A Simulation Magnetic Induction Tomography (MIT) for Agarwood using COMSOL Multiphysics

Magnetic induction tomography is an imaging technique used to image electromagnetic properties of an object by using the eddy current effect. (MIT) is a non-destructive method that greatly is used in the agriculture industry. This method provided an opportunity to improve the quality of agricultural products. MIT simulation was used for agarwood existence detection. This paper presented for the simulation system contains 7 channel coils receiver and a channel transmitter which is a sensing detector. This experiment aims to demonstrate the reaction of induced current density and magnetic field at 10 MHz frequency. Then, it also determines the optimal solenoid coil to be used for a better outcome for the magnetic induction system. The simulation result shows that coil diameter, coil length, and coil layer have a crucial role in the great performance of the induced current and magnetic field. The more coil turns, the greater the strength of the permanent magnetic field around the solenoid coil. The result of the simulation is important and needs to be considered to verify the effectiveness of the system for developing the magnetic induction circuit design.

Design and indirect adaptive fuzzy H∞ control of a novel retarder coupled with eddy current effect and MR effect

To improve the poor braking performance of the traditional eddy current retarder, a novel retarder is developed by coupling the eddy current effect and the magnetorheological effect, which has large torque at low speed and stable torque at high speed. To meet the constant speed requirement in the braking process, the indirect adaptive fuzzy H∞ control strategy is employed to control the rotor speed of the designed retarder. The results show that the proposed retarder has the characteristics of continuously adjustable large torque in full speed section, sensitive control process and constant speed intelligent control.

Research on Absolute Positioning Sensor Based on Eddy Current Reflection for High-Speed Maglev Train

A novel absolute positioning sensor for high-speed maglev train based on eddy current effect is studied in this paper. The sensor is designed with photoelectric switch and four groups of unilateral coplanar code-reading detection coil combination. The photoelectric switch realizes the positioning of the marker plate, and the four groups of detection coils read the mileage code of the mileage sign plate to obtain the absolute mileage information of the vehicle, which effectively reduces the quality and volume of the sensor, and reduces the impact of ice and snow. At the same time, the code-reading reliability and speed adaptability index are proposed. The code-reading reliability of the sensor is analyzed and tested under the fluctuation of levitation guidance, and the positioning error under the speed range of 0–600 km/h is calculated and analyzed. The results show that the novel sensor has the advantages of simple and compact structure. It still satisfies the system’s requirements for absolute vehicle mileage information under the conditions of vehicle operating attitude fluctuations and changes in the full operating speed range.

Interference Analysis of Metal Conductors for Target-Resonance-Based Detection Method

Frequency bifurcation phenomenon is an important input characteristic of the magnetically coupled resonant wireless power transfer (MCR-WPT) system in overcoupling situation. In this paper, frequency bifurcation phenomenon in MCR is extended to the general transmitter-receiver coupling system, and the two main factors affecting the phenomenon are analyzed. Finally, the phenomenon is introduced into the field of signal detection, and a noncontact detection method based on target coil resonance is proposed in this paper. Since the proposed method is a kind of electromagnetic method, the detection system is highly susceptible to the surrounding metal conductors. Therefore, the detection performance of this method under three metal-environment conditions is analyzed, respectively. Simulations and experiments show that the metal barrier can weaken the detection because of the eddy current effect, but as long as the barrier does not completely isolate the two coils, the method still has strong penetrability. Besides, the metal plate placed parallel outside the transmitter has less influence on the detection when compared with the metal barrier, and the metal plate by the side of the transmitter can even enhance the detection effect. As a consequence, this method has strong stability in metal environment.

Metal Object Detection in a Wireless Power Transfer System Based on Double-Layer Symmetric Sensing Coils

The intrusion of a metal object into a wireless charging system could cause safety issues, such as temperature rise and even combustion. This paper proposes a double-layer symmetric sensing coil design for metal object detection (MOD) of wireless electric vehicle charging to prevent the detection blind area. First, the magnetic effect and the eddy current effect of a metal object in high-frequency magnetic fields are analyzed. Second, the principle of the proposed double-layer symmetric sensing coils is detailed. Finally, the finite element simulation is implemented in order to test the performance of the proposed sensing coil design. The simulation results show that the proposed double-layer symmetric sensing coils can effectively detect the presence and position of the metal object simultaneously.