Common mode voltage suppression method, electronic device and storage medium

Abstract

The present application provides a common-mode voltage suppression method, an electronic device, and a storage medium. It belongs to the field of motor control technology. The method is applied to a motor system, and the motor system includes a PWM circuit and a filter circuit. The method includes: obtaining a common-mode voltage signal generated by the PWM circuit, and performing a fast Fourier transform on the common-mode voltage signal to obtain a voltage spectrum; extracting a target harmonic component in the voltage spectrum that belongs to a preset amplitude range; determining a correction frequency and a correction bandwidth of the filter circuit based on the harmonic frequency and harmonic bandwidth of the target harmonic component; and controlling the filter circuit to generate a resonant frequency that matches the target harmonic component based on the correction frequency and the correction bandwidth. The present application can achieve real-time suppression of common-mode voltage, effectively reduce electrical corrosion of bearings, and reduce electromagnetic interference.

Description

Technical Field

[0001] The present application relates to the field of motor control technology, and in particular to a common-mode voltage suppression method, an electronic device, and a storage medium. Background Art

[0002] In modern motor drive control systems, PWM (Pulse Width Modulation) inverters are widely used to adjust the speed and torque of motors. The motor system achieves precise control of motor speed and torque by adjusting the pulse width of the output voltage. However, the high-frequency components in the PWM control signal will generate significant common-mode voltage (CMV), which will not only cause electrical corrosion to the bearings in the motor system, but also cause electromagnetic interference, affecting the normal operation of the equipment.

[0003] To solve this problem, the traditional solution is usually to isolate the motor from the outside world by using insulated bearings or shielded cables to reduce the impact of common-mode voltage. However, this physical isolation method increases the complexity and cost of the system and cannot completely eliminate the common-mode voltage. Alternatively, a fixed filter circuit is installed at the output of the motor system to filter out high-frequency components. However, the design of the fixed filter circuit is relatively fixed and lacks flexibility, making it difficult to adapt to complex operating conditions and different working conditions.

[0004] Therefore, in view of the limitations of the above-mentioned traditional solutions, there is an urgent need for a new method that can suppress common-mode voltage in real time, thereby effectively reducing bearing electrical corrosion and reducing electromagnetic interference. Summary of the invention

[0005] The purpose of the present application is to provide a common mode voltage suppression method, an electronic device and a storage medium to solve the above problems.

[0006] To achieve the above objectives, in a first aspect, the present application proposes a common mode voltage suppression method, the method being applied to a motor system, the motor system comprising a PWM circuit and a filter circuit, the method comprising:

[0007] Acquire a common-mode voltage signal generated by the PWM circuit, and perform a fast Fourier transform on the common-mode voltage signal to obtain a voltage spectrum;

[0008] Extracting target harmonic components in the voltage spectrum that fall within a preset amplitude range;

[0009] Determining a correction frequency and a correction bandwidth of the filter circuit based on the harmonic frequency and the harmonic bandwidth of the target harmonic component;

[0010] Based on the correction frequency and the correction bandwidth, the filter circuit is controlled to generate a resonant frequency that matches the target harmonic component.

[0011] In some implementations, acquiring the common-mode voltage signal generated by the PWM circuit and performing a fast Fourier transform on the common-mode voltage signal to obtain a voltage spectrum includes:

[0012] Acquire a common-mode voltage signal generated by the PWM circuit, wherein the common-mode voltage signal is a continuous analog signal;

[0013] Converting the analog signal into a discrete digital signal through an analog-to-digital converter;

[0014] Performing fast Fourier transform on the digital signal to obtain a voltage spectrum.

[0015] In some implementations, performing a fast Fourier transform on the digital signal to obtain a voltage spectrum includes:

[0016] Decomposing the digital signal into a plurality of sine waves with different frequencies;

[0017] The amplitudes and phases of the multiple sine waves of different frequencies are calculated to obtain a voltage spectrum including the amplitudes and the phases, wherein the amplitude is used to represent the intensity of the corresponding frequency, and the phase is used to represent the offset of the corresponding frequency on the time axis.

[0018] In some implementations, determining the correction frequency and correction bandwidth of the filter circuit based on the harmonic frequency and harmonic bandwidth of the target harmonic component includes:

[0019] Based on the harmonic amplitude of the target harmonic component and a preset amplitude threshold, determining an adjustment strategy corresponding to the target harmonic component, wherein the adjustment strategy includes a general adjustment calculation strategy, a fine adjustment calculation strategy, and a non-adjustment strategy;

[0020] Based on the harmonic frequency and harmonic bandwidth of the target harmonic component and the adjustment strategy corresponding to the target harmonic component, the correction frequency and correction bandwidth of the filter circuit are determined.

