Modal directional suppression method, device and equipment for high-frequency interference and medium

Abstract

The invention relates to a modal directional suppression method, device, equipment and medium for high-frequency interference, and the method comprises the steps: coupling an outer resonator designed based on a space-time symmetry theory on a high-frequency oscillation current conduction path between power electronic equipment and an AC power supply, and directionally transferring the resonance energy of a high-frequency oscillation mode to the outer resonator; effective suppression of high-frequency interference of power electronic equipment is realized. Compared with the prior art, the method has the advantages of simple design, high safety, high suppression efficiency and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic high-frequency interference suppression, and in particular to a method, device, equipment and medium for modal directional suppression of high-frequency interference of power electronic equipment. Background Art

[0002] Power electronic equipment converts electric energy through high-speed switching of power semiconductor devices. It has high energy conversion efficiency and high-precision control characteristics and is widely used in various links of power system, such as source, network, load, and storage. The new power system presents the typical characteristics of a high proportion of power electronic equipment, such as the power system source measurement is increasingly controlled by power electronic devices for new energy generation and distributed power sources, the network measurement of high-voltage direct current transmission is controlled by power electronic converters, the load side of electric vehicles, LED lights, variable frequency speed regulating motors and other new power electronic loads, and energy storage measurement is controlled by power electronic converters for energy storage charging and discharging. While power electronic equipment brings the advantage of high energy conversion efficiency, its high-speed switching action will inevitably excite the generation of high-frequency electromagnetic interference with rich modes. In order to improve the comprehensive perception capability, the new power system deploys a large number of sensors and monitoring terminals for state perception, such as temperature, magnetic field, partial discharge monitoring, etc. However, the high-frequency interference generated by the power electronic equipment itself during operation will seriously threaten the reliable operation of the power grid state perception device, and it is urgent to effectively suppress the high-frequency interference of power electronics.

[0003] Power electronic equipment generally uses PWM pulse width modulation to work, and the electromagnetic interference generated by the high-speed switching of its power devices is mainly divided into differential mode interference and common mode interference. Differential mode interference can be carried out through filters in the power circuit, while high-frequency common mode interference has a complex conduction path and a wide propagation range. It can penetrate into the grounding system through ground coupling capacitors at different locations, making it more difficult to suppress high-frequency common mode interference. At present, the suppression of common mode interference in power electronic equipment is mainly divided into two technical means: reducing the intensity of the excitation source and increasing the impedance of the conduction path.

[0004] Technical means to reduce the intensity of the excitation source include regulating the PWM switching sequence and the switching transient process. However, adjusting the PWM sequence does not perform well in suppressing high-frequency interference in the frequency band above MHz. Whether it is changing the switching frequency or offsetting the common-mode voltage, its effect is limited to the PWM time scale. Switching transient control suppresses common-mode interference by increasing the switching time of power devices, such as active gate drive technology and increasing gate resistance. However, this method will reduce the switching speed of power devices, thereby increasing switching losses.

[0005] There are generally two forms of increasing the impedance of the conduction path, passive filters and active filters. Passive filters produce sufficiently large insertion losses for wide-band conducted interference based on the principle of maximum mismatch impedance, reflecting or shunting interference currents. Active filters detect common-mode voltage or current on the conduction path, and then inject a reverse signal through the amplification circuit to offset it. However, active filters are only effective in the medium and low frequency range, have limited suppression performance in high-frequency bands above MHz, and require precise high-frequency signal measurement and operational amplifier circuits with a wide unity gain bandwidth. However, due to the presence of resonant noise caused by high-frequency common-mode interference, the attenuation performance of electromagnetic interference filters in the high-frequency band will be reduced, and the parasitic parameters that are difficult to avoid in the filter will also have a negative impact on its suppression effect in the high-frequency band, resulting in over-design of the filter and even causing new high-frequency resonant interference. Therefore, it is difficult for the existing technology to effectively and directionally suppress high-frequency common-mode interference.

[0006] Patent CN115360902A proposes a common-mode voltage suppression method for silicon carbide electric drive systems based on a multi-vector modulation model. On the basis of the traditional dual-vector model predictive control, a set of non-zero voltage vectors with a phase difference of 180° is added, the influence of the dead zone effect at the edge of the sector conversion is considered, and the dead zone compensation is performed on the action time of the multi-vector to suppress the common-mode voltage and current distortion. This method can effectively suppress the PWM common-mode voltage (kHz level), but there are problems such as complex models and limited suppression effect on high-frequency bands above MHz.

[0007] Patent CN110350776A proposes a circuit for suppressing common-mode interference between the DC and AC sides of an inverter. By connecting capacitors between the DC input terminals and adding common-mode inductors, the common-mode interference of the inverter is suppressed and electromagnetic compatibility is improved. However, the newly introduced capacitors and inductors will change the physical structure of the original system. The capacitors and inductors themselves have high-frequency parasitic parameters, which may couple to produce new high-frequency common-mode modes and resonance points, reducing the operating reliability of power electronic equipment.

[0008] In summary, the key difficulty is how to reliably and efficiently perform modal directional suppression on high-frequency differential-mode and common-mode interference caused by high-frequency resonance without changing the hardware structure and topology of power electronic equipment. Summary of the invention

[0009] The purpose of the present invention is to provide a method, device, equipment and medium for modal directional suppression of high-frequency interference of power electronic equipment in order to overcome the defects of the above-mentioned prior art. By performing equivalent resonance modeling on the high-frequency interference mode, an external resonator symmetrical with the mode is designed based on the parity-time (PT) symmetry theory, and coupled to the conduction path of the high-frequency interference current in a non-contact manner. Under the condition that the external resonator and the high-frequency interference mode resonate at the same frequency, the modal resonance energy of the high-frequency interference is efficiently transferred to the external resonator, thereby achieving effective suppression of the high-frequency modal interference of power electronic equipment and solving the problems of modal directional suppression and efficient non-contact suppression of high-frequency interference.

[0010] The purpose of the present invention can be achieved by the following technical solutions: According to a first aspect of the present invention, a method for modal directional suppression of high-frequency interference of power electronic equipment is provided. The method couples an external resonator designed based on parity-time symmetry theory to the high-frequency oscillation current conduction path between the power electronic equipment and the AC power supply, and transfers the resonant energy of the high-frequency oscillation mode to the external resonator, thereby effectively suppressing the high-frequency interference of the power electronic equipment.

