64 results about "Differential mode noise" patented technology

The invention relates to a method and circuit for analyzing and reconstructing current type digital active EMI filtering based on a switching frequency spectrum, and the method comprises the steps: obtaining initial common-mode noise data and initial differential-mode noise data of a Buck circuit at a switching frequency point; constructing a common-mode equivalent circuit and a differential-mode equivalent circuit comprising a noise source, a compensation voltage source, a compensation capacitor, a parasitic capacitor and LISN impedance, and calculating initial compensation voltage common-mode data and initial compensation voltage differential-mode data of each frequency point to obtain initial compensation voltage data; synchronously outputting the initial compensation voltage data through a DAC (Digital-to-Analog Converter), and performing initial noise compensation; and measuring noise voltage on the LISN as noise source voltage, calculating to obtain secondary compensation voltage data, and carrying out superposition iteration on the compensation voltage data. The method is suitable for a scene with common-mode noise as a main part, can realize common-mode and differential-mode composite suppression without detection and size reduction, and continuously optimizes an EMI suppression effect through iterative updating.

The invention discloses a self-locking noise suppression level shift circuit with ultra-low delay, relates to the technical field of intelligent power driving, and aims to solve the problem that delay is increased when noise is filtered out through an RC filter circuit in the prior art. Comprising a high-voltage level shifting circuit, a common-mode noise elimination circuit, a differential-mode noise elimination circuit and an RS latch which are electrically connected, the common-mode noise elimination circuit is used for transmitting 1 / 2VDD voltage to the input end of the RS latch when common-mode noise exists, relatively low threshold voltage of the RS latch is designed, the 1 / 2VDD voltage is made to be high level for the RS latch, and therefore the 1 / 2VDD voltage is made to be low level for the RS latch. The state of the RS latch is kept unchanged, the differential mode noise elimination circuit is used for starting the differential mode noise elimination circuit through resistor voltage division when differential mode noise exists, and the input end of the RS latch is kept at a high level. The self-locking noise suppression level shift circuit provided by the invention is used for eliminating common-mode noise and differential-mode noise of dV / dt noise and has lower delay.

According to the current compensation-based level shift circuit provided by the invention, one path of low-voltage pulse signal is accessed through the first level input end and the second level output end respectively, so that the two paths of low-voltage pulse signals are converted into two paths of high-voltage pulse signals; the signals are output to the current compensation circuit and the common-mode noise elimination circuit through the first level output end and the second level output end, and the output of the current compensation circuit and the output of the common-mode noise elimination circuit jointly influence the signal states of the R end and the S end in the latch. And the latch is used for restoring the high-voltage pulse signal into a floating square wave signal with the same phase as the input signal. The level shift circuit not only can resist high common-mode noise, but also has a good inhibition effect on differential-mode noise, and the stability and reliability of the level shift circuit are effectively improved.

An active compensation device including a first element group including an integrated sensing / compensation unit configured to generate a sensing signal corresponding to at least one of common-mode noise and differential-mode noise on at least two high-current paths, and a second element group including a compensation control unit including a negative impedance converter and configured to generate a compensation signal corresponding to the sensing signal and provide the compensation signal to the integrated sensing / compensation unit. The compensation control unit further including a stabilization unit configured to prevent oscillation caused by the sensed noise. The first element group and the second element group are mounted on a single substrate.

The invention discloses an electromagnetic interference suppression circuit and method and a power adapter, and belongs to the technical field of power adapters, the electromagnetic interference suppression circuit comprises a common mode inductor, a first end of the common mode inductor is connected to a live wire input end of the power adapter, a second end of the common mode inductor is connected to a null line input end of the power adapter, and the common mode inductor is used for generating magnetic flux; common-mode noise of the live line input end and the zero line input end of the power adapter is suppressed; the differential mode filter is connected with the common mode inductor in parallel and is used for suppressing differential mode noise between the live wire and the zero wire; and the first end of the grounding resistor is connected with the zero line input end of the power adapter, the second end of the grounding resistor is grounded, and the grounding resistor is used for providing a low-impedance path and guiding an electromagnetic interference signal passing through the input end of the power adapter to the ground. Through the combined action of the common mode inductor, the differential mode filter and the grounding resistor, the electromagnetic compatibility of the power adapter can be effectively improved, and the electromagnetic interference is reduced.

