• Journal of Magnetics
• /
• v.16 no.1
• /
• pp.74-76
• /
• 2011

Interior permanent-magnet synchronous motors (IPMSMs) produce both magnetic and reluctance torques. The reluctance torque is due to the difference between the d- and q-axis inductances based on the geometric rotor structure. The steady-state performance analysis and precise control of the IPMSMs greatly depend on the accurate determination of the parameters. The three essential parameters of the IPMSMs are the armature flux linkage of the permanent magnet, the d-axis inductance, and the q-axis inductance. In the basic design step of an IPMSM, the inductance parameters are very important for determining the motor characteristics, such as the input voltage, torque, and efficiency. Thus, it is very important to accurately estimate the values of the motor inductances. The inductance parameters of IPMSMs have nonlinear characteristics along the magnet size because the iron core is saturated by the magnet and armature reaction fluxes. In this study, the inductance parameters were calculated using both the magnetic-equivalent-circuit method and the finite-element method (FEM). Then the calculated parameters were compensated by the saturation coefficient function, which was also calculated via the magnetic-equivalent-circuit method and FEM.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.10
• /
• pp.600-608
• /
• 2016

This paper proposes a new high-efficient interleaved phase-shift full-bridge (PSFB) converter for low-voltage and high-current power systems. The proposed converter is composed of three switch-bridges and two transformers in the primary side and two rectifiers in the secondary side. Each transformer handles half of the total power with an interleaved operation, so that the proposed converter has high system reliability, as much as the conventional interleaved PSFB converter. The soft-switching characteristics of the proposed converter are better than those of the conventional converter due to the modulated primary side configuration. The proposed converter represents a single lagging-leg bridge, which has a poor soft switching condition in its operation, while the conventional converter has two lagging-leg bridges in its operation. Therefore, the number of switches having hard-switching conditions is reduced by half in the proposed converter. In addition, the reduced switch counts in the primary side of the proposed converter helps decrease the complexity of the proposed converter compared to that of the conventional converter. The operational principle and analysis are presented in this paper and the characteristics are verified using a PSIM simulation with 3kW server power specification.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.8 no.6
• /
• pp.853-861
• /
• 2018

This paper proposes the application of harmonic constraints to address the problems caused by abnormal voltage increases when electric railway vehicles are running. The AC line that supplies the train with power during operation is used to provide electricity of 25kV/60 Hz, but gradually the size and frequency of harmonics involved in the line are varied with the technological evolution of the railroad vehicle electrical equipment. An increase in heat losses due to the failure of the instrument transformer (PT), the main circuit device, which is a serious problem with the recent train safety operation, or to the main displacement voltage. When high frequency components are introduced through low frequency Transformers of the main circuit device, the high intensity of the components is caused by the high intensity of the core and the current flow of the parasitic core is increased, thus generating heat. To solve this problem, the recent adjustment of the sequence has applied artificial NOTCH OFF of the power converter. However, the method of receiving and controlling the OFF signal operates by interaction between the ground and the vehicle's devices, thus it is invalid in the event of failure, and an actual accident is occurring. Therefore, the harmonic currents were required to prevent possible flow of harmonics, and conducted a study to prevent accidental occurrence of train accidents and to verify feasibility of the device through the simulations of the train's experimental analysis and the simulations of the train for safe operation.