160 results about "Magnetic noise" patented technology

The invention relates to the technical field of electrical sensor measurement, and provides a fault test method, system and equipment suitable for a fan converter, and the method comprises the steps: collecting current data in an IGBT module of the fan converter, and taking the current data as an original current signal; screening a plurality of dominant frequencies of the original current signal; decomposing the original current signal to obtain a plurality of component signals, and corresponding to each dominant frequency to obtain a plurality of dominant frequency signals; screening to obtain a reference signal; according to the variation trend difference between each component signal and the reference signal, the variation abnormity of each component signal is obtained; analyzing the energy difference between each component signal and the reference signal in the time-frequency energy matrix to obtain the energy difference index of each component signal; obtaining an anomaly index of each component signal; and performing fault detection on the fan converter based on the anomaly index of each component signal. The invention aims to solve the problem that high-frequency electromagnetic noise affects signal performance of a current sampling loop and covers real fault features.

The invention discloses a phase feedback all-optical non-magnetic temperature control device and method based on an FPGA, the device comprises an interferometer module, an FPGA system module and a temperature control module, and through the coordination work of the interferometer module, the FPGA system module and the temperature control module, magnetic noise can be reduced and high-precision stable temperature control can be completed on the basis that a traditional temperature sensor is not used. According to the method, a corresponding state-space equation is constructed by using a corresponding relation between an interferometric phase and temperature in an interferometer, a segmented Kalman filtering algorithm is executed through an FPGA, temperature information hidden in an interferometer signal is extracted, the temperature information is converted into a voltage signal, and a stable temperature control effect is achieved through interaction with a temperature control chip.

The invention relates to a strain monitoring system and method for a transformer winding. The strain monitoring system comprises the transformer winding and a strain monitoring device. The strain monitoring device comprises a fiber bragg grating array which is arranged on a transformer winding and is used for capturing strain signals of the transformer winding; the signal processor is connected with the fiber grating array and is used for receiving and processing the strain signal to generate an electric signal; the data analysis unit is connected with the signal processor, and the data analysis unit is used for receiving and analyzing the electric signal to obtain strain information of the transformer winding; and the wireless transmission unit is connected with the data analysis unit and is used for wirelessly transmitting the strain information to a monitoring center. According to the invention, the fiber grating array is arranged on the transformer winding, and the fiber grating array transmits the strain information through the optical signal, so that the electromagnetic noise is suppressed and the monitoring accuracy is improved by using the characteristic that the fiber is not interfered by the strong electromagnetic environment of the transformer.

An object of the invention is to provide an electromagnetic noise analysis device capable of analyzing a propagation path in a short time even for electromagnetic noise in a high frequency band and securing a certain level of reliability of an analysis result. For this purpose, an electromagnetic noise analysis device according to the invention includes: a propagation characteristic estimation unit configured to statistically estimate an electromagnetic field characteristic in a housing based on information about a housing structure and an electric wire path to output propagation characteristic probability distribution data; a propagation amount calculation unit configured to statistically estimate a noise propagation amount propagated from a noise source to an affected device based on a frequency characteristic of noise generated by the noise source and the propagation characteristic probability distribution data to output data of noise probability distribution on the affected device; and a malfunction risk determination unit configured to determine a malfunction risk of the affected device based on the data of the noise probability distribution on the affected device.

The application discloses a heat dissipation assembly for reducing electromagnetic noise of a chip, a chip packaging assembly and electronic equipment. The heat dissipation assembly comprises a heat sink, a sealing ring and a suppression ring; the suppression ring is connected between the sealing ring and the heat sink and is used for surrounding the chip; the heat dissipation assembly is used for jointly surrounding a substrate carrying the chip to form a closed space, so that the chip is located in the closed space; and the suppression ring is used for shielding electromagnetic waves radiated by the chip.

