• 한국통신학회논문지
• /
• 제25권10B호
• /
• pp.1769-1776
• /
• 2000

In this paper a new method is proposed to identify a modulation method in the case of unknown digitally modulated input signals. The proposed identification method is implemented with an artificial neural network which is based on characteristic feature extracted from the instantaneous amplitude the instantaneous phase and the instantaneous frequency of the input signals. The proposed method was simulated with 9 type signals (ASK2, FSK2, FSK4, PSK2, PSK4, PSK8, QAM8, QAM16) in a noisy communication environment. The results show that the artificial neural network can accurately recognize all kinds of patterns.

• 한국수자원학회논문집
• /
• 제36권4호
• /
• pp.575-586
• /
• 2003

하천에 오염물질이 순간적으로 유입된 경우에는 연속적인 유입의 경우와 다르게 분산계수의 변화에 따라 오염물질의 거동 특성이 민감하게 변한다. 하천에 순간적으로 유입된 오염물질의 거동특성을 분석하기 위하여 한강하류부에서 수리인자 및 수질인자를 실측하였다. 분산계수 추정에 사용되는 경험식에 실측된 수리인자를 적용하여 갈수시 한강하류부의 분산계수의 규모를 분석하고, 적용 가능성이 큰 경험식을 제시하였다 또한, 실측된 수질인자를 RMA-4 모형의 계산치와 비교하여 만족할 만한 결과를 얻었다. 한강하류부에 순간적으로 유입된 오염물질의 분산계수, 하류단 수위 등의 변화에 따라 오염물질의 분산범위, 분산경로, 최초 및 최대농도 도달시간 등을 파악하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 A
• /
• pp.274-277
• /
• 1996

Vector controlled PMAC(Permanent Magnet AC) motor, with rare-earth permanent magnet, are suitable for servo system demanding fast speed response. However, abrupt acceleration and deceleration control for fast response requires big instantaneous input power. So general PI control of PMAC motors can't be applied for limited power supply system like airplane or portable equipment because of input power fluctuation. Proposed technique to restrain instantaneous input power use variable power limit depends on airgap flux power. Stability check for proposed system is done.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2014년도 전력전자학술대회 논문집
• /
• pp.213-214
• /
• 2014

This paper compares two instantaneous reactive power definitions in DFIG wind turbine with a back-to-back three-level neutral-point clamped voltage source converter under unbalanced grid conditions. In general, conventional definition of instantaneous reactive power is obtained by taking an imaginary component of complex power. The other definition of instantaneous reactive power can be developed based on a set of voltages lagging the grid input voltages by 90 degree. A complex quantity referred as a quadrature complex power is defined. Proposed definition of instantaneous reactive power is derived by taking a real component of quadrature complex power. The characteristics of two instantaneous reactive power definitions are compared using the ripple-free stator active power control algorithm in DFIG. Instantaneous reactive power definition based on quadrature complex power has a simpler current reference calculation control block. Ripple of instantaneous active and reactive power has the same magnitude unlike in conventional definition under grid unbalance. Comparison results of two instantaneous reactive power definitions are verified through simulation.

• 전력전자학회논문지
• /
• 제22권5호
• /
• pp.457-462
• /
• 2017

This paper proposes a digital power control of the LLC resonant half-bridge inverter for high power microwave oven application. Conventional half-bridge inverter for driving a microwave oven uses a hardware-based power control method which varies the frequency according to the AC source voltage. In this case, it is difficult to control the output power according to the variation of the load status of magnetron. The proposed power control consists of an instantaneous current generator and a current controller. Instantaneous current generator makes an instantaneous current reference from power command using input voltage information. Current controller controls input current which has an information of status of magnetron. The proposed power control does not require any compensation algorithm for the change of the load status of the magnetron and change of input voltage. The validity of the proposed method for the control of the change of input voltage and frequency is verified by both simulation and experiment.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
• /
• pp.179-183
• /
• 2001

This paper presents a simple current control strategy for matrix converters based on the extension of PWM method for inverters. A novel and efficient PWM algorithm is developed. The algorithm is verified through simulation and experiments employing a 2-kVA prototype. The results of simulation and experiment prove the instantaneous control capability of the output current with the sinusoidal input current.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 하계학술대회 논문집 B
• /
• pp.721-723
• /
• 1993

A PWM switching control strategy based on instantaneous integration concept for reducing hamonic components of inverter system with fluctuating input voltage is presented. Applying this strategy to single phase full bridge PWM inverter through bipolor switching method and unipolor switching method, reduction of hamonic components of output voltage and current is demonstrated through simulation. The system operation is examined and confirmed by experiments.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2010년도 하계학술대회 논문집
• /
• pp.49-50
• /
• 2010

In this paper, we propose a boost type inverter system for the compensation of instantaneous voltage sag. The system compensate instantaneous voltage sag which magnitude is higher than 10[%] of normal input voltage. When input voltage is higher than 90[%] of normal value, the switch in boost converter is not operated and output voltage is controlled by modulation amplitude in PWM inverter.

• 전자공학회논문지T
• /
• 제35T권3호
• /
• pp.25-30
• /
• 1998

본 논문에서는 미지의 디지털 변조신호가 입력되는 경우에 변조방식을 식별하는 방법을 제안한다. 제안하는 식별 방법은 입력신호의 순시진폭, 순시주파수, 순시 위상을 구하고, 이를 바탕으로 특징벡터를 추출하여 신경망을 이용하여 식별하도록 구성하였다. 식별방법의 타당성을 검증하기 위해 백색 가우스성 잡음환경 하에서 8가지 입력신호를 사용하여 SNR을 변화시켜가며 모의실험을 수행하였다. 모의실험 결과 신경망을 이용하여 SNR 10 [㏈]까지 모든 입력 신호들을 식별해 낼 수 있었다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 전력전자학술대회 논문집
• /
• pp.197-200
• /
• 2001

This paper presents a PWM buck AC-AC converter with instantaneous compensation for input voltage sag and surge. The presented converter use commercial IGBT modules and its output voltage is regulated so as to remain constant AC output voltage. The feedforward control technique is also proposed to establish instantaneous duty level change whereby stable output voltage will be retained. This paper show the characteristics and control algorithm of the converter through various PSPICE simulations.