High-precision high-bandwidth signal processing method
阅读说明：本技术 一种高精度高带宽的信号处理方法 (High-precision high-bandwidth signal processing method ) 是由 章春娟 王慧贞 刘伟峰 宋洁 路通 于 2020-07-13 设计创作，主要内容包括：本发明公开了一种高精度高带宽的信号处理方法,该信号处理方法包括新型同步基频提取滤波器与频率检测单元两个部分,能够在输入信号已知的前提下,利用频率检测单元,准确估计输入信号的频率,反馈到新型同步基频提取滤波器,从而消除输入信号中的高频谐波,提取基波分量,实现输出的估计信号相对于输入信号既无幅值衰减,也无相位滞后,提高了控制精度,且具有较高的通频带,系统易于稳定。本发明具有较高的普适性,该信号处理方法能够广泛地应用在各领域,使系统高效而稳定地工作。(The invention discloses a high-precision high-bandwidth signal processing method, which comprises a novel synchronous fundamental frequency extraction filter and a frequency detection unit, wherein the frequency detection unit can be used for accurately estimating the frequency of an input signal and feeding the frequency back to the novel synchronous fundamental frequency extraction filter on the premise that the input signal is known, so that high-frequency harmonics in the input signal are eliminated, fundamental wave components are extracted, the output estimation signal has no amplitude attenuation or phase lag relative to the input signal, the control precision is improved, the high-precision high-bandwidth signal processing method has a high pass band, and a system is easy to stabilize. The invention has higher universality, and the signal processing method can be widely applied to various fields, so that the system can work efficiently and stably.)
1. A high-precision high-bandwidth signal processing method is characterized by comprising the following steps: the signal processing method adopts the output value X of the synchronous fundamental frequency extraction filter*And its orthogonal signal qX*As input to the frequency detection unit FLL, while the frequency locked loop outputs the estimated frequency ω0Fed back to the filter input.
2. A high accuracy high bandwidth signal processing method according to claim 1, characterized by: the signal processing method comprises the following steps:
step one, multiplying the filter gain by the estimation errorMultiplying by the tracking frequency omega0Obtaining a position related estimation signal a (t);
step two, the position correlation estimation signal a (t) passes through a sine branch and a cosine branch to obtain c (t)1And c (t)2In which the sine branch is multiplied by the reference signal sin (ω)0t) is integrated with the reference signal sin (omega)0t) are multiplied to obtain c (t)1(ii) a Cosine branch routing a (t) by reference signal cos (ω)0t) is integrated with the reference signal cos (omega)0t) are multiplied to obtain c (t)2；
Step three, the sine branch and the cosine branch are added to obtain a filter output value X*I.e. an estimate of the input signal; filter output value X*Of the quadrature signal qX*From X*Multiplying by the estimated frequency ω of the frequency locked loop output0Then obtaining the product through an integration link;
step four, the estimation error of the filterQuadrature signal qX with its output value*Product of (2)fAs the input of the frequency detection unit FLL, the frequency is multiplied by a normalization unit through an amplifier with negative gain-gamma, and the product is integrated to obtain omega0Namely, the estimated frequency is output by the frequency locking loop;
fifthly, the frequency locking loop outputs an estimated frequency omega0The signal is fed back to the input of the filter to form closed-loop control.
3. A high accuracy high bandwidth signal processing method according to claim 2, wherein the transfer function of said filter is:
where, denotes the filter gain, ω0Representing the input signal frequency tracked by the synchronous fundamental frequency extraction filter.
4. A high accuracy high bandwidth signal processing method according to claim 2,
an integrator of- □ is added in the frequency detection unit FLL, so that the frequency-locked loop outputs an estimated frequency omega0Approaches omega, and finally makes the estimated frequency of the frequency detection unit FLL, namely the frequency omega tracked by the novel synchronous fundamental frequency extraction filter0In accordance with the input signal frequency omega, omega0When ω is:
G1the figure of merit of(s) is:
wherein Hα(j ω) is the transfer function G1The frequency response function, H, of(s) with s being substituted by j ωqα(j ω) is the transfer function G2S in(s) is substituted by j ω, the resulting frequency response function.
5. A high accuracy high bandwidth signal processing method according to claim 2, wherein the time constant of the frequency detection unit is:
after normalization, the time constants were:
the influence of the amplitude and frequency change of the input signal on the frequency detection time can be eliminated.
6. A high accuracy high bandwidth signal processing method according to any of claims 2 to 5, characterized in that the estimated frequency of the frequency detection unit, i.e. the synchronous fundamental frequency extraction filterFrequency omega tracked by wave filter0In accordance with the input signal frequency omega, omega0When ω, the filter outputs a signal X*Quadrature signal qX thereof*The amplitudes are the same, the phases differ by 90 DEG and the filter outputs a signal X*Having the same phase and amplitude as the input signal X.
Technical Field
The invention relates to the field of motor control, in particular to a signal processing technology in a permanent magnet synchronous motor control system.
