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This paper presents an asymmetric magnetic pole structure interior permanent magnet synchronous motor (IPMSM) with a simplified magnet shape that uses bonded rare-earth magnets. By adopting the asymmetrical magnet arrangement, the current phase angle, where the magnetic torque is maximized, can be set to almost the same phase while maximizing the reluctance torque. It was shown that the proposed motor can achieve larger torque compared with conventional IPMSMs that use sintered neodymium magnets.

A proposed axial gap induction motor (AGIM) with an improved space factor using toroidal winding exhibited double the output torque of a radial gap induction motor (RGIM) of the same size. The structure of the AGIM’s toroidal winding, in consideration of actual machine production, was then studied, and the results of the torque characteristics analyses were compared with those of previous analyses. The actual machinery was made using a powder core, and its maximum torque was 1.6 times that of a finite element analysis RGIM when set at the same torque. The high efficiency confirmed that the AGIM had improved.

In this paper, we propose a novel method to extract keyframes from motion capture data. A hybrid approach, which combines a curve-simplification algorithm with an initialization procedure including principal component analysis, is adopted. The developed method automatically extracts an appropriate number of keyframes at high speed without performance degradation. Experimental results prove the effectiveness of the present method. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

A laminated-core parametric motor has advantageous features and a planar structure that make it possible to reduce the mass-production costs of the motor. In past work, we presented the practicality of applying a two-dimensional reluctance network model using variable reluctances that enabled dynamic analysis of a motor while the rotor was spinning. We investigated how to improve the analytical accuracy of the reluctance network model of the motor by using parameters δ.

We studied a three-phase parametric motor excited by a single-phase power supply. We carried out many experimental evaluations to improve the characteristics of the motor. An analytical technique was necessary to further improve the motor characteristics and to optimize its design. In the past, we demonstrated the validity of applying reluctance network analysis (RNA) to the dynamic analysis of a laminated core parametric induction motor, which is a basic three-phase parametric motor. Consequently, we applied RNA to a single-phase input three-phase parametric motor.

A laminated core parametric induction motor has desirable features and the planer structure to make it possible to reduce the production cost of the motor by mass production. In the past work, we showed the validity to apply the two-dimensional reluctance network analytical model to the dynamic analysis of the motor while the rotor is driving. In this paper, we investigate the improvement the accuracy of the analytical method of the motor by using new reluctance network analytical model of the motor. In this model, the magnetic circuits of the stator and the rotor are connected by the variable reluctances that are expressed as the function of the rotating angle.

This paper proposes a method to adjust the physical constitution of a human body model used in motion capture data analysis. A physical constitution is adjusted so as to accurately classify motion capture data based on the difference in motion characteristics. The adjustment process is modeled as an optimization problem and solved numerically. Analysis results suggest the effectiveness of the proposed method and the point to which attention should be paid. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

In networked control system (NCS) though IP networks, there are the issues such that time delays, its jitter and packet losses cause control performance degradation. Hence, many control schemes against the issues have been developed. For evaluating the effectiveness of the scheme, control experiments generally need to be done under actual IP networks. However, in actual networks, it is difficult to experiment under various conditions. Hence, the evaluation should be done under networks emulated by emulators because they can make the various realistic conditions. Therefore, it is important to confirm the validity of emulator in the case of using in NCS. In this paper, we discuss the validity of a popular network emulator built-in Linux, called netem, in terms of NCS. As a result, it has been found by experiment that netem in a recent Linux kernel can work well as emulator in NCS.

This paper presents an operating analysis of a ferrite orthogonal core for high-frequency power control and power conversion. The analysis is based on the three-dimensional nonlinear magnetic circuit of the orthogonal core, and is called Reluctance Network Analysis. The magnetization characteristics of the ferrite orthogonal core are calculated accurately by using Reluctance Network Analysis. On the basis of the obtained magnetization curves, we can analyze the operating characteristics of the various application circuits of the orthogonal core. For an example, the control characteristics of a high-frequency variable inductor using the ferrite orthogonal core are calculated in this paper. © 2001 Scripta Technica, Electr Eng Jpn, 137(4): 10–17, 2001

The operating characteristics of parametric transformers and dc-ac converters with an orthogonal core depend heavily on the core shape. Accordingly, to obtain the optimal design for such devices, the quantitative relationship between the orthogonal core shape and the operating characteristics of the application device are determined. In this paper, the application characteristics are discussed analytically in terms of the orthogonal core shape, with reference to a magnetic circuit model of the core.

