This paper describes an automatic d-axis estimation of a magnetic-geared motor using position sensorless control. The magnetic flux due to the permanent magnet appears in the q axis as well as in the d axis in a magnetic-geared motor when a load is applied to the low-speed rotor. Therefore, 2 position sensors are needed to detect the direction of the total permanent magnet flux. In this paper, an automatic d-axis estimation method for a magnetic-geared motor using sensorless control is proposed. The electric circuit equation of a magnetic-geared motor is shown, and mathematical sensorless control model based on an extended electromotive force model is described. Finally, the effectiveness of the proposed d- axis estimation method is investigated by the comparison of the mathematical simulation, finite element analysis, and measurements on a prototype.

　With the recent trend toward electrification of automobiles, traction motors are also required to have a wide range operation and high efficiency. Currently, an interior permanent magnet synchronous motor (IPMSM) is mainly used. However, the improvement of the efficiency in the high-speed area is expected. Therefore, we have focused on a variable flux motor with a draw-out mechanism to achieve a high efficiency in high-speed areas. In our previous study, we proposed a structure that combines two rotors with different torque constants, and verified that the efficiency and variable flux characteristics can be improved. In this paper, we investigate the effect of the rotor structure on the axial electromagnetic force generated in the stator during a draw-out operation. This investigation indicated that the axial electromagnetic force is influenced by the draw-out rotor and the radial electromagnetic force during a draw-out operation.

　An interior permanent magnet magnetic-geared motor (IPMMGM) is proposed in order to decrease the amount of permanent magnets. The assemblability of the IPMMGM is high compared with a conventional surface permanent magnet magnetic-geared motor. However, the maximum transmission torque of the IPMMGM decreases. In this paper, the shape of the stator tooth and pole piece of the low-speed rotor is focused to increase the maximum transmission torque of the IPMMGM. Firstly, the harmonic magnetic flux generating transmission torque is investigated by the Maxwell stress tensor. Secondly, the influence of the harmonic magnetic flux on transmission torque is mathematically described. Finally, the torque due to the harmonic magnetic flux of 4 models is compared.

　This paper proposes a method to reduce torque ripple in axial gap motor by multi-objective optimization of magnet shape using Fourier series expansion. Torque ripple is a problem because it causes vibration and noise and deteriorates the accuracy of position and speed control. Previously, the torque ripple was reduced while maintaining almost the same torque by designing the magnet in the shape of multiplying wave. However, it is necessary to optimize the function that constitutes the magnet shape to obtain a better one. In this study, the functions constituting the magnet shape are expressed as Fourier series, and a genetic algorithm is used to optimize the combination of their coefficients. As a result, the proposed model was almost equivalent to the average torque of the basic model, and the torque ripple was significantly reduced. Furthermore, fillets were applied to it to verify the effect of the fillets on each characteristic.

　Transcutaneous energy transmission system (TETS) has been investigated as an alternative to wired power transmission systems to ventricular assist device. However, TETS has various drawbacks, one of which is the generation of radiated emission from a transcutaneous transformer at 400 kHz. If the emission exceeds the permissible limits of CISPR11 international standard, peripheral equipment may malfunction. In this study, we attempted to suppress radiated emission by enclosing a transcutaneous transformer, which is the main source of radiated emission at low frequency, with a conductive metal box-shaped shield less than 0.3 mm. As a result, a copper plate with a thickness of 0.096 mm showed the best suppression of 14.43 dBµA/m compared to the case without a shield. The next best suppression of 13.10 dBμA/m was achieved with a perforated aluminum plate 0.297 mm thick. The results of this study indicate that material and shape of shielding are more related to the suppression of radiated emission than the thickness of the shielding.

　High-frequency isolation transformers are used to suppress high-frequency leakage currents in insulated parts of medical equipment. In this study, the coil-to-coil capacitance and power transmission efficiency of a high-frequency isolation transformer were analyzed and measured by changing the winding method of the coil on the ferrite core, with and without PTFE, and the material of the core. The results of the electromagnetic simulation showed that the maximum power transmission efficiency was 99.27 % for the N87 equal winding without PTFE and with PTFE, and the minimum coil-to-coil capacitance was 6.9267 pF for the N87 concentrated winding with PTFE. In the actual measurement, the maximum power transmission efficiency was 98.919 % for the N87 equal winding without PTFE, and the minimum coilto-coil capacitance was 4.3924 pF for the N87 concentrated winding with PTFE.

