A motor drive system wideband radiation electromagnetic interference active cancellation method and system

Abstract

The application discloses a motor driving system wideband radiation electromagnetic interference active cancellation method and system, and the method comprises the following steps: S1, perceiving the space radiation electromagnetic interference signals generated by the motor driving system; S2, generating the opposite compensation signals based on the perceived interference signals; S3, radiating the opposite compensation signals to the target cancellation area, and performing vector superposition cancellation on the space radiation electromagnetic interference; and S4, collecting the residual interference signals after the cancellation, and adjusting the parameters of the opposite compensation signals based on the residual interference signals. The application can realize the active cancellation of the motor driving system radiation EMI.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic compatibility technology for motor drive systems, and in particular, relates to a method and system for actively canceling broadband radiated electromagnetic interference in motor drive systems. Background Technology

[0002] Motor drive systems are core power units in modern industrial automation, new energy vehicles, and smart homes. With the widespread application of wide-bandgap semiconductor devices such as silicon carbide (SiC) and gallium nitride (GaN), the switching frequency of motor drive systems has increased from the traditional several kHz to tens of kHz or even MHz levels, significantly improving switching speed. However, this has also made the large-amplitude, wide-bandwidth electromagnetic interference (EMI) problems generated by power switching devices during high-speed switching increasingly prominent.

[0003] Currently, EMI suppression methods for motor drive systems are mainly divided into two categories: passive suppression and active suppression.

[0004] Passive suppression technology relies on passive components to attenuate interference, mainly including EMI filters, metal shields, and ferrite cores. However, passive suppression technology has inherent drawbacks such as large size and weight, limited high-frequency suppression effect (the insertion loss of passive filters decreases with increasing frequency, and the high-frequency loss characteristics of cores degrade sharply above 100MHz), the introduction of additional power loss, and the inability to adjust the suppression strategy in real time according to the dynamic changes of interference.

[0005] To compensate for the shortcomings of passive suppression technology, the industry has gradually developed active electromagnetic interference cancellation technology. Active cancellation technology for conducted paths targets cable conducted interference and achieves interference cancellation by actively injecting reverse noise. For example, the technical solution disclosed in patent document CN108988718A suppresses common-mode voltage from the source by optimizing the PWM modulation strategy; another example is the active common-mode EMI filter solution disclosed in patent document CN208675105U, which achieves conducted interference cancellation by collecting, inverting, and injecting compensation signals. This type of technology has the following defects: (1) It only targets the conducted path and is powerless once the interference signal is radiated through the spatial coupling path; (2) It requires changing the PWM modulation strategy or connecting to the power line / signal line, which is intrusive to the original drive system; (3) The operating frequency band is mostly 150kHz to 30MHz, which cannot cover the radiated interference frequency band above 30MHz.

[0006] Active magnetic field cancellation technology is mainly applied to low-frequency magnetic field stabilization scenarios in the field of precision instruments. It relies on fluxgate sensors to detect low-frequency magnetic fields and uses a controller to drive a compensation coil to generate a reverse magnetic field to cancel static and quasi-static environmental magnetic field interference in the DC to 1kHz frequency band. This type of technology is limited by the bandwidth of fluxgate sensors and cannot respond to high-frequency magnetic field changes above kHz, making it unsuitable for wide-bandgap motor systems with wide-radiated EMI suppression.

[0007] In summary, existing EMI suppression technologies for motor drive systems all have inherent defects and cannot meet the requirements for suppressing wide-bandgap, dynamic radiated EMI in wide-bandgap high-frequency motor drive systems. Summary of the Invention

[0008] In view of this, the purpose of this invention is to achieve active cancellation of radiated EMI in motor drive systems through the core logic of "wideband heterogeneous sensing → spatial phase reversal compensation → adaptive closed-loop control".

[0009] To achieve the above objectives, the first technical solution of the present invention is: A method for actively canceling broadband radiated electromagnetic interference in a motor drive system includes: S1. Sensing the spatial radiated electromagnetic interference signal generated by the motor drive system; S2. Generate an inverse compensation signal based on the sensed interference signal; S3. Radiation of the anti-phase compensation signal to the target cancellation region, and vector superposition and cancellation with the spatial radiated electromagnetic interference; S4. Acquire the residual interference signal after cancellation, and adjust the parameters of the inverting compensation signal based on the residual interference signal.

