Permanent magnet synchronous motor noise reduction control method and system based on wide spectrum high frequency injection

Abstract

The present invention discloses a noise reduction control method and system for a permanent magnet synchronous motor based on wide-spectrum high-frequency injection, which belongs to the field of motor control technology. The existing sensorless control scheme based on high-frequency injection in the zero-low speed domain has the problem of large noise. The present invention is based on a noise reduction control method for a permanent magnet synchronous motor based on wide-spectrum high-frequency injection. By constructing a signal acquisition model, an amplitude dynamic processing model, a signal frequency domain processing model, and a rotor position calculation model, the audio signal is adaptively compressed and processed, and the amplitude of the audio signal is reduced while retaining the main audio characteristics, thereby obtaining a wide-spectrum high-frequency injection signal that can reduce motor noise; then, based on the Hilbert transform mechanism, the wide-spectrum high-frequency injection signal is frequency-domain transformed to obtain a mixed signal; and then the mixed signal is processed to obtain rotor position information, thereby effectively solving the noise problem caused by the high-frequency injection current and effectively improving the estimation accuracy of the rotor position.

Description

Technical Field

[0001] The present invention relates to a permanent magnet synchronous motor noise reduction control method and system based on wide spectrum high frequency injection, belonging to the technical field of motor control. Background Art

[0002] Sensorless control systems for permanent magnet synchronous motors (PMSMs) have been a hot topic of research in recent years, with their advantages of reducing costs, improving reliability, and enhancing environmental adaptability. They have broad applications in areas such as home appliances, drones, and industrial and agricultural automation, and have been a hot topic of research for scholars both domestically and internationally. High-frequency injection is a commonly used method for identifying the rotor position of permanent magnet synchronous motors (PMSMs) at low speeds, enabling heavy-load starting at low speeds. However, the injected high-frequency signal can cause unbearable motor noise, limiting its further application in some systems.

[0003] A Chinese patent application (publication number: CN115276502A) discloses a sensorless control method for permanent magnet synchronous motors using random frequency high-frequency triangular wave voltage injection. This method randomly injects two high-frequency triangular wave voltage signals of different frequencies into an estimated rotor reference frame. The two injected voltage signals adhere to the volt-second area equality principle to ensure equal induced current amplitudes. The high-frequency signal excites the motor's saturation saliency, extracting the estimated position angle and speed from the high-frequency current response. Demodulation is performed using two rotational transformations and absolute value conversion, followed by normalization to eliminate the effects of the injected amplitude and related parameters. Finally, observation is performed using an orthogonal phase-locked loop.

[0004] The above scheme expands the power spectrum density of the high-frequency current by randomly injecting two high-frequency triangular wave voltage signals of different frequencies, thereby reducing the audible noise caused by the high-frequency current. However, the injection of signals of different frequencies will cause the reference signal spectrum to be out of sync, resulting in the inability to accurately recover the position error signal, affecting the accuracy of the rotor position estimation, and thus resulting in low control accuracy of the permanent magnet synchronous motor.

[0005] Furthermore, although the above solution can reduce the audible noise caused by high-frequency current to a certain extent, there is still a problem that the noise is easily heard by people, which makes it unbearable for users and affects the promotion and use of the motor sensorless control solution.

[0006] The information disclosed in this Background Art is only for understanding the background of the present inventive concept and therefore it may include information that does not constitute prior art. Summary of the Invention

[0007] In response to the above problem or one of the above problems, an object of the present invention is to provide a permanent magnet synchronous motor noise reduction control method and system based on wide-spectrum high-frequency injection. By constructing a signal acquisition model, an amplitude dynamic processing model, a signal frequency domain processing model, and a rotor position calculation model, the audio signal is adaptively compressed and processed, and the amplitude of the audio signal is reduced while retaining the main audio characteristics, so as to obtain a wide-spectrum high-frequency injection signal that can reduce motor noise; then, based on the Hilbert transform mechanism, the wide-spectrum high-frequency injection signal is transformed in the frequency domain to obtain a mixed signal; and then the mixed signal is processed to obtain rotor position information, thereby effectively improving the estimation accuracy of the rotor position, and thereby improving the control accuracy of the permanent magnet synchronous motor.

[0008] In response to the above problem or one of the above problems, the second purpose of the present invention is to provide a permanent magnet synchronous motor noise reduction control method and system based on wide spectrum high frequency injection, which can achieve precise noise reduction control of the permanent magnet synchronous motor based on wide spectrum high frequency injection without injecting a voltage signal of a specific frequency, thereby effectively avoiding the problem of reference signal spectrum asynchrony, and then accurately recovering the position error signal, further improving the rotor position estimation accuracy, and at the same time effectively solving the noise problem caused by high frequency injection current, thereby facilitating the promotion and use of motor sensorless control schemes.