　In this research, we investigated the characteristic change of the restoring force caused by arranging two hightemperature superconductors (HTS) with concave step. In order to investigate the characteristics, we created a superconducting magnetic bearing with a structure that uses the side surfaces of the HTS for pinning.

By analyzing the restoring force characteristics of the created bearing in each direction, we verified whether the restoring force characteristics would change. As a result of the experiment, it was confirmed the spring constant of restoring force in each direction is increased by arranging the superconductor with a shape of concave step. Also, comparing it with the gap arrangements it was found that it provides greater the spring constant. Therefore, it was found that the restoring force characteristics was improved by adding steps to the high-temperature superconductor. Experiments have shown the usefulness of applying a concave step arrangement to superconductors.

　In this study, the characteristics of a cylindrical magneto-rheological fluid brake made by using a magneto-rheological fluid are considered in which shear stress is generated by forming a chain structure by applying magnetic field. This brake is targeted for adaptation to aircraft. When the aircraft uses the brakes, the temperature inside the brakes rises to over 300 degree, so the values are evaluated when the operating temperature is changed. Since anti-skid braking systems are usually applied to aircraft, the anti-skid braking system is applied to the experimental device used this time, and the shear stress and time constant are measured by changing the operating temperature. The value of the time constant increases as the mean grain size increases. The values of shear stress have increased with increasing grain size in the order of 25, 45 and 8 µm. The values of shear stress and magnetic flux density do not change with temperature. The characteristics of the decrease in rotational speed over time will be investigated in the future.

　Thin flexible steel plate is used in the manufacture of home appliances and other products. Since they are conveyed by rollers in the manufacturing process, deterioration of the steel plate surface, such as abrasions, has become a problem. To solve this problem, non-contact gripping and conveyance of flexible steel plate using magnetic levitation technology has been proposed. As a method for levitating thin flexible steel plate, an electromagnet placed at the edge of the flexible steel plate is suitable. The conventional control model of the system considers only horizontal motion. This model also levitates; however, the problem is that the steel plate may fall depending on the conditions. In this paper, we proposed a two-degree-of-freedom active vibration control system that considers both horizontal and vertical directions to achieve stable levitation. Furthermore, the control performance was investigated by applying the optimal control theory to the proposed system.

　In recent years, multi-degree-of-freedom spherical actuators have been expected to be utilized to reduce the size and weight of multi-degree-of-freedom drive systems used in product manufacturing. To control spherical actuators, data on the torque characteristics in all positions, called a torque map, is required. However, the torque maps on actual machines are difficult to be measured with high accuracy due to variations in permanent magnet characteristics and friction, leading to reduced control accuracy. In this paper, we propose a torque map identification method using deep reinforcement learning. By using the proposed method, it is possible to create a torque map that includes nonlinear disturbances without measuring the torque map, and to construct a highly accurate control system with excellent stability and computational cost. In this paper, a mathematical model of a spherical actuator is used for verification. Control was performed using the identified torque map, and the effectiveness of the proposed method was verified from its accuracy.

　In order to reduce power consumption, there is a strong demand for low-loss motors. Annealing of iron core materials after machining is an effective way to achieve lower loss in motors, but the time and economic cost of annealing in electric furnaces or gas furnaces, which are commonly used today, is a very high. Therefore, a sample holder for low-frequency induction heating was devised to shorten the annealing time and control the heating rate. In this paper, a comparison of the heat cycle with and without the sample holder is performed by using hybrid finite element analysis and measurement on actual specimens, and the results show that the sample holder is effective in improving the heating rate.