[0011] As a preferred technical solution, the method comprises the following steps: Mode orientation: collect high-frequency oscillating currents of power electronic equipment and calculate equivalent resonance parameters of high-frequency oscillating current modes; Modal suppression: The circuit parameters of the external resonator are determined based on the equivalent resonance parameters of the high-frequency oscillation current mode, and the external resonator is used to directionally transfer the resonant energy of the high-frequency oscillation mode.

[0012] As a preferred technical solution, the high-frequency oscillating current is obtained by extracting a single switching oscillation current segment of the high-frequency switching transient current. The high-frequency switching transient current is collected by inserting a high-frequency current sensor probe sleeve on the high-frequency oscillating current conduction path between the AC power supply and the power electronic equipment. The high-frequency oscillating current exhibits a typical under-damped oscillation characteristic.

[0013] As a preferred technical solution, for single-phase power electronic equipment, the high-frequency current sensor probe includes the following three installation methods: using a high-frequency current sensor probe to be non-contactly inserted on the neutral wire and the live wire at the same time; using two high-frequency current sensor probes to be non-contactly inserted on the neutral wire and the live wire respectively; using a high-frequency current sensor probe to be non-contactly inserted on the ground wire of the power electronic equipment.

[0014] As a preferred technical solution, for three-phase power electronic equipment, the high-frequency current sensor probe includes the following three installation methods: using a high-frequency current sensor probe to be non-contactly inserted on the three-phase line between the AC power supply and the power electronic equipment; using three high-frequency current sensor probes to be non-contactly inserted on the a, b, and c phase lines respectively; using a high-frequency current sensor probe to be non-contactly inserted on the ground wire of the power electronic equipment.

[0015] As a preferred technical solution, the equivalent resonance parameters of the high-frequency oscillating current mode include equivalent inductance, equivalent capacitance and equivalent resistance of the high-frequency oscillating current mode.

[0016] As a preferred technical solution, the equivalent inductance of the high-frequency oscillating current mode is obtained by fitting the high-frequency oscillating current using an iterative local search algorithm as follows: , Among them, U is voltage, L CM is the equivalent inductance of the high-frequency oscillating current mode, ω CM is the resonant angular frequency of the high-frequency oscillating current mode, ζ CM is the damping ratio of the high-frequency oscillating current mode, t is the time, i CM It is a high frequency oscillating current.

[0017] As a preferred technical solution, the equivalent capacitance of the high-frequency oscillating current mode is calculated according to the following resonant frequency formula: , Among them, f CM is the resonant frequency of the high-frequency oscillating current mode, ω CM is the resonant angular frequency of the high-frequency oscillating current mode, C CM is the equivalent capacitance of the high frequency oscillating current mode, L CM is the equivalent inductance of the high frequency oscillating current mode.

[0018] As a preferred technical solution, the equivalent resistance of the high-frequency oscillating current mode is calculated according to the following damping ratio formula: , Among them, R CM is the equivalent resistance of the high-frequency oscillating current mode, ζ CM is the damping ratio of the high frequency oscillating current mode, C CM is the equivalent capacitance of the high frequency oscillating current mode, L CM is the equivalent inductance of the high frequency oscillating current mode.

[0019] As a preferred technical solution, the external resonator is an RLC series resonator, and its circuit parameters include inductance, capacitance and resistance.

[0020] As a preferred technical solution, the inductance of the external resonator is determined according to the coil size.

[0021] As a preferred technical solution, the high-frequency interference includes high-frequency common-mode interference and high-frequency differential-mode interference; when used to suppress high-frequency differential-mode interference, the coil size of the external resonator is determined according to the wire diameter of the phase line; when used to suppress high-frequency common-mode interference, the coil size of the external resonator is determined according to the position of the external resonator coupled on the current conduction path.

[0022] As a preferred technical solution, when the external resonator is coupled to the live wire and the neutral wire in the current conduction path of the single-phase power electronic equipment, the coil size of the external resonator is determined according to the wire diameters of the live wire and the neutral wire and the distance between the live wire and the neutral wire; when the external resonator is coupled to the three-phase wire in the current conduction path of the three-phase power electronic equipment, the coil size of the external resonator is determined according to the wire diameters of the three-phase wire and the distance between the three-phase wires; when the external resonator is coupled to the ground wire of the power electronic equipment, the coil size of the external resonator is determined according to the wire diameter of the ground wire.

[0023] As a preferred technical solution, when the external resonator adopts a toroidal coil, its inductance L reg It is calculated by: , Where a is the inner diameter of the toroidal coil, b is the outer diameter of the toroidal coil, μ 0 is the relative magnetic permeability of the coil frame, N is the number of coil turns, and h is the coil height.

[0024] As a preferred technical solution, the capacitance of the external resonator is designed so that the frequency f reg The resonant frequency f of the high frequency oscillating current mode CM same: , Among them, C reg is the capacitance of the external resonator, L reg is the inductance of the external resonator, C CM is the equivalent capacitance of the high frequency oscillating current mode, L CM is the equivalent inductance of the high frequency oscillating current mode.

[0025] As a preferred technical solution, the external resonator operates under the condition of maximum loss rate.

[0026] As a preferred technical solution, the resistance of the external resonator is determined based on the parity-time symmetry theory, and the determination process includes the following steps: The Hamiltonian matrix H is constructed according to the coupled mode theory, and its eigenvalue λ is calculated: , , Among them, f CM is the resonant frequency of the high-frequency oscillating current mode, ω CM is the resonant angular frequency of the high-frequency oscillating current mode, i is the high-frequency oscillating current, κ is the coupling rate between the external resonator and the conductor, γ 1 is the loss rate of the high-frequency oscillating current mode, γ 2 is the loss rate of the external resonator, λ 1,2 is the eigenvalue λ The two solutions of a 1 , a 2 are the amplitudes of the high-frequency oscillation mode inside the power electronic equipment and the oscillation mode of the external resonator, respectively; According to the parity-time symmetry theory, when the eigenvalue λ is a single real number solution, that is, When the external resonator operates at the phase transition point, the loss rate γ 2 Maximum, the external resonator resistance is obtained by solving the following loss rate: , Among them, R reg is the resistance of the external resonator, C reg is the capacitance of the external resonator, L reg is the inductance of the external resonator.