[0009] To achieve one of the above purposes, the first technical solution of the present invention is:

[0010] A permanent magnet synchronous motor noise reduction control method based on wide spectrum high frequency injection includes the following steps:

[0011] Step 1: Using a pre-built signal acquisition model, the audio signal is collected based on the frequency noise generation characteristics of the permanent magnet synchronous motor;

[0012] Step 2: Using a pre-built amplitude dynamic processing model, the audio signal is adaptively compressed to reduce its amplitude while preserving the main audio features, thereby obtaining a wide-spectrum high-frequency injection signal that can reduce motor noise.

[0013] Step 3: Using the pre-built signal frequency domain processing model and based on the Hilbert transform mechanism, the wide spectrum high frequency injection signal is transformed in the frequency domain to obtain the mixed signal;

[0014] Step 4: Use the pre-built rotor position calculation model to process the mixed signal to obtain rotor position information and realize permanent magnet synchronous motor noise reduction control based on wide spectrum high frequency injection.

[0015] After continuous exploration and experimentation, the present invention constructs a signal acquisition model, an amplitude dynamic processing model, a signal frequency domain processing model, and a rotor position calculation model to perform adaptive compression processing on the audio signal, reduce the amplitude of the audio signal while retaining the main audio characteristics, and obtain a wide-spectrum high-frequency injection signal that can reduce motor noise; then, based on the Hilbert transform mechanism, the wide-spectrum high-frequency injection signal is transformed in the frequency domain to obtain a mixed signal; and then the mixed signal is processed to obtain rotor position information, thereby effectively improving the estimation accuracy of the rotor position, and thereby improving the control accuracy of the permanent magnet synchronous motor.

[0016] Furthermore, the present invention adaptively compresses the audio signal and performs frequency domain transformation on the wide-spectrum high-frequency injection signal based on the Hilbert transform mechanism. Therefore, there is no need to inject a voltage signal of a specific frequency. It can achieve precise noise reduction control of the permanent magnet synchronous motor based on wide-spectrum high-frequency injection, thereby effectively avoiding the problem of reference signal spectrum asynchrony, and then accurately recovering the position error signal, further improving the rotor position estimation accuracy. The solution is scientific, reasonable and feasible.

[0017] Furthermore, the present invention can effectively solve the noise problem caused by high-frequency injection current by generating a wide-spectrum high-frequency injection signal and a mixing signal, thereby facilitating the promotion and use of sensorless motor control solutions.

[0018] The specific frequency commonly used in existing technologies is generally 0.5-2kHz, and the specific value generally needs to be selected according to the actual scenario.

[0019] As preferred technical measures:

[0020] Step 1: Using a pre-built signal acquisition model and based on the frequency noise generation characteristics of the permanent magnet synchronous motor, the method for collecting audio signals is as follows:

[0021] Calculate the required spectrum of the injection signal based on the frequency noise generation characteristics of the permanent magnet synchronous motor;

[0022] Based on the required spectrum, generate audio feature standard information that meets the spectrum requirements;

[0023] According to the audio feature standard information, audio signals about flowing water or rain sounds in nature are collected.

[0024] As preferred technical measures:

[0025] Step 2: Use the pre-built amplitude dynamic processing model to perform adaptive compression processing on the audio signal, reducing the amplitude of the audio signal while retaining the main audio characteristics. The method for obtaining a wide-spectrum high-frequency injection signal that can reduce motor noise is as follows:

[0026] Step 21, extracting a finite length signal from the audio signal to obtain an initial signal sequence;

[0027] Step 22: Adaptively compress the initial signal sequence to preliminarily reduce the amplitude of the initial signal sequence while retaining the main audio features, thereby obtaining a compressed pre-injection sequence.

[0028] Step 23: Based on the intrinsic time-varying characteristics of the signal, perform empirical mode decomposition on the pre-injection sequence to obtain its first-order intrinsic mode function, which is used to preserve the auditory perception of the main signal while making the upper and lower envelopes locally symmetrical with respect to the time axis to ensure that the mean value of the response current is stable near zero;

[0029] In step 24, the retained intrinsic mode function is resampled according to the current loop frequency to obtain an injection order signal sequence; and based on the saturation limiting function, the injection order signal sequence is saturated and limited to remove invalid signal spike pulses, thereby obtaining a wide spectrum high frequency injection signal.

[0030] As preferred technical measures:

[0031] Step 21, extracting the finite length signal from the audio signal to obtain the initial signal sequence is as follows:

[0032] Set the upper and lower cutoff frequencies. The upper cutoff frequency is used to prevent sampling aliasing and its value should be less than the current loop frequency. The lower cutoff frequency is used to keep the extracted signal away from the motor's base frequency and its value should be greater than the rated frequency.

[0033] Extract the finite length signal from the audio signal according to the upper cutoff frequency and the lower cutoff frequency;

[0034] Perform bandpass filtering on the finite-length signal to remove invalid frequency bands and obtain a filtered signal;

[0035] The initial signal sequence is calculated based on the filtered signal and the impulse response of the bandpass filter.