The invention relates to an electromagnetic noise value determination method and device, electronic equipment and a storage medium, and the method comprises the steps: obtaining a slip ratio corresponding to a target working condition point of a motor; determining a theoretical electromagnetic force frequency corresponding to the motor based on the slip rate; acquiring a plurality of actual electromagnetic force frequencies corresponding to the at least two electric cycles of the motor, and determining whether a target electromagnetic force frequency meeting a preset condition exists in the plurality of actual electromagnetic force frequencies; and when the target electromagnetic force frequency exists, performing simulation processing on the amplitudes and phases corresponding to the plurality of actual electromagnetic force frequencies to obtain an electromagnetic noise value corresponding to the motor, so that the electromagnetic noise value corresponding to the motor can be obtained according to the plurality of actual electromagnetic force frequencies corresponding to at least two electric periods corresponding to the target electromagnetic force frequency which is approximately equivalent to the theoretical electromagnetic force frequency. The electromagnetic noise value corresponding to the motor is obtained, and the accuracy of the obtained electromagnetic noise value is improved.

The invention discloses a high-precision identification method and system for a noise source of an asynchronous motor, and relates to the technical field of asynchronous motor detection, and the method comprises the following steps: constructing a finite element model of a to-be-analyzed asynchronous motor, dividing the surface into a plurality of detection sub-regions, and carrying out the operation simulation of the finite element motor, analyzing vibration speed and sound pressure signal data of each sub-region, synchronously acquiring actual signals, calculating relative differences with simulation data, evaluating detection priorities by combining historical fault times, forming a detection sequence according to the priorities, and sequentially performing sound-vibration coherence analysis and coherence function calculation to obtain a sound-vibration coherence detection result; according to the method, noise frequency bands are classified into structural noise and air noise, order tracking analysis is performed on the structural noise obtained through classification, an amplitude stability index and an amplitude change gradient are calculated, automatic classification and identification of electromagnetic noise and mechanical noise are realized based on a preset threshold value, and the efficiency and accuracy of fault processing are remarkably improved.

The invention discloses a lithium battery control system supporting wireless charging, which dynamically avoids an interference signal frequency band through a frequency adjustment module, and effectively reduces the influence of electromagnetic interference on wireless charging efficiency. The voltage response detection module monitors the voltage change of the adjusted battery in real time to provide a feedback basis for interference identification and shielding strategies; the shielding signal generation module generates a dynamic shielding signal in combination with voltage response characteristics, and an interference propagation path is inhibited in a targeted manner; and the magnetic field correction module further integrates the shielding signal into the magnetic field distribution model to optimize the space energy transmission environment. According to the technical scheme, effective interference suppression and stability enhancement on the wireless charging process in a complex electromagnetic environment are achieved through synergistic effects, the safety and energy receiving efficiency of the lithium battery in the wireless charging state are improved, and the wireless charging method is particularly suitable for industrial driving or feeding mechanism application scenes with multi-band electromagnetic noise.

The invention relates to the field of quantum sensing, and provides an SERF atom magnetometer based on pi pulse pumping detection and a magnetic field detection method. According to the method, 770nm pumping light and 795nm detection light are modulated into an alternating pulse sequence through an acousto-optic modulator, optical frequency shift interference is avoided by adopting a time division multiplexing technology, and pumping pulses are configured to have a pi rotation effect so as to enhance atomic spin polarization. The device comprises an alkali metal gas chamber with multiple layers of magnetic shielding, a graphene heat conduction non-magnetic heating system based on infrared laser, a time division control light path module and a synchronous signal processing unit. Electric heating is replaced by laser heating to eliminate magnetic noise, a pulse interval tau adjustable mechanism is utilized to balance sensitivity and measuring range, and common-mode noise is suppressed in combination with differential photoelectric detection and phase-locked amplification technologies. The alternating current stark effect caused by continuous illumination and magnetic field interference of traditional heating are overcome, the magnetic field measurement precision, the system stability and the signal-to-noise ratio are improved, and a high-precision weak magnetic field detection scheme is provided for biomedical detection and quantum navigation.

Provided is an electromagnetic noise countermeasure member that can reduce resonance of a noise countermeasure member even when vibration occurs at a mounting portion of the noise countermeasure member. An electromagnetic noise countermeasure member (1) that is mounted to a prescribed portion by a mounting member (60) and is secured by a securing member (63) that constitutes the mounting member, the electromagnetic noise countermeasure member including: a magnetic core for surrounding a periphery of an electric wire; and a holding member (10, 50) for holding the magnetic core to an inner surface thereof, the securing member being made of metal, an insertion opening (22) for inserting the securing member being formed in the holding member, and an elastic member (30) being mounted, the elastic member securing the securing member that is inserted into the insertion opening and being elastically deformed by vibration of the securing member.