Provided is an active filter device capable of effectively reducing common mode noise and differential mode noise and optimizing filter characteristics. The active filter device includes an inverting amplifier circuit 37 that inverts and amplifies a common mode voltage and a differential amplifier circuit 64 that differentially amplifies a differential mode voltage, and an output voltage of the inverting amplifier circuit 37 is applied as a common mode compensation voltage to Y capacitors 21, 22, an output of the differential amplifier circuit 64 obtained by amplifying a voltage of a positive-side power supply line 11 is applied as a differential mode compensation voltage to a negative-side X capacitor 42, and an output of the differential amplifier circuit 64 obtained by amplifying a voltage of a negative-side power supply line 12 is applied as a differential mode compensation voltage to a positive-side X capacitor 41.

Disclosed in the present invention is a filter circuit. A first PCB layer consists of a power line, a power interface, a second filter capacitor, and a first filter capacitor; the power line comprises a power supply network and a GND network; the second PCB layer is provided with a conductor plane; the power interface is connected to the GND network and is further connected to the conductor plane; the GND network, the second filter capacitor, and the conductor plane are sequentially connected; the power supply network, the first filter capacitor, and the conductor plane are sequentially connected. The circuit design of the circuit structure and the overall layout design idea in the present invention have a good suppression effect on common-mode noise, differential mode noise, radiation noise and conduction noise.

This utility model discloses a frequency converter controller, including a control unit, a first filtering topology, and a second filtering topology. The first filtering topology includes a differential-mode inductor unit, and the second filtering topology includes a common-mode inductor unit. The first filtering topology is connected to the live wire, neutral wire, and protective ground wire, and receives the input signal from the power input terminal, suppresses the differential-mode noise and common-mode noise of the input signal from the power input terminal, and generates a first electrical signal. The second filtering topology receives the first electrical signal, suppresses the differential-mode noise and common-mode noise of the first electrical signal, and generates a second electrical signal. The control unit receives the second electrical signal. Because a differential-mode inductor unit is added to the first filtering topology, the number of magnetic rings can be reduced, the number of installation steps can be reduced, and costs can be optimized.

To provide a technique capable of suppressing differential mode noise in addition to common mode noise in a noise filter connected to a pair of power lines.SOLUTION: A noise filter disclosed in the present specification is a noise filter connected to a pair of power lines, and includes a first bypass capacitor connected between one of the pair of power lines and a ground, a second bypass capacitor connected between the other of the pair of power lines and the ground, a first resistive element connected in series with the first bypass capacitor, and a second resistive element connected in series with the second bypass capacitor.SELECTED DRAWING: Figure 2

The invention relates to the technical field of direct-current brush motors, and discloses a disturbance voltage filter circuit of a direct-current brush motor, which comprises a wiring terminal J1 connected to a live wire, a wiring terminal J2 connected to a zero wire and a rectifier bridge BR1, and a filter circuit is also connected between the rectifier bridge BR1 and the direct-current brush motor; differential-mode noise is suppressed through the added differential-mode inductor, the amplitude and frequency of the noise are effectively reduced, the electromagnetic compatibility of the circuit is improved, the filtering effect can be further improved through the design that the resistor is connected to the differential-mode inductor in parallel, a damping network can be formed through the addition of the resistor, residual energy in the inductor can be absorbed and dissipated, the resonance phenomenon is reduced, and the filtering effect is improved. The two same differential mode inductors are added, and the resistors are connected to the differential mode inductors in parallel, so that the configuration of the filter circuit is more flexible, the values of the differential mode inductors and the resistors can be adjusted according to actual needs, and the optimal filtering effect is achieved.

The utility model discloses an active choking coil, which comprises at least three groups of coils, two groups of coils are used for power current of a power line to flow through, and the other group of coils are used for active suppression current to flow through; the active suppression current generating circuit is coupled with the coils and generates the suppression current; the capacitor is connected in parallel with the two groups of coils through which power current flows, so as to serve as a filter of the power line; according to the utility model, the common-mode and differential-mode noise suppression effect or the EMI suppression effect is enhanced mainly through the active current generator circuit, so that the cost and the size of the isolator or the EMI suppression circuit are reduced. Because the length of the copper wire is reduced, the energy consumption of the isolator or the EMI suppression circuit is lower than that of the traditional method, and the energy loss is reduced.