[0036] As preferred technical measures:

[0037] Step 22, adaptively compressing the initial signal sequence to preliminarily reduce the amplitude of the initial signal sequence while retaining the main audio features, and obtaining a compressed pre-injection sequence is as follows:

[0038] Obtaining an initial signal sequence and monitoring the amplitude of the initial signal sequence in real time;

[0039] According to the initial signal sequence, the compression threshold and the compression ratio, the instantaneous target gain reduction is calculated to suppress the signal exceeding the threshold;

[0040] The smoothing coefficient is calculated based on the amplitude, the compressor attack time constant and the release time constant;

[0041] Calculating the adaptive control gain reduction based on the instantaneous target gain reduction and the smoothing coefficient to suppress the signal amplitude;

[0042] According to the initial signal sequence and the gain reduction amount, a compressed pre-injection sequence is obtained while retaining the main features of the audio.

[0043] As preferred technical measures:

[0044] Step 3: Using the pre-built signal frequency domain processing model and based on the Hilbert transform mechanism, the wide spectrum high frequency injection signal is transformed in the frequency domain to obtain the mixed signal as follows:

[0045] Decompose the wide spectrum high frequency injection signal into the form of the sum of several cosine functions to obtain the signal function expression;

[0046] Based on the signal function expression, the injected signal is Fourier transformed to obtain the signal frequency domain expression;

[0047] According to the frequency domain expression of the signal, the Hilbert transform mechanism is used to introduce a -90-degree phase shift to the positive frequency component and a 90-degree phase shift to the negative frequency component to obtain the operator expression;

[0048] Perform Hilbert transform on the operator expression to obtain the signal transformation expression after frequency domain transformation;

[0049] Use inverse Fourier transform to perform time domain signal recovery on the signal transformation expression to obtain the coherent signal;

[0050] Combining the signal transformation expression and the coherent signal, the response current calculation formula is obtained;

[0051] According to the response current calculation formula, the mixing signal is obtained.

[0052] As preferred technical measures:

[0053] Step 4: Use the pre-built rotor position calculation model to process the mixed signal to obtain the rotor position information as follows:

[0054] Project the mixed signal onto In the coordinate system, the projection expression of the first signal is obtained;

[0055] Perform absolute value and low-pass filtering operations on the signal projection expression to obtain the signal conversion expression;

[0056] Then back-project the signal conversion expression to In the coordinate system, the second signal projection expression is obtained;

[0057] Based on the second signal projection expression, an orthogonal phase-locked loop is constructed, and the rotor position information is obtained through a proportional-integral controller and an integrator.

[0058] As preferred technical measures:

[0059] The method of constructing an orthogonal phase-locked loop is as follows:

[0060] Multiplying the orthogonal components in the second signal projection expression with the sine and cosine values ​​of the estimated angle of the previous cycle of the phase-locked loop, respectively, to obtain a multiplication result;

[0061] performing a difference calculation on the multiplication result to generate a rotor estimated position error signal;

[0062] Inputting the rotor estimated position error signal into a proportional-integral controller for dynamic regulation, and obtaining the rotor estimated electrical angular velocity when the rotor estimated position error signal converges to zero;

[0063] The estimated electrical angular velocity of the rotor is integrated by an integrator to obtain the estimated rotor position;

[0064] The estimated electrical angular velocity of the rotor is converted into units and added to the motor pole logarithm gain to obtain the estimated value of the mechanical speed;

[0065] Then, based on the estimated value of the mechanical speed, the three-phase drive voltage is obtained to complete the construction of the orthogonal phase-locked loop.

[0066] As preferred technical measures:

[0067] The method further includes step 5 of evaluating the rotor position information using a pre-built position accuracy analysis model to obtain an evaluation result, which includes the following steps:

[0068] Establish a response current calculation formula and add the system random noise interference term to obtain the quadrature-axis high-frequency response current, which is the superposition of the effective signal and the noise;

[0069] According to the quadrature-axis high-frequency response current, the input signal-to-noise ratio calculation formula is obtained;

[0070] The quadrature-axis high-frequency response current is multiplied by the Hilbert-transformed high-frequency carrier through a synchronous multiplier, and low-pass filtered to obtain an output signal;

[0071] According to the power of the noise term, the output noise power is calculated and the power of the output signal is kept constant;

[0072] Based on the output noise power, the input signal-to-noise ratio calculation formula is converted to obtain the output signal-to-noise ratio calculation formula;

[0073] According to the output signal-to-noise ratio calculation formula, the output signal-to-noise ratio is obtained;

[0074] Based on the output signal-to-noise ratio, the rotor position information is analyzed for accuracy and the evaluation results are obtained.

[0075] To achieve one of the above purposes, the second technical solution of the present invention is:

[0076] A permanent magnet synchronous motor noise reduction control system based on wide spectrum high frequency injection includes:

[0077] one or more processors;

[0078] a storage device for storing one or more programs;

[0079] When the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned permanent magnet synchronous motor noise reduction control method based on wide spectrum high frequency injection.

