• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1836-1842
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• 2012

Torque is proportional to the rate of change of inductance in a switched reluctance motor (SRM), and hence, phase inductance is an important parameter in determining the behavior of an SRM. Therefore, the accurate prediction of inductance with respect to rotor position makes a significant contribution to designing an SRM and its analytical approach is not straightforward due to nonlinear flux distribution. Although several different approaches using a finite element analysis (FEA) or curve-fitting tool have been employed to compute phase inductance [2-5], they are not suitable for a simple design procedure because the FEA necessitates a large amount of time in both modeling and solving with complexity for every motor design, and the curve-fitting requires the data of flux linkage from either an experimental test or an FEA simulation. In this paper, phase inductance is predicted by means of a permeance method, and the proposed approach is analytically verified in terms of the accuracy of estimated inductance compared to inductance obtained by FEA.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.34-40
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• 2012

Flux linkage of phase windings or phase inductance is an important parameter in determining the behavior of a switched reluctance motor (SRM) [1-8]. Therefore, the accurate prediction of inductance at aligned and unaligned rotor positions makes a significant contribution to the design of an SRM and its analytical approach is not straightforward due to nonlinear flux distribution. Although several different approaches using a finite element analysis (FEA) or curve-fitting tool have been employed to compute phase inductance [2-5], they are not suitable for a simple design procedure because the FEA necessitates a large amount of time in both modeling and solving with complexity for every motor design, and the curve-fitting requires the data of flux linkage from either an experimental test or an FEA simulation. In this paper, phase inductance at aligned and unaligned rotor positions is estimated by means of numerical method and magnetic equivalent circuit as well, and the proposed approach is analytically verified in terms of the accuracy of estimated inductance compared to inductance computed by an FEA simulation.

• ETRI Journal
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• v.43 no.6
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• pp.1103-1112
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• 2021

In this study, we present a venting clip for high-power applications that is intended to reduce stray inductance. To reduce the stray inductance of packages in high-power applications, the proposed venting clip features slots are inserted onto a conventional clip. A conventional clip and the proposed venting clip were designed and fabricated to compare the respective stray inductance. The inductance of the proposed venting clip was approximately 15.8% than that of the conventional clip at a frequency of 100 kHz. Through a comparison between the conventional and venting clips, it is confirmed that the proposed venting clip is superior for high-power applications in terms of decreasing inductance. With reduced inductance, the switching-loss for such applications is also expected to decrease. Moreover, the impedance of the venting clip decreased by approximately 15.5% compared with that of the conventional clip at a frequency of 100 kHz. The venting clip, which has reduced resistive component, is also expected to decrease conduction loss in highpower applications.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.1141-1144
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• 1998

A new design methodology for the shortchannel CMOS IC-package is presented. It is developed by representing the package inductance with an effective lumpedinductance. The worst case maximum-simultaneous-switching noise (SSN) and gate propagation delay due to the package are modeled in terms of driver geometry, the maximum number of simultaneous switching drivers, and the effective inductance. The SSN variations according to load capacitances are investigated with this model. The package design techniques based on the proposed guidelines are verified by performing HSPICE simulations with the $0.35\mu\textrm{m}$ CMOS model parameters.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.6
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• pp.23-30
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• 2013

This paper shows the method of winding connection and the balance of three phase of dual inverter systems used for offshore wind power generator. In order to satisfy low cost manufacturing of large scaled wind generator, the number of slot per pole per phase should be reduced. For this reason, in this research, the number is selected as '1' which is the minimum number that stator can have. Based on the prototype machine, three types of machine for the analysis are selected, and various performances especially in terms of electrically balanced condition are also investigated. Moreover, in this paper, new inductance modeling of dual 3-phase considering cross-coupling between two inverter systems is proposed. The several inductances such as mutual-, synchronous inductances are studied. By using FEA, based on calculated the flux linkage of d and q-axis, the validity of the proposed inductance modeling is confirmed.

