Kohei Aiso

• Doctor of Engineering
• Associate Professor at Shibaura Institute of Technology

Technical innovations for the downsizing of motor systems are necessary to realize energy savings and roomy and comfortable car interior space in electric vehicles. In this paper, a novel motor drive system with multiple high‐speed motors and a magnetic multiple spur gear (MMSG) is proposed for electric vehicles. Furthermore, the factors leading to...

Technical innovations for the downsizing of motor systems are necessary to realize energy savings and roomy and comfortable car interior space in electric vehicles. In this paper, a novel motor drive system with multiple high speed motors and a Magnetic Multiple Spur Gear (MMSG) is proposed for electric vehicles. Furthermore, the factors leading to...

The WPT is an additional system compared to the conventional contact power supply. Therefore, the volume and efficiency decrease because of increase in the number of conversion stages. This study focuses on design issues specific to small-capacity high-frequency wireless transformers based on the amount of conductors and clarify the appropriate dis...

It is predicted that the maximum speed of EV traction motors will increase in the future due to reductions in size and weight. The high-speed motors are required to have high mechanical strength of the rotor for high-speed rotation, in addition to satisfying the required output and high efficiency in the wide operation area. Therefore, it is necess...

This paper proposes a method to determine the fuel cell voltage of hybrid powered railway vehicles for reducing traction circuit weight. The fuel cell voltage affects traction circuit weight because the number of fuel cell and the required cooling performance of power converters depend on the voltage. Therefore, the voltage should be determined suc...

The current limit of the traction inverters has been relaxed by using silicon carbide devices. The integrated design of the traction circuit system is required. In this paper, the relationship between the speed-torque characteristics of the railway vehicle and the energy saving effect is presented. We considered a model for calculating the mass of...

Magnetic gears realize the characteristics such as low acoustic noise and low vibration, maintenance-free by contact-less power transformation. However, conventional magnetic gears are not suitable for high-speed motor drive systems because of their low mechanical strength, which results from the permanent magnets of the input rotor. This paper pro...

The high speed motor is effective to realize downsizing motor in an electric vehicle (EV). Switched Reluctance Motor (SRM) is possible to the high speed drive because the rotor structure has simple and robust. However, the vibration and the acoustic noise are large from the drive principle. Moreover, the conventional complicated current excitation...

Magnetic gears are expected as the system with maintenance-free, low noise and low vibration characteristics by contact-less power transformation. However, conventional magnetic gears are not suitable system for high speed motors because the mechanical strength is weak due to permanent magnets of the high speed rotor. Adding that, the magnet eddy c...

In this paper, a design of an axial type switched reluctance motor (SRM) is presented that considers the magnetic characteristics of soft magnetic composite (SMC) material. These characteristics are changed by the press and cutting processes for producing the motor core. It is shown that the magnetic characteristics of the vertical and the parallel...

This paper presents a novel single-phase switched reluctance motor (SRM) that can be directly driven by a commercial AC power supply without any switching circuit and sensor. This proposed SRM is optimized based on a simple design technique. The optimized machine has higher motor efficiency compared with conventional induction motors. In addition,...

This paper presents a novel single phase switched reluctance motor (SRM) which can be directly driven by commercial AC power supply without any switching circuit and sensor. This proposed SRM is optimized based on a simple design technique. The optimized machine has aimed to be higher motor efficiency than conventional induction motors (IMs). In ad...