　In order to realize a new heat treatment method for Fe-based amorphous magnetic materials (FeSiB) by means of induction heating, effect of the heat treatment in AC magnetic field on magnetic properties is firstly investigated. In this time, the heat treatment is performed by using an electric furnace. The samples used in this measurement are 60 mm x 350 mm sheets. The temperature is controlled to be a reference temperature well below the crystallization temperature of FeSiB. The AC magnetic field is added to the samples with a solenoid coil and the excitation frequency during heat treatment is changed from 60 Hz to 2 kHz. After heat treatment, the magnetic properties of the samples are measured with the single sheet tester (SST). The results showed that the magnetic properties heat-treated in an AC magnetic field show similar tendency to one of the conventional methods in a DC magnetic field.

　We are developing a non-contact magnetostrictive guided wave transceive technology using ultrasonic guided waves for the inspection of long pipes. Our main target is a STPG370 pipe, which is often used inside insulation materials. In this study, we investigated a technique for transmitting and receiving longitudinal guided waves by magnetizing entire circumference of the pipe uniformly in axial direction using cylindrical electromagnets. Burst excitation field parallel to the pipe axis was applied to the magnetized part in the pipe to generate the longitudinal guided waves. A differential induction coil was used to receive magnetic signal due to the guided wave, and signal distribution around the circumference of the pipe was measured. As a result, it was confirmed that the longitudinal guided wave was uniformly distributed around the circumference of the pipe. Defect detection was also successfully demonstrated.

　The objective of this study was to derive an empirical expression for the amount of polishing removal in the case of simultaneous application of magnetic and electric fields using MCF (magnetic compound fluid) processing fluid. In the experiments, a polishing apparatus using disk-shaped permanent magnet tool, a parallel-disk type polisher that enable simultaneously apply magnetic and electric fields, which were developed for this study, and parallel-disk type rheometer that enable apply magnetic field were used. Using these experimental apparatuses, it was shown that the amount of polishing removal in the case of simultaneous application of magnetic and electric fields on the MCF processing fluid is related to the superposition of the processing pressure due to the magnetic field and the processing pressure due to the electric field.

　One type of electromagnetic vibration devices is the bone conduction devices. It utilizes bone-conducted sound transmitted through bones and is expected to be used in hearing aids and noise reduction due to the difference in sound propagation paths. However, since the skull is vibrating, a large thrust force is required. In this paper, we examine increasing the power output of electromagnetic bone-conduction devices. The analysis method combines magnetic field analysis and structural analysis to derive the vibration acceleration level, which is an evaluation parameter of bone conduction devices. In this analysis, we focused on the yoke shape to improve the output and changed the device shape.

　We have developed a homopolar magnetically levitated motor for implantable total artificial hearts. The maglev motor has been developed based on the three-dimensional magnetic field analysis and can produce a magnetic suspension force of 12.4 N and a rotational torque of 50.8 mNm. The outer diameter of the motor is 50 mm and its height, including the coil ends, is 45 mm. A rotor with an outer diameter of 15 mm is suspended with an air gap of 1.5 mm in the inner space of an 18 mm diameter of the maglev motor. The developed maglev motor indicates sufficient magnetic levitation and rotation performance within 0.20 mm of vibration amplitude in the air. The maglev motor is a candidate as an actuator of a total artificial heart.

　Eddy-current rail displacement sensors are mounted on track inspection vehicles for rail inspection on railroads and can measure rail displacement in a non-contact manner. Currently, there is a problem that if a high dielectric constant such as water is deposited near the sensor, the capacitance between the coil and the rail changes, affecting rail displacement detection. Therefore, we compared the characteristics of a 25-turns coil used in existing sensors and a 3-turns coil with the same Quality factor but fewer turns, and studied a coil structure that is less susceptible to the effects of water.

　The authors have been proposed a heating method for a motor core with an induced current to develop stress-relief annealing technique for a simple method and short time. In this paper, we examined the influence of lamination and conductor arrangement on the temperature distribution and magnetic properties of the motor core by heating with an induced current. The temperature of the motor core was increased to 600 ^o C by laminating the core. The motor core is heated by inserting a heating conductor in the slot of the motor core, and the temperature difference on the surface of the motor core reduced. In addition, the magnetic properties of the stress-relief annealed motor core in the new heating conductor arrangement was improved at positions in the upper and middle parts in comparison with that of the conventional heating conductor arrangement.