[0027] As a preferred technical solution, the coupling rate κ and the high-frequency oscillation current modal loss rate γ 1 They are: , , Among them, M reg For mutual induction.

[0028] As a preferred technical solution, when the external resonator adopts a ring coil, the calculation method of the mutual inductance is:

[0029] Where a is the inner diameter of the toroidal coil, b is the outer diameter of the toroidal coil, μ 0 is the relative magnetic permeability of the coil frame, N is the number of coil turns, and h is the coil height.

[0030] According to a second aspect of the present invention, there is provided a modal directional suppression device for high-frequency interference of power electronic equipment, comprising power electronic equipment and an AC power supply. The device further comprises: an external resonator designed based on the parity-time symmetry theory and coupled to a high-frequency oscillation current conduction path between the power electronic equipment and the AC power supply, wherein the external resonator transfers the resonant energy of the high-frequency oscillation mode to the external resonator in a directionally manner, thereby achieving effective suppression of the high-frequency interference of the power electronic equipment.

[0031] According to a third aspect of the present invention, there is provided an electronic device, comprising a memory and a processor, wherein a computer program is stored in the memory, and the method described above is implemented when the processor executes the program.

[0032] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, wherein the program implements the method described when executed by a processor.

[0033] Compared with the prior art, the present invention has the following beneficial effects: (1) Simple design: The process of designing the parameters of the external resonator in the present invention is simple and does not require complex high-frequency modeling and parasitic parameter extraction of the power electronic equipment and its grounding loop.

[0034] (2) High safety: The present invention does not require changing the original hardware structure of the power electronic equipment and its grounding circuit. Instead, the external resonator is coupled to the high-frequency current conduction path in a non-contact manner, which will not interfere with the normal operation of the system and ensure reliability.

[0035] (3) High suppression efficiency: The present invention can accurately calculate the optimal external resonator parameters, achieve efficient directional suppression of the target mode under the condition of maximum loss rate, and improve the suppression efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a flow chart of the method of the present invention; Figure 2 Schematic diagrams of the installation position of the high-frequency current sensor of the present invention, wherein (a) is a schematic diagram of the installation position of the high-frequency current sensor of single-phase power electronic equipment, and (b) is a schematic diagram of the installation position of the high-frequency current sensor of three-phase power electronic equipment; Figure 3Schematic diagrams of coil size design for an external resonator of the present invention, wherein (a) is a schematic diagram of coil size design when a toroidal coil is used to suppress high-frequency differential mode interference, (b) is a schematic diagram of coil size design when a toroidal coil is used to suppress high-frequency common mode interference and the coil is coupled to the live wire and the neutral wire in the current conduction path of a single-phase power electronic equipment, (c) is a schematic diagram of coil size design when a toroidal coil is used to suppress high-frequency common mode interference and the coil is coupled to the three-phase wire in the current conduction path of a three-phase power electronic equipment, and (d) is a schematic diagram of coil size design when a toroidal coil is used to suppress high-frequency common mode interference and the coil is coupled to the ground wire of the power electronic equipment; Figure 4 is a schematic diagram of an experimental system in an embodiment; Figure 5 is a FFT spectrum diagram of a high-frequency common-mode switch transient current in an embodiment; Figure 6 is a comparison diagram of the measurement result and the fitting result of the high-frequency common-mode switch transient current in an embodiment; Figure 7 is the loss rate corresponding to different values ​​of the resistance of the internal and external resonators in an embodiment; Figure 8 In one embodiment, high frequency common mode modal currents before and after suppression are suppressed; Fig. 9 FIG. 4 is an EMI spectrum of high frequency common mode current in one embodiment. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0038] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0039] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation, and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships, for example, "A and / or B" can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0040] High-frequency interference of power electronic equipment refers to the electromagnetic interference generated by the nonlinear high-frequency switching behavior of semiconductor switching devices in power electronic systems. The frequency of this interference is usually high, which may pose a threat to the normal operation of power electronic equipment and its surrounding electronic equipment. Power electronic high-frequency interference has the problems of high dominant frequency, multiple modal couplings, and difficult resonance suppression. Therefore, how to accurately and efficiently suppress high-frequency resonance points is the main difficulty at present. From the perspective of solving this problem, in order to suppress the high-frequency interference of power electronic equipment, this application provides the following solution: through a non-contact magnetically coupled external device, and designing the parameters of the external device so that the modes match, thereby transferring the resonant energy from the original circuit to the external device. Based on this idea, its implementation technical path includes:

[0041] 1. Modal orientation: how to identify high-frequency interference modes; 2. Modal matching: how to match the modal characteristics of high-frequency interference; 3. Modal suppression: How to efficiently transfer high-frequency interference modal energy.

[0042] In order to effectively suppress these high-frequency interferences, it is first necessary to identify their modes, that is, to understand the source, characteristics and propagation mode of the interference. For modal orientation, the problem to be solved is to accurately identify the modal of high-frequency interference in view of modal aliasing and external interference. The existing methods mainly use:

[0043] 1. Spectrum analysis: Use a spectrum analyzer or related software to perform spectrum analysis on the output signal of the power electronic system to determine the frequency range and intensity of high-frequency interference.

[0044] The spectrum diagram can intuitively show which frequency bands have obvious interference signals, thereby determining the main mode of high-frequency interference.

[0045] 2. Waveform analysis: Monitor and analyze the voltage and current waveforms of the power electronic system to observe whether there are abnormal fluctuations or spikes.

[0046] Waveform analysis can be used to determine whether high-frequency interference is caused by factors such as the switching process of the switching device, current and voltage mutations, etc.

[0047] 3. Electromagnetic field measurement: Use electromagnetic field measuring instruments to measure the electromagnetic field around the power electronic system to determine the intensity and distribution of electromagnetic interference.

[0048] Electromagnetic field measurements can be used to understand the propagation path and range of high-frequency interference and thus determine its mode.

[0049] 4. Circuit simulation: Use circuit simulation software to model and simulate power electronic systems and simulate the generation and propagation of high-frequency interference.

[0050] Circuit simulation can be used to predict the modes and characteristics of high-frequency interference, providing a basis for the design of suppression measures.

[0051] However, the above methods have more or less problems in solving the problem of how to accurately identify modes from complex mode aliasing. From different perspectives of technical implementation ideas, the improved methods that can be used include but are not limited to endpoint detection method, multi-modal decomposition method, transient energy screening, etc.