The invention relates to a reconstruction voltage type digital active EMI filtering method and circuit based on switching spectrum analysis, and the method comprises the steps: obtaining common-mode noise data and differential-mode noise data of a Buck circuit at a switching frequency point; constructing a common-mode equivalent circuit and a differential-mode equivalent circuit comprising a noise source, a compensation voltage source, a parasitic capacitor and LISN impedance, and calculating common-mode compensation voltage data and differential-mode compensation voltage data of each frequency point to obtain compensation voltage data; the compensation voltage data and PWM are synchronously output through a DAC, and the compensation voltage data are injected into a positive bus and a negative bus through an injection inductor for noise compensation. The reconstruction voltage type digital active EMI filtering method and circuit based on switch spectrum analysis are suitable for scenes with differential mode noise as a main part, and common suppression of common mode interference and differential mode interference can be achieved while no detection exists and the size is reduced.

The application provides a level shift circuit based on current compensation, a low-voltage pulse signal is connected to a first level input end and a second level output end respectively, so that the two low-voltage pulse signals are converted into two high-voltage pulse signals, and the high-voltage pulse signals are output to a current compensation circuit and a common mode noise elimination circuit through a first level output end and a second level output end; the output of the current compensation circuit and the common mode noise elimination circuit jointly influences the signal state of R end and S end in a latch, and the latch is used for restoring the high-voltage pulse signal into a floating square wave signal with the same phase as the input signal. The application not only can resist high common mode noise, but also has a good inhibitory effect on differential mode noise, and effectively improves the stability and reliability of the level shift circuit.

The invention discloses an air communication equipment power supply filter and a working method thereof. The power supply filter comprises a self-recovery protection module, a transient suppression module, a surge protection module and a power supply filtering module which are connected in sequence, the self-recovery protection module is used for isolating the circuit from a power supply end when the circuit is short-circuited or overcurrent is input, and recovering a normal state when the fault of the power supply input end is removed or the power is cut off; the transient suppression module is used for instantaneously absorbing and releasing transient energy generated by the bidirectional spike pulse; the surge protection module is used for bearing overvoltage surge and maintaining a short-time working state of an equipment circuit in an undervoltage state; the power supply filtering module is used for suppressing common-mode and differential-mode noise generated by power supply conduction. The power supply is small in size, low in power consumption and strong in function, has the functions of large-current overvoltage resistance, undervoltage resistance, surge suppression, spike pulse suppression, short-circuit protection and self-recovery, improves the reliability and stability of the power supply of the air communication equipment, and reduces the maintenance cost of the power supply.

The utility model belongs to the technical field of electronic components, and particularly relates to a common-mode inductor integrated with differential-mode filtering, which comprises a bottom plate and a common-mode magnetic core, a partition plate is fixedly connected to the top of the bottom plate, a placement groove is formed in the partition plate, a magnetic conductive sheet is arranged in the placement groove, and the common-mode magnetic core is arranged in the placement groove. According to the common-mode inductor, the common-mode magnetic core is matched with the two winding coils, common-mode noise is effectively restrained, the containing groove is formed in the partition plate in the middle of the common-mode inductor, and the magnetic conductive sheet is arranged in the containing groove, so that the common-mode inductor is integrated with a differential-mode inductor and has the capability of filtering differential-mode noise, and the common-mode inductor has the advantages of being simple in structure and convenient to use. An additional differential mode inductor is avoided, and cost reduction and space saving are realized.

The utility model relates to a microwave oven and a filter circuit thereof, the filter circuit is used for being matched with a drive circuit of the microwave oven, the drive circuit comprises a rectification circuit and an inversion circuit, and the filter circuit comprises a differential mode filter circuit used for being connected with an alternating current power supply to filter differential mode noise in the alternating current power supply; the common-mode filter circuit is connected with the differential-mode filter circuit and the rectifying circuit and is used for filtering common-mode noise in the alternating-current power supply; and the linear voltage stabilizing circuit is connected with the rectifying circuit and the inverter circuit, and is used for performing linear conversion on the direct-current power supply output by the rectifying circuit and outputting a linear power supply to the inverter circuit. According to the utility model, the alternating current power supply input to the microwave oven driving circuit can be filtered, the microwave oven is helped to meet the electromagnetic compatibility requirement, the stability of the direct current voltage is improved, and the working condition of the inverter circuit is more stable.