[0021] In some implementations, determining the adjustment strategy corresponding to the target harmonic component based on the harmonic amplitude of the target harmonic component and a preset amplitude threshold includes:

[0022] Based on the harmonic amplitude of the target harmonic component and a preset amplitude threshold, calculating the interference amplitude of the target harmonic component;

[0023] When the interference amplitude is greater than a preset safety threshold, determining that the adjustment strategy corresponding to the target harmonic component is a general adjustment calculation strategy;

[0024] When the interference amplitude is greater than a preset basic threshold and less than or equal to the preset safety threshold, determining that the adjustment strategy corresponding to the target harmonic component is a fine-tuning calculation strategy;

[0025] When the interference amplitude is less than or equal to the preset basic threshold, it is determined that the adjustment strategy corresponding to the target harmonic component is a non-adjustment strategy.

[0026] In some embodiments, after controlling the filter circuit to generate a resonant frequency matching the target harmonic component based on the corrected frequency and the corrected bandwidth, the method further includes:

[0027] Obtaining a filtered voltage signal of the motor system;

[0028] Performing a fast Fourier transform on the filtered voltage signal to obtain a frequency spectrum of the filtered voltage signal;

[0029] Extracting new target harmonic components belonging to the preset amplitude range in the spectrum graph;

[0030] Determining an adjustment strategy corresponding to the new target harmonic component based on the new harmonic amplitude of the new target harmonic component and the preset amplitude threshold;

[0031] When the adjustment strategy corresponding to the new target harmonic component is a non-adjustment strategy, the resonant frequency generated by the filter circuit and matching the target harmonic component is not adjusted;

[0032] When the adjustment strategy corresponding to the new target harmonic component is a general adjustment strategy or a fine adjustment strategy, the filter circuit is controlled to generate a resonant frequency matching the new target harmonic component.

[0033] In some implementations, controlling the filter circuit to generate a resonant frequency matching the target harmonic component based on the correction frequency and the correction bandwidth includes:

[0034] Calculating a target capacitance value of the filter circuit based on the correction frequency and the inductance value of the filter circuit;

[0035] Based on the correction frequency and the correction bandwidth, a target Q value of the filter circuit is calculated;

[0036] Based on the target capacitance value and the target Q value, a target resistance value of the filter circuit is calculated;

[0037] The filter circuit is controlled to adjust to the target capacitance value and the target resistance value, so that the filter circuit generates a resonant frequency matching the target harmonic component.

[0038] In some implementations, the filter circuit includes a digital capacitor array and a digital resistor array, and controlling the filter circuit to adjust to the target capacitance value and the target resistance value includes:

[0039] Determining a capacitor combination matching the target capacitance value and a resistor combination matching the target resistance value based on the digital capacitor array and the digital resistor array;

[0040] Based on the capacitor combination and the resistor combination, the filter circuit is adjusted to the target capacitance value and the target resistance value.

[0041] In a second aspect, the present application provides an electronic device, comprising:

[0042] one or more processors;

[0043] a memory for storing one or more programs,

[0044] When the one or more programs are executed by the one or more processors, the one or more processors execute the common mode voltage suppression method as described above.

[0045] In a third aspect, the present application proposes a storage medium, wherein the storage medium stores executable instructions, and when the instructions are executed by a processor, the processor executes the common-mode voltage suppression method as described above.

[0046] Compared with the prior art, the beneficial effects of this application include:

[0047] On the one hand, by acquiring the common-mode voltage signal generated by the PWM circuit in real time and performing a fast Fourier transform, the target harmonic component in the high-frequency component can be accurately identified. This allows the motor system to dynamically adjust the circuit parameters of the filter circuit during operation, thereby achieving real-time suppression of the common-mode voltage. On the other hand, since the target harmonic component is extracted by fast Fourier transform, and the filter circuit is controlled according to the actual detected harmonic characteristics to generate a resonant frequency matching the target harmonic component, the present application can flexibly adapt to different operating conditions and working conditions, and has high adaptability and robustness. On the third hand, by performing frequency domain analysis on the common-mode voltage signal and suppressing the target harmonic component in a targeted manner, the generation of shaft current can be significantly reduced, thereby effectively preventing electrical corrosion on the bearing surface, extending the bearing life, and reducing maintenance costs. At the same time, the electromagnetic compatibility of the motor system can be improved, ensuring the normal operation of the motor and other peripheral electronic equipment, and avoiding system instability or failure caused by electromagnetic interference. On the fourth hand, compared with traditional physical isolation methods (such as using insulated bearings or shielded cables), the present application does not require the addition of additional mechanical structures or special materials, simplifies system design, and reduces manufacturing and maintenance costs. Fifthly, compared with fixed filtering circuits, the adaptive filtering method proposed in this application can dynamically adjust filtering parameters according to actual operating conditions, avoiding the limitations of traditional fixed filter design and improving the overall performance and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0049] Figure 1 is a schematic flow chart of a common mode voltage suppression method in one embodiment;

