199 results about "Magnetic noise" patented technology

A noise pattern acquisition device includes: a geomagnetic sensor; a coordinate estimation unit configured to estimate current position coordinates; and a geomagnetic noise pattern management unit configured to, when an abnormality occurs in a magnetic field strength detected by the geomagnetic sensor during movement of the noise pattern acquisition device, store in a geomagnetic noise pattern storage unit a geomagnetic noise pattern which is a pattern representing a time-series change of the magnetic field strength detected by the geomagnetic sensor. This makes it possible to not only acquire a geomagnetic noise pattern but also detect a proper position with a simple structure and process at reduced cost.

Provided is a highly accurate optical pumping magnetometer, in which a static magnetic field and an oscillating field to be applied to a vapor cell are stabilized. To this end, the optical pumping magnetometer includes: Helmholtz coils for applying a constant static magnetic field to a vapor cell serving as a magnetic field detector; fluxgate magnetometers for detecting environmental magnetic noise in two directions of X-axis direction and Y-axis direction other than Z-axis direction which is a direction for detecting a magnetic field coming out of a measurement object while locating the vapor cell in the center thereof; magnetometer drive circuits for driving the fluxgate magneotometers; current converters for converting outputs of the magnetometer drive circuits into amount of currents; and magnetic field generating coils for generating a magnetic field in a phase opposite to the environmental magnetic noise in the two directions.

The invention provides techniques for reducing or altering the magnetic noise of an AC rotary electric machine. A magnetic noise reducing harmonic current of order n, whose frequency is n times the frequency of the fundamental frequency component of a polyphase AC current fed to an armature of a polyphase AC rotary electric machine, is superimposed on the polyphase AC current, thereby reducing or altering a harmonic component having a frequency (n−1) times the frequency of the fundamental frequency component and occurring due to a radial magnetic excitation force acting radially on an iron core of the AC rotary electric machine. Magnetic noise is caused by a vibration whose energy is the sum of the circumferential and radial vibrations of the iron core occurring due to the magnetomotive force of the rotor, and altering the radial vibration is particularly effective in altering the magnetic noise; as the harmonic component of the radially acting magnetic excitation force, occurring due to harmonic components having frequencies 3, 5, 7, and 13 times the fundamental frequency, has a frequency 6 or 12 times the fundamental frequency, the magnetomotive force of the rotor can be effectively reduced or altered when a current having a frequency 7 or 13 times the fundamental frequency is superimposed on the stator current.

Provided is a highly accurate optical pumping magnetometer, in which a static magnetic field and an oscillating field to be applied to a vapor cell are stabilized. To this end, the optical pumping magnetometer includes: Helmholtz coils for applying a constant static magnetic field to a vapor cell serving as a magnetic field detector; fluxgate magnetometers for detecting environmental magnetic noise in two directions of X-axis direction and Y-axis direction other than Z-axis direction which is a direction for detecting a magnetic field coming out of a measurement object while locating the vapor cell in the center thereof; magnetometer drive circuits for driving the fluxgate magneotometers; current converters for converting outputs of the magnetometer drive circuits into amount of currents; and magnetic field generating coils for generating a magnetic field in a phase opposite to the environmental magnetic noise in the two directions.

A torque sensing device for measuring the torque applied to a rotatable shaft, and also measuring the magnetic field noise affecting the device. The device incorporates a switching function thereby enabling the device to operate in a common signal detection mode and a differential noise detection mode. The device is capable of determining the torque applied to the rotatable shaft based upon output signals obtained from magnetic field sensors operating in both the common signal detection mode and the differential noise detection mode. The device is capable of accurately measuring a torque induced magnetic field and is capable of canceling measurement error resulting from noise induced magnetic fields.