The application discloses a wideband active EMI filter circuit and a control method thereof, which comprises a high-frequency common-mode inductance module, an amplification filter module and a differential-mode filter module, the high-frequency common-mode inductance module further comprises two sampling signal output ports, and the sampling common-mode noise is connected to two input ports of the amplification filter module respectively after sampling; the output port of the amplification filter module is connected to the differential-mode filter module, and the differential-mode noise is filtered in the differential-mode filter module after the loop noise current is eliminated. Through the wideband active EMI filter circuit and the control method thereof, the compensation current signal is obtained through a novel sampling mode, the novel sampling mode is adopted, the purpose of wideband filtering is achieved, the stability of the filter is improved, meanwhile, the filter is small in size, wide in frequency band, high in stability, applicable to various space-limited scenes such as aerospace and industrial application, and the hardware design can make the matched product meet the electromagnetic compatibility requirement.

An active compensation device is provided. An active compensation device includes an integrated sensing / compensation unit configured to generate a sensing signal corresponding to at least one of common-mode noise and differential-mode noise on at least two high-current paths, and a compensation control unit including a negative impedance converter and configured to generate a compensation signal corresponding to the sensing signal and provide the compensation signal to the integrated sensing / compensation unit. The compensation control unit further includes a stabilization unit configured to prevent oscillation caused by the sensed noise.

The utility model discloses an LDO circuit, LDO and power supply system relates to power supply management technical field, the LDO circuit includes: LDO main body circuit, including first input terminal, second input terminal, output terminal and ground terminal, the first input terminal is used for receiving reference voltage, the second input terminal is connected with power supply, the output terminal is connected with load, the ground terminal is used for ground connection, the ground terminal is used for ground connection. The voltage processing module is used for processing an input voltage input by an input end of the voltage processing module according to a reference voltage to obtain a constant output voltage and outputting the output voltage through an output end of the voltage processing module; the input end of the noise optimization circuit is connected with the input end of the LDO main body circuit, the grounding end of the noise optimization circuit is grounded, and the noise optimization circuit is used for filtering differential-mode noise and common-mode noise accessed to the input end of the LDO main body circuit; according to the technical scheme provided by the utility model, the noise optimization capability in the LDO circuit can be effectively improved.

A transformer includes an iron core including an iron core main body, a first main winding wire, a second main winding wire, a first detection winding wire, and a second detection winding wire. The iron core main body includes a first through hole, a second through hole, and a first leg portion positioned between the first through hole and the second through hole, the first through hole and the second through hole being positioned at intervals in a first direction. The first main winding wire is wound around the first leg portion and includes winding ends positioned in the first through hole. The second main winding wire is wound around the first leg portion and includes winding ends positioned in the second through hole. The first detection winding wire is wound around the iron core in a state where a magnetic flux generated by a common mode noise is cancelable and configured to detect a normal mode noise current. The second detection winding wire is wound around the iron core in a state where a magnetic flux generated by the normal mode noise current is cancelable and configured to detect the common mode noise current.

The invention belongs to the technical field of power electronics, and relates to a three-phase star-shaped active EMI filter, which comprises a detection link, an amplification link, an injection link and a star-shaped detection injection enhancement link, and is characterized in that the detection link consists of a detection resistor and a detection capacitor and is used for detecting common-mode noise of a three-phase system; the amplification link consists of a resistor, a capacitor and an operational amplifier and is used for amplifying the detected common-mode noise; the injection link consists of injection resistors and is used for generating compensation current; the star-shaped detection injection enhancement link is composed of three capacitors in star-shaped connection and used for providing branches for common-mode noise current and compensation current and attenuating differential-mode noise of a three-phase system. The detection link and the injection link share a star-connected capacitor branch, and the limitation that detection and injection in a traditional three-phase common-mode AEF both need three branches can be eliminated. Therefore, the number of elements required by the active EMI filter is reduced, the design is simpler and more convenient, and common-mode noise and differential-mode noise are greatly attenuated.