[0052] For modal matching, the problem to be solved is to realize the dominant mode identification and resonant parameter identification of the high-frequency dominant mode. Modal identification in power electronic systems mainly refers to the identification of the characteristics and propagation mode of high-frequency interference sources. This usually involves analyzing the electromagnetic interference generated by different components in the system (such as switching devices, filters, transformers, etc.). Resonant parameter identification mainly focuses on the frequency points and related parameters that may produce resonance in the system. In power electronic high-frequency interference suppression, modal identification and resonant parameter identification are interrelated. Through modal identification, the source and propagation mode of high-frequency interference in the system can be understood; and through resonant parameter identification, the frequency points and related parameters that may produce resonance in the system can be determined. This information together provides a basis for formulating effective suppression measures. In practical applications, it is usually necessary to combine these two methods to comprehensively analyze and solve the high-frequency interference problem in power electronic systems. From different perspectives of technical implementation ideas, the methods that can be used include but are not limited to dominant mode identification, nonlinear parameter fitting, modal feature extraction, etc.

[0053] For modal suppression, the problem to be solved is to achieve efficient transfer of resonant energy. Modal suppression refers to identifying high-frequency interference modes in power electronic systems and taking corresponding suppression measures to reduce or eliminate these interferences. The main methods of modal suppression include:

[0054] 1. Filter design: Type selection: Select the appropriate filter type, such as low-pass filter, band-stop filter, etc., according to the frequency range and characteristics of high-frequency interference.

[0055] Parameter design: According to system requirements, design the filter's cutoff frequency, bandwidth, attenuation characteristics and other parameters to ensure that it can effectively filter out high-frequency interference.

[0056] Layout and installation: The layout and installation position of the filter have a great influence on the suppression effect and need to be carefully considered and optimized.

[0057] 2. Switching device optimization: Soft switching technology: By introducing auxiliary circuits or changing the driving mode of switching devices, the switching devices can be turned on and off under zero voltage or zero current conditions, thereby reducing the generation of high-frequency interference.

[0058] Switching frequency selection: Under the premise of meeting the system performance requirements, selecting a lower switching frequency can reduce the intensity and frequency range of high-frequency interference.

[0059] 3. Grounding and shielding: Reasonable grounding: Ensure that the ground connection of the power electronic system is good to avoid common-mode interference and differential-mode interference caused by poor grounding.

[0060] Shielding measures: Use metal shielding materials to shield sensitive components and circuits in the system to reduce the spread of radiated interference.

[0061] 4. Power converter design: Harmonic suppression: Reduce the generation and propagation of harmonic interference by reasonably designing the parameters and circuit structure of the power converter.

[0062] Multi-stage conversion structure: A multi-stage conversion structure is used to reduce the amplitude and frequency range of harmonic interference.

[0063] 5. Circuit layout and wiring: Optimize layout: Arrange the layout of components in the circuit reasonably to avoid electromagnetic interference and coupling between components.

[0064] Wiring specifications: Use twisted pair cables, shielded cables and other cables with good anti-interference performance for wiring to reduce the spread of high-frequency interference.

[0065] However, the above methods either require structural adjustments to the original circuit or the introduction of auxiliary circuits associated with the original circuit, which will change the original hardware structure and are not convenient in practical applications. Therefore, an innovative non-contact device for high-frequency interference suppression can be proposed. Under this idea, an online warning device for high-frequency interference, a high-frequency interference non-contact suppression device, and a high-frequency interference energy capture device can be provided.

[0066] Accordingly, from the perspective of not changing the original circuit structure, based on the above-mentioned device, according to different technical implementation ideas, the resonance suppression methods that can be used include but are not limited to anti-resonance matching method, parity-time symmetry method (the method adopted by the present invention), frequency dynamic tracking method and multi-mode suppression method, etc.

[0067] Example 1 This embodiment provides a method for modal directional suppression of high-frequency interference of power electronic equipment. The method couples an external resonator designed based on parity-time symmetry theory to the high-frequency oscillation current conduction path between the power electronic equipment and the AC power supply, and transfers the resonant energy of the high-frequency oscillation mode to the external resonator, thereby effectively suppressing the high-frequency interference of the power electronic equipment.

[0068] like Figure 1 As shown, the technical steps of this method mainly consist of two parts: internal resonator parameter calculation (modal orientation) and external resonator parameter design (modal suppression).

[0069] S1, modal orientation: Install a high-frequency current sensor on the high-frequency oscillating current conduction path between the power electronic equipment and the AC power supply to collect the high-frequency switching transient current i CM , and extract the single switching oscillation current fragment; S2, modal suppression: Use the oscillation model to fit the oscillating current segment to obtain the equivalent RLC resonance parameters of the high-frequency oscillating current mode, and use the high-frequency oscillating current mode as an internal resonator; next, use the external resonator frequency f reg and the high frequency oscillating current modal frequency f CM The same constraint condition is used to design the coil self-inductance L of the external resonator. reg and resonant capacitor C reg ; Finally, the resistance R of the external resonator when it is running at the phase change point is calculated according to the loss rate formula reg , complete the circuit parameter design of the external resonator, so as to use the external resonator to directionally transfer the resonant energy of the high-frequency oscillation mode.

[0070] In this embodiment, the high-frequency interference targeted includes high-frequency common-mode interference and high-frequency differential-mode interference. High-frequency common-mode interference refers to interference voltages with the same amplitude and polarity on the signal line and its return line (usually referred to as the signal ground line). This interference voltage is based on any nearby object (such as the earth, metal chassis, reference ground plate, etc.) as the reference potential. The interference current loop flows in the loop formed by the wire and the reference object. High-frequency common-mode interference may cause the signal quality to degrade, or even make the signal unable to be used normally, and it may also cause greater interference to the surrounding environment and other electronic equipment. High-frequency differential-mode interference refers to symmetrical interference transmitted between two wires. This interference voltage exists between the power phase line and the neutral line, or on the differential signal path. High-frequency differential-mode interference may cause the transmission quality of the differential signal to degrade, thereby affecting the accuracy and stability of the system. In some cases, differential-mode interference may also cause system misoperation or failure.

[0071] 1) High frequency oscillating current i CM collection The high-frequency current sensor probe is inserted into the common-mode current conduction path between the AC power supply and the power electronic equipment to collect the high-frequency switching transient current.