[0050] Figure 2 A schematic diagram of a simulation signal of a common mode voltage suppression method in one embodiment;

[0051] Figure 3 A schematic diagram of FFT transformation results of a common mode voltage suppression method in one embodiment;

[0052] Figure 4 A partial flow chart of a common mode voltage suppression method in one embodiment;

[0053] Figure 5 is a flow chart of a common mode voltage suppression method in yet another embodiment;

[0054] Figure 6 Schematic diagram of the structure of an electronic device involved in the common-mode voltage suppression method in an embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0056] All terms (including technical and scientific terms) used in this application have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used here should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0057] For example, the terms "first", "second", etc. used in this application may be used in this document to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element.

[0058] For another example, the terms “include”, “comprising”, etc. used in this application indicate the existence of features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0059] As mentioned above, in order to solve the negative impact of common-mode voltage on the motor system, the traditional solution is usually to isolate the motor from the outside world by using insulating bearings or shielded cables, thereby reducing the impact of common-mode voltage. However, this physical isolation method increases the complexity and cost of the system, and cannot completely eliminate the common-mode voltage. Or install a fixed filter circuit at the output end of the motor system to filter out high-frequency components. However, the design of the fixed filter circuit is relatively fixed, lacks flexibility, and is difficult to adapt to complex operating conditions and different working conditions. Therefore, in view of the limitations of the above-mentioned traditional solutions, there is an urgent need for a new method that can suppress common-mode voltage in real time, thereby effectively reducing bearing electrical corrosion and reducing electromagnetic interference. To this end, the present application proposes a common-mode voltage suppression method, an electronic device, and a storage medium that can suppress common-mode voltage in real time, effectively reduce bearing electrical corrosion, and reduce electromagnetic interference.

[0060] like Figure 1 As shown, an embodiment of the present application provides a common mode voltage suppression method, which is applied to a motor system including a PWM circuit and a filter circuit, and the method includes the following steps:

[0061] Step S10, acquiring a common-mode voltage signal generated by the PWM circuit, and performing a fast Fourier transform on the common-mode voltage signal to obtain a voltage spectrum.

[0062] In this embodiment, the PWM circuit is the core part of the motor system, which is responsible for controlling the speed and torque of the motor by changing the duty cycle of the output voltage. The common-mode voltage signal is a voltage signal caused by the high-frequency component generated by the PWM circuit, which may cause electromagnetic interference and electrical corrosion to the motor system. In order to monitor the common-mode voltage signal in real time, a voltage sensor can be installed in the motor system. The installation point of the voltage sensor can be set at the input and output ends of the PWM circuit, or at the input and output ends of the filter circuit, or at other locations in the motor system.

[0063] Since the common-mode voltage signal collected by the voltage sensor is a continuous analog signal, that is, a voltage signal that changes continuously over time, it reflects the actual output of the PWM circuit. For the fast Fourier transform (FFT) algorithm, the input signal must be discrete and have a fixed sampling frequency. Assuming that the sampling rate of the signal is Fs, the time interval between each sampling of the signal is Ts=1 / Fs. Therefore, it is necessary to first convert the analog signal into a discrete digital signal through an analog-to-digital converter (ADC). The digital signal can be further subjected to a fast Fourier transform (FFT) to obtain the voltage spectrum.

[0064] Specifically, Fast Fourier Transform (FFT) is a mathematical tool that converts time domain signals into frequency domain signals. It can be completed with the assistance of FPGA (Field Programmable Gate Array) or DSP (Digital Signal Processor). Its basic idea is to convert a signal such as Figure 2 The time domain signal shown is decomposed into the sum of several sine waves of different frequencies, each sine wave corresponds to a frequency component, thus forming Figure 3 The FTT transformation result is shown. In this embodiment, the digital signal is decomposed into a plurality of sine waves of different frequencies; the amplitude and phase of the plurality of sine waves of different frequencies are calculated to obtain a voltage spectrum containing the amplitude and the phase, wherein the amplitude is used to represent the intensity of the corresponding frequency, and the phase is used to represent the time position of the corresponding frequency. Formula (1) of the FTT transformation result is described as follows:

[0065] (1)

[0066] in, It is the complex representation of the kth frequency component in the voltage spectrum, which contains amplitude and phase information. is the total number of samples of the digital signal. is the nth sampling point of the digital signal. j is the imaginary unit, which represents the imaginary part of the complex number.

[0067] Step S20, extracting target harmonic components in the voltage spectrum that belong to a preset amplitude range.

