300 results about "Magnetic noise" patented technology

The invention relates to the field of excavation equipment obstacle avoidance based on image analysis, in particular to a coal mine excavation equipment obstacle avoidance method and system based on machine vision, and the method comprises the steps: obtaining the frequency domain characteristic parameters of the current electromagnetic noise during the operation of underground electromechanical equipment, and synchronously collecting the current original image frame output by a visual sensor; after a current de-noised image frame is obtained after dynamic de-noising processing, an obstacle contour feature point set is extracted through multi-scale edge detection, and an obstacle position confidence map is obtained according to space-time consistency analysis; obtaining point cloud coordinates of an image data loss area caused by electromagnetic interference, and mapping the point cloud coordinates to an image coordinate system to obtain a three-dimensional geometric complemented image; and constructing a dynamic occupation grid map of the underground environment according to the three-dimensional geometric complementation image and the obstacle position confidence map, and planning an obstacle avoidance path of the mining equipment according to the dynamic occupation grid map. And the obstacle avoidance capability of the mining equipment is improved, and safe and efficient coal mining operation is guaranteed.

A dual antiphase read-head arranged card reader is provided. The card reader includes a first read-head arrangement and a second read-head arrangement. Electromagnetic noise is applied to both the first and second arrangements. Waves associated with the electromagnetic noise on the second arrangement is transformed and applied to the first arrangement canceling the noise on a first read head of the first arrangement. The first read head reads magnetically encoded information on a magnetic strip of a card inserted into a card slot of the card reader free of noise. However, the noise remains present such that any skimmer read head of a skimmer inserted into the card slot is unable to read the magnetically encoded information off the magnetic strip of the card.

The utility model discloses a wafer carrying table assembly, which comprises a wafer carrying table, a heating sheet and a shielding sheet, the wafer carrying table is provided with an adsorption hole for adsorbing a wafer, the heating sheet is arranged below the wafer carrying table, the shielding sheet is arranged above the heating sheet, the shielding sheet can conduct electricity, and the shielding sheet can shield a magnetic field generated by the heating sheet and shield electromagnetic noise. And the influence of a magnetic field generated by the heating sheet on subsequent wafer processing procedures is avoided.

A reference noise cancellation device for a transient electromagnetic field is provided. The device includes a transmitter, a transmitting loop, a reference coil, a signal coil and a receiver. The transmitter generates a measurement timing sequence to trigger the receiver to synchronously record the induction signal in the signal coil and the electromagnetic noise in the reference coil. A bipolar current waveform is generated and is injected into the transmitting loop through the first connecting line. The signal coil receives an induced magnetic field of an underground conductor and surrounding magnetic field noise. The reference coil receives surrounding electromagnetic noise. The receiver receives and records the induced magnetic field and surrounding electromagnetic noise of the underground conductor in the signal coil and the surrounding electromagnetic noise in the reference coil.

The embodiment of the invention provides a method and device for positioning electromagnetic noise, a storage medium and a processor, and belongs to the technical field of electrics. The method for positioning the electromagnetic noise comprises the steps that noise signals generated by a noise source are synchronously received through an audio receiving device array, wherein the audio receiving device array at least comprises a first audio receiving device A1, a second audio receiving device A2 and a third audio receiving device A3 which are arranged in a triangular shape; determining a correction coefficient k of the noise signal amplitude and the sound transmission distance in the space where the high-voltage equipment is located according to a correction algorithm; and determining distances L1, L2 and L3 between the noise source and A1, A2 and A3 according to the correction coefficient k and the noise signal amplitude, and calculating the three-dimensional coordinates of the noise source in the three-dimensional rectangular coordinate system according to the obtained coordinates of L1, L2 and L3 and the coordinates of A1, A2 and A3. The method is used for positioning the position of a component generating electromagnetic noise in the high-voltage equipment which is inconvenient to approach and observe so as to judge whether the high-voltage equipment is abnormal or not and determine a maintenance scheme.

The invention relates to a large-size double-layer splicing type ferrite magnetic shielding structure, in particular to a low-noise magnetic shielding barrel structure which is particularly suitable for an ultra-high sensitive magnetic field and inertial measurement device and miniaturization integration application of the ultra-high sensitive magnetic field and inertial measurement device. The magnetic shielding barrel is manufactured by splicing single large-size ferrite blocks into a double-layer cylinder. And the seam at the splicing part of the inner layer is blocked by the ferrite on the outer layer, so that the splicing does not generate large magnetic flux leakage. The double-layer configuration improves the shielding coefficient and reduces the magnetic noise at the same time. The novel large-size double-layer splicing type ferrite magnetic shielding structure shielding barrel is simple in processing technology, the shielding effect is not affected while the material cost is saved, the magnetic noise is reduced through the double-layer barrel structure, and the defect that the magnetic noise caused by a traditional single-layer ferrite magnetic shielding barrel cannot be further reduced is overcome.

