This paper presents simulation based design (SBD), which is an indispensable technique, particularly for emerging advanced machine developments. This makes the support of SBD a requirement for Computer-Aided Engineering (CAE) tools.

While experience plays a crucial role in conventional CAE, in SBD, the design is created solely via simulations to achieve a highly optimal design with high reliability. SBD primarily relies on large scale optimizations with a vast design space and on solving large scale problems for virtual prototyping. Both require high computation power, however large computations result in better designs. Therefore, an SBD tool is expected to motivate and inspire users to aggressively use the latest computational power, instead of minimizing simulations.

Unlike conventional CAE, SBD workflow is not a simple waterfall type, instead, it adopts a multi-perspective iterative process to effectively improve the design. The workflow in practice is primarily dictated by the tool. If the necessary functions are divided into multiple tools, the workflow will also be divided, which negatively affects iterations. The tool is expected to integrate the functions into one environment and encourage users to perform an adequate number of iterations in multi-perspective studies.

The implementation of SBD is demonstrated via practical examples, and the expected functionality of an SBD tool is discussed.

This study analyzes and evaluates the stator core loss density of an interior permanent magnet synchronous motor (IPMSM) by proposing and developing conceptual diagrams of an extended building factor while considering the nonlinearity of the magnetic properties of the material. The IPMSM, whose stator and rotor are composed of non-oriented electrical steel, is investigated. First, the motor is driven by a three-phase inverter with the pulse width modulation (PWM) excitation method and then with the three-phase sinusoidal excitation technique at a rotational speed of 1500rpm in each condition. The calculation procedure of the stator core loss of the IPMSM is improved from our previous method. The finite element method (FEM) is used to support the identification and computation of motor iron losses, where the PWM carrier frequency is 10kHz. In addition, experimental results of the extended building factor diagrams for the ring and IPMSM cores under the sinusoidal and inverter excitations are shown and discussed. The main objectives of this study are to investigate and clarify the reasons for increasing the IPMSM stator core loss density owing to the effects of the core shapes and two excitation methods, as well as to thoroughly identify the dominant impact between the core shape and excitation method on the increase in the iron loss density. Furthermore, based on the extended building factor, particular values of the IPMSM stator and rotor core losses in the experiment can be relatively separated and determined.

Recent research in the field of robotics has primarily focused on motion generation methods using imitation learning to adapt to various environments. Human-level speed motion can be imitated by combining imitation learning with bilateral control. In this approach, prediction errors accumulate in the leader because this method requires a leader state that does not exist during autonomous operation. This issue is caused by the low-frequency prediction error of the leader's responses during autonomous operation. Therefore, this paper describes a training model for predicting a leader's state by eliminating low-frequency prediction errors during autonomous operations. The proposed training model predicts the high-frequency state of the leader-follower differential. Because the low-frequency of the leader is not included in the information input and output of the proposed training model, the low frequency prediction error of the leader does not occur during autonomous operation. During our analysis, while writing letters on a paper on a slope, the previous training model failed to write letters when the paper position moved away from the robot. By contrast, only the proposed training model achieved writing at all positions in the experiment.

A high voltage bidirectional DC/DC converter is necessary for interconnecting a medium voltage (MV) DC network to a low voltage DC network in future DC power distribution networks. Several multilevel converter topologies have been investigated to handle the high voltage stress on the MV network, including a diode/capacitor clamped converter, a modular multilevel converter, and a cascaded H-bridge converter. However, these converters face the problem of voltage imbalance. In this study, a novel bidirectional isolated hybrid ripple-cancel dual active bridge (HRCDAB) converter for high voltage applications is developed. The proposed converter inherits the cancellation of the high-frequency ripple of DC-link capacitors, zero-voltage switching (ZVS), elimination of the DC bias current of the transformer, and automatic voltage and current sharing between stacked semiconductors. The circuit operation and certain features of the proposed circuit are comprehensively analyzed in this paper. Moreover, the design methodology of the proposed converter is presented. A scaled-down 900-V/600-V/1.2-kW prototype of the proposed converter is fabricated to experimentally demonstrate the validity of the comprehensive operation analysis and design theory.

In an electrolytic capacitor-less inverter, source current harmonics are caused by LC-circuit resonance, and the source power factor deteriorates. Therefore, an inverter must reduce harmonics control without additional circuits. This paper proposes a source current control method to reduce source current harmonics in a three-phase to three-phase electrolytic capacitor-less inverter of a permanent magnet synchronous motor drive. The proposed method consists of a source current control using the full-state feedbacks of a LC-resonance state observer. The validity of the proposed method is confirmed through experimental results.