[0010] Preferably, in step S1, a frequency band division strategy is used to sense low-frequency interference signals and high-frequency interference signals respectively, wherein, When the low frequency band is 10kHz to 1MHz, a tunnel magnetoresistive linear magnetic field sensor array is used for sensing. When the high frequency band is 1MHz to 1GHz, an electric field probe or an electrically small antenna array is used for sensing.

[0011] Preferably, the tunnel magnetoresistive linear magnetic field sensor array has multiple sensing nodes arranged in three-dimensional orthogonal polar coordinates. Each sensing node has a built-in three-axis tunnel magnetoresistive sensitive direction, and each sensing node performs synchronous sampling with the PWM master clock of the motor drive system as the global synchronization reference.

[0012] Preferably, step S2 includes: S21. Inject test signals through the compensation transmission array and identify the transfer function of the compensation channel from the compensation signal generation end to the target cancellation region online; S22. The sensed interference signal is processed using an adaptive filtering algorithm to generate the inverse compensation signal that minimizes the residual interference in the target cancellation area.

[0013] Preferably, the adaptive filtering algorithm is the filter-x least mean square algorithm, and its weight coefficient iteration formula is: W(n+1)=W(n)+μ∙e(n)∙x'(n); where W(n) is the adaptive filter weight coefficient, μ is the step size factor, e(n) is the residual interference signal, and x'(n) is the filtered-x signal obtained after the sensed interference signal is filtered by the transfer function of the compensation channel.

[0014] Preferably, in step S3, a frequency band division strategy is used to radiate low-frequency compensation signals and high-frequency compensation signals respectively, wherein, When the low frequency band is 10kHz to 1MHz, a multi-turn coil array is used to radiate a low-frequency compensation magnetic field. When the high frequency band is 1MHz to 1GHz, a phased array antenna array is used to radiate a high-frequency compensated radiation field.

[0015] Preferably, the use of a phased array antenna array to radiate a high-frequency compensated radiation field specifically includes: By adjusting the feed phase of each element in the phased array antenna array, a spatial cancellation beam with opposite phase and matching amplitude to the high-frequency interference signal is formed in the target cancellation region.

[0016] To achieve the above objectives, the second technical solution of the present invention is: A broadband radiated electromagnetic interference active cancellation system for a motor drive system, comprising: The sensing module is used to sense spatial radiated electromagnetic interference signals generated by the motor drive system; A digital signal processing and control module is connected to the output of the sensing module and is used to generate an anti-phase compensation signal based on the interference signal sensed by the sensing module. The compensation transmission module is connected to the output of the digital signal processing and control module and is used to radiate the inverted compensation signal to the target cancellation region. A feedback module is provided, located in the target cancellation area and connected to the feedback input of the digital signal processing and control module, for collecting the residual interference signal after cancellation and feeding it back to the digital signal processing and control module.

[0017] Preferably, the digital signal processing and control module includes: The spectrum analysis unit is used to perform spectrum decomposition on the signal acquired by the sensing module to identify the main frequency components and amplitude of the interference signal. The secondary channel online identification unit is used to identify the transfer function of the compensation channel by injecting test signals; An adaptive filter unit is used to generate the inverse compensation signal using the filter-x least mean square algorithm.

[0018] Preferably, the sensing module includes a low-frequency sensing unit and a high-frequency sensing unit, and the compensation transmission module includes a low-frequency transmission unit and a high-frequency transmission unit; the low-frequency sensing unit and the low-frequency transmission unit are used for sensing and transmission in the 10kHz to 1MHz frequency band, and the high-frequency sensing unit and the high-frequency transmission unit are used for sensing and transmission in the 1MHz to 1GHz frequency band.

[0019] The main technical effects of this invention are reflected in the following aspects: (1) Realize active spatial cancellation of radiated EMI: By generating an antiphase compensation field directly in the target cancellation area through the compensation emission module, the problem that the existing conduction path cancellation scheme cannot handle EMI that has been radiated into space is fundamentally solved.