The present invention aims to achieve that geomagnetism can be sensed in high precision while eliminating an adverse influence by magnetic noise with respect to a geomagnetic sensor provided in a housing, and correct azimuth information can be acquired.A portable terminal apparatus according to the present invention is arranged by that both a first housing (11) and a second housing (12) are coupled to each other by way of a hinge portion (13) under pivotable condition, a geomagnetic sensor (33) is provided on a circuit board (32) in the second housing (12), and also, a speaker (19) is provided on the side of a rear surface thereof. Both this geomagnetic sensor (33) and a speaker (19) corresponding to a component for generating magnetic noise which gives an adverse influence with respect to the geomagnetic sensor (33) are provided in the vicinity of each other within the same second housing (12), and both the members are arranged on the same plane. In this structure, since a magnetic force line (35) which is caused by magnetic noise generated from a magnet (19a) of the speaker (19) is intersected with respect to the geomagnetic sensor (33) at a right angle, and thus, a horizontal direction component thereof is not produced, the geomagnetic sensor (33) can correctly sense the geomagnetism without being adversely influenced by the magnetic noise.

A stator core for a rotary electric machine is provided. The stator includes an annular stator core having a plurality of slots punched and arranged in the circumferential direction, being straight in the axial direction, and a stator winding consisting of wire members. The wire members have respective straight portions accommodated in respective slots. Each of the wire members has a conductor portion having a rectangular cross section and an insulating coating covering the conductor portion. An adhesive member is provided between each of the straight portions and the wall surface of each slot. In each slot, the adhesive member adheres the straight portions to the wall surface. Thus, the stator core can maintain the space factor of the wire members accommodated in each slot and suppress vibration of the wire members during the operation of the rotary electric machine to reliably reduce generation of peculiar noise or magnetic noise.

The invention provides techniques for reducing or altering the magnetic noise of an AC rotary electric machine. A magnetic noise reducing harmonic current of order n, whose frequency is n times the frequency of the fundamental frequency component of a polyphase AC current fed to an armature of a polyphase AC rotary electric machine, is superimposed on the polyphase AC current, thereby reducing or altering a harmonic component having a frequency (n−1) times the frequency of the fundamental frequency component and occurring due to a radial magnetic excitation force acting radially on an iron core of the AC rotary electric machine. Magnetic noise is caused by a vibration whose energy is the sum of the circumferential and radial vibrations of the iron core occurring due to the magnetomotive force of the rotor, and altering the radial vibration is particularly effective in altering the magnetic noise; as the harmonic component of the radially acting magnetic excitation force, occurring due to harmonic components having frequencies 3, 5, 7, and 13 times the fundamental frequency, has a frequency 6 or 12 times the fundamental frequency, the magnetomotive force of the rotor can be effectively reduced or altered when a current having a frequency 7 or 13 times the fundamental frequency is superimposed on the stator current.

An electric rotating machine is disclosed which includes a stator and a rotor. The stator includes a hollow cylindrical stator core and first and second three-phase stator coils. The stator core has a plurality of stator core teeth formed at a predetermined pitch in a circumferential direction of the stator core. Each of the first and second three-phase stator coils is comprised of three phase windings. Each of the phase windings of the first and second three-phase stator coils is wound around each of a predetermined number of the stator core teeth by a predetermined number of turns. The rotor has a plurality of magnetic poles the polarities of which alternate between north and south in the circumferential direction of the stator core. Further, the first and second three-phase stator coils are offset in the circumferential direction of the stator core to have a phase difference of π / 6 therebetween.

A torque sensing device for measuring the torque applied to a rotatable shaft, and also measuring the magnetic field noise affecting the device. The device incorporates a switching function thereby enabling the device to operate in a common signal detection mode and a differential noise detection mode. The device is capable of determining the torque applied to the rotatable shaft based upon output signals obtained from magnetic field sensors operating in both the common signal detection mode and the differential noise detection mode. The device is capable of accurately measuring a torque induced magnetic field and is capable of canceling measurement error resulting from noise induced magnetic fields.

The present invention discloses a triaxial magnetoresistive sensor. It comprises a substrate integrated with a biaxial magnetic field sensor, a Z-axis sensor that has a sensing direction along Z-axis perpendicular to the two axes of the biaxial magnetic field sensor, and an ASIC. The biaxial magnetic field sensor comprises an X-axis bridge sensor and a Y-axis bridge sensor. The Z-axis sensor and the two-axis sensor are electrically interconnected with the ASIC. A single-chip implementation of the triaxial magnetic field sensor comprises a substrate, onto which a triaxial magnetic field sensor and an ASIC are stacked. The triaxial magnetic field sensor comprises an X-axis bridge sensor, a Y-axis bridge sensor, and a Z-axis bridge sensor. The above design provides a highly integrated sensor with high sensitivity, low power consumption, good linearity, wide dynamic range, excellent thermal stability, and low magnetic noise.