[0068] The frequency component corresponding to each sine wave in the voltage spectrum is usually an integer multiple of the PWM operating frequency. For example, if the operating frequency of the PWM inverter is f0, the frequency of the fundamental wave (base frequency) f0 and the frequencies of the higher harmonic components may be 3f0 (third harmonic), 5f0 (fifth harmonic), 7f0 (seventh harmonic), etc. These higher harmonic components are the secondary signals of the PWM circuit during operation and need to be filtered.

[0069] Since a corresponding filter circuit is required to filter and eliminate the harmonic components of each frequency point, this embodiment sets a preset amplitude range to filter out several target harmonic components that need to be eliminated most due to cost considerations in practical applications. For example, the top three harmonic components in descending order of harmonic amplitude can be selected as target harmonic components.

[0070] The purpose of this is to minimize the number of filter circuits while ensuring the filtering effect, thereby reducing costs. Because not all harmonic components will have a significant impact on the system, only those with larger amplitudes need to be eliminated first.

[0071] In addition, the preset amplitude range can be further optimized according to specific system characteristics and application scenarios. For example, in some applications with extremely high signal quality requirements, a larger amplitude range may need to be set to ensure that as many harmonic components as possible are eliminated; while in some applications that are more cost-sensitive, the amplitude range can be appropriately narrowed to reduce the number of filtering circuits.

[0072] Step S30, determining a correction frequency and a correction bandwidth of the filter circuit based on the harmonic frequency and the harmonic bandwidth of the target harmonic component.

[0073] In this embodiment, the harmonic frequency refers to the frequency position of the target harmonic component in the voltage spectrum. The harmonic bandwidth refers to the frequency range occupied by the target harmonic component. The correction frequency refers to the operating frequency of the filter circuit adjusted according to the target harmonic component. The correction bandwidth refers to the operating bandwidth of the filter circuit adjusted according to the target harmonic component.

[0074] Taking the elimination of the target harmonic component of a single frequency point as an example, assuming that the harmonic frequency of the target harmonic component is 30kHz and the harmonic bandwidth is 2kHz (29kHz-31kHz), the correction frequency is the corresponding 30kHz and the correction bandwidth is the corresponding 2kHz.

[0075] In some embodiments, Figure 4 As shown, the step S30 includes:

[0076] Step S31, based on the harmonic amplitude of the target harmonic component and a preset amplitude threshold, determining an adjustment strategy corresponding to the target harmonic component, wherein the adjustment strategy includes a general adjustment calculation strategy, a fine adjustment calculation strategy and a non-adjustment strategy.

[0077] In this embodiment, the preset amplitude threshold is a threshold used to determine whether the filter circuit needs to be adjusted. If the harmonic amplitude of the target harmonic component is greater than the preset amplitude threshold, it is determined that the filter circuit needs to be adjusted. If the harmonic amplitude of the target harmonic component is less than or equal to the preset amplitude threshold, it is determined that the filter circuit is not adjusted.

[0078] For example, the preset amplitude threshold may be -40 dB, and when the harmonic amplitude of the target harmonic component is greater than -40 dB, the filter circuit is adjusted. When the harmonic amplitude of the target harmonic component is less than or equal to -40 dB, the filter circuit is not adjusted.

[0079] Furthermore, when the harmonic amplitude of the target harmonic component is greater than the preset amplitude threshold, the interference amplitude of the target harmonic component is calculated based on the harmonic amplitude of the target harmonic component and the preset amplitude threshold. The interference amplitude is the difference between the harmonic amplitude of the target harmonic component and the preset amplitude threshold, which is used to measure the impact of the target harmonic component. The larger the interference amplitude, the more serious the impact of the target harmonic component on the motor system.

[0080] Example 1: When the harmonic amplitude of the target harmonic component is -20 dB and the preset amplitude threshold is -40 dB, the interference amplitude is 20 dB.

[0081] Example 2: When the harmonic amplitude of the target harmonic component is -30dB and the preset amplitude threshold is -40dB, the interference amplitude is 10dB.

[0082] Example 3: When the harmonic amplitude of the target harmonic component is -38dB and the preset amplitude threshold is -40dB, the interference amplitude is 2dB.

[0083] Furthermore, by presetting a safety threshold, corresponding adjustment strategies are selected for target harmonic components with different impact levels, and by presetting a basic threshold, when the interference amplitude is lower than the minimum adjustment granularity of the motor system for the filter circuit, the adjustment of the filter circuit is stopped.

[0084] Specifically, when the interference amplitude is greater than the preset safety threshold, the adjustment strategy corresponding to the target harmonic component is determined to be a general adjustment calculation strategy; when the interference amplitude is greater than the preset basic threshold and less than or equal to the preset safety threshold, the adjustment strategy corresponding to the target harmonic component is determined to be a fine-tuning calculation strategy to prevent oscillation caused by excessive adjustment amplitude; when the interference amplitude is less than or equal to the preset basic threshold, the adjustment strategy corresponding to the target harmonic component is determined to be a non-adjustment strategy. Among them, the general adjustment calculation strategy has a larger adjustment amplitude for the filter circuit than the fine-tuning calculation strategy.