[0020] (2) Wideband coverage (10kHz~1GHz): The use of heterogeneous sensing (TMR + electric field probe) and heterogeneous transmission (coil + phased array antenna) with frequency band division solves the technical problem that a single sensor / transmitter cannot cover the ultra-wideband.

[0021] (3) Adaptive closed-loop control: Through online identification of secondary channels and FxLMS adaptive algorithm, the problem of pair disappearance caused by spatial phase delay at high frequency is solved, and dynamic adaptive control with response time ≤5ms is realized when the operating conditions change.

[0022] (4) External attachment, non-intrusive: The sensing module, compensation transmission module and feedback module are all independently arranged outside the motor drive system, without changing the PWM modulation strategy of the original drive system, and are not connected to power lines or signal lines.

[0023] (5) High versatility: The external add-on architecture is independent of the motor drive system topology and can be adapted to any motor drive topology.

[0024] (6) Small size and low efficiency loss: No need for large passive filters and shielding covers, and the power amplifier loss of the active cancellation scheme is controllable. Attached Figure Description

[0025] Figure 1-2 This is a schematic diagram of the cancellation system in the embodiment.

[0026] Reference numerals: 100, Sensing module; 110, Low-frequency sensing unit; 120, High-frequency sensing unit; 200, Digital signal processing and control module; 210, Spectrum analysis unit; 220, Phase detection unit; 230, Secondary channel online identification unit; 240, Adaptive filter unit; 250, Interference source spatial positioning unit; 300, Compensated transmission module; 310, Low-frequency transmission unit; 320, High-frequency transmission unit; 400, Feedback module. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so that the technical solution of the present invention can be more easily understood and mastered. Example 1

[0028] Reference Figure 1-2 This embodiment aims to provide a broadband radiated electromagnetic interference active cancellation system for a motor drive system. The system includes a sensing module 100, a digital signal processing and control module 200, a compensation transmission module 300, and a feedback module 400. The following is a detailed description of each module.

[0029] The sensing module 100 includes a low-frequency sensing unit 110 and a high-frequency sensing unit 120. The low-frequency sensing unit 110 consists of a tunnel magnetoresistive (TMR) linear magnetic field sensor array. Six sensing nodes are arranged in three-dimensional orthogonal polar coordinates around the main radiation sources of the motor drive system (power inverter bridge, motor stator windings). Each node has a built-in 3-axis TMR sensing direction to synchronously acquire near-field magnetic field vectors. Each sensing node uses the PWM master clock of the drive system as a global synchronization reference, with a sampling rate of no less than 100 MSps. In addition to TMR magnetoresistive sensors, fluxgate sensors (such as those used in traditional active demagnetization systems) combined with a high-frequency compensation circuit, or giant magnetoresistive (GMR) sensors, can also be used to acquire low-frequency magnetic field signals.

[0030] The high-frequency sensing unit 120 consists of distributed miniaturized broadband electric field probes or electrically small antennas (bandwidth 100kHz~3GHz). Four to six sensing nodes are arranged around the target cancellation area. The envelope amplitude and instantaneous phase of the interference signal are extracted through down-conversion mixing and high-speed ADC (sampling rate ≥2.5GSps). In addition to electric field probes / electrically small antennas, photoelectric magnetic field sensors (based on magneto-optical effect) or miniaturized search coils can also be used to realize the sensing of high-frequency radiation fields.

[0031] The output of the sensing module 100 is connected to the input of the digital signal processing and control module 200. The digital signal processing and control module 200 is implemented based on an FPGA. Internally, it includes a spectrum analysis unit 210, a phase detection unit 220, a secondary channel online identification unit 230, an adaptive filter unit 240, and an interference source spatial localization unit 250.

[0032] The spectrum analysis unit 210 is used to perform a fast Fourier transform (FFT) on the acquired signal to identify the main frequency components and amplitudes of the interference signal.

[0033] The phase detection unit 220 is used to calculate the spatial phase distribution of each frequency component by using the PWM synchronization signal as a reference and a cross-correlation algorithm.

[0034] The secondary channel online identification unit 230 is used to identify the impulse response function of the compensation channel online by injecting a white noise test signal and using the recursive least squares method. In addition to the white noise injection method, a sinusoidal frequency sweep method or a passive identification method based on operating data can also be used.