When IP network-based control systems of small DC motors are controlled, varying time delays and packet losses through the network cause the performance degradation. A simple scheme for overcoming it is that, using jitter buffer, varying delays is treated as constant delays in the systems. That is, control designs are done as the systems with dead times. Here the issues are how much buffering time jitter buffer needs. In this paper, a scheme applying gain scheduling and jitter buffer is proposed. For confirming the effectiveness, speed control experiments of a small DC motor through IP networks are conducted, and it is shown that the scheme is effective.

The operating characteristics of parametric transformers and dc-ac converters with an orthogonal core greatly depend on the core shapes. Accordingly, in the optimal design for the applications, we used to clarify the quantitative relationship between the orthogonal-core shape and the operating characteristics of the application devices. In this paper, the application characteristics in terms of the orthogonal-core shape are discussed analytically with reference to a magnetic circuit model of the orthogonal core.

This paper describes a push-pull parametric transformer constructed using a pair of orthogonal-cores. The operating characteristics of the parametric transformer with a rectifier load were analyzed based on SPICE simulations. The analysis results show good agreement with experiment. It was found that the input surge current of the full-wave rectifier circuit with a smoothing capacitor can be compensated by the parametric transformer. Use of the parametric transformer as a power stabilizer is anticipated owing to its various functions, such as for voltage regulation and overload protection.

In a previous paper, the authors proposed an orthogonal-core type dc-ac converter for use in photovoltaic power systems. The dc-ac converter has such desirable features as a simple construction, high degree of safety, and, ease of maintenance. The operating characteristics of a single-phase converter for residential photovoltaic power systems have also been reported. In this paper, we discuss the basic operation of an orthogonal-core type dc-ac converter for a three-phase power system based on simulations and experiments. An optimal construction of the orthogonal-core type three-phase dc-ac converter has been developed.

A pole-changing induction motor with pole-amplitude modulation allows a speed ratio other than 1:2 using a single winding. Furthermore it has a good energy-saving performance when used for the flow rate control of pump or blower, and also it provides a low manufacturing cost. However, the pole-changing induction motor with pole-amplitude modulation has a problem that its simple calculation method of characteristics has not been presented.A purpose of this paper is to derive the calculation method by using an equivalent circuit in when an 8-pole cage type induction motor is changed into a 10-pole motor by pole-amplitude modulation. In this paper, the authors suggest the equivalent circuit in which the space harmonic effects are considered, because the 10-pole motor has large harmonic magnetomotive forces. This paper also describes a simple determination method of equivalent circuit constants.Torque-slip characteristics and output-characteristics are obtained, and it has been confirmed that they agree well with the experimental values. This calculation method of characteristic is practical and useful for the future designing of pole-changing induction motors with pole-amplitude modulation.

The orthogonal-core has various applications such as a parametric transformer and a DC-AC converter. The operating characteristics of the application devices can be calculated based on the measured flux-MMF relationship of the orthogonal-core. For the optimum design of the applications, we have to predict the flux-MMF relationship. However, in order to calculate the relationship, we need to solve the three-dimensional nonlinear problem. In this paper, we calculate the flux-MMF relationship based on the magnetic circuit model of the orthogonal-core. The computed results agree well with the experimental ones. It is obvious that the method on this study is valid for the calculation and useful for the optimum design of the applications.

This paper describes an analysis of the behavior of orthogonal-core type push-pull parametric transformers, taking the iron loss of the orthogonal-cores and the copper loss of the windings into consideration. The analysis was performed for the magnetic circuit of the orthogonal-core under magnetic saturation and with hysteresis. To improve the accuracy of calculations, the saturation characteristic was approximated by a series which includes terms of up to 21st order in the flux, and the hysteresis curve by a series including terms of up to 5th order in the exciting voltage. The calculated results show good agreement with experimental data. The analytical method presented here is useful for optimizing the design of push-pull parametric transformers.

A laminated core parametric induction motor utilizing a parametric oscillation has a flat and slotless structure suitable for mass-production. This paper analyzes the laminated core parametric induction motor when the rotor is driving by the use of a three dimensional reluctance network model. The dimensions and materials of the motor were also shown. An analytical model of the rotor is constituted of the electrical circuit to evaluate the induced currents on the rotor bar and end ring and the magnetic circuit to express the MMFs corresponding the induced currents on the rotor.

This is a co-publication with Journal of Physics D: Applied Physics. The bulk of the papers, after peer review, are published in Journal of Physics: Conference Series. However a selection of papers, are published separately in a special issue of Journal of Physics D: Applied Physics.