This invention discloses a precision grinding process for machining the shaft of a swimming pool pump motor, relating to the field of shaft precision grinding technology. The process includes: Step 1: Establishing an incident window using a coherent jet nozzle, allowing the jet to penetrate the air gap into the grinding zone, first wetting and then introducing the load, and recording the incident window, jet posture, and dressing rhythm as working condition metadata; Step 2: After precision grinding, according to the material type, magnetic noise is used for ferromagnetic steel and X-ray diffraction is used for austenitic steel to obtain thermal damage and residual stress, and combining this with cleanliness to generate a surface integrity label and bind it to the working condition metadata; Step 3: Performing deionized ultrasonic cleaning and rinsing according to the label to remove chloride salts and free iron, rebuilding the passivation film according to specifications using chemical passivation, controlled drying, and clean sealing; Step 4: Under the premise of qualified chemical condition, performing isotropic ultra-finishing and low-plasticity rolling on the sealed working zone to form surface compressive stress and maintain geometric tolerances, quickly indicating inspection and writing back the label.

A low-noise magnetic shielding device for liquid nitrogen environments provides a stable, weak magnetic field environment for ultra-high-sensitivity magnetic field measurement devices, inertial measurement devices, and basic physics experimental equipment. The device primarily consists of a cooling chamber, sealing studs, a cooling chamber cover, a ferrite barrel, a temperature sensor, and a gasket. The ferrite barrel is placed in a cooling chamber filled with liquid nitrogen. By utilizing the low temperature of liquid nitrogen, the device reduces the magnetic noise generated by the ferrite barrel. This device can significantly improve the sensitivity of measurement devices that are otherwise limited by the magnetic noise generated by the magnetic shielding device.

The utility model relates to the technical field of high-voltage power supplies, in particular to an electromagnetic shielding type high-voltage power supply, which increases the sealing effect, prevents water and impurities outside the high-voltage power supply from entering a power supply shell, reduces electromagnetic noise or interference, and protects normal operation of equipment and a system. Comprising a power source shell, a covering assembly, fixing and pressing assemblies, a sealing assembly, a shielding assembly and a heat dissipation assembly, electronic components are arranged in the power source shell, the covering assembly is located at the top of the power source shell, the fixing and pressing assemblies are installed on the side walls of the front end and the rear end of the power source shell and fix the covering assembly, and the sealing assembly is installed between the bottom of the covering assembly and the power source shell. A shielding assembly is installed in the power source shell, and a heat dissipation assembly is installed in the power source shell.

The application discloses a method for improving low-frequency precision of an atomic magnetometer, and relates to the technical field of weak magnetic detection. In the method, the closed-loop atomic magnetometer is in a zero-locking state, a direct-current bias system is automatically and accurately adjusted, the atomic magnetometer is caused to work in a critical interval between a zero-locking region and a linear region, the zero-locking region has the suppression on low-frequency magnetic noise, and the linear region has a higher response to a measured magnetic field, so that the low-frequency measurement precision of the atomic magnetometer is improved. The application is suitable for an optical pumping atomic magnetometer system, and is favorable for improving the precision and stability of the atomic magnetometer, and can significantly improve the magnetic field sensitivity in the low-frequency part.

The utility model discloses a fractional-slot concentrated winding outer rotor permanent magnet motor, which comprises an inner stator assembly positioned on the inner periphery and an outer rotor assembly positioned on the outer periphery, and is characterized in that a winding of the inner stator assembly adopts a fractional-slot concentrated winding structure; the outer rotor assembly comprises a plurality of permanent magnets which are fixedly arranged on the inner side wall surface of the motor shell and are uniformly and circumferentially distributed at intervals, and a first permanent magnet surface, adjacent to the winding, of each permanent magnet is in an arc-shaped convex shape relative to the winding; the distance between the first permanent magnet surface protruding point located in the middle and the winding is larger than the distance between the first permanent magnet surface protruding point located in the non-middle position and the winding. According to the utility model, harmonic waves and torque pulsation of the fractional-slot concentrated winding outer rotor permanent magnet motor are substantially weakened, magnetic noise during operation of the motor is reduced, a vibration value during operation of the motor is reduced, and the service life of the motor installation structure is prolonged; and the rotation of the motor is smoother.