This paper proposes a novel method for measuring the characteristics of a wireless power receiver of an electric field wireless power transfer (eWPT) system. The proposed measurement method allows us to obtain the frequency response of the eWPT receiver's power-receiving characteristics with respect to the spatial electric field frequency. Conventionally, it was not possible to measure the reception characteristics of a single independent receiver. This is because a resonant eWPT transmitter has pronounced frequency dependent characteristics. As a result, frequency-dependent electric fields are emitted into space and act on the receiver. The proposed measurement method overcomes this obstacle by using the proposed device that generates a high-frequency electric field almost independently of the frequency. The proposed device generates high-frequency electric fields in space by using a terminating resistor instead of resonator circuits. Therefore, unlike resonant transmitters, the strength of the electric field generated by the proposed device does not exhibit a large frequency dependence. The proposed measurement method will also be useful for the prototyping, evaluation, and optimization of new advanced eWPT systems whose characteristics are not yet fully understood. Here, 85kHz series resonant eWPT receivers are evaluated using the proposed measurement method, and the details of this experimental device are also described.

This paper presents the design of a hybrid-excitation-type DC brush motor, simulation and analysis of a commercially available diesel generator starter, and use of the finite-element analysis software, Maxwell 3D, to develop the motor model. Moreover, an improvement is proposed for magnet fixing and compared with the traditional dovetail groove design. Magnet fixation via the splicing method effectively mitigates magnetic saturation; therefore, a power density analysis is performed to demonstrate that the proposed improved design can increase the power density of the magnet per unit volume. Additionally, this work involves another structural improvement, i.e., the hybrid-excitation-type optimization design, along with the use of the Taguchi algorithm to optimize the power of a part of the stator structure; variance analysis and sensitivity are also considered. The analyses justify the selection of control factors for the optimization design. At a rated speed of 3,400rpm, the output power of the motor increases by 25.1% relative to the prototype. Considering the economic benefits and applications to automobile engines in product development, the new motor configuration enables performance improvements without increasing the weight of the car body.

This paper presents a stabilization method for different dual parallel surface permanent magnet synchronous motor (SPMSM) systems with a single inverter. When a single inverter drives two synchronous motors, disturbance can cause a torque difference between the two motors. This can cause the motor's electrical and mechanical resonance. Several damping control methods have been proposed to suppress such resonance. However, such methods consider that the parameters of the two motors are identical. When a single inverter controls two motors with different parameters, the damping control performance deteriorates. Besides, the motor's resonance sound and current ripple increase. To address these problems, this paper proposes a control method for dual-parallel-SPMSM drive systems with a single inverter.

Unbalanced parameters of the parasitic components in a three-phase inverter cause unbalanced losses in the device. This research focuses on equalizing the device's losses for an unbalanced three-phase inverter. This letter proposes a novel two-phase (2ϕ) PWM scheme that uses the variable switching pause period. This letter numerically equalizes the device's losses for the unbalanced three-phase inverter.

This study provides a circuit analysis model of a DC brush motor to predict spike surges at mechanical contacts and conducted EMI by considering the behavior of steady arc discharge. The mechanical contacts model comprises multiple variable resistors, constant voltage sources, ideal diodes, and stray capacitances. In the proposed model, spike surges with steady arc could be predicted with 90% accuracy. Moreover, simulated conducted EMI according to CISPR 25 standard is deviated from the measured value at a maximum of 25dB. Therefore, it is demonstrated that the quantitative prediction of conducted EMI requires consideration of a showering arc model at mechanical contacts.

The purpose of this research is to develop an electromagnetic pump system for electrification of casting applications, and this paper reports the evaluation results of drive characteristics considering the electromagnetic fluid elements or time harmonics that are inverter driven. First, considering the electromagnetic fluid elements, an alternative experiment is proposed using oil mixed with aluminum powder, and the results of the lift speeds driven at variable frequencies by a pure sinusoidal power supply are demonstrated. Then, considering the time harmonics driven by a pulse-width modulation control inverter, another experiment is performed through aluminum pipe lifting. The experimental results for lift speed when the combination of carrier frequency and excitation frequency are changed is reported. These results clarify the effects of the two factors on the lift speed.