[0080] Compared with the existing technical solutions, the present invention has the following beneficial effects:

[0081] After continuous exploration and experimentation, the present invention constructs a signal acquisition model, an amplitude dynamic processing model, a signal frequency domain processing model, and a rotor position calculation model to perform adaptive compression processing on the audio signal, thereby reducing the amplitude of the audio signal while retaining the main audio characteristics, thereby obtaining a wide-spectrum high-frequency injection signal that can reduce motor noise; then, based on the Hilbert transform mechanism, the wide-spectrum high-frequency injection signal is transformed in the frequency domain to obtain a mixed signal; and then the mixed signal is processed to obtain rotor position information, thereby effectively improving the estimation accuracy of the rotor position and thereby improving the control accuracy of the permanent magnet synchronous motor;

[0082] Furthermore, the present invention adaptively compresses the audio signal and performs frequency domain transformation on the wide-spectrum high-frequency injection signal based on the Hilbert transform mechanism. Therefore, there is no need to inject a voltage signal of a specific frequency. It can achieve precise noise reduction control of the permanent magnet synchronous motor based on wide-spectrum high-frequency injection, thereby effectively avoiding the problem of reference signal spectrum asynchrony, and then accurately recovering the position error signal, further improving the rotor position estimation accuracy. The solution is scientific, reasonable and feasible.

[0083] Furthermore, the present invention can effectively solve the noise problem caused by high-frequency injection current by generating a wide-spectrum high-frequency injection signal and a mixing signal, thereby facilitating the promotion and use of sensorless motor control solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figure 1 A schematic flow chart of a noise reduction control method for a permanent magnet synchronous motor according to the present invention;

[0085] Figure 2 This is a principle block diagram of the permanent magnet synchronous motor noise reduction control system of the present invention;

[0086] Figure 3 A flowchart of the present invention for estimating the rotor position;

[0087] Figure 4 This is a relationship diagram of the coordinate system of the present invention. DETAILED DESCRIPTION

[0088] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0089] Rather, the present invention encompasses any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention as defined by the claims. Furthermore, to facilitate a better understanding of the present invention, certain specific details are described in detail below in the detailed description of the present invention. Those skilled in the art will be able to fully understand the present invention without these details.

[0090] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used herein, the term "or / and" includes any and all combinations of one or more of the associated listed items.

[0091] like Figure 1 As shown, the first specific embodiment of the permanent magnet synchronous motor noise reduction control method of the present invention is:

[0092] A permanent magnet synchronous motor noise reduction control method based on wide spectrum high frequency injection includes the following steps:

[0093] Step 1: Using a pre-built signal acquisition model, the audio signal is collected based on the frequency noise generation characteristics of the permanent magnet synchronous motor;

[0094] Step 2: Using a pre-built amplitude dynamic processing model, the audio signal is adaptively compressed to reduce its amplitude while preserving the main audio features, thereby obtaining a wide-spectrum high-frequency injection signal that can reduce motor noise.

[0095] Step 3: Using the pre-built signal frequency domain processing model and based on the Hilbert transform mechanism, the wide spectrum high frequency injection signal is transformed in the frequency domain to obtain the mixed signal;

[0096] Step 4: Use the pre-built rotor position calculation model to process the mixed signal to obtain rotor position information and realize permanent magnet synchronous motor noise reduction control based on wide spectrum high frequency injection.

[0097] A second specific embodiment of the noise reduction control method for a permanent magnet synchronous motor according to the present invention:

[0098] The noise reduction control method of permanent magnet synchronous motor based on wide spectrum high frequency injection is applied to the noise reduction control system of permanent magnet synchronous motor based on wide spectrum high frequency injection, which can be found in Figure 2 , which includes Space Vector Pulse Width Modulation (SVPWM), Park transform, IPark transform, Clarke transform, magnetic field oriented control strategy, broadband noise reduction signal injection method based on adaptive compression transform, and rotor position estimation method based on Hilbert transform.

[0099] At the same time, in order to verify that the method and system of the present invention can improve the accuracy of rotor position estimation, a mathematical model of current demodulation under Gaussian noise interference is established and analyzed and calculated.

[0100] In this embodiment, the broadband noise reduction signal injection method based on adaptive compression transformation includes the following contents:

[0101] The single frequency of the cosine injection signal is the direct cause of the fixed-frequency noise problem generated by the traditional pulse injection method. Therefore, the injection signal itself needs to have a sufficiently wide spectrum. This signal is called white noise or colored noise. Its sound is relatively smooth and soft, without obvious pitch changes.