The purpose of the present invention is to sufficiently suppress electromagnetic noise in an IGBT structure. The upper layer electrode (14) and the lower layer electrode (12) inside the trench (8) are separated by an intermediate insulating film (16). The first resistor (R1) is connected between the upper layer electrode (14) and the input terminal (10). The second resistor (R2) is connected between the lower layer electrode (12) and the input terminal (10). The gate-emitter capacitance of the lower layer electrode (12) is smaller than the gate-emitter capacitance of the upper layer electrode (14).

A converter arrangement (10A) comprises at least one first string of electrically interconnected modules (12A, 14A, 16A, 18A, 20A, 22A) and a first shield and a second shield (24A, 26A), wherein the first shield (24A) is connected to a first defined potential and placed adjacent to a first group of modules (G1A) in said first string comprising at least one first module (14A), and the second shield (26A) is connected to a second defined potential and placed adjacent to a second group of modules (G2A) in said first string comprising at least one second module (18A), wherein, in operation, a resonance loop is created from the first module (14A) via the first and second shields (24A, 26A) and the second module (18A) back to the first module (14A), and the converter arrangement further comprises a damping unit (32A) in the resonance loop, said damping unit being arranged to damp electromagnetic noise.

To provide an electric vehicle driving device that can prevent the generation of electromagnetic noise.SOLUTION: An electric vehicle driving device 1 comprises a motor 10, and a gearbox 20 that is connected to the motor 10 and changes the speed of rotation of the motor 10 and outputs the changed rotation. The motor 10 comprises a motor housing 11 and a rotor shaft 15, and the rotor shaft 15 projects in an axial direction from the motor housing 11. A speed reducer 20 comprises a speed reducer housing 21 and an input shaft 25, the speed reducer housing 21 is fixed to the motor housing 11 in the axial direction, and the input shaft 25 is coaxially connected to the rotor shaft 15. A conductive plate 51 is fixed to the rotor shaft 15 or the input shaft 25 and extends to the outside in the radial direction of the shaft, and is provided between the motor housing 11 and the speed reducer housing 21. The motor housing 11 is provided with a conductive brush 52 that is in contact with an end face of the conductive plate 51 and electrically connects the motor housing 11 and the conductive plate 51 to each other.SELECTED DRAWING: Figure 2

This suppresses the leakage of electromagnetic noise from the outer conductor. [Solution] The shield connector A comprises an L-shaped inner conductor 21 connected to a circuit board P, and an outer conductor 30 having a housing space 43 for housing the inner conductor 21. The outer conductor 30 is constructed by assembling a first shell 31 and a second shell 36. A partition wall 50 is formed on one of the pair of mating surfaces 45, 46 of the first shell 31 and the second shell 36 that are close to each other and face each other, on the first mating surface 45, so as to separate the housing space 43 from the outer surface of the outer conductor 30. A groove 51 is formed on the other of the pair of mating surfaces 45, 46, on the second mating surface 46, into which the partition wall 50 is fitted.

This invention provides an electromagnetic noise analysis apparatus and method that achieves both reduced analysis time and improved analysis accuracy. [Solution] The electromagnetic noise analysis device 1 includes: a noise spectrum analysis unit that performs frequency-axis noise analysis on any observation point of a power conversion circuit in which at least two switches are connected between power supplies, representing each switch as a voltage source or current source on the frequency axis; a voltage source / current source noise source parameter generation unit that generates a parameter table for representing switching operation as a voltage source or current source on the frequency axis according to operating conditions including power supply voltage, gate resistance of each switch, or current; a worst-case condition extraction unit that extracts phase relationships and current amounts in which the noise amount can become the worst-case condition in the time-axis operation of each switch based on control; and a worst-case condition noise source model generation unit that sets the worst-case condition noise source parameters using the extraction results by the worst-case condition extraction unit.

