• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.6
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• pp.445-451
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• 2019

An input power estimation method of a three-phase inverter for the high-efficiency operation of AC motors is proposed. Measuring devices, such as DC link voltage and input current sensors, are required to obtain the input power of the inverter. In the proposed method, the input power of the inverter can be estimated without the input current sensor by using the phase current information of the AC motor and the switching pattern of the inverter. The proposed method is more robust to parameter error than conventional method. The validity of the input power estimation method is verified through experiments conducted on a 1 kW permanent-magnet synchronous motor drive system.

• The Journal of Korea Robotics Society
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• v.10 no.1
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• pp.9-15
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• 2015

We present a robust power transmission lines detection method based on vanishing point estimation. Vanishing point estimation can be helpful to detect power transmission lines because parallel lines converge on the vanishing point in a projected 2D image. However, it is not easy to estimate the vanishing point correctly in an image with complex background. Thus, we first propose a vanishing point estimation method on power transmission lines by using a probabilistic voting procedure based on intersection points of line segments. In images obtained by our system, power transmission lines are located in a fan-shaped area centered on this estimated vanishing point, and therefore we select the line segments that converge to the estimated vanishing point as candidate line segments for power transmission lines only in this fan-shaped area. Finally, we detect the power transmission lines from these candidate line segments. Experimental results show that the proposed method is robust to noise and efficient to detect power transmission lines.

• Journal of IKEEE
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• v.22 no.2
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• pp.460-475
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• 2018

In the variable-speed wind energy system, to achieve maximum power point tracking (MPPT), the wind turbine should run close to its optimal angular speed according to the wind speed. Non-linear control methods that consider the dynamic behavior of wind speed are generally used to provide maximum power and improved efficiency. In this perspective, the mechanical power is estimated using Kalman filter. And then, from the estimated mechanical power, the wind speed is estimated with Newton-Raphson method to achieve maximum power without anemometer. However, the blade shape and air density get changed with time and the generator efficiency is also degraded. This results in incorrect estimation of wind speed and MPPT. It causes not only the power loss but also incorrect wind resource assessment of site. In this paper, the adaptive maximum power point tracking control algorithm for wind turbine system based on the estimation of wind speed is proposed. The proposed method applies correction factor to wind turbine system to have accurate wind speed estimation for exact MPPT. The proposed method is validated with numerical simulations and the results show an improved performance.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2520-2527
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• 2000

An improved transition density propagation method for power estimation is proposed. The power estimation for the zero delay model is a proper criteria for the.lower boutldlIry for power consumption. A transition propagation method, including the zero delay model as a lower boundary for power stimation was studied. However, there were some redundancy factors in the process of transition density propagation. Hence this paper will explore the transition density propagation behavior to eliminate the redundancy factors and present theirriprQved estimation methodology for the signal transition density. The experiments show that the proposed method has comparably better estimation accuracy than the conventional methods.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.80-84
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• 2000

Network parameters in power systems are indispensable for all of power system engineering studies, including the power flow calculation and the state estimation. The network parameters required for the studios, in general, are estimated by using several estimation techniques, since it Is very difficult to measure. To improve the estimation accuracy of the network parameters, this paper adopt the synchronized phasor measurements which are acquired from the Phasor Measurement Unit with built-in GPS receiver. In this paper, the parameter estimation problem is formulated with over-determined nonlinear measurement equations and solved with Newton-Raphson method and pseudo-inverse. The effectiveness of the proposed parameter estimation with the synchronized phasor measurements is verified through some case studies with IEEE sample system. The results are very promising.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.222-225
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• 2000

In this paper, a synchronous CDMA system accepted for the cdma2000 standard is simulated to propose optimized reverse link power ratio and channel estimation lengths. Differently from IS-95, the pilot channel is used in the proposed system to estimate fading channel, so optimized estimation lengths are needed. Therefore, in this paper we analyze optimized estimation lengths which is needed to decide the power ratio of pilot channel and fundamental channel. From fixed estimation lengths, we calculate FER with various power ratio values.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.4
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• pp.148-155
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• 1986

This paper presents a new decoupled power system state estimation method. The decoupling is achieved via simple linear transformation on power measurements in contrast with the modified fast decoupled state estimation method which assumes decoupling by direct negligence of the off-diagonal blocks of the observation functions. The new estimation method is compared with the modified decoupled state estimation method against IEEE-14 bus model power system and 25 bus model power system in several system conditions. It is observed that the proposed method shows better convergence performance and filtering performance than a modified fast decoupled state estimation.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.145-147
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• 2002

Recently, according to business conditions ;in domestic are beginning to liven up, there is a lively discussion about new housing construction around the center of the Metropolitan area. It is considerable difficult for estimation of power demand exactly to expand power facilities in these area. However. criterion thesis for estimation of power demand which has been applied in present condition is already passed through the 10 years, the reliability to calculate power demand in these area go down far away. Accordingly, it is raised for methodology to evaluate new type of power demand in new housing development in domestic. This paper presents new criterion thesis for estimation of power demand in new housing development through survey and analysis in example area.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.61-65
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• 2015

For effective distribution planning and operation, we need a reliable estimation of operation capacity. But it is difficult to ensure reliability due to the low accuracy of section load data, which is used as a basis in estimating the operation capacity. This paper discusses how to improve the accuracy of section load data by analyzing the existing method of estimating the section load, using statistical techniques to adjust the acquired data, and using the section load estimation algorithm to estimate the section load based on the adjusted data.

• The Transactions of the Korea Information Processing Society
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• v.6 no.3
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• pp.766-772
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• 1999

With the increase of portable system and high-density IC, power consumption of VLSI circuits is very important factor in design process. Power estimation is required in order to estimate the power consumption. A simple and correct solution of power estimation is to use circuit simulation. But it is very time consuming and inefficient way. Probabilistic method has been proposed to overcome this problem. Transition density using probability was an efficient method to estimate power consumption using BDD and Boolean difference. But it is difficult to build the BDD and compute complex Boolean difference. In this paper, we proposed Propowest. Propowest is building a digraph of circuit, and easy and fast in computing transition density by using modified COP algorithm. Propowest provides an efficient way for power estimation.