In a magnetic measurement system for a battery, a magnetic signal generated by electric currents in the battery for charging and discharging can be accurately measured without saturating the output of a magnetic sensor even in an environment having strong magnetic noise, and electric current distribution in the lithium-ion battery is visualized. Generating a antiphase magnetic field having an antiphase magnetic field to a magnetic field measured by each magnetic sensor into the cancel coil disposed around each the magnetic sensor before charging and discharging; thereafter, reducing magnetic noise by subtracting the magnetic data recorded before charging and discharging (the correction-magnetic field data) from the magnetic data for charging and discharging; and accurately measuring the magnetic signal generated from the lithium-ion battery for charging and discharging are included.

An electrical generator having a stator, a rotor, two windings, and a rectifying circuit. The stator has a first winding arranged in a wye configuration and a second winding arranged in a delta configuration. The wye winding is wound in a full pitch pattern around three stator teeth while the delta winding is wound in a short pitch pattern around two stator teeth, or vice versa. The wye and delta windings are connected to a single bridge rectifying circuit.

Each of program cell and memory cells includes a magnetic storage portion of the same configuration. The program cell further includes a state change portion. That is, the program cell has the same structure as the memory cell, except that the state change portion is additionally provided thereto. As such, the program cell can be provided efficiently, as it can be designed the same as the memory cell in terms of the magnetic storage portion and others. The state change portion makes a transition to a fixed state based on an electrical change. Thus, the state change portion prevents program information from being rewritten by a magnetic noise or the like, and ensures stable storage of the program information.

In an electric rotating machine, a stator coil is comprised of first and second winding groups. The stator coil is wound around a stator core in a concentrated winding manner so that the phase difference in electrical angle between each corresponding pair of windings of the first and second winding groups is equal to π / 6. Further, the windings of the first and second winding groups are connected to form Δ-Y connections. Consequently, the sixth harmonic components of the electromagnetic forces created by the windings of the first winding group can be offset by those of the electromagnetic forces created the windings of the second winding group. As a result, the total magnetic noise and torque ripple generated in the machine can be reduced. Moreover, the machine can be driven with only a single three-phase inverter to achieve the effects of reducing the total magnetic noise and torque ripple.

An automotive alternator including a rotor having a plurality of poles; a plurality of phases in operable communication with the plurality of poles; and a stator core in operable communication with the rotor, the stator having a number of slots defined by:S=(P×PH)+((M×PH)+N)where S=number of slots P=number of poles PH=number of phases M=a whole integer greater than or equal to 0 N=a whole integer selected from a group of integers ranging from, and including, 1 through the number of phases minus 1. A method for reducing magnetic noise in an automotive alternator includes selecting a number of poles, selecting a number of phases, selecting a number of stator core slots, the foregoing selections interacting in the automotive alternator to produce an order of frequency of a tangential force different than any multiple of the number of phases and different than an order of frequency of a radial force of the alternator.

The invention relates to a children ASD diagnosis device based on a magnetoencephalogram and an electroencephalogram. The children ASD diagnosis device comprises a magnetic shielding system, a head-mounted electroencephalogram and magnetoencephalogram array type sensor system, an electroencephalogram and magnetoencephalogram data acquisition system, a sensory stimulation system, a signal processing system and a data analysis system. The magnetic shielding system can effectively reduce background magnetic field noise. The head-mounted electroencephalogram and magnetoencephalogram array type sensor system can carry out whole-brain collection on a tested child in a combined nesting mode. The electroencephalogram and magnetoencephalogram data acquisition system can record brain electrical activity information. The sensory stimulation system can present visual and auditory sensory stimulation for the tested child. The signal processing system removes biological magnetic noise and backgroundmagnetic noise. The data analysis system can extract pathological features in the signals for analysis. The children ASD diagnosis device provided by the invention has the advantages of high sensitivity and specificity, multiple information sources, high signal quality, easy acceptance by children and the like. The children ASD diagnosis device has the advantages of high sensitivity and specificity in the aspect of ASD diagnosis of children.

