In this paper, a new active clamping current-fed half-bridge converter is proposed, which is suitable for fuel cell power generation systems. The proposed converter is superior to conventional dc-dc converters in terms of efficiency and component utilization. The overall efficiency is estimated to be 94% at full load.

This paper propose a fault detection algorithm for stator inter-turn faults (SITFs), dynamic eccentricity faults (DEFs), and hybrid faults (a combination of SITF and DEF) in a permanent magnet (PM) brushless dc motor. We analyzed specific frequency patterns of the stator input current to diagnosis and distinguish the fault types. First, we developed a two-dimensional (2-D) finite element method (FEM) program using a system matrix, and then we confirmed additional specific frequency patterns of the input current by a fast Fourier transform. Finally, specific frequency patterns for each fault type were verified by experimental results.

This paper presents a novel design method to reduce the cogging torque of interior-type permanent-magnet (PM) motor. In the design method, the optimal notches are put on the rotor pole face, which have an effect on the variation of PM shape or the residual flux density of PM. Through the space harmonic field analysis, the positions of notches are found, and the optimal shapes of notches are determined by using finite element method. The validity of the proposed method is confirmed by experiments.

This paper proposes a new design of SPOKE-type PM brushless direct current (BLDC) motor without using neodymium PM (Nd-PM). The proposed model has an improved output characteristic as it uses the properties of the magnetic flux effect of the SPOKE-type motor with an additional pushing assistant magnet and subassistant magnet in the shape of spoke. In this paper, ferrite PM (Fe-PM) is used instead of Nd-PM. First, the air-gap flux density and backelectromotive force (BEMF) are obtained based on the field model. Second, the analytical expressions of magnet field strength and magnet flux density are obtained in the air gap produced by Fe-PM. The developed analytical model is obtained by solving the magnetic scalar potential. Finally, the air-gap field distribution and BEMF of SPOKE-type motor are analyzed. The analysis works for internal rotor motor topologies. This paper validates results of the analytical model by finite-element analysis for wing-shaped SPOKE-type BLDC motors.

This paper presents design and analysis results of a 2.6-kW interior permanent-magnet synchronous motor developed for an electrohydraulic power steering system. The motor was designed by using the proposed equivalent magnetic circuit model in consideration with a core loss. To analyze motor characteristics by using the equivalent magnetic circuit model, inductance and iron-loss resistance, which are affected critically by magnetic saturation, are obtained by using finite-element analysis. Finally, motor characteristics such as armature current, torque, and efficiency are calculated by the equivalent magnetic circuit model and verified by experimental results.

This paper proposes a harmonic elimination method for vibration and noise minimization of an interior-type permanent-magnet motor, achieved by alternating the distribution of the radial flux density. The minimization of vibration and noise is realized by forming optimal notches corresponding to the shape of the magnetic field on the rotor pole face. The variations in vibration are computed by a nonlinear finite element method, and the validity of the analysis and rotor shape design is confirmed by performing vibration and performance experiments.