[0035] The adaptive filter unit 240 is used to execute the Filtered-x LMS adaptive algorithm to generate an inverse compensation signal. In addition to the FxLMS adaptive algorithm, the Recursive Least Squares (RLS) adaptive algorithm (which has a faster convergence speed but a larger computational load) or the Model Predictive Control (MPC) strategy can also be used to achieve closed-loop adaptive control.

[0036] The interference source spatial positioning unit 250 is used to reconstruct the spatial location and radiation pattern of the interference source based on the phase difference of multi-node acquired data and through a spatial interpolation algorithm.

[0037] The digital signal processing and control module 200 outputs two compensation signals: one is a low-frequency time-domain waveform (16-bit DAC, 50MSps sampling rate), and the other is a high-frequency modulated carrier. Both signals are output to the compensation transmission module 300.

[0038] The compensation transmission module 300 includes a low-frequency transmission unit 310 and a high-frequency transmission unit 320. The low-frequency transmission unit 310 consists of a multi-turn hollow coil array (each coil corresponds to the acquisition area of ​​a sensing node), driven by a Class-D high-current power amplifier to generate a low-frequency compensation magnetic field. In addition to multi-turn hollow coils, ferrite core coils (which can reduce size) or planar helical coils (suitable for thin-film installation scenarios) can also be used.

[0039] The high-frequency transmitting unit 320 consists of a phased array patch antenna array (4-8 elements), arranged around the target cancellation area. It is driven by a Class-A broadband linear power amplifier (bandwidth not less than 1.2 GHz), and spatial beamforming is achieved by adjusting the feed phase of each element. The low-frequency compensation signal and the high-frequency compensation signal are combined through a duplexer and then fed into the corresponding transmitting arrays. In addition to the patch antenna array, a dipole antenna array or a log-periodic antenna array can also be used, all of which can achieve spatial beamforming of the high-frequency radiation field.

[0040] The feedback module 400 consists of a reference sensor arranged in the target cancellation area, which is the same model as the sensing module 100, and collects the residual magnetic field strength after cancellation in real time. The output of the feedback module 400 is connected to the feedback input of the digital signal processing and control module 200, and transmits the residual interference signal back to the FPGA in real time, forming a complete closed-loop control loop.

[0041] The system is integrated as an independent active cancellation unit, combining the sensing array, FPGA controller, DAC, power amplifier, and transmitter array into one unit. It communicates with the motor drive system via a CAN-FD bus to acquire PWM synchronization signals and operating parameters. Before system deployment, a full-band (10kHz–1GHz) frequency sweep test was conducted on motor drive systems of different power levels and operating conditions in an anechoic chamber to establish an initial secondary channel model and filter weight coefficient library. After on-site deployment, the system automatically adapts to the actual spatial layout through online identification and adaptive algorithms, requiring no manual intervention.

[0042] During system operation, the sensing module 100 collects the original interference signal and sends it to the digital signal processing and control module 200. The FPGA extracts the interference features and generates an inverse compensation signal. The compensation transmission module 300 radiates the compensation signal to the target cancellation area and performs vector superposition and cancellation with the original interference. The feedback module 400 collects the residual signal and sends it back to the FPGA to complete the closed-loop adjustment, which is the complete closed-loop control process of "sensing → compensation → feedback → adjustment". Example 2

[0043] Based on the system of Embodiment 1, this embodiment provides a method for active cancellation of broadband radiated electromagnetic interference in a motor drive system, which specifically includes: S1, sensing the spatial radiated electromagnetic interference signal generated by the motor drive system.

[0044] In this step, a frequency band division strategy is adopted to sense low-frequency interference signals and high-frequency interference signals respectively. When the low-frequency band is 10kHz to 1MHz, a tunnel magnetoresistive linear magnetic field sensor array is used for sensing. Specifically, the tunnel magnetoresistive linear magnetic field sensor array is arranged with multiple sensing nodes in three-dimensional orthogonal polar coordinates. Each sensing node has a built-in three-axis tunnel magnetoresistive sensitive direction. Each sensing node uses the PWM master clock of the motor drive system as the global synchronization reference for synchronous sampling.