The invention discloses an electromagnetic noise suppression method, which comprises the following steps: S1, designing an asymmetric magnetic pole winding: the pole-arc coefficient is the ratio of the magnetic pole arc length to the pole distance, the pole-arc coefficient of odd teeth is 1.2, the pole-arc coefficient of even teeth is 1.0, the symmetry of a magnetic field is broken through asymmetric magnetic field distribution, and low-order harmonics in cogging torque pulsation are suppressed; s2, winding optimization of the winding: adopting a distributed winding technology, adopting a precise winding process with the error of the number of conductors in each groove being less than or equal to + / -2%, and reducing the content of higher harmonics by adjusting the pitch and the distribution mode of the winding (adopting a short-pitch winding or a fractional-slot winding); and S3, designing a nanocrystalline alloy shielding layer: additionally arranging the nanocrystalline alloy shielding layer with the thickness of 0.3 mm between the back side of the stator yoke part and the rotor magnetic steel. According to the invention, the design is reasonable, through the multi-physical field collaborative design of the asymmetric magnetic poles and the nanocrystalline shielding layer, the motor noise is systematically suppressed from both an electromagnetic force harmonic source and a high-frequency magnetic leakage path, and both efficiency and reliability are considered.

One embodiment according to the present disclosure provides an electric junction box that can be reduced in weight while suppressing electromagnetic noise radiation. An electrical junction box (1) comprises: a negative-side bus bar (20) that has a cylindrical part (21) which extends along a first axis (X), and a negative-side connection tab (22) and a bus bar-side male tab (23) which protrude along the first axis (X) from a part of the cylindrical part (21) in the circumferential direction; a plurality of fuses (41) that are accommodated inside the cylindrical part (21); a positive-side connection tab (32) and a male tab (43) that are electrically connected to the plurality of fuses (41) and that protrude to the outside of the cylindrical part (21) along the first axis (X); a resin housing (10) that accommodates the negative-side bus bar (20); and a first magnetic body (101) and a second magnetic body (102) that are provided to the portions of the housing (10) corresponding to the peripheries of the positive-side connection tab (32) and the male tab (43) which protrude to the outside of the cylindrical part (21).

The invention discloses an alkali metal gas chamber non-magnetic heating method based on double-sided laser temperature control, which can eliminate magnetic interference introduced by traditional electric heating from a physical source and more effectively realize uniform, stable and continuous heat source temperature field distribution through double-sided laser closed-loop control. Comprising the steps that diamond sheets used for photo-thermal conversion are attached to the top face and the bottom face of a heat conduction layer defining an alkali metal air chamber, a first laser heating surface and a second laser heating surface are formed on the heat conduction layer respectively, the thickness of each diamond sheet ranges from 4 mm to 6 mm, the heat conductivity of each diamond sheet is 2000 W / m.K, a first temperature sensor is arranged on the first laser heating surface, and a second temperature sensor is arranged on the second laser heating surface. And a second temperature sensor is arranged on the second laser heating surface. The laser heating material has the main differences that the laser heating material has ultra-low material magnetic noise and ultra-high thermal conductivity; uniform heating of a large-size air chamber is realized through double-sided temperature control; a heating laser light path is separated from a pumping and detecting light path, and laser temperature control can be independently adjusted.

The utility model relates to the technical field of stator, concretely relates to a kind of noise reduction stator, motor and compressor;Wherein, noise reduction stator, including annular yoke and the alternate arrangement of continuation part and abutting portion on the outer periphery of annular yoke, abutting portion abuts to the inner side wall of shell;Continuation part is formed along the radial recess in the direction of departing from shell, and the corresponding central angle of continuation part is SA1;With the lowest point of continuation part recessing, the annular P formed by surrounding is reference, the distance of abutting portion to annular P is T1;Continuation part includes the first arc segment and second arc segment of connection, and the radius of first arc segment is RR1;The radius of second arc segment is RR2;The utility model limits the relationship between the corresponding central angle of continuation part in noise reduction nail, the distance of abutting portion to the lowest point of continuation part and the specific size between continuation part structure, to make noise reduction stator produce good effect in reducing electromagnetic noise.