[0102] Therefore, this embodiment collects audio signals of flowing water or rain in nature as the source of the injection signal, and uses an injection signal processing strategy based on adaptive compression transform to process the injected wave so that it can stably excite the current for rotor position estimation. The specific method is as follows:

[0103] First, take any finite-length audio signal of the white noise type , perform band-pass filtering (BPF) on it to preliminarily remove invalid frequency bands. Set the lower cutoff frequency away from the motor operating base frequency, generally more than 2 times the rated frequency, and set the upper cutoff frequency to prevent sampling aliasing, generally less than 0.4 times the current loop frequency, thus obtaining the signal sequence , which is calculated as follows:

[0104]

[0105] Where: represents a discrete time series, represents the impulse response of the bandpass filter.

[0106] Secondly, the signal is adaptively compressed (abbreviated as: Comp) to initially reduce the signal dynamics while preserving the main audio characteristics. The compressor monitors the input signal amplitude in real time and adaptively controls the gain reduction. In order to suppress the signal dynamics, in actual practice, a first-order low-pass filter is usually used to set the dynamic response. The calculation formula is as follows:

[0107]

[0108]

[0109]

[0110] Where: is the smoothing coefficient, which is related to the compressor attack time and release time Related; 、 The time constants for the attack and release of the compressor are usually 、 ; is a natural constant; is the audio signal sampling frequency; is the compression threshold; is the instantaneous target gain reduction, used to suppress signals exceeding the threshold; is the compression ratio.

[0111] This can be used to obtain the compressed pre-injection sequence , which is calculated as follows:

[0112]

[0113] Again, for the pre-injection sequence Perform Empirical Mode Decomposition (EMD), the calculation formula is as follows:

[0114]

[0115] Where: For the m Intrinsic mode functions; is the total number of extracted eigenmode functions; is the residual.

[0116] Get its first-order eigenmode function This can preserve the auditory perception of the main signal and make the upper and lower envelopes locally symmetrical relative to the time axis to ensure that the mean value of the response current is stable near zero.

[0117] Finally, the retained intrinsic mode function is resampled according to the current loop frequency to obtain the exact injection order signal sequence; the signal is saturated and limited to remove the invalid spike pulses of the signal to ensure that the peak-to-average ratio of the signal is close to the peak-to-average ratio of the ideal sine wave, that is, The actual injection signal sequence is obtained , which is calculated as follows:

[0118]

[0119] Where: is the resampling function; is the saturation limiting function.

[0120] like Figure 3 As shown, in this embodiment, the rotor position estimation method based on Hilbert transform includes the following contents:

[0121] The rotor position estimation method based on Hilbert transform includes current demodulation, coordinate transformation, and orthogonal phase-locked loop, and specifically includes the following steps:

[0122] First, the finite length injection signal can be mathematically regarded as the sum of several cosine functions, so the actual injection signal sequence Rewrite it to get the following new expression:

[0123]

[0124] Where: Indicates the total number of cosine waves contained in the signal; represents the serial number of the cosine function, 、 、 is the amplitude, frequency and phase of the cosine function; Represents a discrete time series.

[0125] Perform Fourier transform on the injected signal to obtain the frequency domain expression , which is expressed as follows:

[0126]

[0127] Where: represents the Fourier transform operator, then represents the inverse Fourier transform operator; is a plural unit; 、 are complex exponential terms, carrying the phase information of positive and negative frequencies respectively; is a continuous frequency variable; is the Dirac impulse function.

[0128] The Hilbert transform introduces a -90-degree phase shift to the positive frequency component and a 90-degree phase shift to the negative frequency component. Therefore, its frequency domain operator It can be expressed as:

[0129]

[0130]

[0131] Where: is a symbolic function.

[0132] Performing Hilbert transform on the frequency domain expression yields the frequency domain transform expression , which is as follows:

[0133]

[0134] Using inverse Fourier transform to recover the time domain signal from the frequency domain transform expression, we can get the coherent signal. , which is expressed as follows:

[0135]

[0136] like Figure 4 As shown, in this embodiment, the rotation transformation relationship between the coordinate systems is as follows:

[0137]

[0138] Where: 、 For the real synchronous rotating coordinate system Vectors such as voltage and current below the axis; 、 is a stationary coordinate system Vectors such as voltage and current below the axis; 、 To estimate the synchronous rotation coordinate system Vectors such as voltage and current below the axis; 、 Synchronous rotation of the coordinate system for measurement Vectors such as voltage and current below the axis; is the true electrical angle of the rotor; is the rotor electrical angle estimation error; Estimate the position of the rotor; is the rotation matrix operator.

[0139] Rotation matrix operation symbols The expression is as follows:

[0140]

[0141] The motor a Phase current and b Phase current Through Clarke transformation, we get Current components in the coordinate system 、 , and then through Park transformation, we get Current components in the coordinate system 、 Since the frequency of the injected signal is as far away from the fundamental frequency of the motor rotation as possible, and the low-frequency components are filtered out by the high-pass filter (HPF) during the subsequent demodulation process, the high-frequency voltage mathematical model of the PMSM in the synchronous rotating coordinate system can be simplified to:

[0142]

[0143] Where: 、 、 、 For PMSM running at zero low speed High-frequency voltage and current components of the shaft; 、 They are The inductance component of the shaft.