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.

The invention discloses a self-adaptive filtering device for electromagnetic noise amplitude detection and a working method of the self-adaptive filtering device, and a detection circuit is characterized in that a sampling resistor R and a capacitor C are connected in series and then are connected to an optocoupler circuit, and a diode protection optocoupler is reversely connected in parallel to the primary side of the optocoupler and is connected to a digital signal controller. The detection circuit is realized by an RC circuit and a voltage transformer, an electromagnetic noise signal in a power loop is coupled by the voltage transformer, conditioned and amplified by an operational amplifier and then sent to an AD sampling pin of the controller, and the controller compares the detected noise amplitude with a set threshold value and controls the on-off of Ry1-Ry6 according to a calculation result. The device can also detect the electromagnetic noise amplitude of the power loop in real time through an optocoupler circuit and a digital signal controller, and actively control the filter parameters according to the noise amplitude. Therefore, the device not only can effectively reduce electromagnetic noise, but also can save energy, reduce reactive power content and reduce leakage current, so that the risk of electric shock caused by poor grounding is avoided.

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 invention discloses an electrocardio gating signal processing device and method used under nuclear magnetic resonance, and belongs to the technical field of nuclear magnetic resonance electrocardio gating processing.The method comprises the steps that an integrated circuit board of physical magnetic shielding collects superposed signals of electrocardio signals and nuclear magnetic noise, and the superposed signals serve as original electrocardio signals after noise filtering and amplification are conducted on the superposed signals in sequence; the method comprises the following steps: performing real-time frequency analysis on an original electrocardiosignal, extracting various electrocardiosignal characteristics, reconstructing a mask vector to filter noise and reconstruct a time-domain R-wave signal, reconstructing an electrocardiosignal based on the reconstructed time-domain R-wave signal and the various electrocardiosignal characteristics, detecting an R-wave trigger point based on the reconstructed electrocardiosignal and generating a gating signal, missed triggering and false triggering detection is carried out on R-wave triggering points in real time; and the reconstructed electrocardiosignal, the gating signal and various electrocardiosignal characteristics are output to a nuclear magnetic resonance system, and matching of different gating trigger conditions based on a magnetic resonance scanning sequence is supported, so that accurate positioning of R waves can be realized.

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 discloses a non-magnetic electric heating film configuration design method based on region division, and belongs to the technical field of electric heating magnetic field suppression, and the method comprises the steps: carrying out the region division of a heating film plane according to the contribution value; establishing a primary function in the area to represent a flow function of current distribution, and calculating magnetic field distribution and temperature distribution of the alkali metal air chamber based on the flow function; establishing constraint conditions about each coefficient in the primary function according to the magnetic noise uniformity and the temperature uniformity; establishing a cost function according to the principle of the minimum magnetic noise mode of the air chamber, and calculating the optimal solution of each coefficient in a primary function to obtain a flow function expression of current distribution; and heating film configuration is designed according to current isoline distribution. By adopting the method, the magnetic noise of the heating film can be effectively reduced, the heating uniformity is considered, and the magnetic resonance signal quality in the quantum sensor can be improved.

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 relates to the field of anti-electromagnetic interference, in particular to an anti-electromagnetic interference method for a field inspection device of a transformer monitoring device, which comprises the following steps of: actually measuring a transformer substation, and performing simulation excitation processing by utilizing environmental interference data of the transformer monitoring inspection device to obtain an electromagnetic interference shielding simulation result of the transformer monitoring inspection device; acquiring a high-frequency electromagnetic noise suppression result of the transformer monitoring and checking device based on Matlab by taking the environmental interference data as an excitation condition; and performing verification processing on the electromagnetic interference shielding simulation result and the high-frequency electromagnetic noise suppression result of the transformer monitoring and checking device to obtain an anti-electromagnetic interference result of the transformer monitoring and checking device. The acquisition precision of sensing signals and the stability of data transmission are effectively 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 technical field of explosion-proof packaging operation monitoring, and particularly discloses an explosion-proof equipment operation maintenance monitoring system based on an internet of things cloud platform, which comprises a power supply module, an internet of things, a data acquisition module, a data transmission module and a data storage module, the sensor unit comprehensively monitors the operation state of the explosion-proof equipment by virtue of various sensors, for example, a temperature sensor focuses on temperature monitoring, is not interfered by other irrelevant signals, ensures that the overheating problem is timely perceived and is complementary with a fault instruction transmission anti-interference measure, and the signal conditioning unit amplifies and filters weak signals and removes electromagnetic noise in a targeted manner; in the data transmission module, an instruction noise reduction compensation unit suppresses specific frequency electromagnetic noise through band elimination filtering, frequency compensation is carried out to eliminate distortion, the anti-interference capability of fault instruction signals is improved, accurate transmission is guaranteed, and electromagnetic noise interference is solved from multiple aspects of a source end and a transmission process.

