Inductive sensor

About: Inductive sensor is a research topic. Over the lifetime, 2282 publications have been published within this topic receiving 21984 citations.

Characterization of High- $Q$ Inductors Up to its Self-Resonance Frequency for Wireless Power Transfer Applications

Abstract: The primary coil of an efficient asymmetric inductive link (IL) has a high quality factor and operates near its self-resonance frequency (SRF). Therefore, its characterization is challenging, especially because the measurement instruments must be able to measure a large reactance and a very small resistance at a frequency where the inductor radiates. In this letter, we present a method suitable for characterizing high- $Q$ inductors up to its SRF. The proposed method uses an inductive sensor to characterize the inductor under test without galvanic contact. The method was validated by applying it to the primary coil of an asymmetric IL. The empirical results are consistent with the theoretical model and the full-wave simulations.

Research and development on the air-core coil sensor for mine transient electromagnetic exploration

Abstract: The interior space of mine is narrow,and many roadways′width and height are less than 2meters.At present,overlapping multi-turn device is mainly used in the mine transient electromagnetic method,of which the shape and area is not fixed,so it can not guarantee the correctness of the received signal.Its data processing and geological interpretation are essentially based on ground half-space transient electromagnetic method,which has many technical problems to be solved at the application level.For the limitation of the detection space and the whole space distribution of detected target in the mine transient electromagnetic method,this paper developed a kind of inductive air-core coil sensors suitable for this method.The effective area of the sensor at home and abroad meets the requirements of the mine,but the bandwidth is too narrow.And the blind spot is too long,which limits the scope of the mine transient electromagnetic detection.So it is significant to develop a kind of inductive sensor suitable for the mine transient electromagnetic detection.According to the needs of the mine transient electromagnetic detection,the basic technical indicators of the inductive air-core coil sensor are determined.By analyzing the physical structure ofthe air-core coil and the equivalent noise circuit of the pre-amplifier circuit,the main source of introduced noise is obtained.Constructing the equivalent model of inductive air-core coil sensor,we realize the analysis of the amplitude-frequency characteristics and low noise of the sensor,and give the regular pattern of each noise source which affects the noise level of sensor with frequency.The method of reducing the sensor noise in the mine transient electromagnetic detection is designed,with which the SNR(signal to noise ratio)of the sensor at the resonant frequency improves 15.6dB.Test results showed that the noise performance and output characteristics of inductive air-core coil sensor surpasses 3D-1HF-coil sensor of Canada′s Geonics,which meets the needs of mine transient electromagnetic detection.Inductive sensor has been used as a key component of transient electromagnetic receiving system,and its noise level determines the minimum resolution of the received signal directly,which affects the result of the detection.In the production of the air-core coil,a LCR equivalent model is established.Winding the coil hierarchically and segmentally can reduce the distributed capacitance and inductance of the coil,which thereby increases the resonant frequency and broadens the response bandwidth.Small size,wide bandwidth,large effective area and low noise inductive aircore coil sensors are designed for the whole space response of limited space inside the mine.In this paper,a air-core coil sensor with mean diameter of 0.6m,equivalent area of 30m2,bandwidth of700 kHz is produced based on the study of the equivalent model,frequency characteristics,and the noise model.

An inductive sensor assembly for use on a ground vehicle

Abstract: An inductive sensor assembly for use on a ground vehicle to provide signals representing deviations of the vehicle from a reference path defined by a current-carrying- guidewire. The assembly includes: a plurality of coils (L1, L2, L3, L4, L5, L6) arranged in a predetermined pattern, each of the coils (L1, L2, L3, L4, L5, L6) providing a respective voltage which varies in accordance with horizontal displacement of the coil from the guidewire, and means for combining the voltages to provide a first signal which is proportional to the heading of the vehicle independent of lateral displacement and means for combining the voltages to provide a second signal proportional to the lateral displacement of the vehicle independent of heading.

A hydraulic cylinder comprising at least one electric position indicator

Abstract: A hydraulic cylinder (1) with a piston (5) made completely or partially of electrically conductive material comprises at least one opening (19, 20) for the mounting of an electric position indicator (21, 22). The openings (19, 20) are closed in a liquid and pressure-proof manner towards the interior of the cylinder (1) by means of circular plate-shaped bodies (17, 18) glued to the inner surface of the cylinder (1). As the plate-shaped bodies (17, 18) are made of a ceramic material, preferably steatite, they may allow passage of the magnetic field transmitted from the electric position indicators (21, 22). The openings (19, 20) are adapted in the end covers (2, 3) of the cylinder (1) for the determination of the end positions of the piston (5). Furthermore the cylinder may be provided with piston-braking means in the form of seal rings (12, 13). As the piston (5) penetrates the magnetic field, an altered signal indicating the position of the piston (5) will be transmitted from the electric position indicator, which is preferably an inductive sensor. Very narrow inductive sensors being used it is now possible to built these into even very small hydraulic cylinders, so that these inductive sensors can be built into hydraulic cylinders of all sizes without being influenced by the high pressure of the cylinders. The hydraulic cylinder (1) according to the invention may even be manufactured in a very inexpensive and simple manner, and by building in the inductive sensors a previously unknown exact and reliable determination of the positions of the piston may furthermore be obtained.

Object proximity detector and object position detector

Abstract: The present invention offers an object proximity detector and object position detector. The variation of frequency of an oscillator is used to detect the proximity of an object to a sensor plate. The dependence of the sensitivity of the detector on the area of the sensor plate is reduced by conducting the sensor plate to two capacitors in series. The conducting wire of the sensor plate can be flexible without causing error detection. In the sensor element of the sensor oscillator, a resistor is connected at one terminal of the sensor plate to form a high pass filter. A resistor and a capacitor are added to the sensor oscillator to form a low pass filter. The high pass filter is used to reduce the low frequency electromagnetic interference. The low pass filter is used to reduce the high frequency electromagnetic interference.