Background
The permanent magnet synchronous motor system without the position sensor has the advantages of low cost, high robustness and the like, and is an important research direction in the field of alternating current transmission at present. Rotor position estimation is the key to sensorless control of permanent magnet synchronous motors. The motor back electromotive force contains rotor angle information, and in a high-speed area of the motor, the method for estimating the position of the rotor by using the back electromotive force is a preferred method.
Harmonic waves and high-frequency noise caused by a control algorithm, a dead zone effect, load disturbance and the like cause noise and harmonic waves in back electromotive force estimated by a position-free sensor, and how to extract rotor position information from the back electromotive force is a difficult point of research. The rotor position of the motor is directly obtained by the counter electromotive force arctangent, and particularly when the counter electromotive force observed value passes through zero, the observation error of the rotor position can be further amplified. In practical application, a low-pass filter is usually adopted to process signals, the processing mode is simple and easy to implement, the calculation amount is small, but the defects that the response speed is slow, the phase shift is influenced by the frequency shift, and the response speed and the detection precision are mutually contradictory exist. The rotor position can be estimated more accurately by utilizing the phase-locked loop technology, but the estimated rotating speed contains higher noise, filtering is needed, the dynamic performance of rotating speed observation is inevitably influenced, and the real-time performance is poor. In order to overcome these disadvantages, a new signal processing method needs to be proposed.
Disclosure of Invention
The invention aims to solve the technical problems that the existing filter has larger time delay, the existing signal processing method of the filter and the phase-locked loop has the defects of low observation precision, poor real-time performance and the like, and aims to provide a signal processing method with high precision and high bandwidth, so that the output estimated signal has no amplitude attenuation or phase lag relative to the input signal, the control precision is improved, and the problems are solved.
The invention adopts the following technical scheme for solving the problems:
a high-precision high-bandwidth signal processing method is a closed-loop control and comprises a novel synchronous fundamental frequency extraction filter and a frequency detection unit. As shown in fig. 1, the novel synchronous baseband extraction filter included in the signal processing method, x (t), is an input signal,is the estimated error of the filter; x (t) multiplying the estimated error by the filter gain
As a preferred embodiment of the present invention, the transfer function of the novel synchronous fundamental frequency extraction filter is:
where, denotes the filter gain, ω0Representing the frequency, X, of the input signal tracked by the filter*Extracting the output of the filter, i.e. the estimated value of the input signal, for the new synchronous fundamental frequency; qX*Is lagging X*A 90 quadrature signal.
The frequency response characteristic of the frequency detection unit is:
the time constant is:
adding a normalization unitThen, the FLL frequency response characteristic and time constant are:
the influence of the amplitude and frequency change of the input signal on the frequency detection time can be eliminated.
FLL is added withThe integrator of (2) can make the estimated frequency omega0Approaches omega, and finally makes the estimated frequency of the detection unit, i.e. the frequency omega tracked by the synchronous fundamental frequency extraction filter0Coincident with the input signal frequency ω (i.e., ω)0ω) is:
wherein Hα(jω) To transfer function G1The frequency response function, H, of(s) with s being substituted by j ωqα(j ω) is the transfer function G2S in(s) is substituted by j ω, the resulting frequency response function.
Filter output signal X*And qX*Equal in amplitude, 90 ° out of phase, and X*The phase and amplitude of the input signal X are the same, so that high-frequency harmonics in the input signal can be eliminated, and fundamental wave components can be extracted. X additionally obtainable by means of a filter unit*And qX*The positive and negative sequence components are separated according to the instantaneous symmetric component method to obtain the positive and negative sequence components of the input signal, thereby eliminating the influence caused by asymmetry of the input signal.
As a preferred embodiment of the present invention, G1The figure of merit of(s) is:
where Q represents the quality factor and represents the filter gain. The quality factor of the novel synchronous fundamental frequency extraction filter is not influenced by frequency, the frequency bandwidth is only influenced by frequency, and the tracking frequency omega is0Is irrelevant.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
1. the frequency bandwidth of the signal processing method is only affected by the value and the central frequency omega0Irrelevant; on the premise that the input signal is known, the frequency of the input signal is accurately estimated by using the frequency locking loop unit and fed back to the novel synchronous fundamental frequency extraction filter, so that the purposes of eliminating high-frequency harmonics in the input signal and extracting fundamental wave components are achieved, the estimated signal output by the signal processing method has no amplitude attenuation or phase lag relative to the input signal, and the control precision is improved.
2. The frequency detection time of the signal processing method is irrelevant to the amplitude and the frequency of the input signal, and the signal processing method is suitable for occasions with wide-range frequency change.
3. The invention has higher universality, high control precision, strong real-time property and high robustness, and the signal processing method can be widely applied to a plurality of fields, so that the system can work efficiently and stably.
Drawings
FIG. 1 is a detailed functional block diagram of the signal processing method of the present invention;
FIG. 2 is a Bode diagram illustrating the signal processing method of FIG. 1;
fig. 3 is a schematic block diagram of sliding mode control based on the signal processing method according to the embodiment of the present invention.
Detailed Description
The invention is described in detail below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary only for the purpose of illustrating the present invention and are not to be construed as limiting the present invention.