[0045] A high-frequency response tunnel magnetoresistive linear magnetic field sensor is used as the low-frequency sensing unit 110. Six sensing nodes are arranged in three-dimensional orthogonal polar coordinates around the main radiation source of the motor drive system. Each node has a built-in 3-axis TMR sensing direction to synchronously collect near-field magnetic field vectors. Each sensing node uses the PWM master clock of the motor drive system as the global synchronization reference for synchronous sampling, with a sampling rate of not less than 100MSps.

[0046] When the high frequency band is 1MHz to 1GHz, an electric field probe or an electric small antenna array is used for sensing. Specifically, by adjusting the feed phase of each element in the phased array antenna array, a spatial cancellation beam with the opposite phase and matching amplitude to the high frequency band interference signal is formed in the target cancellation area.

[0047] A distributed miniaturized broadband electric field probe is used as a high-frequency sensing unit 120, which is placed 30-50cm outside the chassis. The envelope amplitude and instantaneous phase of the interference signal are extracted by down-conversion mixing and high-speed ADC. The sampling rate of the high-speed ADC is not less than 2.5GSps.

[0048] S2. Generate an inverse compensation signal based on the sensed interference signal. Step S2 specifically includes: S21. Inject test signals through the compensation transmission array and identify the transfer function of the compensation channel from the compensation signal generation end to the target cancellation region online. In this step, the adaptive filtering algorithm is the filter-x least mean square algorithm, and its weight coefficient iteration formula is: W(n+1)=W(n)+μ∙e(n)∙x'(n); where W(n) is the adaptive filter weight coefficient, μ is the step size factor, e(n) is the residual interference signal, and x'(n) is the filtered-x signal obtained after the sensed interference signal is filtered by the transfer function of the compensation channel.

[0049] S22. Adaptive filtering algorithm is used to process the sensed interference signal and generate an inverse compensation signal that minimizes the residual interference in the target cancellation area.

[0050] The compensation signal y(n) = W(n)∙x(n) is the optimal transmission signal that minimizes the residual magnetic field in the target cancellation region.

[0051] S3. Radiation of the anti-phase compensation signal to the target cancellation area, and vector superposition and cancellation with spatial radiated electromagnetic interference.

[0052] In this step, a frequency band division strategy is adopted to radiate low-frequency compensation signals and high-frequency compensation signals respectively. Specifically, when the low-frequency band is 10kHz to 1MHz, a multi-turn coil array is used to radiate the low-frequency compensation magnetic field; when the high-frequency band is 1MHz to 1GHz, a phased array antenna array is used to radiate the high-frequency compensation radiation field.

[0053] S4. Acquire the residual interference signal after cancellation, and adjust the parameters of the inverting compensation signal based on the residual interference signal.

[0054] Specifically, the residual magnetic field signal after cancellation is collected in real time by feedback sensors arranged in the target cancellation area; the residual magnetic field signal is fed back to the FPGA digital signal processing module and compared with the preset target threshold; the amplitude, phase and frequency of the compensation signal are adjusted in real time by the filter-x least mean square adaptive algorithm to minimize the residual magnetic field strength; when the operating conditions of the motor drive system change, the system automatically senses the change in the spectrum of the feedback signal and re-converges the adaptive filter weight coefficients.

[0055] Of course, the above are just typical examples of the present invention. In addition, the present invention may have many other specific embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. A method for actively canceling broadband radiated electromagnetic interference in a motor drive system, characterized in that, include: S1. Sensing the spatial radiated electromagnetic interference signal generated by the motor drive system; S2. Generate an inverse compensation signal based on the sensed interference signal; S3. Radiation of the anti-phase compensation signal to the target cancellation region, and vector superposition and cancellation with the spatial radiated electromagnetic interference; S4. Acquire the residual interference signal after cancellation, and adjust the parameters of the inverting compensation signal based on the residual interference signal.

2. The method for active cancellation of broadband radiated electromagnetic interference in a motor drive system as described in claim 1, characterized in that the steps are as follows: In S1, a frequency band division strategy is used to sense low-frequency interference signals and high-frequency interference signals respectively. When the low frequency band is 10kHz to 1MHz, a tunnel magnetoresistive linear magnetic field sensor array is used for sensing. When the high frequency band is 1MHz to 1GHz, an electric field probe or an electrically small antenna array is used for sensing.

