notch filter by using the single-point filtering capability of the adaptive notch filter through a Steiglitz-McBride system identification method so that the notch center frequency of the adaptive notch filter is converged to the envelope angular frequency; Establishing an analysis relation between the parameters of the adaptive notch filter and the envelope angular frequency by combining the preset sampling frequency, and obtaining an estimated value of the envelope angular frequency; And respectively estimating the amplitude values, the phase offset and the direct current offset of the sine envelope signal and the cosine envelope signal by using the envelope angular frequency estimated value and adopting a gradient descent algorithm to obtain the amplitude value, the phase offset estimated value and the direct current offset estimated value of the sine envelope signal and the cosine envelope signal.
3. The method of claim 2, wherein the adaptive notch filter transfer function is formulated as follows: In the above-mentioned method, the step of, For the notch center digital angular frequency, In order to control the notch bandwidth, Is a delay operator; Parameters of the order Then And Second order and first order coefficient is Is a polynomial of (a).
4. The method of claim 3, wherein said establishing an analytical relationship between the adaptive notch filter parameter and the envelope angular frequency in combination with the preset sampling frequency, to obtain the envelope angular frequency estimation value, comprises: Setting a preset sampling frequency as When (when) Gradually approach 1, and Output of adaptive notch filter Approximate minimization by minimizing Parameters of adaptive notch filter Gradually converge to Wherein Is the envelope signal angular frequency; in the iterative identification process of the transfer function of the adaptive notch filter by using the Steiglitz-McBride system identification method, parameters in a period of time under the steady state of the estimation process are taken As a parameter Final estimate of (2) ; Based on the final estimate And Calculating an envelope angular frequency estimate The formula is: 。
5. The method for correcting and decoding an envelope signal of a resolver according to claim 1, wherein the steps of collecting the sinusoidal envelope signal and the cosine envelope signal based on a preset sampling frequency and performing offline parameter estimation, estimating an envelope angular frequency estimation value of the envelope signal, and then estimating an amplitude estimation value, a phase offset estimation value, and a dc offset estimation value of the envelope signal using the envelope angular frequency estimation value, further comprise: Based on a preset sampling frequency, the sine envelope signal and the cosine envelope signal are collected through a DSP chip, and sampling values are sent to a computer for offline parameter estimation.
6. The method of claim 1, wherein the acquiring the sine envelope signal and the cosine envelope signal and performing on-line non-ideal envelope signal correction and angular position decoding using an amplitude estimate, a phase offset estimate, and a dc offset estimate comprises: Respectively carrying out amplitude asymmetric correction and direct current offset correction on the sine envelope signal and the cosine envelope signal by using the amplitude estimated value, the phase offset estimated value and the direct current offset estimated value to obtain corrected sine envelope signal and cosine envelope signal; harmonic suppression is carried out on the corrected sine envelope signal and the corrected cosine envelope signal by adopting a second-order generalized integrator, and linear processing is carried out on the filtered envelope signal, so that a sine signal and a cosine signal after linear processing are obtained; taking the sine signal and the cosine signal after the linear processing as the input of a phase-locked loop, and compensating the two-channel phase offset in the output error by utilizing the phase offset estimation value after the output error of the phase detector is obtained, so as to obtain a compensated error signal; And performing angular position decoding on the compensated error signal by using a phase-locked loop.
7. The method of claim 6, wherein the harmonic suppression of the corrected sine envelope signal and cosine envelope signal by using a second-order generalized integrator, and the linear processing of the filtered envelope signal to obtain a linearly processed sine signal and cosine signal, comprises: and adopting a second-order generalized integrator to carry out harmonic suppression on the corrected sine envelope signal and cosine envelope signal, wherein the formula is as follows: In the above-mentioned method, the step of, Is the phase offset value of the sinusoidal envelope signal, A phase offset value for the cosine envelope signal; Respectively at 、 The first order taylor expansion is performed on the neighborhood of (1), and the formula is as follows: And carrying out linear processing on the envelope signal after filtering to obtain a sine signal and a cosine signal after linear processing, wherein the formula is as follows: In the above-mentioned method, the step of, Is a sinusoidal signal after being processed in a linear manner, Is a linearly processed cosine signal.
8. The method of claim 7, wherein the step of compensating for a two-channel phase offset in the output error by using the phase offset estimation value after the output error of the phase detector is obtained by using the linearly processed sine signal and cosine signal as inputs of a phase locked loop, and obtaining a compensated error signal comprises: series proportion link between phase detector and loop filter The formula is as follows: In the above-mentioned method, the step of, For a phase offset estimate of the sinusoidal envelope signal, A phase offset estimate for the cosine envelope signal; taking the sine signal and the cosine signal after the linear processing as the input of a phase-locked loop to obtain the output error of the phase detector, wherein the formula is as follows: In the above-mentioned method, the step of, An angular position solution obtained by the phase-locked loop solution; The phase deviation estimated value of the sine envelope signal and the cosine envelope signal is utilized to simultaneously compensate two channels of the sine signal and the cosine signal, and the two channels are subjected to a proportional link The compensated error signal is given by: In the above-mentioned method, the step of, Representation and representation And Related higher order small amounts.