• Journal of electromagnetic engineering and science
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• v.16 no.2
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• pp.112-118
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• 2016

Alternative analytic expressions for the mutual inductance ($L_m$) and coupling coefficient (k) between circular loops are presented using more familiar and convenient expressions that represent the property of reciprocity clearly. In particular, the coupling coefficients are expressed in terms of structural dimensions normalized to a geometric mean of radii of two loops. Based on the presented expressions, various aspects of the mutual inductances and coupling coefficients, including the regions of positive, zero, and negative value, are examined with respect to their impacts on the efficiency of wireless power transmission.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.2
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• pp.223-246
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• 2015

Structural vibration control using a piezoelectric shunt is an established control technique. This technique involves connecting a piezoelectric patch, which is bonded onto or embedded into the vibrating structure, to an electric shunt circuit. Thus, vibration energy is converted into electrical energy and is dissipated through a network of electrical components. Different configurations of shunt have been researched, among which the negative capacitance-inductance shunt has gained prominence recently. It is basically an analog, active circuit consisting of operational amplifiers and passive elements to introduce real and imaginary impedance on the vibrating structure. The present study attempts to model the behavior of a negative capacitance-inductance shunt in terms of power output and efficiency using circuit modeling software. The shunt model is validated experimentally and is used to control the structural vibration of an aluminum beam, connected to a pair of piezoelectric patches, under broadband excitation. The model is also used to determine the optimal parameters of a negative capacitance-inductance shunt to increase the efficiency and predict the voltage output limit of op-amp against the supply voltage.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.6
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• pp.507-514
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• 2022

This study proposes an optimal design process for a high-frequency transformer that has a large leakage inductance for dual-active-bridge converters. Notably, conventional design processes have large errors in designing leakage transformers because mathematically modeling the leakage inductance of such transformers is difficult. In this work, the geometric parameters of a shell-type transformer are identified, and finite element analysis(FEA) simulation is performed to determine the magnetization inductance, leakage inductance, and copper loss of various shapes of shell-type transformers. Regression models for magnetization and leakage inductances and copper loss are established using the simulation results and the machine learning technique. In addition, to improve the regression models' performance, the regression models are tuned by adding featured parameters that consider the physical characteristics of the transformer. With the regression models, optimal high-frequency transformer designs and the Pareto front (in terms of volume and loss) are determined using NSGA-II. In the Pareto front, a desirable optimal design is selected and verified by FEA simulation and experimentation. The simulated and measured leakage inductances of the selected design match well, and this result shows the validity of the proposed design process.

• Journal of Power Electronics
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• v.19 no.4
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• pp.922-933
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• 2019

The arm inductance (AI) of a modular multilevel converter (MMC) affects both the fault and circulating current magnitudes. In addition, it has an impact on the inverter efficiency and harmonic content. In this study, the AI of a three-phase MMC is optimized in a novel way in terms of DC voltage utilization, harmonics and efficiency. This MMC has 10 submodules (SM) per arm and the power circuit topology of the SM is a half-bridge. The optimum AI is adopted and verified in an MMC that has 100 SMs per arm. Then the phase shift (PS) and phase disposition (PD) pulse width modulation (PWM) methods are investigated for better DC voltage utilization, efficiency and harmonics. It is found that similar performances are obtained for both modulation techniques in terms of DC voltage utilization. However, the total harmonic distortion (THD) of the PS-PWM is found to be 0.02%, which is slightly lower than the THD of the PD-PWM at 0.16%. In efficiency calculations, the switching and conduction losses for all of the semiconductor are considered separately and the minimum efficiency of the 100-SM based MMC is found to be 99.62% for the PS-PWM and 99.64% for the PD-PWM with the optimal value of the AI. Simulation results are verified with an experimental prototype of a 6-SM based MMC.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.425-430
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• 2018

The battery system of an electric vehicle suffers from the problem the battery output and the service life decrease at low temperature. A Positive Temperature Coefficient(PTC) heater is used for maintaining room temperature but is heavy due to a complicated insulation structure. The larger the weight is, the lower the fuel economy of the electric vehicle is. On the other hand a induction heater have a simple insulation structure, which is effective in weight reduction and has a rapid temperature rise. The induction heater consists of an LC resonance circuit. The larger the capacitance is, the higher the price and weight is. Therefore, the inductance should be increased to reduce the capacitance. Also, the main heat source of the induction heater is coreloss. So, it is important to optimize inductance and coreloss in terms of electromagnetic field design. In this paper, the inductance and the coreloss according to the change of the induction heater structure were optimized through the Taguchi method and Finite Element Method(FEM) simulation.