　Magnetic geared motors have many advantages over mechanical gearboxes, such as reduced maintenance and overload protection. However, the limited life of the mechanical bearings that hold the high-speed rotor is a problem in terms of durability. In order to solve this problem, the authors proposed a magnetic geared motor with additional three-phase windings to magnetically levitate the high-speed rotor. In this paper, a novel motor that applies the principle of a bearingless motor to a high-speed rotor is proposed for a consequent-pole type magnetic geared motor. Compared to the previously proposed magnetic geared motor with a magnetically suspended high-speed rotor, this method has the advantage of high torque density and improved controllability. In addition, the magnetic suspension and attraction forces in each topology were analyzed by finite element analysis.

　The axial-flux self-bearing permanent magnet motor combines a disk motor and magnetic bearings that can generate rotational torque and perform five-axis active suspension. The radial force and tilt torque are generated by superimposing the magnetic fields with plus two and minus two poles on the number of rotor poles. In this paper, the forces and torques acting on the rotor are derived from a simple magnetic field analysis and their characteristics are shown. The analysis results are verified by measuring the forces and torques of a prototype motor using a six-axis force sensor. The results show that the proposed method can generate the bearing's forces.

　In recent years, demand for ultra-compact mobility has increased due to environmental issues and an aging society. Because of their light weight and compact size for one or two passengers, vibrations from the road surface are easily transmitted to these vehicles, resulting in a deterioration of riding comfort. It is also known that the vibration input from the road surface occurs in various directions, such as vertical and pitch, and that the ride quality perceived by the occupants differs depending on the direction of the vibration. In this report, an active seat suspension system that controls multi-directional vibration by installing an actuator under the seat of a vehicle is proposed. A control method to design the vibration frequency characteristics in the vertical and pitch directions separately is also discussed.

　In this paper, we propose a magnetostrictive vibrational generator with a narrow air gap, where the volume of permanent magnets used can be greatly reduced by reducing the reluctance of the air gap. We perform theoretical calculations to verify the feasibility of the proposal. The height of the additional frame teeth is continuously adjusted by finite element analysis to maximize the variation of the magnetic flux density. The results show that the variation of magnetic flux density can be significantly improved when the tooth height is 4 mm or 5 mm, with an average increase of 20%. Finally, control experiments were conducted under the same amplitude conditions, and the results confirmed that the enhanced structure achieved a larger flux density variation, leading to higher voltage generation.

　This paper describes experimental verification to evaluate the modeling method to simplify reinforced concrete structure, whose fine steel structure causes an increase in computation amount, in a numerical analysis of electric field generated by a railway. In the experiment, the electric field generated by electric wires near a reinforced concrete pole is measured by a field mill. The electric field distribution in this problem is evaluated also by the finite element analysis using this simplification method. In this study, the electric field analysis considering the atmospheric electric field is also discussed. As a result of comparing the experimental results and the numerical results, it was found that the analysis using this simplification method was effective when high voltage was applied to the electric wires. However, a large error of the numerical result to the experimental result observed when the electric wires were in blackout.

　In this study, we propose a design method to obtain the optimal parameters of the energy storage mechanism depending on the specifications of the magnetostrictive vibration power generation device and the excitation condition using the Differential Evolution (DE). The dynamic model of the device is assumed to be a linear one-degree-of -freedom damped vibration system, and the half wave voltage doubler, consisting of two capacitors and two diodes, is adopted as the energy storage mechanism. The dynamic characteristics of the entire system subjected to the base excitation are mathematically modeled, and the time response is numerically calculated to derive the time required for the system to reach a given amount of power. The values of capacitance that minimizes the time required for energy storage were explored by using DE, and the optimal solution was verified through analyses and experiments. Through this research, it was shown that DE is effective for the optimal design of the energy storage mechanisms. However, the experimental and analytical time response results did not completely match due to several causes, which were further investigated and clarified.