[0072] For single-phase power electronic equipment, such as Figure 2 As shown in (a), L and N represent the live wire and the neutral wire respectively. i L , i N Represents the current of the live wire and the neutral wire respectively. i G Indicates the ground current of power electronic equipment. The high-frequency current sensor probe includes the following three installation methods: ①Use a high-frequency current sensor probe to be non-contact and put on the neutral wire and the live wire at the same time; ② Use two high-frequency current sensor probes to be non-contactly pierced on the neutral line and the live line respectively; ③ Use a high-frequency current sensor probe to non-contactly wear it on the ground wire of the power electronic equipment.

[0073] For three-phase power electronic equipment, such as Figure 2 As shown in (b), a, b, and c represent the three phases of the AC power supply. i a , i b , i c Represent the current of phase a, phase b, and phase c respectively. i G Indicates the ground current of power electronic equipment. The high-frequency current sensor probe includes the following three installation methods: ①Use a high-frequency current sensor probe to non-contactly and simultaneously put it on the three-phase line between the AC power supply and the power electronic equipment; ② Use three high-frequency current sensor probes to be non-contactly inserted on the a, b, and c phase lines respectively; ③ Use a high-frequency current sensor probe to non-contactly wear it on the ground wire of the power electronic equipment.

[0074] After collecting the high-frequency switching transient current, a single switching oscillation current fragment with a period of 4μs and a resonant frequency above MHz is extracted. The oscillation current shows a typical underdamped oscillation characteristic. CM .

[0075] 2) Extraction of equivalent parameters of high-frequency oscillating current modal In this embodiment, the equivalent resonance parameters of the high-frequency oscillating current mode include an equivalent inductance, an equivalent capacitance, and an equivalent resistance of the high-frequency oscillating current mode.

[0076] 21) Equivalent inductance The equivalent inductance of the high-frequency oscillating current mode is based on the following model (1), and the high-frequency oscillating current is fitted using an iterative local search algorithm: (1) Where, U is voltage (when it is for common mode, U is common mode voltage; when it is for differential mode, U is differential mode voltage), L CM is the equivalent inductance of the high-frequency oscillating current mode, ω CM is the resonant angular frequency of the high-frequency oscillating current mode, ζ CM is the damping ratio of the high-frequency oscillating current mode, t is the time, i CM It is a high frequency oscillating current.

[0077] 22) Equivalent capacitance The equivalent capacitance of the high-frequency oscillating current mode is calculated according to the following resonant frequency formula (2): (2) Among them, f CM is the resonant frequency of the high frequency oscillating current mode.

[0078] 23) Equivalent resistance The equivalent resistance of the high-frequency oscillating current mode is calculated according to the damping ratio formula (3): (3) Among them, R CM is the equivalent resistance of the high frequency oscillating current mode.

[0079] 3) External resonator design In this embodiment, the external resonator used is an RLC series resonator, and its circuit parameters include inductance, capacitance and resistance. In other embodiments, an RLC parallel resonator may also be used, and the design of its parameters may refer to the design process of the RLC series resonator in this embodiment, and the constraints satisfied are the same, which can be obtained by reasonable deduction by those skilled in the art, and will not be described in detail in this embodiment.

[0080] 31) Inductance of external resonator The inductance of the external resonator is determined according to the coil size. High-frequency interference includes high-frequency common-mode interference and high-frequency differential-mode interference. When designing the size of the external resonator coil, it is necessary to consider which type of interference is being targeted.

[0081] When used to suppress high-frequency differential mode interference, the coil size of the external resonator is determined according to the wire diameter of the phase line, and the external resonator should at least be able to be non-contactly sleeved on the outside of the phase line.

[0082] In one embodiment, if a toroidal coil is used, the inner diameter of the coil should be at least larger than the outer diameter of the phase line, and a certain margin should be left so that the phase line can be non-contactly sheathed inside the outer resonator coil, that is, r≥r'+m, r is the radius of the toroidal coil, r' is the radius of the phase line, and m is the preset margin, such as Figure 3 (a) shown.

[0083] When used to suppress high frequency common mode interference, the coil size of the external resonator is determined according to the location of the external resonator coupling on the current conduction path: 1. One-way power electronic equipment When the external resonator is coupled to the live wire and the neutral wire in the current conduction path of the single-phase power electronic equipment, the coil size of the external resonator is determined according to the wire diameters of the live wire and the neutral wire and the distance between the live wire and the neutral wire. The external resonator should at least be able to be put on the outside of the live wire and the neutral wire without contact.

[0084] In one embodiment, when a toroidal coil is used, the inner diameter of the outer resonator should be at least larger than the sum of the distance between the centers of the cross sections of the live wire and the neutral wire and the radius of the live wire and the neutral wire, and a certain margin should be left, that is, r ≥ r 1 +r 2 +d+m, r is the radius of the toroidal coil, r 1 is the radius of the firing line, r 2 is the radius of the zero line, d is the distance between the centers of the live and zero line cross sections, and m is the preset margin, such as Figure 3 (b) shown.

[0085] 2. Three-phase power electronic equipment When the external resonator is coupled to the three-phase line in the current conduction path of the three-phase power electronic equipment, the coil size of the external resonator is determined according to the wire diameter of the three-phase line and the distance between the three-phase lines. The external resonator should at least be able to be inserted outside the three-phase line without contact.

[0086] In one embodiment, the three phase lines are placed symmetrically, and the distances between phases a, b, and c are equal, that is, the three form an equilateral triangle. When a toroidal coil is used, the inner diameter of the outer resonator should be at least greater than the sum of the distance between the center of the equilateral triangle and the center of any phase line cross section and the radius of the phase line, and a certain margin should be left, that is, r ≥ r a,b,c +dis+m, r is the radius of the annular coil, r a,b,c is the radius of the a-phase, b-phase or c-phase line, dis is the distance between the center of the equilateral triangle and the a-phase, b-phase or c-phase line, and m is the preset margin, such as Figure 3 (c) shown.

[0087] When the external resonator is coupled to the ground wire of the power electronic equipment, the coil size of the external resonator is determined according to the wire diameter of the ground wire, and the external resonator should at least be able to be inserted outside the ground wire without contact.

[0088] In one embodiment, if a toroidal coil is used, the inner diameter of the coil should be at least larger than the outer diameter of the ground wire, and a certain margin should be left, that is, r ≥ r g +m, r is the radius of the toroidal coil, r g is the radius of the ground wire, and m is the preset margin, such as Figure 3 (d) shown.