[0085] Example 1: When the interference amplitude is 20 dB and the preset safety threshold is 5 dB, it is determined that the adjustment strategy corresponding to the target harmonic component is the general adjustment calculation strategy.

[0086] Example 2: When the interference amplitude is 10 dB and the preset safety threshold is 5 dB, it is determined that the adjustment strategy corresponding to the target harmonic component is the general adjustment calculation strategy.

[0087] Example 3: When the interference amplitude is 2 dB, the preset safety threshold is 5 dB, and the preset basic threshold is 0 dB, it is determined that the adjustment strategy corresponding to the target harmonic component is the fine-tuning calculation strategy.

[0088] Step S32, determining a correction frequency and a correction bandwidth of the filter circuit based on the harmonic frequency and the harmonic bandwidth of the target harmonic component and an adjustment strategy corresponding to the target harmonic component.

[0089] When the adjustment strategy corresponding to the target harmonic component is the general adjustment calculation strategy, the harmonic frequency of the target harmonic component corresponds to the correction frequency of the filter circuit, and the harmonic bandwidth of the target harmonic component corresponds to the correction bandwidth of the filter circuit.

[0090] When the adjustment strategy corresponding to the target harmonic component is the fine-tuning calculation strategy, the frequency deviation between the harmonic frequency of the target harmonic component in the current adjustment round and the harmonic frequency in the previous adjustment round is calculated, and the first ratio of the frequency deviation is taken as the adjustment part, and the adjustment part is added to the harmonic frequency of the current adjustment round, which is the corrected frequency of the current adjustment round. Similarly, the bandwidth deviation between the harmonic bandwidth of the target harmonic component in the current adjustment round and the harmonic bandwidth in the previous adjustment round is calculated, and the second ratio of the loan deviation is taken as the adjustment part, and the adjustment part is added to the harmonic bandwidth of the current adjustment round, which is the corrected bandwidth of the current adjustment round. Among them, the first ratio and the second ratio can be set according to actual application requirements, and this embodiment does not impose specific restrictions on the first ratio and the second ratio.

[0091] For example, assuming that the harmonic frequency of the target harmonic component in the current adjustment round is 30.08 kHz, the harmonic frequency of the target harmonic component in the previous adjustment round is 30.1 kHz, and the first ratio is 0.5. Then the frequency deviation is: =30.1-30.08=0.02kHz, the corrected frequency is: =30.08+0.5 0.02=30.09 kHz.

[0092] Assume that the harmonic bandwidth of the target harmonic component in the current adjustment round is 2.35kHz, the harmonic bandwidth of the target harmonic component in the previous adjustment round is 2.4kHz, and the first ratio is 0.1. Then the correction bandwidth is: =2.35+0.1 (2.4-2.35)=2.355 kHz.

[0093] Step S40: Based on the correction frequency and the correction bandwidth, control the filter circuit to generate a resonant frequency that matches the target harmonic component.

[0094] In this embodiment, the filter circuit refers to an electronic circuit used to filter out target harmonic components, and its operating characteristics can be changed by adjusting circuit parameters.

[0095] Specifically, based on the correction frequency and the inductance value of the filter circuit, the target capacitance value of the filter circuit is calculated. Based on the correction frequency and the correction bandwidth, the target Q value of the filter circuit is calculated. Based on the target capacitance value and the target Q value, the target resistance value of the filter circuit is calculated. The filter circuit is controlled to adjust to the target capacitance value and the target resistance value so that the filter circuit generates a resonant frequency that matches the target harmonic component. It should be noted that the Q value (Quality Factor) mentioned in this embodiment is an indicator to measure the quality of the filter circuit, and has a certain relationship with the bandwidth (Bandwidth) of the filter circuit. A higher Q value indicates that the filter circuit has a narrower bandwidth and can better distinguish different frequency components of the input signal. On the contrary, a lower Q value indicates that the filter circuit has a wider bandwidth and allows a larger frequency range to pass.

[0096] Example 1: Assume the correction frequency fc is 30kHz and the inductance is The target capacitance value of the filter circuit is The calculation formulas (2) to (3) are as follows:

[0097] (2)

[0098] (3)

[0099] .

[0100] Furthermore, assuming the correction bandwidth is 2kHz, the target Q value of the filter circuit is The calculation formula (4) is as follows: (4).

[0101] Furthermore, the target resistance value of the filter circuit is calculated The formulas (5)~(6) are as follows:

[0102] (5)

[0103] (6)

[0104] .

