Yoshitsugu Otomo

This paper presents the topology optimization of the magnetic core for a wireless power transfer (WPT) device. In this optimization, the coil and magnetic-core shapes for WPT are represented by the Gaussian basis functions. They are sequentially optimized using the genetic algorithm and 3-D finite-element analysis so that the coupling coefficient of the WPT device is maximized. Moreover, a robust optimization method is proposed to keep the interlinkage flux as large as possible against misalignm

This article proposes a novel topology optimization method using the Gabor filter, which is widely used in the field of image processing. The proposed method is applied to the optimization of a synchronous reluctance motor; its average torque is maximized, and simultaneously, the torque ripple is minimized. It is shown that the proposed method results in a motor with thin layer-shaped flux barriers, which achieves a better torque performance in comparison with a conventional model and a motor op

This article proposes a novel analysis method for the losses in a litz wire considering the circulating and eddy currents. In the proposed method, the macroscopic complex permeability is introduced to evaluate the eddy current loss owing to the proximity effect. Homogenization-based finite element analysis using the macroscopic complex permeability can effectively compute the proximity effect loss. The loss owing to the circulating currents is evaluated by solving the corresponding circuit equat

In this paper, the multi-turn coil used in a wireless power transfer (WPT) device is modeled as a uniform material using the homogenization method to consider the proximity effect. By fitting the coil impedance to the numerical results, the Cauer equivalent circuit of the multi-turn coil is synthesized for the design and optimization of the power circuits in the WPT device. It is shown that the results obtained from the equivalent circuit and measurement are in good agreement. Moreover, the impe

This article proposes a novel 2.5-D multi-phase topology optimization method using a Gaussian basis function for permanent magnet motors. The design region in the rotor was sliced into cylindrical layers; the 2-D topology optimization was performed for each layer such that the average torque was maximized, while the torque ripple was suppressed to the maximum possible extent. The proposed topology optimization could determine the rotor core and magnet shapes, as well as the magnetization directi

This article proposes a novel optimization method to design the transmitting and receiving coils of a wireless power transfer (WPT) device considering its magnetic and circuit properties. In the proposed optimization, the coil shapes are determined by parameter optimization (PO) for manufacturability, whereas the magnetic core shapes introduced near them are determined by topology optimization (TO). The power transfer efficiencies of the optimized WPT device are evaluated using the SPICE simulat

This article proposes a method for modeling electric devices based on a Cauer circuit whose circuit parameters are directly determined from measured or computed data using the adjoint variable method. It has been shown that electric devices that are governed by the quasi-static Maxwell's equation can be modeled by the Cauer circuit. From the synthesized Cauer circuit, eddy current losses can be evaluated for a wide frequency range. Moreover, it can be embedded into a circuit simulator to perform

This paper proposes a novel optimization method, Boolean geometry projection method, for the determination of permanent magnet configuration in interior permanent magnet motors. In the proposed optimization, the magnet configurations are freely modified without the upper and lower limits of shape parameters that have to be carefully determined by users. It is shown that the proposed method leads to the torque performance better than that obtained by conventional approaches.

This article proposes a two-step topology optimization method based on the normalized Gaussian functions. The proposed method is shown to be effective for design of a claw-pole alternator. In this method, the global search using the micro-genetic algorithm (μGA) is followed by the local search using the sensitivity analysis based on the adjoint variable method. The 3-D structure of the rotor is optimized using the proposed method under low- and high-speed conditions.

Purpose The purpose of this study is to search for an optimal core shape that is robust against misalignment between the transmitting and receiving coils of the wireless power transfer (WPT) device. During the optimization process, the authors maximize the coupling coefficients while minimizing the leakage flux around the coils to ensure the safety of the WPT device. Design/methodology/approach In this study, a novel topology optimization method for WPT devices using the geometry projection meth

This paper presents topology optimization of magnetic couplers for wireless power transfer (WPT) device considering electromagnetic shields. In this optimization, the magnetic coupler shape for WPT is represented by the Gaussian basis functions. The coupler shape is optimized so that the coupling factor is maximized while the leakage flux is minimized. Moreover, a robust optimization method is proposed to keep the interlinkage flux as large as possible against misalignment between the coils. It

This paper presents three-dimensional topology optimization of magnetic cores for wireless power transfer with double-sided winding coils. In this optimization, the magnetic core shape is represented by the linear combination of the normalized Gaussi

Novel rotor structures of an asymmetric interior permanent magnet (IPM) motor are realized by using the topology optimization (TO) in this study. The TO method to be presented in this article takes into account both the configuration of the magnet and the geometry of the magnetic core. In the optimization, the shape of the magnetic core is determined by a linear combination of the Gaussian basis functions, whereas the magnet configuration is determined by a Boolean geometry projection for its ma

In this study, we propose a novel topology optimization method for permanent magnet (PM) motors by using a Gabor filter (GF) to obtain slit-shaped magnetic cores. Moreover, we propose a hybrid optimization method by combining a GF with a normalized Gaussian network to simultaneously realize slit-shaped and smooth magnetic cores. In the proposed optimization, we minimize the torque ripple while maximizing the average torque. The proposed hybrid optimization results in a PM motor with slit-shaped

ABSTRACT In this paper, we present a quasi‐3D multi‐material topology optimisation (MMTO) method to improve the torque density of a surface permanent magnet (SPM) motor. In the proposed MMTO approach, the 3D optimisation model is segmented into multiple layers along the axis of rotation. The material distributions and magnetisation directions of the permanent magnets in each layer are simultaneously optimised. Furthermore, we propose a hybrid quasi‐3D MMTO method that incorporates parameter opti