As materials with various properties have been developed for the improvement of performance and lowering material cost of Permanent Magnet (PM) motors, the properties of the materials have become major factors in determining the motor performance. As such a material, the recently-developed anisotropic bonded NdFeB PM showed a nonlinear demagnetization curve. Thus in this paper, by considering the nonlinear property of the PM, a process to calculate the operating point, coupled with a nonlinear analysis of the core, is proposed, and by applying this process, the characteristics of Interior Permanent Magnet Synchronous Motor according to different rotor designs are investigated.Index Terms-Demagnetization, finite element analysis, nonlinear magnetics, operating point, permanent magnet motors.

Solenoid valve is a very important hydraulic actuator for an automatic transmission in terms of shift quality. The same form of pressure for the clutch and the input current are required for an ideal control. However, the gap between a pressure and a current can occur which brings a delay in a transmission and a decrease in quality. This problem is caused by hysteresis phenomenon. As the ascending or descending magnetic field is applied to the solenoid, different thrust forces are generated. This paper suggests the calculation method of the thrust force considering the hysteresis phenomenon and consequently the accurate force can be obtained. Such hysteresis occurs in ferromagnetic materials, however the hysteresis phenomenon includes a minor hysteresis loop which begins with an initial magnetization curve and is generated by DC biased field density. As the core of the solenoid is ferromagnetic material, an accurate thrust force is obtained by applying the minor hysteresis loop compared to the force calculated by considering only the initial magnetization curve. An analytical background and the detailed explanation of measuring the minor hysteresis loop are presented. Furthermore experimental results and finite element analysis results are compared for the verification.

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Electronic of military vehicle that had relied on pure machinery system is ongoing. A large part of electronic of small-sized military vehicle has been already commercialized, which will expand to large-sized military vehicle field. Design of solenoid valve for automatic transmission is significantly important for stable driving performance of military vehicle. This research aims to develop simulation method which is capable of predicting performance of solenoid valve quantitatively according to its variation of ATF temperature. The research has been conducted in line with Maxwell, a magnetic field analysis program, and AMESim, a hydraulic analysis program. After simulation, it turned out to have been very similar to the test result in temperature range which excludes high temperature (over 120°C) and extremely low temperature (below -20°C).

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