[0089] In this embodiment, there is no limitation on the shape of the external resonator, and it may be in the shape of a ring, rectangle, square, ellipse, etc., as long as it is hollow.

[0090] In a preferred embodiment, when the external resonator adopts a toroidal coil, its inductance L reg It is calculated by: (4) Where a is the inner diameter of the toroidal coil, b is the outer diameter of the toroidal coil, μ 0 is the relative magnetic permeability of the coil frame, N is the number of coil turns, and h is the coil height.

[0091] When coils of other shapes are used, the equivalent inductance can be calculated after being equivalent. The specific calculation method is well known to those skilled in the art and will not be described in detail in this embodiment to avoid ambiguity in the application purpose.

[0092] 32) Capacitance of external resonator According to formula (5), the capacitance of the external resonator is designed so that the frequency of the external resonator f reg The resonant frequency f of the high frequency oscillating current mode CM same: (5) Among them, C reg is the capacitance of the external resonator, L reg is the inductance of the external resonator, C CM is the equivalent capacitance of the high frequency oscillating current mode, L CM is the equivalent inductance of the high frequency oscillating current mode.

[0093] 33) Resistance of the external resonator The resistance of the external resonator is determined based on the parity-time symmetry theory, and the determination process includes the following steps: The Hamiltonian matrix H is constructed according to the coupled mode theory, and its eigenvalue λ is calculated: (6) (7) Among them, f CM is the resonant frequency of the high-frequency oscillating current mode, ω CM is the resonant angular frequency of the high-frequency oscillating current mode, i is the high-frequency oscillating current, κ is the coupling rate between the external resonator and the conductor, γ 1 is the loss rate of the high-frequency oscillating current mode, γ 2 is the loss rate of the external resonator, λ 1,2 is the eigenvalue λ The two solutions of a 1 , a 2 The coupling rate κ and the high-frequency oscillation current modal loss rate γ are respectively the amplitudes of the high-frequency oscillation mode inside the power electronic equipment and the oscillation mode of the external resonator. 1 They are:

[0094] (8) (9) Among them, M reg For mutual inductance, when the external resonator adopts a ring coil, the calculation method of mutual inductance is: (10) Where a is the inner diameter of the toroidal coil, b is the outer diameter of the toroidal coil, μ 0 is the relative magnetic permeability of the coil frame, N is the number of coil turns, and h is the coil height.

[0095] According to the parity-time symmetry theory, when the eigenvalue λ is a single real number solution, that is, When the external resonator operates at the phase transition point, the loss rate γ 2 The maximum value is obtained by solving the loss rate formula (11) to obtain the external resonator resistance: (11) Among them, R reg is the resistance of the external resonator, C reg is the capacitance of the external resonator, L reg is the inductance of the external resonator.

[0096] The present invention proposes a modal directional suppression method for high-frequency interference of power electronic equipment, which is applicable to differential mode and common mode interference, and solves the problem of reliable operation of power grid partial discharge monitoring system caused by high-frequency common mode interference of power electronic equipment. The proposed method equates the high-frequency oscillating current mode to an internal resonator, and designs an external resonator that meets the PT symmetry theory according to the parameters of the internal resonator. By transferring the modal energy to the external resonator, high-frequency modal directional suppression is achieved. The external resonator designed by the inventive method works under the condition of maximum loss rate, and can achieve efficient suppression of high-frequency common mode.

[0097] Example 2 The above is an introduction to a method embodiment. The following is a further explanation of the solution of the present invention through an apparatus embodiment.

[0098] The device includes power electronic equipment and an AC power supply, and also includes: an external resonator designed based on parity-time symmetry theory and coupled to a high-frequency oscillation current conduction path between the power electronic equipment and the AC power supply, wherein the external resonator transfers the resonant energy of the high-frequency oscillation mode to the external resonator in a directionally manner, thereby effectively suppressing the high-frequency interference of the power electronic equipment.

[0099] The parameter design of the external resonator and its working process can refer to the description of the method part in Example 1. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific implementation process of the device can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0100] Example 3 Since it is more difficult to suppress high-frequency common-mode interference, this embodiment only conducts experiments on high-frequency common-mode interference to verify the feasibility and effectiveness of the present invention. Figure 4 As shown in the figure, it consists of an AC power supply, an external resonator, an LED driver and an LED lamp. In order to collect the high-frequency common-mode modal current of the LED lamp online, a high-frequency current sensor (CYBERTEK CP9030S) is installed between the LED driver and the AC power supply and the experimental data is recorded by a digital oscilloscope (Pico 5444D). The sampling rate of the oscilloscope is 250MHz. The high-frequency current sensor can effectively extract the 3.15MHz high-frequency common-mode switching transient current signal, as shown in Figure 1. Figure 5 shown.

[0101] The collected time domain waveform of the high-frequency common-mode switching transient current is fitted and equivalent to an internal resonator. The fitting results are shown in Figure 6 The equivalent RLC resonance parameters obtained by fitting are shown in Table 1.

[0102] Table 1 Basic parameters of internal resonator <![CDATA[R CM ]]> 7.4 Ω <![CDATA[L CM ]]> 3.6 μH <![CDATA[C CM ]]> 730 pF Based on the basic parameters of the inner resonator, an outer resonator that satisfies PT symmetry is designed. The outer resonator is non-contact mounted on the neutral and live wires between the LED driver and the AC power supply. Considering that the diameter of the neutral and live wires is 16 mm, the dimensions of the magnetic ring are determined as follows: inner diameter a=18 mm, outer diameter b=31 mm, and height h=7 mm. A circular nickel-zinc ferrite (relative magnetic permeability μ 0 =200 H / m) is the iron core, and the winding is 9 turns in total. The parameters of the external resonator are shown in Table 2.

[0103] Table 2 Basic parameters of external resonator <![CDATA[Relative magnetic permeability μ 0 > 200 Number of turns N 9 <![CDATA[Resistor R reg > 87Ω <![CDATA[Inductor L reg > 12.33 μH <![CDATA[Capacitor C reg > 221 pF <![CDATA[Mutual inductance M reg > 1.37 μH Figure 7 shows different external resonator resistance R reg The loss rate when R reg = 87, the loss rate is the maximum. Therefore, the external resonator designed by the method of the present invention can achieve high efficiency suppression of high-frequency common-mode dominant mode interference under the condition of maximum loss rate.