3. The method for active cancellation of broadband radiated electromagnetic interference in a motor drive system as described in claim 2, characterized in that, The tunnel magnetoresistive linear magnetic field sensor array has multiple sensing nodes arranged in three-dimensional orthogonal polar coordinates. Each sensing node has a built-in three-axis tunnel magnetoresistive sensitive direction. Each sensing node performs synchronous sampling with the PWM master clock of the motor drive system as the global synchronization reference.

4. The method for active cancellation of broadband radiated electromagnetic interference in a motor drive system as described in claim 1, characterized in that, Step S2 includes: S21. Inject test signals through the compensation transmission array and identify the transfer function of the compensation channel from the compensation signal generation end to the target cancellation region online; S22. The sensed interference signal is processed using an adaptive filtering algorithm to generate the inverse compensation signal that minimizes the residual interference in the target cancellation area.

5. The method for active cancellation of broadband radiated electromagnetic interference in a motor drive system as described in claim 4, characterized in that, The adaptive filtering algorithm is the filter-x least mean square algorithm, and its weight coefficient iteration formula is: W(n+1)=W(n)+μ∙e(n)∙x'(n); where W(n) is the adaptive filter weight coefficient, μ is the step size factor, e(n) is the residual interference signal, and x'(n) is the filtered-x signal obtained after the sensed interference signal is filtered by the transfer function of the compensation channel.

6. The method for active cancellation of broadband radiated electromagnetic interference in a motor drive system as described in claim 1, characterized in that, In step S3, a frequency band division strategy is used to radiate low-frequency compensation signals and high-frequency compensation signals respectively. When the low frequency band is 10kHz to 1MHz, a multi-turn coil array is used to radiate a low-frequency compensation magnetic field. When the high frequency band is 1MHz to 1GHz, a phased array antenna array is used to radiate a high-frequency compensated radiation field.

7. The method for active cancellation of broadband radiated electromagnetic interference in a motor drive system as described in claim 6, characterized in that, The use of a phased array antenna array to radiate a high-frequency compensated radiation field specifically includes: By adjusting the feed phase of each element in the phased array antenna array, a spatial cancellation beam with opposite phase and matching amplitude to the high-frequency interference signal is formed in the target cancellation region.

8. A broadband radiated electromagnetic interference active cancellation system for a motor drive system, characterized in that, include: The sensing module (100) is used to sense the spatial radiated electromagnetic interference signals generated by the motor drive system; A digital signal processing and control module (200) is connected to the output of the sensing module (100) and is used to generate an anti-phase compensation signal based on the interference signal sensed by the sensing module (100). The compensation transmission module (300) is connected to the output end of the digital signal processing and control module (200) and is used to radiate the anti-phase compensation signal to the target cancellation area; And a feedback module (400) is set in the target cancellation area and connected to the feedback input terminal of the digital signal processing and control module (200) for collecting the residual interference signal after cancellation and feeding it back to the digital signal processing and control module (200).

9. A broadband radiated electromagnetic interference active cancellation system for a motor drive system according to claim 8, characterized in that, The digital signal processing and control module (200) includes: The spectrum analysis unit (210) is used to perform spectrum decomposition on the signal collected by the sensing module (100) to identify the main frequency components and amplitude of the interference signal; Secondary channel online identification unit (230) is used to identify the transfer function of the compensation channel by injecting test signals; An adaptive filter unit (240) is used to generate the inverse compensation signal using the filter-x least mean square algorithm.

10. A broadband radiated electromagnetic interference active cancellation system for a motor drive system according to claim 8, characterized in that, The sensing module (100) includes a low-frequency sensing unit (110) and a high-frequency sensing unit (120), and the compensation transmission module (300) includes a low-frequency transmission unit (310) and a high-frequency transmission unit (320); the low-frequency sensing unit (110) and the low-frequency transmission unit (310) are used for sensing and transmission in the 10kHz to 1MHz frequency band, and the high-frequency sensing unit (120) and the high-frequency transmission unit (320) are used for sensing and transmission in the 1MHz to 1GHz frequency band.

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