Junya Kaneda

Effects of heat treatments on microstructure and mechanical properties of Mg-15Gd-5Y-0.5Zr alloy

Abstract Microstructure and mechanical properties of Mg-15wt.%Gd-5 wt.%Y-0.5wt.% Zr alloy were investigated in a series of conditions. The eutectic was dissolved into the matrix and there was no evident grain growth after solutionized at 525 °C for 12 h. The evolution of the phase constituents from as-cast to cast-T4 was as follows: α-Mg solid solution+Mg 5 (Gd,Y) eutectic compound → α-Mg solid solution+ spheroidized Mg 5 (Gd, Y) phase → α-Mg supersaturated solid solution+cuboid-shaped compound (Mg 2 Y 3 Gd 2 ). And the precipitation sequences of Mg-15Gd-5Y-0.5Zr alloy were observed, according to the hardness response to isothermal ageing at 225–300 °C for 0–128 h.

Cogging torque due to roundness errors of the inner stator core surface

Cogging torque of brushless permanent magnet (PM) motors employing segmented stator cores with narrow slot openings has been investigated. Two types of test motors were examined: one with a segmented Halbach cylinder rotor and the other with a radially oriented ring PM rotor. The measured cogging torque was predicted from the measured dimensional errors for the inner radius of the stator core in both types.

Motor design approach utilizing regularity of a two-dimensional magnetic field

An approach for finding and optimizing two-dimensional (2-D) motor geometries, based on the regularity of 2-D magnetic fields, is reported. In particular, solving optimization problems such as cogging torque minimization and maximization of time-averaged motor torque, the effectiveness of our approach in cutting computational time is verified. The elapsed time to find the optimal solution is less than 1/10 of the time by a conventional approach whose objective function is calculated from the toque waveform.

A fundamental investigation about maximum torque control of synchronous reluctance motor

Synchronous reluctance motors (SynRMs) can be made of iron and copper. Therefore, they are suitable for low cost manufacturing and recycling when no longer operable. However, SynRMs have nonlinear inductance characteristics and nonlinear torque characteristics. So it is important to clarify those characteristics for SynRM control. In this paper, we manufactured an experimental SynRM with 4 poles. Measured results for inductance and torque characteristics of the motor are shown. We achieve maximum torque control of SynRM. The effectiveness of this control is shown by experimental results.