[0144] Furthermore, combining the rotation transformation relationship between coordinate systems, the high-frequency voltage mathematical model and the expression of the sum of several cosine functions, we can obtain Injection response current in the coordinate system 、 The simplified calculation formula is as follows:

[0145]

[0146]

[0147] Multiplying the coherent signal with the simplified calculation formula, we get Mixing current in the coordinate system 、 , which is expressed as follows:

[0148]

[0149] Where: 、 represents the serial number of the cosine function, 、 is the amplitude of the cosine function; 、 is the frequency of the cosine function; 、 is the phase of the cosine function.

[0150] Second, project the mixed signal onto In the coordinate system, the first signal projection expression is obtained:

[0151]

[0152] Where: 、 To measure the current value in the synchronous rotating coordinate system; .

[0153] Performing absolute value (ABS) and low-pass filtering operations on the first signal projection expression, we can obtain the signal conversion expression:

[0154]

[0155] Where: 、 To measure the calculated current value in the synchronous rotating coordinate system; is a low-pass filter function.

[0156] Then back-project the signal conversion expression to In the coordinate system, the second signal projection expression can be obtained:

[0157]

[0158] Where: 、 is the calculated current value in the stationary rotating coordinate system.

[0159] In this embodiment, the method for constructing an orthogonal phase-locked loop is as follows:

[0160] The method of constructing an orthogonal phase-locked loop is to convert the 、 Multiplying it with the sine and cosine of the estimated angle calculated in the previous phase-locked loop cycle and taking the difference, we get the rotor position estimation error:

[0161]

[0162] The error is then passed to the Proportional-Integral Controller (PI). When the error approaches zero, the output is close to the true electrical angular velocity. The estimated rotor position is then obtained by integrating it through the Integral Controller (I):

[0163]

[0164] Where: is the integral function; is the estimated electrical angular velocity.

[0165] The estimated electrical angular velocity is converted to mechanical speed by unit conversion:

[0166]

[0167] Where: is the estimated rotation speed; is the unit conversion gain, is the number of motor pole pairs.

[0168] By its given speed The error obtained by comparison is used as the input of the current loop PI controller, and then the given voltage vector of the field oriented control strategy is calculated. Combined with the estimated rotor position, the conduction time of the three-phase inverter bridge can be calculated through IPark transformation and SVPWM, and finally the bus power supply The three-phase voltage required to drive the motor is output through the rectification of the three-phase inverter bridge.

[0169] In this embodiment, the position estimation accuracy analysis method based on the signal-to-noise ratio includes the following:

[0170] In order to compare the superiority of the rotor position estimation method based on Hilbert transform proposed in this embodiment compared with the traditional rotor position estimation method based on envelope demodulation in reducing position estimation error, this embodiment establishes mathematical models of the current envelope demodulation method and the current coherent demodulation method containing Gaussian white noise interference, and illustrates the two methods by comparing the output signal-to-noise ratio parameters.

[0171] Combining the rotation transformation relationship between coordinate systems, high-frequency voltage mathematical model and voltage response expression, we can get The calculation formula of the response current in the coordinate system is as follows:

[0172]

[0173] When the rotor position is estimated correctly, the system random noise interference term is added, and the quadrature axis high frequency response current is defined as the superposition of the effective signal and the noise. The calculation formula is as follows:

[0174]

[0175] Where: is the gain coefficient between the effective signal amplitude and the position error; is the effective signal related to the position error; is a high frequency carrier, and ; is Gaussian white noise, and its average power , is the power spectral density value, For bandwidth.

[0176] So the input signal-to-noise ratio It can be defined as:

[0177]

[0178] Where: is the effective signal power.

[0179] Since coordinate transformation and absolute value operation do not affect the signal-to-noise ratio, the envelope demodulation core algorithm can be directly applied to the signal superposition formula to extract the signal vector through rectification and low-pass filtering. , the output signal is:

[0180]

[0181] Then the signal power Sum noise power They become:

[0182]

[0183]

[0184] Where: is the expected function; , are the compression ratios of the bandwidth of the effective signal and noise after low-pass filtering, both greater than 1.

[0185] Finally, the output signal-to-noise ratio is obtained for:

[0186]

[0187] The coherent demodulation method uses a synchronous multiplier to combine the current and the carrier Multiply and low-pass filter, and finally output the signal for:

[0188]

[0189] The signal power remains unchanged, and the noise power becomes the output noise power for:

[0190]

[0191] Finally, the output signal-to-noise ratio is obtained for:

[0192]

[0193] Then we can get Therefore, coherent demodulation can maintain a higher output signal-to-noise ratio by synchronously suppressing noise, and thus the rotor position observer based on coherent demodulation can obtain higher position accuracy.