Noise compensation in controlled source electromagnetics (CSEM) comprises measuring time-varying magnetic gradients of the marine environment subjected to CSEM. From the measured magnetic gradients, oceanographic electric and magnetic field noise is determined and used for noise compensation of CSEM measurements of electric and magnetic fields. Selection of magnetic gradient measurement provides improved measurement of oceanographic magnetic noise as other electromagnetic noise sources produce negligible magnetic gradients in the marine environment. Electric field noise is then predicted from the magnetic measurements.

The invention discloses an on-line detecting method for three-dimensional force in closed iron magnetic shell, which adopts Barkhausen magnetic noise detection device, applies variable-frequency electromagnetic excitation and rotating electromagnetic excitation to the iron magnetic shell to be measured, to obtain electromagnetic MBN, MAE signals at different depths in the iron magnetic shell body, performs three-dimensional rebuilding to the MBN, MAE signals, and ultimately detects the three-dimensional stress and flaw distribution in the iron magnetic shell to be measured. The invention has beneficial technology effects of simple operation, wide application range, non harm to human body during operations, and capability of performing three-dimensional scanning and detection to the internal stress and defect in the iron magnetic shell.

An electrical machine (20) includes a stator core (54) having slots (80) and a set of windings (58) disposed within the slots (80). The windings (58) are configured in 2N+1 phases, where N in greater than 1. Such a machine is particularly useful for automotive alternators.

A differential circuit includes first and second side circuits which are coupled to receive control signals in such a way as to introduce an intentional imbalance in the differential circuit for certain benefits discussed herein. An exemplary pseudo-differential LC tank circuit is described which includes first and second side nodes, and an inductance circuit and a variable capacitance circuit coupled between the nodes. The inductance and variable capacitance circuits may be broken out into separate tanks to achieve certain magnetic noise reduction benefits. Each exemplary variable capacitance circuit includes a first variable capacitance coupled between the first side node and a common ground node, and a second variable capacitance coupled between the second side node and the common ground. Each of the first and second variable capacitances is coupled to receive control lines for controlling the capacitance of the first and second variable capacitance circuits in a pseudo-differential manner. Each variable capacitance includes at least one of many types of switch-capacitor cells, some of which are described herein.

An object tracking system includes a sensor grid having a plurality of sensor clusters configured to sense the presence of a magnetic field of an object. Each sensor cluster includes three or more single-axis magnetic sensors. The sensors in a cluster may be arranged with their axes parallel to one another. The sensor grid may account for ambient magnetic noise by measuring the magnetic field in a zone a distance away from the object to update the ambient magnetic field noise measurement. The sensor grid or a portion thereof may include a plurality of sensors printed on a common sheet. The sensor grid may comprise one or more sheets overlapped or interconnected. The system may track an object and determine up to three degrees of positioning and three degrees of orientation by using a geometric solution of the intercepts of magnetic field strengths obtained from information collected by the magnetic sensors.

The invention relates belongs to the technical field of communication and relates to a monitoring system, in particular to a transformer partial discharge online monitoring system. The transformer partial discharge online monitoring system comprises a diagnostic analysis unit, and a communication unit is connected to the diagnostic analysis unit. A plurality of collecting units are connected to the communication unit, and a plurality of sensing units connected with an electric transducer are connected to each collecting unit. A plurality of different types of sensors bound together are connected to each sensing unit, and a power supply module is arranged on each sensor. Compared with the prior art, the transformer partial discharge online monitoring system has the advantages that a piezoelectric sensor keeps away from the magnetic noises of an iron core and the mechanical vibration and noises of a transformer; a super-high-frequency sensor does not play a role of capacity coupling but plays a role of an antenna for receiving super-high-frequency signals, the diagnostic analysis unit can simultaneously start the operation of a plurality of modules to realize data reference among the different modules; the communication unit has diversified ways and also can be suitable for all kinds of environment in the data transmission process.