A high-precision high-bandwidth signal processing method is disclosed, as shown in figure 1, the signal processing method is a closed-loop control, and comprises a novel synchronous fundamental frequency extraction filter and a frequency detection unit; novel synchronous fundamental frequency extraction filter output X*、qX*And
The signal processing method comprises the following steps:
step one, multiplying the filter gain by the estimation errorMultiplying by the tracking frequency omega0Then obtaining a position related estimation signal a (t);
step two, the position correlation estimation signal a (t) passes through a sine branch and a cosine branch to obtain c (t)1And c (t)2In which the sine branch is multiplied by the reference signal sin (ω)0t) is integrated with the reference signal sin (omega)0t) are multiplied to obtain c (t)1(ii) a Cosine branch routing a (t) by reference signal cos (ω)0t) is integrated with the reference signal cos (omega)0t) are multiplied to obtain c (t)2；
Step three, the sine branch and the cosine branch are added to obtain a filter output value X*I.e. an estimate of the input signal; filter output value X*Of the quadrature signal qX*From X*Multiplying by the estimated frequency ω of the frequency locked loop output0Then obtaining the product through an integration link;
step four, the estimation error of the filterQuadrature signal qX with its output value*Product of (2)fAs the input of the frequency detection unit FLL, the frequency is multiplied by a normalization unit through an amplifier with negative gain-gamma, and the product is integrated to obtain omega0Namely, the estimated frequency is output by the frequency locking loop;
fifthly, the frequency locking loop outputs an estimated frequency omega0The signal is fed back to the input of the filter to form closed-loop control.
Further, the transfer function of the filter is:
where, denotes the filter gain, ω0Representing the input signal frequency tracked by the synchronous fundamental frequency extraction filter.
Further, the frequency detection unit FLL is added withThe integrator of (2) causes the frequency-locked loop to output an estimated frequency ω0Approaches omega, and finally makes the estimated frequency of the frequency detection unit FLL, namely the frequency omega tracked by the novel synchronous fundamental frequency extraction filter0In accordance with the input signal frequency omega, omega0When ω is:
G1the figure of merit of(s) is:
wherein Hα(j ω) is the transfer function G1The frequency response function, H, of(s) with s being substituted by j ωqα(j ω) is the transfer function G2S in(s) is substituted by j ω, the resulting frequency response function.
Furthermore, the time constant of the frequency detection unit is:
after normalization, the time constants were:
the influence of the amplitude and frequency change of the input signal on the frequency detection time can be eliminated; the estimated frequency of the frequency detection unit, i.e. the frequency ω tracked by the synchronous fundamental frequency extraction filter0In accordance with the input signal frequency omega, omega0When ω, the filter outputs a signal X*Quadrature signal qX thereof*The amplitudes are the same, the phases differ by 90 DEG and the filter outputs a signal X*Having the same phase and amplitude as the input signal X. As shown in FIG. 2, the signal processing method outputs X*And qX*Equal in amplitude, 90 ° out of phase, and X*The phase and the amplitude of the input signal X are the same, high-frequency harmonic waves in the input signal can be eliminated, fundamental wave components are extracted, and the signal amplitude is not attenuated and phase delay is avoided, so that the control precision is improved; in addition, X can be utilized*And qX*Signal obtaining positive and negative sequence of input signalAnd components, thereby eliminating the influence caused by the asymmetry of the input signal.
The invention aims to solve the technical problems that the existing filter has larger time delay, the existing signal processing method of the filter with a phase-locked loop has the defects of low observation precision, poor real-time performance and the like, and the invention aims to provide the signal processing method with high precision and high bandwidth.
As shown in fig. 3, which is a schematic block diagram of a sliding-mode position-free control principle based on the signal processing method in the embodiment of the present invention, the back emf estimated by the sliding-mode observer includes a large amount of high-frequency harmonics, and after the signal processing method based on the novel synchronous fundamental frequency extraction filter and the frequency-locked loop and having high precision and high bandwidth is used, an accurate back emf signal and rotor speed information are obtained, and then position information of the motor rotor is obtained by using a phase-locked loop technology for system control. In the embodiment of the invention, the rotating speed signal omega required by the motor control0The frequency-locked loop in the signal processing method is used for obtaining the motor position signal, and the phase-locked loop technology is used for obtaining the motor position signal, so that the accuracy of tracking frequency is improved, and the control accuracy of a position-free system is improved. On the premise that the tracking frequency is accurately obtained by the frequency detection unit FLL, the signal amplitude before and after the processing of the method is not attenuated and has no phase delay.
In summary, the present invention provides a high-precision high-bandwidth signal processing method, which can accurately estimate the frequency of an input signal by using a frequency-locked loop unit on the premise that the input signal is known, and feed the frequency back to a novel synchronous fundamental frequency extraction filter, thereby eliminating high-frequency harmonics in the input signal, extracting a fundamental component, and realizing that the estimated signal output by the signal processing method has neither amplitude attenuation nor phase lag with respect to the input signal, thereby improving the control precision, and having a high passband, and the system is easy to stabilize.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
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