[0105] Example 2: Suppose the correction frequency The inductance is 30.1kHz. The target capacitance value of the filter circuit is The calculation formulas (7)~(8) are as follows:

[0106] (7)

[0107] (8)

[0108] .

[0109] Furthermore, assuming the correction bandwidth is 2.4kHz, the target Q value of the filter circuit is The calculation formula (9) is as follows: (9).

[0110] Furthermore, the target resistance value of the filter circuit is calculated The formulas (10)~(11) are as follows:

[0111] (10)

[0112] (11)

[0113] .

[0114] Example 3: Suppose the correction frequency is 30.09kHz, and the inductance is The target capacitance value of the filter circuit is The calculation formula (12) is as follows:

[0115] (12)

[0116] .

[0117] Furthermore, assuming the correction bandwidth is 2.355kHz, the target Q value of the filter circuit is The calculation formula (13) is as follows: (13).

[0118] Furthermore, the target resistance value of the filter circuit is calculated The formula (14) is as follows:

[0119] (14)

[0120] .

[0121] In some embodiments, the filtering circuit includes a digital capacitor array and a digital resistor array. Based on the digital capacitor array and the digital resistor array, a logic control module in the motor system determines a capacitor combination that matches the target capacitance value and a resistor combination that matches the target resistance value; based on the capacitor combination and the resistor combination, the logic control module controls the signal (such as ) are respectively sent to the control circuits of the digital capacitor array and the digital resistor array through a digital interface (such as I2C, SPI), so that the filter circuit is adjusted to the target capacitance value and the target resistance value, wherein "SW" refers to the switch control signal (Switch).

[0122] Specifically, the digital capacitor array may include a group of fixed capacitors (such as 1nF, 500pF, 250pF, etc.) to form a binary weight combination. Through the switch matrix, the capacitors can be dynamically selected for combination to achieve the target capacitance value. For example, if the target capacitance value is 2.52nF, the capacitor combination that matches the target capacitance value is determined to be 2nF + 200pF + 250pF + 70pF = 2.52nF.

[0123] In some implementations, the filter circuit may not use a digital capacitor array, but may include a variable dielectric capacitor, and the variable dielectric capacitor may be adjusted to the target capacitance value by controlling the pressure applied to the variable dielectric capacitor, or the variable dielectric capacitor may be adjusted to the target capacitance value by controlling the voltage applied to the variable dielectric capacitor.

[0124] In addition, the specific implementation of controlling the digital resistor array in this embodiment can basically refer to the implementation process of controlling the digital capacitor array, and this embodiment will not be repeated here. In some embodiments, the filter circuit may not use a digital resistor array, but a digital potentiometer (Digipot), MEMS (micromotor) or piezoelectric variable resistor. The motor system dynamically controls the resistance value of the filter circuit through piezoelectric drive or micromotor.

[0125] Further, in some embodiments, Figure 5 As shown, after step S40, the following steps are further included:

[0126] Step S50, obtaining a filtered voltage signal of the motor system.

[0127] Step S60, performing fast Fourier transform on the filtered voltage signal to obtain a frequency spectrum of the filtered voltage signal.

[0128] Step S70: extracting new target harmonic components in the frequency spectrum that belong to the preset amplitude range.

[0129] Step S80: determining an adjustment strategy corresponding to the new target harmonic component based on the new harmonic amplitude of the new target harmonic component and the preset amplitude threshold.

[0130] Step S90: when the adjustment strategy corresponding to the new target harmonic component is a non-adjustment strategy, the resonant frequency generated by the filter circuit and matching the target harmonic component is not adjusted.

[0131] Step S100 , when the adjustment strategy corresponding to the new target harmonic component is a general adjustment strategy or a fine adjustment strategy, controlling the filter circuit to generate a resonant frequency matching the new target harmonic component.

[0132] In this embodiment, the previously arranged voltage sensor can be used to collect the filtered voltage signal at preset time intervals for in-depth analysis. By analyzing the spectrum diagram, the system can identify new target harmonic components. Then, the system compares the amplitude of these new harmonic components with the preset amplitude threshold to determine the corresponding adjustment strategy. This is a cyclic process, and the motor system continuously collects, analyzes and adjusts until there are no harmonic components higher than the preset amplitude threshold to ensure that the common mode voltage is effectively suppressed. The specific implementation process can refer to the corresponding steps in the above embodiment, and no further details will be given here.

[0133] Take the preset amplitude threshold as -40dB, the preset basic threshold as 0dB, and the preset safety threshold as 5dB as an example to adjust the target harmonic component. The relevant parameters measured or calculated in the initial state before adjustment and the relevant parameters measured or calculated after each adjustment are shown in Table 1 below:

[0134] Table 1

[0135]

[0136] It can be seen that in the initial state before adjustment, the harmonic amplitude of the target harmonic component is -20dB. When the preset amplitude threshold is -40dB, the interference amplitude is 20dB>5dB, and the adjustment strategy is determined to be the general adjustment calculation strategy. The target capacitance value and target resistance value are calculated according to calculation formulas (2) to (6).