A method for compensating for magnetic noise fields in spatial volumes includes determining the strength of a magnetic field outside said spatial volume; defining the correlation between the noise field outside the spatial volume and the corresponding noise field inside said spatial volume; generating a magnetic compensation field for neutralizing the noise field in said spatial volume. The method further provides separate detection of noise fields with frequencies in the range of at least two different frequency bands.

A magnetic ink character reading apparatus has a magnetic detection unit for detecting magnetic ink characters on the check and generating magnetic detection signals, a noise data generator for generating magnetic noise data by accumulating magnetic detection signals before the check passes the magnetic detection unit, and a magnetic noise cancellation unit for removing magnetic noise by subtracting the magnetic noise data from the magnetic detection signals.

Embodiments of the present invention help to reduce mag-noise in a magnetoresistive head without deterioration in reproduced output and improve the signal / noise ratio (SNR) of the magnetoresistive head. According to one embodiment, the magnetoresistive head uses a synthetic ferri free layer and it is arranged such that the magnetic field which is applied to an end of a free layer with smaller film thickness and saturation magnetization in the track width direction by a coupling field is larger than the magnetic field which is applied to it by a bias layer.

A scanning microscope for high resolution current imaging by direct magnetic field sensing of a sample maintained in an ambient environment. The scanning microscope uses a magnetic sensor such as a SQUID and a fiber probe magnetically coupled between the SQUID sensor and the sample under study. The fiber probe has a sharply defined tip for high resolution probing and for reaching minute cavities on the surface of the sample. The coupling between the tip of the fiber probe and the sample is controlled by a distance control mechanism, in the range of 1-100 nm. The material of the fiber probe with high permeability and low magnetic noise is chosen to optimize flux transmission to the magnetic sensor. Magnetic coupling to the sensor is maximized by keeping the distance between the end of the fiber probe and the sensor to approximately 0-100 μm. The fiber probe is integrated into the fiber holder for easy replacement of the fiber probe.

The invention belongs to the technical field of environmental protection and particularly relates to a preparation method of intelligent magnetic noise-reducing polyurethane foam. The preparation method comprises the following specific steps: treating the surface of carbonyl iron powder with a silane coupling agent; mechanically dispersing and prepolymerizing treated carbonyl iron powder, polyhydric alcohol and a chain extender; adding a crosslinking agent, a surfactant, a catalyst and isocyanate, rapidly stirring and pouring; and under the action of an external magnetic field, enabling carbonyl iron particles to form chain structures and be arranged in a foam skeleton and foaming at room temperature to produce anisotropic magnetic polyurethane foam. The entire preparation process has specific flow and is relatively simple and convenient to operate. The magnetic polyurethane foam is prepared by a one-step foaming process, the product combines the advantages of magnetic particles and polyurethane foam, has a flexible damping characteristic and is conductive to weakening the sound so that controllable acoustic and mechanical properties are achieved and the magnetic polyurethane foam can be used as a sound-absorption noise-reducing material. The magnetic polyurethane foam can be applied in fields such as civil use, automobiles and aerospace and has higher application values.

the present invention aims to achieve that geomagnetism can be sensed in high precision while eliminating an adverse influence by magnetic noise with respect to a geomagnetic sensor provided in a housing, and correct azimuth information can be acquired. A portable terminal apparatus according to the present invention is arranged by that both a first housing (11) and a second housing (12) are coupled to each other by way of a hinge portion (13) under pivotable condition, a geomagnetic sensor (33) is provided on a circuit board (32) in the second housing (12), and also, a speaker (19) is provided on the side of a rear surface thereof. Both this geomagnetic sensor (33) and a speaker (19) corresponding to a component for generating magnetic noise which gives an adverse influence with respect to the geomagnetic sensor (33) are provided in the vicinity of each other within the same second housing (12), and both the members are arranged on the same plane. In this structure, since a magnetic force line (35) which is caused by magnetic noise generated from a magnet (19a) of the speaker (19) is intersected with respect to the geomagnetic sensor (33) at a right angle, and thus, a horizontal direction component thereof is not produced, the geomagnetic sensor (33) can correctly sense the geomagnetism without being adversely influenced by the magnetic noise.