　The authors have developed vector magnetic property control technology, which is a technology for reducing iron loss of grain-oriented electrical steel sheets. This technology can reduce iron loss caused by rotating magnetic flux and alternating magnetic flux in arbitrary directions. The purpose of this research is to apply this technology to a divided stator motor core using grain-oriented electrical steel sheets to reduce iron loss. In this paper, as a first step, we report the results of applying the technology to a divided ring-shaped magnetic core. Undivided, 2-divided, and 4-divided samples were prepared. For each sample, the application area of the technology was examined using the electromagnetic field analysis method. Each sample was manufactured using a wire electric discharge machine. By measuring and comparing the magnetic properties before and after applying the technology, it was confirmed that the vector magnetic property control technology reduced iron loss.

　Acoustic metamaterials are artificial materials designed to passively attenuate waves in the resonant frequency range by periodically placing resonant structures in the material that are sufficiently smaller than the propagating wavelength. In general, acoustic metamaterial research often suppresses the propagation of elastic waves by means of mechanical local resonant structures. In this study, however, the local resonant structure is replaced by an electrical system to create a coupled electrical/structural vibration system to reduce vibration near the resonant frequency. Numerical simulations using the finite element method were performed to investigate the change in the vibration of elastic waves propagating through a plate in the ultrasonic range when the resonance frequency of the local resonance structure of the electrical system is changed.

　Lung cancer is the leading cause of cancer-related deaths in Japan, with high morbidity rates among younger individuals and women. Treatment options primarily include surgical intervention, drug therapy, and chemotherapy, all of which pose significant psychological and physical burdens and carry high risks. In this study, we investigated a novel treatment approach using atmospheric pressure low temperature plasma (ALTP) and its effects on lung adenocarcinoma cells. Although previous research suggested that APLTP could suppress tumor growth and inhibit cell proliferation in a colorectal cancer model in rats, several issues remained, including the determination of optimal irradiation conditions and elucidation of the underlying inhibitory mechanisms. In this paper, we examined the optimal irradiation time for APLTP treatment on lung adenocarcinoma cell cultures by assessing cell motility and analyzing gene expression profiles.

　Acoustic metamaterials with local resonance structures shorter than the elastic wave wavelength can have frequency bands where elastic wave propagation is suppressed due to their resonance characteristics. Ultrasonic guided waves, which are expected to be an efficient nondestructive evaluation method for long structures, have various modes. The authors have investigated the possibility of using an electromagnetic acoustic transducer (EMAT) to transmit these guided waves and selectively excite the modes due to the relationship between the coil pitch and wavelength. This paper focuses on the propagation behavior of S0 modes selectively transmitted by EMAT to acoustic metamaterials, and investigates the existence of frequency bands where wave propagation is suppressed and the degree of wave amplitude reduction.

　In this study, the relationship between the vibration suppression effect of a gyroscopic damper and the excitation amplitude when a system supported elastically by a superconducting magnetic levitation system is subjected to vibration was investigated through numerical calculations and experiments. While superconducting magnetic levitation systems are capable of uncontrolled and stable levitation, they are prone to nonlinear vibrations caused by magnetic forces due to their non-contact and low damping. We have found that the use of a gyroscopic damper may be effective in simultaneously suppressing translational and tilting vibrations. Experimental results showed that the vibration suppression effect was weakened when the excitation amplitude was increased, and that the waveform had nonlinearity. In this report, the resonance characteristics of a superconducting magnetic levitation system and the possible effects of the vibration damping effect of the gyroscopic damper on the vibration amplitude are evaluated.

　Although superconducting magnetic levitation systems are capable of stable levitation without control, vibration suppression is required due to low damping. One possible way to achieve this is to use an electromagnetic shunt damper with an LCR electrical circuit. However, the direct application of conventional modal analysis is difficult for the LCR parallel type because of the significant velocity term coupling in the circuit equations of the subsystem. Our previous study proposed a method to effectively reduce the amplitude of the main system by applying non-classical modal analysis, which also takes the velocity term into account. On the other hand, in the present study, the impedance expression of the subsystem is used to eliminate the velocity term coupling, allowing the application of conventional classical modal analysis. This study investigates the effect of parameter values on resonance, comparing the results of this classical and nonclassical modal analysis.