[0137] After the first adjustment, the harmonic amplitude of the first round of target harmonic components was measured to be -30 dB, and the interference amplitude was 10 dB>5 dB, and the adjustment strategy was determined to be the general adjustment calculation strategy. The target capacitance value and target resistance value were calculated according to calculation formulas (7) to (11).

[0138] After the second adjustment, the harmonic amplitude of the second round of target harmonic components was measured to be -38 dB, and the interference amplitude was 2 dB < 5 dB, and the adjustment strategy was determined to be the fine-tuning calculation strategy. The target capacitance value and target resistance value were calculated according to calculation formulas (12) to (14).

[0139] After the third adjustment, the harmonic amplitude of the third round of target harmonic components was measured to be -41dB. Since the harmonic amplitude dropped below the preset amplitude threshold (-40dB) after the third adjustment, the adjustment was stopped.

[0140] It can be understood that when there are multiple target harmonic components that need to be suppressed, filtering can be performed by setting multiple filter circuits, that is, a target harmonic component of one frequency point corresponds to one filter circuit, and the filtering process can refer to the specific implementation method in the above embodiment.

[0141] In the common-mode voltage suppression method proposed in the embodiment of the present application, on the one hand, by acquiring the common-mode voltage signal generated by the PWM circuit in real time and performing a fast Fourier transform, the target harmonic component in the high-frequency component can be accurately identified. This allows the motor system to dynamically adjust the circuit parameters of the filter circuit during operation, thereby achieving real-time suppression of the common-mode voltage. On the second hand, since the target harmonic component is extracted by fast Fourier transform, and the filter circuit is controlled according to the harmonic characteristics actually detected, so that it produces a resonant frequency matching the target harmonic component, the present application can flexibly adapt to different operating conditions and working conditions, and has a high degree of adaptability and robustness. On the third hand, by performing frequency domain analysis on the common-mode voltage signal and suppressing the target harmonic component in a targeted manner, the generation of shaft current can be significantly reduced, thereby effectively preventing electrical corrosion on the bearing surface, extending the bearing life, and reducing maintenance costs. At the same time, the electromagnetic compatibility of the motor system can be improved, ensuring the normal operation of the motor and other peripheral electronic equipment, and avoiding system instability or failure caused by electromagnetic interference. Fourthly, compared with traditional physical isolation methods (such as using insulated bearings or shielded cables), this application does not require the addition of additional mechanical structures or special materials, which simplifies system design and reduces manufacturing and maintenance costs. Fifthly, compared with fixed filter circuits, the adaptive filtering method proposed in this application can dynamically adjust the filtering parameters according to actual operating conditions, avoiding the limitations of traditional fixed filter design and improving the overall performance and reliability of the system.

[0142] In one embodiment, a computer-readable storage medium is provided, on which executable instructions are stored. When the instructions are executed by a processor, the processor executes the steps in the above-mentioned method embodiments.

[0143] In one embodiment, an electronic device is also provided, including one or more processors; a memory, in which one or more programs are stored, wherein when the one or more programs are executed by one or more processors, the one or more processors execute the steps in the above-mentioned method embodiments.

[0144] In one embodiment, Figure 6 As shown, it shows a schematic diagram of the structure of an electronic device for implementing an embodiment of the present application. The electronic device 600 includes a central processing unit (CPU) 601, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage part 608 to a random access memory (RAM) 603. In the RAM 603, various programs and data required for the operation of the electronic device 600 are also stored. The CPU 601, the ROM 602, and the RAM 603 are connected to each other via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0145] The following components are connected to the I / O interface 605: an input section 606 including a keyboard, a mouse, etc.; an output section 607 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card such as a LAN card, a modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to the I / O interface 605 as needed. A removable medium 611, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 610 as needed, so that a computer program read therefrom is installed into the storage section 608 as needed.

[0146] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, including a computer-readable medium carrying instructions, in such an embodiment, the instructions can be downloaded and installed from a network through a communication part 609, and / or installed from a removable medium 611. When the instructions are executed by a central processing unit (CPU) 601, the various method steps described in the present application are executed.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0148] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A common mode voltage suppression method, characterized in that: The method is applied to a motor system, the motor system comprising a PWM circuit and a filter circuit, and the method comprises: Acquire a common-mode voltage signal generated by the PWM circuit, and perform a fast Fourier transform on the common-mode voltage signal to obtain a voltage spectrum; Extracting target harmonic components in the voltage spectrum that fall within a preset amplitude range; Based on the harmonic amplitude of the target harmonic component and a preset amplitude threshold, determining an adjustment strategy corresponding to the target harmonic component, wherein the adjustment strategy includes a general adjustment calculation strategy, a fine adjustment calculation strategy, and a non-adjustment strategy; Determining a correction frequency and a correction bandwidth of the filter circuit based on the harmonic frequency and the harmonic bandwidth of the target harmonic component and an adjustment strategy corresponding to the target harmonic component; Based on the correction frequency and the correction bandwidth, the filter circuit is controlled to generate a resonant frequency that matches the target harmonic component.