9. The method of claim 1, wherein the acquiring the sine envelope signal and the cosine envelope signal and performing on-line non-ideal envelope signal correction and angular position decoding using an amplitude estimate, a phase offset estimate, and a dc offset estimate, further comprises: And writing the amplitude estimation value, the phase offset estimation value and the direct current offset estimation value into a program of the DSP chip, and carrying out on-line non-ideal envelope correction and angular position decoding by using the DSP chip.
10. A rotary transformer envelope signal correction decoding system, comprising: The signal excitation module is used for generating a sine excitation signal to be injected into an excitation winding of the rotary transformer; A rotary transformer for receiving the sinusoidal excitation signal and generating an output signal; the demodulation module is used for demodulating the output signal of the rotary transformer by using the frequency shift to obtain a sine envelope signal and a cosine envelope signal; The off-line estimation module is used for acquiring the sine envelope signal and the cosine envelope signal based on a preset sampling frequency and carrying out off-line parameter estimation, firstly estimating an envelope angular frequency estimation value of the envelope signal, and then estimating an amplitude estimation value, a phase offset estimation value and a direct current offset estimation value of the envelope signal by utilizing the envelope angular frequency estimation value; And the on-line correction and decoding module is used for collecting the sine envelope signal and the cosine envelope signal and carrying out on-line non-ideal envelope signal correction and angular position decoding by using the amplitude estimation value, the phase offset estimation value and the direct current offset estimation value.

Description

Rotary transformer envelope signal correction decoding method and system Technical Field The invention belongs to the technical field of rotary transformer signal processing, and particularly relates to a rotary transformer envelope signal correction decoding method and system. Background The rotary transformer is used as a rotor angular position sensor commonly used for the permanent magnet synchronous motor, has the advantages of simple structure, high precision, low manufacturing cost, strong environmental adaptability and the like, and is widely applied to a permanent magnet synchronous motor control system. In the decoding system of the rotary transformer, the decoding system is inevitably influenced by circuit non-idealities and manufacturing tolerances, so that amplitude mismatch, phase deviation, direct current bias and harmonic interference (mainly three or five times) occur on two paths of envelope signals obtained by demodulating output signals, and the above non-idealities can obviously deteriorate the resolution precision of the rotor angular position. In a permanent magnet synchronous motor control system based on resolver rotor angular position detection, inaccurate rotor angular position feedback can cause torque accuracy control to be reduced, speed control to be unstable, motor efficiency to be reduced, heat to be increased, and work efficiency and service life of a motor to be affected. In order to improve rotor angular position detection accuracy based on a resolver, a learner proposes an envelope signal correction strategy based on a biquad generalized integrator. And obtaining two paths of envelope signals with equal amplitude and completely orthogonal phases by using two paths of signals output by the second-order generalized integrator through linear operation and average value taking. However, the angle calculation of the method still has residual errors, and the rotor position calculation precision of the method still needs to be improved. For resolver envelope signal correction, a learner proposes another technical route of offline parameter estimation combined with online envelope correction. Since the magnitude of the envelope signal amplitude, phase offset and dc offset are independent of rotational speed, only one off-line estimation is typically required for any given set of resolver digital resolution systems. In the development of recent years, the method realizes decoupling of a parameter estimation process and relieves parameter estimation errors caused by high coupling in the estimation process, but the existing state equation-based envelope signal angular frequency estimation method is sensitive to harmonic waves, is easily influenced by the harmonic waves, and reduces the angular frequency estimation precision, and the parameter estimation and signal correction precision are reduced. In addition, in the conventional phase offset correction, a sine channel is used as a reference to orthogonalize a cosine channel, and if the sine channel itself has a phase offset, a fixed error related to the offset is introduced in the angle calculation, so that the rotor angular position detection accuracy is reduced. Disclosure of Invention In view of the above, the present invention is directed to a method and a system for correcting and decoding an envelope signal of a rotary transformer, so as to solve the problem that the correction accuracy of the envelope signal of the rotary transformer is poor and the detection accuracy of the rotor angle position of a permanent magnet synchronous motor based on the rotary transformer is affected. In order to achieve the above purpose, the technical scheme of the invention is realized as follows: In a first aspect, the present invention provides a rotary transformer envelope signal correction decoding method, including: Generating a sinusoidal excitation signal and injecting the sinusoidal excitation signal into an excitation winding of the rotary transformer; demodulating the output signal of the rotary transformer by using the frequency shift to obtain a sine envelope signal and a cosine envelope signal; Based on a preset sampling frequency, acquiring the sine envelope signal and the cosine envelope signal, performing off-line parameter estimation, estimating an envelope angular frequency estimated value of the envelope signal, and then estimating an amplitude estimated value, a phase offset estimated value and a direct current offset estimated value of the envelope signal by using the envelope angular frequency estimated value; and acquiring the sine envelope signal and the cosine envelope signal, and carrying out on-line non-ideal envelope signal correction and angular position decoding by using an amplitude estimation value, a phase offset estimation value and a direct current offset estimation value. Further, the acquiring the sine envelope signal and the cosine envelope signal based on a preset sampling frequency and performing off-line