[0104] Figure 8 , Fig. 9 The suppressive effect of the method of the present invention on the high-frequency common-mode dominant modal interference of the LED driver is demonstrated from the perspectives of time domain and frequency domain respectively.

[0105] Figure 8The time domain waveforms of the high-frequency common-mode current before and after the external resonator is installed are compared. The current amplitude is significantly attenuated after suppression, with the first peak decreasing by 30%. The oscillation period of the current is also reduced from 5μs to 1.5μs, a decrease of 70%.

[0106] Fig. 9 The high-frequency common-mode current EMI spectrum before and after the external resonator is installed is compared. In the spectrum, a clear peak can be observed at 3.15MHz. The external resonator effectively suppresses the spectrum amplitude at the peak, achieving a 13dB attenuation, while having no effect on other frequency bands.

[0107] Example 4 The electronic device of the present invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in a read-only memory (ROM) or loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for device operation can also be stored. The CPU, ROM and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0108] Multiple components in the device are connected to the I / O interface, including: input units, such as keyboards, mice, etc.; output units, such as various types of displays, speakers, etc.; storage units, such as disks, optical disks, etc.; and communication units, such as network cards, modems, wireless communication transceivers, etc. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunication networks.

[0109] The processing unit performs the various methods and processes described above, such as methods S1 to S2. For example, in some embodiments, methods S1 to S2 may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via a ROM and / or a communication unit. When the computer program is loaded into the RAM and executed by the CPU, one or more steps of methods S1 to S2 described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute methods S1 to S2 in any other appropriate manner (e.g., by means of firmware).

[0110] For the improvement of a technology, it can be clearly distinguished whether it is a hardware improvement (for example, improvement of the circuit structure of diodes, transistors, switches, etc.) or a software improvement (improvement of the method flow). However, with the development of technology, many improvements of the method flow today can be regarded as direct improvements of the hardware circuit structure. Designers almost always obtain the corresponding hardware circuit structure by programming the improved method flow into the hardware circuit. Therefore, it cannot be said that the improvement of a method flow cannot be implemented with a hardware entity module. For example, a programmable logic device (PLD) (such as a field programmable gate array (FPGA)) is such an integrated circuit whose logical function is determined by the user's programming of the device. Designers can "integrate" a digital system on a PLD by programming themselves, without having to ask chip manufacturers to design and make dedicated integrated circuit chips. Moreover, nowadays, instead of manually making integrated circuit chips, this kind of programming is mostly implemented by "logic compiler" software, which is similar to the software compiler used when developing and writing programs, and the original code before compilation must also be written in a specific programming language, which is called hardware description language (HDL). There is not only one kind of HDL, but many kinds, such as ABEL (Advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Cornell University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, PALASM, RHDL (Ruby Hardware Description Language), etc. The most commonly used ones are VHDL (Very-High-Speed ​​Integrated Circuit Hardware Description Language) and Verilog. Those skilled in the art should also know that it is only necessary to program the method flow slightly in the above-mentioned hardware description languages ​​and program it into the integrated circuit, and then it is easy to obtain the hardware circuit that implements the logic method flow.

[0111] The program code for implementing the method of the present invention can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0112] The controller may be implemented in any suitable manner, for example, the controller may take the form of a microprocessor or processor and a computer-readable medium storing a computer-readable program code (such as software or firmware) executable by the (micro)processor, a logic gate, a switch, an application-specific integrated circuit (ASIC), a programmable logic controller, and an embedded microcontroller. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicone Labs C8051F320. The memory controller may also be implemented as part of the control logic of the memory. It is also known to those skilled in the art that, in addition to implementing the controller in a purely computer-readable program code manner, the controller may be implemented in the form of a logic gate, a switch, an application-specific integrated circuit, a programmable logic controller, and an embedded microcontroller by logically programming the method steps. Therefore, such a controller may be considered as a hardware component, and the devices for implementing various functions included therein may also be considered as structures within the hardware component. Or even, the devices for implementing various functions may be considered as both software modules for implementing the method and structures within the hardware component.

[0113] In the context of the present invention, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0114] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0115] It should be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0116] The present invention may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0117] Each embodiment of the present invention is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0118] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for modal directional suppression of high-frequency interference of power electronic equipment, characterized in that: This method couples an external resonator designed based on parity-time symmetry theory to the high-frequency oscillation current conduction path between the power electronic equipment and the AC power supply, and transfers the resonant energy of the high-frequency oscillation mode to the external resonator in a directionally manner, thereby effectively suppressing the high-frequency interference of the power electronic equipment.

2. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 1, characterized in that: The method comprises the following steps: Mode orientation: collect high-frequency oscillating currents of power electronic equipment and calculate equivalent resonance parameters of high-frequency oscillating current modes; Modal suppression: The circuit parameters of the external resonator are determined based on the equivalent resonance parameters of the high-frequency oscillation current mode, and the external resonator is used to directionally transfer the resonant energy of the high-frequency oscillation mode.

3. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 2, characterized in that: The high-frequency oscillating current is obtained by extracting a single switching oscillation current segment of the high-frequency switching transient current. The high-frequency switching transient current is collected by inserting a high-frequency current sensor probe sleeve on the high-frequency oscillating current conduction path between the AC power supply and the power electronic equipment. The high-frequency oscillating current exhibits a typical under-damped oscillation characteristic.

4. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 3, characterized in that: For single-phase power electronic equipment, the high-frequency current sensor probe includes the following three installation methods: using a high-frequency current sensor probe to be non-contactly pierced on the neutral wire and the live wire at the same time; using two high-frequency current sensor probes to be non-contactly pierced on the neutral wire and the live wire respectively; using a high-frequency current sensor probe to be non-contactly pierced on the ground wire of the power electronic equipment.

5. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 3, characterized in that: For three-phase power electronic equipment, the high-frequency current sensor probe includes the following three installation methods: using a high-frequency current sensor probe to be non-contactly inserted on the three-phase wires between the AC power supply and the power electronic equipment; using three high-frequency current sensor probes to be non-contactly inserted on the a, b, and c phase wires respectively; using a high-frequency current sensor probe to be non-contactly inserted on the ground wire of the power electronic equipment.

6. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 2, characterized in that: The equivalent resonance parameters of the high-frequency oscillating current mode include equivalent inductance, equivalent capacitance and equivalent resistance of the high-frequency oscillating current mode.

7. A method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 6, characterized in that: The equivalent inductance of the high-frequency oscillating current mode is obtained by fitting the high-frequency oscillating current using an iterative local search algorithm as follows: ， Among them, U is voltage, L CM is the equivalent inductance of the high-frequency oscillating current mode, ω CM is the resonant angular frequency of the high-frequency oscillating current mode, ζ CM is the damping ratio of the high-frequency oscillating current mode, t is the time, i CM It is a high frequency oscillating current.

8. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 6, characterized in that: The equivalent capacitance of the high frequency oscillating current mode is calculated according to the following resonant frequency formula: ， Among them, f CM is the resonant frequency of the high-frequency oscillating current mode, ω CM is the resonant angular frequency of the high-frequency oscillating current mode, C CM is the equivalent capacitance of the high frequency oscillating current mode, L CM is the equivalent inductance of the high frequency oscillating current mode.

9. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 6, characterized in that: The equivalent resistance of the high-frequency oscillating current mode is calculated according to the following damping ratio formula: ， Among them, R CM is the equivalent resistance of the high-frequency oscillating current mode, ζ CM is the damping ratio of the high frequency oscillating current mode, C CM is the equivalent capacitance of the high frequency oscillating current mode, L CM is the equivalent inductance of the high frequency oscillating current mode.

10. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 2, characterized in that: The external resonator is an RLC series resonator, and its circuit parameters include inductance, capacitance and resistance.

11. A method for modal directional suppression of high frequency interference of power electronic equipment according to claim 10, characterized in that: The inductance of the external resonator is determined according to the coil size.

12. A method for modal directional suppression of high frequency interference of power electronic equipment according to claim 11, characterized in that: The high-frequency interference includes high-frequency common-mode interference and high-frequency differential-mode interference; when used to suppress high-frequency differential-mode interference, the coil size of the external resonator is determined according to the wire diameter of the phase line; when used to suppress high-frequency common-mode interference, the coil size of the external resonator is determined according to the position of the external resonator coupled on the current conduction path.

13. A method for modal directional suppression of high frequency interference of power electronic equipment according to claim 12, characterized in that: When the external resonator is coupled to the live wire and the neutral wire in the current conduction path of the single-phase power electronic equipment, the coil size of the external resonator is determined according to the wire diameters of the live wire and the neutral wire and the distance between the live wire and the neutral wire; when the external resonator is coupled to the three-phase wire in the current conduction path of the three-phase power electronic equipment, the coil size of the external resonator is determined according to the wire diameters of the three-phase wire and the distance between the three-phase wires; when the external resonator is coupled to the ground wire of the power electronic equipment, the coil size of the external resonator is determined according to the wire diameter of the ground wire.

14. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 11, characterized in that: When the external resonator adopts a toroidal coil, its inductance L reg It is calculated by: ， Among them, a is the inner diameter of the annular coil, b is the outer diameter of the annular coil, μ0 is the relative magnetic permeability of the coil frame, N is the number of coil turns, and h is the coil height.

15. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 10, characterized in that: The capacitance of the external resonator is designed so that the frequency f reg The resonant frequency f of the high frequency oscillating current mode CM same: ， Among them, C reg is the capacitance of the external resonator, L reg is the inductance of the external resonator, C CM is the equivalent capacitance of the high frequency oscillating current mode, L CM is the equivalent inductance of the high frequency oscillating current mode.

16. The method for modal directional suppression of high-frequency interference of power electronic equipment according to claim 10, characterized in that: The external resonator operates under the condition of maximum loss rate.

17. A method for modal directional suppression of high frequency interference of power electronic equipment according to claim 10, characterized in that: The resistance of the external resonator is determined based on the parity-time symmetry theory, and the determination process includes the following steps: The Hamiltonian matrix H is constructed according to the coupled mode theory, and its eigenvalue λ is calculated: ， ， Among them, f CM is the resonant frequency of the high-frequency oscillating current mode, ω CM is the resonant angular frequency of the high-frequency oscillating current mode, i is the high-frequency oscillating current, κ is the coupling rate between the external resonator and the wire, γ1 is the loss rate of the high-frequency oscillating current mode, γ2 is the loss rate of the external resonator, λ 1,2 is the eigenvalue λ The two solutions of a 1. a 2 are the amplitudes of the high-frequency oscillation mode inside the power electronic equipment and the oscillation mode of the external resonator, respectively; According to the parity-time symmetry theory, when the eigenvalue λ is a single real number solution, that is, When , the external resonator operates at the phase change point, and the loss rate γ2 is the largest. The resistance of the external resonator is obtained by solving the following loss rate: ， Among them, R reg is the resistance of the external resonator, C reg is the capacitance of the external resonator, L reg is the inductance of the external resonator.

18. A method for modal directional suppression of high frequency interference of power electronic equipment according to claim 17, characterized in that: The coupling rate κ and the high-frequency oscillation current modal loss rate γ1 are respectively: ， ， Among them, M reg For mutual induction, C CM is the equivalent capacitance of the high frequency oscillating current mode, L CM is the equivalent inductance of the high frequency oscillating current mode, R CM is the equivalent resistance of the high frequency oscillating current mode.

19. A method for modal directional suppression of high frequency interference of power electronic equipment according to claim 18, characterized in that: When the external resonator adopts a toroidal coil, the calculation method of mutual inductance is: ， Among them, a is the inner diameter of the annular coil, b is the outer diameter of the annular coil, μ0 is the relative magnetic permeability of the coil frame, N is the number of coil turns, and h is the coil height.

20. A modal directional suppression device for high frequency interference of power electronic equipment, comprising power electronic equipment and an AC power supply, characterized in that: The device also includes: an external resonator designed based on parity-time symmetry theory and coupled to the high-frequency oscillation current conduction path between the power electronic equipment and the AC power supply, wherein the external resonator transfers the resonant energy of the high-frequency oscillation mode to the external resonator in a directionally manner, thereby effectively suppressing the high-frequency interference of the power electronic equipment.

21. An electronic device comprising a memory and a processor, wherein a computer program is stored in the memory, wherein: When the processor executes the program, the method according to any one of claims 1 to 19 is implemented.

22. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 19 is implemented.

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