2. The common mode voltage suppression method according to claim 1, characterized in that: The acquiring the common mode voltage signal generated by the PWM circuit and performing a fast Fourier transform on the common mode voltage signal to obtain a voltage spectrum includes: Acquire a common-mode voltage signal generated by the PWM circuit, wherein the common-mode voltage signal is a continuous analog signal; Converting the analog signal into a discrete digital signal through an analog-to-digital converter; Performing fast Fourier transform on the digital signal to obtain a voltage spectrum.

3. The common mode voltage suppression method according to claim 2, characterized in that: The performing fast Fourier transform on the digital signal to obtain a voltage spectrum includes: Decomposing the digital signal into a plurality of sine waves with different frequencies; The amplitudes and phases of the multiple sine waves of different frequencies are calculated to obtain a voltage spectrum including the amplitudes and the phases, wherein the amplitude is used to represent the intensity of the corresponding frequency, and the phase is used to represent the offset of the corresponding frequency on the time axis.

4. The common mode voltage suppression method according to claim 1, characterized in that: The determining, based on the harmonic amplitude of the target harmonic component and a preset amplitude threshold, an adjustment strategy corresponding to the target harmonic component includes: Based on the harmonic amplitude of the target harmonic component and a preset amplitude threshold, calculating the interference amplitude of the target harmonic component; When the interference amplitude is greater than a preset safety threshold, determining that the adjustment strategy corresponding to the target harmonic component is a general adjustment calculation strategy; When the interference amplitude is greater than a preset basic threshold and less than or equal to the preset safety threshold, determining that the adjustment strategy corresponding to the target harmonic component is a fine-tuning calculation strategy; When the interference amplitude is less than or equal to the preset basic threshold, it is determined that the adjustment strategy corresponding to the target harmonic component is a non-adjustment strategy.

5. The common mode voltage suppression method according to claim 1, characterized in that: After controlling the filter circuit to generate a resonant frequency matching the target harmonic component based on the correction frequency and the correction bandwidth, the method further includes: Obtaining a filtered voltage signal of the motor system; Performing a fast Fourier transform on the filtered voltage signal to obtain a frequency spectrum of the filtered voltage signal; Extracting new target harmonic components belonging to the preset amplitude range in the spectrum graph; Determining an adjustment strategy corresponding to the new target harmonic component based on the new harmonic amplitude of the new target harmonic component and the preset amplitude threshold; When the adjustment strategy corresponding to the new target harmonic component is a non-adjustment strategy, the resonant frequency generated by the filter circuit and matching the target harmonic component is not adjusted; When the adjustment strategy corresponding to the new target harmonic component is a general adjustment strategy or a fine adjustment strategy, the filter circuit is controlled to generate a resonant frequency matching the new target harmonic component.

6. The common mode voltage suppression method according to claim 1, characterized in that: The controlling the filter circuit to generate a resonant frequency matching the target harmonic component based on the correction frequency and the correction bandwidth comprises: Calculating a target capacitance value of the filter circuit based on the correction frequency and the inductance value of the filter circuit; Based on the correction frequency and the correction bandwidth, a target Q value of the filter circuit is calculated; Based on the target capacitance value and the target Q value, a target resistance value of the filter circuit is calculated; The filter circuit is controlled to adjust to the target capacitance value and the target resistance value, so that the filter circuit generates a resonant frequency matching the target harmonic component.

7. The common mode voltage suppression method according to claim 6, characterized in that: The filter circuit includes a digital capacitor array and a digital resistor array, and the controlling the filter circuit to adjust to the target capacitance value and the target resistance value includes: Determining a capacitor combination matching the target capacitance value and a resistor combination matching the target resistance value based on the digital capacitor array and the digital resistor array; Based on the capacitor combination and the resistor combination, the filter circuit is adjusted to the target capacitance value and the target resistance value.

8. An electronic device, characterized in that: include: one or more processors; a memory 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 are enabled to perform the common mode voltage suppression method according to any one of claims 1 to 7.

9. A storage medium, characterized in that: The storage medium stores executable instructions, and when the instructions are executed by the processor, the processor executes the common mode voltage suppression method according to any one of claims 1 to 7.

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