　Current skin wound treatments have side effects such as skin atrophy and drug allergies, and there is a need for less invasive treatment methods. Medical applications of atmospheric low-temperature plasma (ALTP) have been promoted in recent years. Skin wound treatment is one of these applications. In this study, we focused on burn wounds, which are one of skin wounds and can form scars and investigated the effect of ALTP on burn wounds: ALTP treatment shortened the healing time of the burn site, and gene expression analysis by RT-qPCR showed that the expression levels of VEGF-a and HIF1a, which are related to angiogenesis, increased. These results suggest that ALTP accelerates healing by activating the HIF1a/VEGF-a pathway and promoting angiogenesis in wound tissue.

　When a system consisting of a beam and a movable mass (slider) is vibrated, the slider may move along the beam, resulting in a change in the natural frequency of the system and resonances, including nonlinearities. This phenomenon, called passive self-resonance, is caused by the nonlinear coupling between the vibration of the beam and the motion of the slider, and can exhibit interesting behavior. In particular, the passive tuning of natural frequencies and the wide excitation frequency bandwidth over which resonance can occur have attracted much interest for applications in vibration power generation. In this paper, considering an electrical system coupled with the vibration of a beam-slider system that undergoes self-resonance, we attempt to expand the excitation frequency bandwidth in which sufficient power can be generated, and evaluate this effect on its vibration energy harvesting.

　This paper proposes a linear oscillatory actuator (LOA) that can switch its degree of freedom (DOF) for the purpose of achieving a wider bandwidth. Electropermanent magnet (EPM) is utilized as an energy-saving solution to switch the DOF by absorbing and desorbing secondary mass with primary mass. Finite element analysis and measurement using a prototype clarify the effectiveness of the proposed LOA.

　A new polyurethane foam that has the properties of permanent magnet, a permanent magnet urethane foam elastomer, has been developed. Since the surrounding magnetic field distribution changes because of the change in the internal neodymium particles’ arrangement due to the deformation of the urethane foam elastomer, it is possible to use it for vibration power generation. Since the induced electromotive force depends on the deformation velocity according to Faraday’s law, the permanent magnet urethane foam elastomer can be sued for a velocity sensor. In this study, a permanent magnet polyurethane foam elastomer was placed in a coil and the relationship between the deformation velocity and induced electromotive force under repeated compression deformation was investigated experimentally. The waveform and topology of the deformation velocity and induced electromotive force were generally consistent and it is shown that it is possible to estimate the deformation velocity from the induced electromotive force.

　The permanent magnet urethane elastomer is a highly deformable permanent magnet, which is expected to realize a battery-free wireless sensor. In the present study, the effect of the shape of the permanent magnet urethane elastomer on the induced electromotive force was investigated. The results show that shaping the material suppresses radial expansion, and adding grooves (45-degree grooves) led to a higher induced electromotive force. Additionally, it was revealed that the induced electromotive force is generated in opposite intensity simultaneously in the upper and lower parts of the sample during compression deformation. These results imply that adjusting the coil's position and roll direction can optimize the induced electromotive force. Finally, we successfully conducted wireless transmission of temperature data using a Bluetooth Low Energy module when the permanent magnet urethane elastomer is utilized as a power source for vibration power generation.

　Switched reluctance motors (SRMs) are reliable and have a low manufacturing cost. However, due to the high vibration and acoustic noise of SRMs, SRMs are not being widely used in industry and electric vehicles. This paper introduces a novel approach for controlling the radial force in switched reluctance motors to reduce acoustic noise. The method relies on strain gauges attached to the stator teeth to measure the radial force. Simulation results from MATLAB and finite element analysis demonstrate that the proposed control method accurately converges the generated radial force to the reference value.

　In recent years, IH cooker have become widely used in general households. However, there have been reports of cases in which IH cooker generate high-frequency noise outside the audible range with a very high sound pressure level of approximately 100 dB, causing discomfort to the human body. The ultimate goal of this study is to propose a method for reducing and improving the discomfort caused by the ultrasonic exposure problem of IH cooker. Among biological signals, we focused on electroencephalography as an evaluation index of discomfort. First, we confirmed the changes in the subject's electroencephalography during the use of the IH cooker. Then, to eliminate external factors other than ultrasonic exposure, we conducted the same experiment with high-frequency noise outside the audible range emitted from a loudspeaker. The results suggest that electroencephalography is useful as an evaluation index of discomfort.