The utility model relates to a winding structure filter, including a winding copper busbar assembly, a grounding capacitor assembly, a filter bracket assembly and a magnetic ring. The winding copper busbar assembly and the grounding capacitor assembly are installed on the filter bracket assembly. One end of the grounding capacitor assembly is connected to the winding copper busbar assembly, and the other end is connected to the filter bracket assembly. The magnetic ring passes through the winding copper busbar assembly; the winding copper busbar assembly is a flat copper wire laminated arrangement structure. Compared with the prior art, the utility model has the advantages of adopting a winding copper busbar assembly with a flat copper wire laminated arrangement structure to increase the inductance and improve the filtering performance of the filter, and improve the ability of the filter to suppress differential mode noise; the winding copper busbar assembly passes through the same magnetic ring, which strengthens the ability of the filter to suppress differential mode noise; the structure of the first grounding capacitor back to the second grounding capacitor makes the filter structure compact, shortens the equivalent series inductance of the capacitor absorption loop, and thus improves the high-frequency noise suppression performance of the filter.

This application provides an AC switching power supply. In this AC switching power supply, the input terminal of each inverter bridge arm is connected to the output terminal of a DC switching power supply; each output terminal of the AC switching power supply is connected to the output terminal of the corresponding inverter bridge arm. In this application, since the common-mode noise of at least two DC switching power supplies cancels each other out, the common-mode noise of the AC switching power supply is suppressed. Furthermore, since in the prior art, the drive signal frequencies of each DC switching power supply in the AC switching power supply are the same, i.e., the number of noise sources at the same frequency point is equal to the number of DC switching power supplies, when the number of DC switching power supplies is the same, the noise sources of this AC switching power supply at the same frequency point will not exceed those in the prior art. Therefore, the differential-mode noise of this AC switching power supply can at least remain unchanged. In summary, the AC switching power supply provided in this application suppresses its own EMI.

The utility model relates to the technical field of motor EMI noise suppression, and more specifically to a three-phase common-mode filter of a brushless motor, comprising a three-phase common-mode inductor and a common-mode capacitor, wherein the three-phase common-mode inductor is fixed on a lower partition plate, the three-phase common-mode inductor is fixed on a PCB board through the lower partition plate, the common-mode capacitor is arranged in the PCB board, the PCB board is fixed on the bottom of an outer shell, the upper part of the outer shell is buckled and fixed on the bottom of the outer shell, and the three-phase common-mode inductor is arranged in the upper part of the outer shell through the lower partition plate and the PCB board; the three-phase common-mode inductor comprises a magnetic ring and an inner partition plate, the magnetic ring is plugged and provided with the inner partition plate, and the inner partition plate divides the inner part of the magnetic ring into three spaces; the beneficial effect of the utility model is that the electromagnetic noise generated by the switch tube of the driving module of the three-phase brushless motor can be solved, and the switching noise, in addition to the common-mode noise, will also drive the equivalent antenna to be emitted outward in the form of differential mode; thereby solving the problem that the common-mode and differential-mode noises cannot be effectively suppressed at the same time.

Motor-driven compressor (11) with: a compression section (18) which compresses fluid, an electric motor (19) which drives the compression section (18), an inverter device (30) which drives the electric motor (19), and a metal housing (14) accommodating the inverter device (30), wherein the inverter device (30) an inverter circuit (31) which converts direct current power into alternating current power, and a noise reduction device (32) arranged on an input side of the inverter circuit (31), the noise reduction device (32) reducing common-mode noise and differential-mode noise contained in the DC power before supply to the inverter circuit, the interference reduction device (32) a common mode choke coil (34), and a smoothing capacitor (35) which forms a low-pass filter circuit (36) together with the common-mode choke coil (34), the common mode choke coil (34) a loop-shaped core (50), a first winding (60) wound around the core (50), a second winding (61) wound around the core (50), the second winding (61) being located away from the first winding (60) and opposite the first winding (60), and a loop-shaped conductor (70) covering the core (50) while extending over the first winding (60) and the second winding (61), where the conductor (70) has sections which are opposite to each other and are located away from each other, with the first winding (60) and the second winding (61) therebetween, the conductor (70) has a heat radiation section (71) which is thermally coupled to the housing (14), and an average value of the electrical resistance value per unit length in a circumferential direction of the heat radiation portion (71) of the conductor (70) is greater than an average value of the electrical resistance value per unit length of locations other than the heat radiation portion (71).

