Yuki Ohno

Permanent magnet assisted current superimposition variable flux machine

Electric and hybrid electric vehicles require traction motors that have a high power and efficiency over a wide rotation speed range . In order to satisfy these requirements and reduce the motor cost, variable flux reluctance motors (VFRMs) have been studied . Conventional VMFRMs have DC-field windings and armature windings. However, because there are two kinds of windings, the coil space factor decreases and the wiring becomes complicated . In order to solve these problems, we have developed a motor called the variable flux reluctance motor (CSVFRM) that does not have any DC-field coils, and instead uses current superimposition . In this paper, we propose a modified model whereby permanent magnets are introduced into the stator to increase the efficiency . The structure and operational principle of this machine are described and the N-T characteristics are computed by FEA.

Finite-Element Analysis and Experiment of Current Superimposition Variable Flux Machine Using Permanent Magnet

We have proposed a current superimposition variable flux reluctance machine that can control its torque constant. This machine can be operated by using a six-phase superimposition current composed of ac-armature and dc-field currents. In this paper, we propose a current superimposition variable flux machine using permanent magnets. The permanent magnets increase the dc magnetic flux. First, the structure and operational principle of this machine are described. Next, the torque characteristics are computed under vector control. Finally, the computed characteristics are verified by carrying out measurements on a prototype.

Design and Analysis of Magnetic-Geared Motor With Field Windings

Magnetic-geared motors have been attracting attention as a type of low-speed and high-torque motor. The maximum torque is, however, limited by the maximum transmission torque between the rotors. This paper proposes a magnetic-geared motor with field windings which can increase and decrease the maximum transmission torque. Its N-T curve is then calculated and compared with a magnetic-geared motor without field windings. The characteristics are determined using finite element analysis.

Magnetizing directions of the permanent magnets of the magnetic-geared motor

We have clarified that a magnetic-geared motor with permanent magnets in the high-speed rotor and stator slots shows a good performance in terms of the output power and transmission torque. This paper describes the influence of the magnetizing directions of the permanent magnets in the high-speed rotor and stator slots. The torque characteristics are computed using finite element analysis and are verified by carrying out measurements on a prototype.

Study on a current superimposition variable flux reluctance machine with distributed winding

A current superimposition variable flux reluctance machine that can control its torque constant has been proposed. This machine requires only a single set of windings that can perform both armature and field winding functions simultaneously. Therefore, it is easy to apply a distributed winding and sprit core to our proposed machine. In this paper, a current superimposition variable flux machine using distributed windings is proposed and compared with that using concentrated winding. First, the structure and operational principle of the proposed machine are described. Next, the static characteristics are computed using 2D finite element analysis. Finally, the N-T characteristics are computed under vector control and the effectiveness of the proposed machine is discussed.