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.

An example wearable electronic device includes a compute core with a skin contact surface and a cavity region that houses: a battery, an electrode located at the skin contact surface configured to sense neuromuscular signals, an analog front end (AFE) configured to partially process the sensed neuromuscular signals into partially processed neuromuscular signals, a printed circuit board (PCB), and a metallic base plate (MBP). The PCB receives the partially-processed neuromuscular signals and determines gestures based on the partially processed neuromuscular signals. The MBP provides an electrical ground for the electrode and electrically shields the electrode from electrical and magnetic noise that is generated at least partially from at least one of the PCB and the battery. The AFE is placed on a first side of the MBP and the PCB is placed on a second side that is opposite to the first side of the MBP.

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.

A dual antiphase read-head arranged card reader is provided. The card reader includes a first read-head arrangement and a second read-head arrangement. Electromagnetic noise is applied to both the first and second arrangements. Waves associated with the electromagnetic noise on the second arrangement is transformed and applied to the first arrangement canceling the noise on a first read head of the first arrangement. The first read head reads magnetically encoded information on a magnetic strip of a card inserted into a card slot of the card reader free of noise. However, the noise remains present such that any skimmer read head of a skimmer inserted into the card slot is unable to read the magnetically encoded information off the magnetic strip of the card.

To provide an electric power conversion device capable of suppressing the generation of electromagnetic noise while ensuring a wide driving range for an input voltage.SOLUTION: A dual inverter type electric power conversion device 1 switches switching elements 4A to 4F of a first inverter 6 in a first control mode that switches the voltage vector six times during one rotation of a motor 3. The electric power conversion device 1 switches switching elements 5A to 5F of a second inverter 7 in a second control mode that is pulse width modulation that outputs only odd-numbered voltage vectors during one rotation of the motor 3, or pulse width modulation that outputs only even-numbered voltage vectors during one rotation of the motor 3.SELECTED DRAWING: Figure 1

The invention discloses a cable intermediate joint temperature measurement method and system based on a thermomagnetic noise signal, relates to the field of cable joint temperature measurement, and aims to solve the problem that the precision and stability of an existing temperature measurement method in a complex environment are affected by external factors and are easy to cause measurement errors. The method comprises the following steps: acquiring material information and physical size of a cable joint shielding layer; establishing a relation model of the thermomagnetic noise intensity level and the temperature; two magnetometers are used for measuring and obtaining magnetic field intensity signals B1 and B2 at the center of the shielding layer; obtaining the signal intensity of the thermomagnetic noise at the center; and calculating the temperature under the corresponding thermomagnetic noise signal intensity according to the obtained thermomagnetic noise signal intensity and a model, and obtaining the temperature data T of the cable joint. Compared with a traditional measurement method, the technical scheme has the advantages of being high in precision, insensitive to environmental change influences and suitable for scenes needing long-term stable operation.

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 present invention relates to the field of earphone technology, and in particular to a dual-magnetic noise reduction earphone and a control method thereof, comprising an earphone holder; both ends of the earphone holder are provided with a telescopic frame; one end of a fixed part is provided with a push rod for abutting against the earphone holder; the other end of the fixed part is provided with a body; the body is provided with a first diaphragm; a accommodating cavity is formed between the first diaphragm and the body; a driving unit is provided in the accommodating cavity; a lifting bracket is provided for lifting and lowering activities in the accommodating cavity; a permanent magnet is provided at the top of the lifting bracket; a second diaphragm is provided at the bottom of the first diaphragm; a magnetorheological fluid is provided between the first diaphragm and the second diaphragm; a transmission mechanism is provided between the push rod and the lifting bracket. The present invention adjusts the extension and retraction of the telescopic frame according to the size of the user's head, thereby driving the lifting bracket to drive the permanent magnet to move up and down, and uses the second permanent magnet to change the stiffness of the magnetorheological fluid, thereby limiting the amplitude of the first diaphragm, controlling the volume output, and preventing excessive volume from damaging the hearing of child users.

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.