The invention discloses an improved XY capacitor plate, and belongs to the field of electronic circuits, the improved XY capacitor plate comprises an X capacitor connected in parallel between a live wire and a zero line, and a first Y capacitor and a second Y capacitor respectively connected between the live wire and a ground wire and between the zero line and the ground wire, and the first Y capacitor and the second Y capacitor adopt symmetrical design and jointly form a pi-type filtering structure; compared with the prior art, differential mode and common mode noise can be efficiently suppressed, the harsh EMC requirement of a ship is met, the safety and reliability of the circuit are greatly improved through the application of the safety capacitor and the redundancy design of the Y capacitor, the electric shock risk caused by element failure is avoided, and part of the filtering function can still be reserved when a single point of fault occurs.

The invention discloses equipment for quickly positioning differential and common mode interference of electronic equipment for a CE102 test item, and belongs to the technical field of electromagnetic compatibility test. Comprising a metal shell, a differential-mode noise suppression module and a common-mode noise suppression module are arranged in the metal shell, four banana sockets and four control switches are arranged on a panel of the metal shell, the banana sockets are used for being connected with a test loop, and the control switches comprise two common-mode control switches and two differential-mode control switches. The two common-mode control switches are respectively connected with the input end and the output end of the common-mode noise suppression module, the two differential-mode control switches are respectively connected with the input end and the output end of the differential-mode noise suppression module, and the control switches are used for selectively connecting the differential-mode noise suppression module or the common-mode noise suppression module into a test loop. According to the invention, the interference type can be rapidly judged, multiple instrument functions are integrated, visual operation is realized through switch switching and light indication, the test efficiency and the positioning accuracy are improved, and on-site rapid troubleshooting is facilitated.

The invention relates to the technical field of signal processing, and discloses a touch integrated display module signal processing method and system. The method comprises the following steps: performing signal acquisition on a display driving circuit of a touch display module during a display frame interval to obtain mixed signal data; performing common-mode noise separation on the mixed signal data according to a common-mode noise reference to obtain touch signal data; identifying a differential mode noise component generated by a pixel driving voltage according to the touch signal data to obtain a differential mode noise separation result and a multi-point touch signal; extracting mixed coordinate data containing real touch points and phantom points according to the multi-point touch signal; based on the differential mode noise separation result, space geometric constraint verification and signal intensity inspection are conducted on the phantom points in the mixed coordinate data, and a touch positioning result is obtained.The phantom point recognition accuracy is ensured, the misjudgment rate is effectively reduced, and the touch reliability of the display module is improved.

The invention relates to a filter, an inverter and a vehicle, the filter comprises a connecting busbar, a magnetic ring and a capacitor, the connecting busbar is used for being electrically connected with an external electronic element, the magnetic ring sleeves part of the connecting busbar, the capacitor can be electrically connected with the connecting busbar, the capacitor comprises a first capacitor and a second capacitor, and the first capacitor and the second capacitor are electrically connected. The first capacitor can be matched with the magnetic ring to form a first differential-mode filter circuit, the second capacitor can be matched with the magnetic ring to form a second differential-mode filter circuit, and the frequency of differential-mode noise suppressed by the first differential-mode filter circuit is different from that of differential-mode noise suppressed by the second differential-mode filter circuit. According to the filter, the first capacitor and the second capacitor are arranged, the frequencies of suppressed noise are different, and a multi-stage and broadband noise absorption network is formed, so that the noise of different frequencies can be suppressed, the frequency of suppressing the noise can be widened, and applicable scenes can be increased.

The invention relates to a filter, an inverter and a vehicle, the filter comprises a connecting busbar, a first magnetic ring, a second magnetic ring and a capacitor, the connecting busbar is used for being electrically conducted with an external electronic element, the first magnetic ring sleeves a part of the connecting busbar, the second magnetic ring sleeves a part of the connecting busbar, and the capacitor is electrically connected with the first magnetic ring and the second magnetic ring. The capacitor can be electrically conducted with the connecting busbar, the first magnetic ring is a common-mode magnetic ring, the first magnetic ring can be matched with the capacitor to form a common-mode filter circuit, the second magnetic ring is a differential-mode magnetic ring, and the second magnetic ring can be matched with the capacitor to form a differential-mode filter circuit. According to the filter, common-mode noise and differential-mode noise are jointly suppressed, the filter can be applied to a high-voltage direct-current system, the first magnetic ring and the second magnetic ring are independent of each other and are designed in a split mode, and measurement of differential-mode inductance and impedance and measurement of common-mode inductance and impedance can be decoupled.