[0194] In summary, the present invention can effectively solve the fixed frequency noise problem caused by the traditional pulse high-frequency injection method, while improving the rotor position estimation accuracy under low voltage injection amplitude and improving the accuracy of rotor position estimation under low signal-to-noise ratio.

[0195] An embodiment of a device applying the method of the present invention:

[0196] An electronic device comprising:

[0197] one or more processors;

[0198] a storage device for storing one or more programs;

[0199] When the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned permanent magnet synchronous motor noise reduction control method based on wide spectrum high frequency injection.

[0200] A computer medium embodiment of the method of the present invention:

[0201] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the above-mentioned permanent magnet synchronous motor noise reduction control method based on wide-spectrum high-frequency injection.

[0202] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, optical storage, etc.) containing computer-usable program code.

[0203] The present application is described in terms of flowcharts or / and block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process or / and block in the flowchart or / and block diagram, as well as the combination of processes or / and blocks in the flowchart or / and block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0204] The model in this application is an object that objectively describes the morphological structure with the help of physical or virtual representation. The object is not equal to the physical body and is not limited to physical and virtual. It can be a data processing function, software program, processing mode, usage method, operation method, workflow, application process, electronic hardware, circuit module, processing system, system imitation or simulation object.

[0205] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field can still modify or replace the specific implementation methods of the present invention. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A noise reduction control method for a permanent magnet synchronous motor based on wide spectrum high frequency injection, characterized by: The following steps are involved: Step 1: Using a pre-built signal acquisition model, the audio signal is collected based on the frequency noise generation characteristics of the permanent magnet synchronous motor; Step 2: Using a pre-built amplitude dynamic processing model, the audio signal is adaptively compressed to reduce its amplitude while preserving the main audio features, thereby obtaining a wide-spectrum high-frequency injection signal that can reduce motor noise. Step 3: Using the pre-built signal frequency domain processing model and based on the Hilbert transform mechanism, the wide spectrum high frequency injection signal is transformed in the frequency domain to obtain the mixed signal; Step 4: Use the pre-built rotor position calculation model to process the mixed signal to obtain rotor position information and realize permanent magnet synchronous motor noise reduction control based on wide spectrum high frequency injection.

2. The method for noise reduction control of a permanent magnet synchronous motor based on wide spectrum high frequency injection according to claim 1, characterized in that: Step 1: Using a pre-built signal acquisition model and based on the frequency noise generation characteristics of the permanent magnet synchronous motor, the method for collecting audio signals is as follows: Calculate the required spectrum of the injection signal based on the frequency noise generation characteristics of the permanent magnet synchronous motor; Based on the required spectrum, generate audio feature standard information that meets the spectrum requirements; According to the audio feature standard information, audio signals about flowing water or rain sounds in nature are collected.

3. The method for controlling noise reduction of a permanent magnet synchronous motor based on wide spectrum high frequency injection according to claim 1, characterized in that: Step 2: Use the pre-built amplitude dynamic processing model to perform adaptive compression processing on the audio signal, reducing the amplitude of the audio signal while retaining the main audio characteristics. The method for obtaining a wide-spectrum high-frequency injection signal that can reduce motor noise is as follows: Step 21, extracting a finite length signal from the audio signal to obtain an initial signal sequence; Step 22: Adaptively compress the initial signal sequence to preliminarily reduce the amplitude of the initial signal sequence while retaining the main audio features, thereby obtaining a compressed pre-injection sequence. Step 23: Based on the intrinsic time-varying characteristics of the signal, perform empirical mode decomposition on the pre-injection sequence to obtain its first-order intrinsic mode function, which is used to preserve the auditory perception of the main signal while making the upper and lower envelopes locally symmetrical with respect to the time axis to ensure that the mean value of the response current is stable near zero; In step 24, the retained intrinsic mode function is resampled according to the current loop frequency to obtain an injection order signal sequence; and based on the saturation limiting function, the injection order signal sequence is saturated and limited to remove invalid signal spike pulses, thereby obtaining a wide spectrum high frequency injection signal.

4. The method for noise reduction control of a permanent magnet synchronous motor based on wide spectrum high frequency injection according to claim 3, characterized in that: Step 21, extracting the finite length signal from the audio signal to obtain the initial signal sequence is as follows: Set the upper and lower cutoff frequencies. The upper cutoff frequency is used to prevent sampling aliasing and its value should be less than the current loop frequency. The lower cutoff frequency is used to keep the extracted signal away from the motor's base frequency and its value should be greater than the rated frequency. Extract the finite length signal from the audio signal according to the upper cutoff frequency and the lower cutoff frequency; Perform bandpass filtering on the finite-length signal to remove invalid frequency bands and obtain a filtered signal; The initial signal sequence is calculated based on the filtered signal and the impulse response of the bandpass filter.