A sensor controller that controls a touch sensor detects a position of a passive pointer. The sensor controller includes a transmission circuit that transmits a transmission signal to the touch sensor in a plurality of third periods, each including a first period for measuring electromagnetic noise and a second period for detecting the position of the passive pointer and a processor configured to measure a level of electromagnetic noise at a frequency associated with the first period and a frequency associated with the second period, and select, as a scan frequency of the transmission signal in the second period, the frequency associated with the first period or the frequency associated with the second period according to a measurement result of the level of the electromagnetic noise at the frequency associated with the first period and the level of the electromagnetic noise at the frequency associated with the second period.

This invention provides a compact noise filter that sufficiently reduces high-frequency electromagnetic noise even when used in a power converter with a changeable number of drive phases. [Solution] The power converter comprises a common mode choke coil connected to the output side of a multi-phase power converter with a changeable number of drive phases, a variable gain circuit connected to the output side of the common mode choke coil that changes the gain according to the number of drive phases of the power converter and outputs a signal that inverts and cancels high-frequency noise, and a Y capacitor that outputs the signal from the variable gain circuit to the output side of the common mode choke coil.

A biomagnetic sensor that incorporates an integrated active noise cancellation unit that uses a gradiometer to remove ambient magnetic noise from a detection signal obtained from a tunnelling magnetoresistive (TMR) sensor unit that is indicative of a magnetic field adjacent to biological tissue. The ambient magnetic noise can thus be removed in real time at a front end of the sensor (e.g. as part of circuitry in the sensor body itself). The active noise cancellation technique proposed herein may be effective enough to enable the biomagnetic sensor to be used in an unshielded environment (i.e. an environment that is subject to the Earth's magnetic field, for example), which widens significantly the potential uses for the sensor.

The present disclosure relates to a stator for an electric motor, comprising: a stator body forming a ring extending along an axis between a front end face and a rear end face the stator body including an outer peripheral face and an inner peripheral face provided with teeth the teeth defining, in pairs, a plurality of notches open towards the inside of the stator body; a plurality of conductor segments inserted at least partially into the notches of the stator body; wherein the stator body is provided with at least one internal cavity, the at least one internal cavity housing at least one sound-absorbing or structural damping element, the at least one sound-absorbing or structural damping element being able to attenuate the vibrations and / or mechanical and / or magnetic noises generated by the stator during its operation within the electric motor.

The invention discloses an unmanned aerial vehicle magnetic detection efficiency evaluation method based on an underwater target composite magnetic signal, and the method comprises the steps: constructing a comprehensive magnetic signal fusing a target magnetic anomaly field and a wake flow magnetic field, designing a plurality of typical unmanned aerial vehicle detection paths, and carrying out the detection of the unmanned aerial vehicle under the conditions of ideal Gaussian noise and wave magnetic noise. The detection probability of the unmanned aerial vehicle is simulated and analyzed, and scientific prediction and quantitative evaluation of the magnetic detection efficiency of the unmanned aerial vehicle are realized. According to the method, the target comprehensive magnetic signal model in the marine environment is constructed, multiple typical unmanned aerial vehicle detection paths are designed, and a systematized solution thought is provided for systematized and quantitative analysis of the efficiency of an unmanned aerial vehicle magnetic detection scheme.

The invention discloses a rotor and magnetic steel structure for a permanent magnet motor. The rotor and magnetic steel structure comprises a rotor core body, magnetic steel grooves are formed in the rotor core body at equal angles, and the magnetic steel grooves formed at equal angles are of arc-shaped structures with flat outer parts and multiple inner diameters; the interior of the magnetic steel groove is divided into a first hole groove and second hole grooves, and the second hole grooves are symmetrically distributed on the outer side of the first hole groove. Ferrite magnetic steel is installed in a first hole groove in the middle of the magnetic steel groove, and neodymium iron boron magnetic steel is installed in second hole grooves in the two sides of the magnetic steel groove. Wherein the ferrite magnetic steel and the neodymium iron boron magnetic steel are magnetized after being installed. The rotor and magnetic steel structure for the permanent magnet motor can reduce electromagnetic noise and mechanical vibration of the motor, can improve the efficiency of the motor, can prolong the service life of the motor, saves the cost, improves the stability, is flexible in design, and meets the requirements of different motor application scenes.