• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2015년도 제46회 하계학술대회
• /
• pp.958-959
• /
• 2015

This paper proposes adaptive incremental conductance(A-IC) algorithm for maximum power point tracking(MPPT) control of photovoltaic. Conventional Perturbation & Observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small fixed step size will cause the tracking speed to decrease and tracking accuracy of the MPP will decrease due to large fixed step size. Therefore, this paper proposes N-IC MPPT algorithm that adjust automatically step size according to operating conditions. To improve tracking speed and accuracy, when operating point is far from maximum power point(MPP), step size uses maximum value and when operating point is near from MPP, step size uses variable step size that adjust according to slope of P-V curve. The validity of MPPT algorithm proposed in this paper prove through compare with conventional IC MPPT algorithm.

• The Journal of the Acoustical Society of Korea
• /
• 제27권2E호
• /
• pp.64-68
• /
• 2008

This paper investigates noise reduction performance and performs convergence analysis of a Variable Error Data Normalized Step-Size Least Mean Square(VEDNSS LMS) algorithm. Adopting VEDNSS LMS results in higher system complexity, but noise is reduced providing fast convergence speed Mathematical analysis demonstrates that tap coefficient misadjustment converges. This is confirmed by computer simulation with the proposed algorithm.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1997년도 추계학술대회 논문집
• /
• pp.114-119
• /
• 1997

Natural vibration of the rotor system having multi-step cross-sections is analyzed. The rotary inertia and the shear deformation are considered. Torque is also included in order to simulate the power transmission system. The complex displacement and the variable separation are introduced. The exact solutions in uniform cross-section segment and the boundary conditions are used. Natural frequencies and mode shapes are obtained, especially the mode shapes are countinuous.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2017년도 추계학술대회
• /
• pp.191-192
• /
• 2017

본 6-스텝 운전은 하드웨어의 수정 없이 운전 영역을 확장할 수 있다는 장점을 가진다. 하지만, 샘플링 주파수 대비 기본파 주파수가 크면 저주파수 전류 맥동 문제가 발생한다. 이는 시스템의 효율을 낮추고 안정성 문제를 일으킨다. 따라서, 본 논문에서는 가변 시간 제어 방법을 제안한다. 선형화과정을 통해 정확한 전달 함수를 구하고, 이를 이용하여 추가적인 약 자속 제어기나 전류 지령 생성기 없이 6-스텝 운전을 구현 할 수 있다.

• 대한전기학회논문지
• /
• 제36권8호
• /
• pp.539-546
• /
• 1987

In case of operating at Variable speed the induction motor by a frequency transformer, it will cause ripples in motor torque and considerably bad effects on the machines because the output side of the frequency transformer involves a great number of harmonics. This paper Presents the methods of decreasing torque ripples in induction motor and of improving current waveform, by means of forming the waveforms of output current into multi-step waveforms similiar to sinusoid, and also by means of eliminating the harmonic components maximally, in case of operating a 18-phase multi-inverter combining 3-step current source inverter.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2002년도 ICCAS
• /
• pp.87.2-87
• /
• 2002

$\textbullet$ Introduction of an adaptive echoes canceller in telephone network and the propose $\textbullet$ The echoes canceller structure $\textbullet$The Lattice/Transversal Joint structure $\textbullet$ The propose robust variable step-size algorithm for lattice form structure $\textbullet$ Performance evaluation $\textbullet$ Simulation results $\textbullet$ Conclusion

• Journal of applied mathematics & informatics
• /
• 제11권1_2호
• /
• pp.201-213
• /
• 2003

In this paper we present a second order PVT (parallel variable transformation) algorithm converging to second order stationary points for minimizing smooth functions, based on the first order PVT algorithm due to Fukushima (1998). The corresponding stopping criterion, descent condition and descent step for the second order PVT algorithm are given.

• 대한기계학회논문집
• /
• 제12권6호
• /
• pp.1350-1357
• /
• 1988

A computer software was developed for predictions of fatigue crack initiation life of notched members under variable loadings. The software was constructed based on a new fatigue life prediction method utilizing modified .epsilon.-N curves, which can account for the stress interaction effect. The effect of mean plastic strain on low-cycle fatigue life was also incorporated in the software. The software can be utilized for the first step approximation when fundamental data of material fatigue properties are not available.

• Journal of Electrical Engineering and Technology
• /
• 제4권1호
• /
• pp.135-142
• /
• 2009

In this paper the Simplified Refined Instrumental Variable (SRIV) identification algorithm for SISO systems is extended to MIMO systems described by a Left Matrix Fraction Description (LMFD). The performance of the extended algorithm is compared to the well-known MIMO four-step instrumental variable (IV4) algorithm. Monte Carlo simulations for different signal to noise ratios are conducted to assess the performance of the algorithm. Moreover, the algorithm is applied to a simulated quadruple tank process.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제3권1호
• /
• pp.71-79
• /
• 1999

We consider multi-step quasi-Newton methods for unconstrained optimization. These methods were introduced by Ford and Moghrabi [1, 2], who showed how interpolating curves could be used to derive a generalization of the Secant Equation (the relation normally employed in the construction of quasi-Newton methods). One of the most successful of these multi-step methods makes use of the current approximation to the Hessian to determine the parameterization of the interpolating curve in the variable-space and, hence, the generalized updating formula. In this paper, we investigate new parameterization techniques to the approximate Hessian, in an attempt to determine a better Hessian approximation at each iteration and, thus, improve the numerical performance of such algorithms.