5. The method for noise reduction control of a permanent magnet synchronous motor based on wide spectrum high frequency injection according to claim 3, characterized in that: Step 22, adaptively compressing the initial signal sequence to preliminarily reduce the amplitude of the initial signal sequence while retaining the main audio features, and obtaining a compressed pre-injection sequence is as follows: Obtaining an initial signal sequence and monitoring the amplitude of the initial signal sequence in real time; According to the initial signal sequence, the compression threshold and the compression ratio, the instantaneous target gain reduction is calculated to suppress the signal exceeding the threshold; The smoothing coefficient is calculated based on the amplitude, the compressor attack time constant and the release time constant; Calculating the adaptive control gain reduction based on the instantaneous target gain reduction and the smoothing coefficient to suppress the signal amplitude; According to the initial signal sequence and the gain reduction amount, a compressed pre-injection sequence is obtained while retaining the main features of the audio.

6. The method for noise reduction control of a permanent magnet synchronous motor based on wide spectrum high frequency injection according to claim 1, characterized in that: Step 3: Using the pre-built signal frequency domain processing model and based on the Hilbert transform mechanism, the wide spectrum high frequency injection signal is transformed in the frequency domain to obtain the mixed signal as follows: Decompose the wide spectrum high frequency injection signal into the form of the sum of several cosine functions to obtain the signal function expression; Based on the signal function expression, the injected signal is Fourier transformed to obtain the signal frequency domain expression; According to the frequency domain expression of the signal, the Hilbert transform mechanism is used to introduce a -90-degree phase shift to the positive frequency component and a 90-degree phase shift to the negative frequency component to obtain the operator expression; Perform Hilbert transform on the operator expression to obtain the signal transformation expression after frequency domain transformation; Use inverse Fourier transform to perform time domain signal recovery on the signal transformation expression to obtain the coherent signal; Combining the signal transformation expression and the coherent signal, the response current calculation formula is obtained; According to the response current calculation formula, the mixing signal is obtained.

7. The method for controlling noise reduction of a permanent magnet synchronous motor based on wide spectrum high frequency injection according to claim 1, characterized in that: Step 4: Use the pre-built rotor position calculation model to process the mixed signal to obtain the rotor position information as follows: Project the mixed signal onto the coordinate system to obtain the first signal projection expression; Perform absolute value and low-pass filtering operations on the signal projection expression to obtain the signal conversion expression; Then, the signal conversion expression is back-projected into the coordinate system to obtain the second signal projection expression; Based on the second signal projection expression, an orthogonal phase-locked loop is constructed, and the rotor position information is obtained through a proportional-integral controller and an integrator.

8. The method for controlling noise reduction of a permanent magnet synchronous motor based on wide spectrum high frequency injection according to claim 7, characterized in that: The method of constructing an orthogonal phase-locked loop is as follows: Multiplying the quadrature components in the second signal projection expression by the sine and cosine values ​​of the estimated angle of the previous cycle of the phase-locked loop, respectively, to obtain a multiplication result; performing a difference calculation on the multiplication result to generate a rotor estimated position error signal; Inputting the rotor estimated position error signal into a proportional-integral controller for dynamic regulation, and obtaining the rotor estimated electrical angular velocity when the rotor estimated position error signal converges to zero; The estimated electrical angular velocity of the rotor is integrated by an integrator to obtain the estimated rotor position; The estimated electrical angular velocity of the rotor is converted into units and combined with the motor pole logarithm gain to obtain the estimated value of the mechanical speed; then, based on the estimated value of the mechanical speed, the three-phase drive voltage is obtained to complete the construction of the orthogonal phase-locked loop.

9. The method for controlling noise reduction of a permanent magnet synchronous motor based on wide spectrum high frequency injection according to claim 1, characterized in that: The method further includes step 5 of evaluating the rotor position information using a pre-built position accuracy analysis model to obtain an evaluation result, which includes the following steps: Establish a response current calculation formula and add the system random noise interference term to obtain the quadrature-axis high-frequency response current, which is the superposition of the effective signal and the noise; According to the quadrature-axis high-frequency response current, the input signal-to-noise ratio calculation formula is obtained; The quadrature-axis high-frequency response current is multiplied by the Hilbert-transformed high-frequency carrier through a synchronous multiplier, and low-pass filtered to obtain an output signal; According to the power of the noise term, the output noise power is calculated and the power of the output signal is kept constant; Based on the output noise power, the input signal-to-noise ratio calculation formula is converted to obtain the output signal-to-noise ratio calculation formula; According to the output signal-to-noise ratio calculation formula, the output signal-to-noise ratio is obtained; Based on the output signal-to-noise ratio, the rotor position information is analyzed for accuracy and the evaluation results are obtained.

10. A permanent magnet synchronous motor noise reduction control system based on wide spectrum high frequency injection, characterized by: It includes: one or more processors; a storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the permanent magnet synchronous motor noise reduction control method based on wide spectrum high frequency injection as described in any one of claims 1 to 9.

Images