• 한국전자파학회논문지
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• 제23권4호
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• pp.457-467
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• 2012

본 논문에서는 도파관의 단면(waveguide transverse plane)에 아이리스(iris)를 갖는 구조들을 도파관의 진행 방향으로 일정한 간격으로 배치하여 소형의 대역 통과 여파기를 구현하는 방법을 제시하고자 한다. 이를 위하여 리지가 장하된 원형 개구 아이리스를 여파기 설계의 기본 공진기 구조로 활용하며, 임피던스 인버터(impedance inverter)로 동작하게 되는 L형 아이리스를 새롭게 제안하여 여파기의 길이 방향 크기를 줄이는데 사용하였다. 최종 제작된 여파기는 중심 주파수 10 GHz에서 400 MHz의 대역폭을 갖는데, 기존의 여파기 설계 방식에 비하여 70 %의 소형화를 달성하였다.

• 전력전자학회논문지
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• 제22권5호
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• pp.457-462
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• 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.

• 전력전자학회논문지
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• 제7권1호
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• pp.48-54
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• 2002

본 논문에서는 간접 유도가열 되는 DPH시스템과 주파수 범위가 20kHz에서 50kHz사이에서 작동되는 전압형 직렬공진 고주파인버터를 이용하여 열 기체를 발생시키는 전압형 공진형 인버터에 관하여 설명하였다. 얇은 스텐레스 판재가 서로 스폿 용접되어 연결되어 있고 미세한 많은 구멍을 갖고있는 적층형 충진발열테로 특수하게 설계된 유도 가열기는 외부에 워크 코일로 감겨져 있는 불소수지계의 절연용기 안에 삽입되어 있다. 이 워크 코일은 공진형 인버터와 연결되어 있으며 유도가열기를 통해 흐르는 관 유체를 1단가열부에서 저압의 포화증기를 2단가열부에서 열방사성 증발유체를 생성하는 본 DPH시스템의 성능 및 효용성을 실용적인 측면에서 논의하고 평가 할 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.502-504
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• 1994

This paper describes an induction heating system which is full-bridge parallels resonant inverter. This system consists of current-fed type inverter, and a parallels resonant circuit with a matching transformer. A parallels resonant scheme is employed, and operating range of the proposed circuit with operating frequency and load parameter is demonstrated from the result of steady state. Also, this equipments testing result introduces, good efficiency and reliability of the system. Finally, this paper experimental results are given.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.311-314
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• 2003

In this paper, proposed circuit proposes that Active-Clamp-Circuits basis of a current-fed inverter linked type high frequency resonant dc-dc converter of conventional. and the paper the most of characteristics of the reduced high voltage stress main switches with active clamp circuits and output current constant with the resonant part consists of L, C resonant tank circuit. Also, the capacitor (C$_1$, C$_2$) connected in switches are a common using by resonance capacitor and ZVS capacitor. and circuit analysis used state equation of each part modes. Also we conform a rightfulness theoretical analysis by comparing a parameters values and simulation values obtained from simulation using Power MOS-FET as switching devices.

• 전력전자학회논문지
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• 제20권2호
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• pp.115-121
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• 2015

Stand-alone inverter supplies constant voltage to loads. However, when a three-phase stand-alone inverter supplies unbalanced load, the generated output voltages also become unbalanced. The nonlinear characteristics of inverter dead time cause a more serious distortion in the output voltage. With unbalanced load, voltage distortion caused by dead time differs from voltage distortion under balanced load. Phase voltages in the stationary reference frame include unbalanced odd harmonics and then, d-q axis voltages in the synchronous reference frame have even harmonics with different magnitude, which are mitigated by the proposed multiple resonant controller. This study analyzes the voltage distortion caused by unbalanced load and dead time, and proposes a novel dead time compensation method. The proposed control method is tested on a 10-kW stand-alone inverter system, and shows that total harmonic distortion (THD) is reduced to 1.5% from 4.3%.

• 전기학회논문지
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• 제65권4호
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• pp.567-575
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• 2016

This paper proposed the voltage control of stand-alone inverter for power quality improvement under unbalanced and non-linear load. The 3-phase DC-AC inverter controls CVCF(Constant Voltage Constant Frequency) and selective harmonic eliminate method in stand-alone mode by PR controller, and the stand-lone inverter supplies stable sinusoidal voltage to balanced, unbalanced and non-linear loads. The total harmonic distortion(THD) of line-to-line load voltage($V_{LL}$) is 1.2% in the balanced load. THD of $V_{LL}$ is reduced from 5.2% to 1.4% and 6.7% to 3.5%, respectively unbalanced and non-linear load. The stand-alone inverter can be supplies sinusoidal balanced voltage to unbalanced load because the voltage unbalanced factor(VUF) of $V_{LL}$ is reduced from 5.2% to 1.4% in the unbalanced load. Feasibility of control method for a stand-alone inverter will be verified through 30kW stand-alone inverter system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.339-342
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• 1996

Driving the electrodeless fluorescent lamp, the high ac voltage with high frequency is required. The linear power amplifier has been widely used as a driving circuit of electrodeless fluorescent lamp. However, the low efficiency of the power amplifier causes the driving circuit to be replaced by a PWM switching inverter. In order to use a PWM switching inverter as the driving circuit of an electrodeless fluorescent lamp, the high switching frequency is required. But due to the switching loss at switches of the inverter, the limitation of high switching frequency appears in the inverter. One solution to this limitation is to reduce the switching loss by using the zero voltage switching technique. In this paper, zero voltage switching resonant inverter for driving an electrodeless fluorescent lamp is discussed. The results of analysis about the inverter are presented and the equations for design are established. And the validity of the analyzed results are verified through the experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.164-166
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• 1991

This paper achieved by Pulse-Withed Modulation of the inverter switchs. But Conventional PWM inverter is employed hard switching by means a switching device. Moreover, this paper presents resonant DC link Voltage type inverter thet it was not necessary snubber circuit and dead time and modeling of motor drive control system and simulating analysis are discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.495-497
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• 1996

This paper proposes LCC type high frequency resonant inverter to be used as a source of induction heating device or ultrasonic device and considers of operating characteristic for it. The inverter is operated safely over wide range load, because it has both panel loaded capacitor and series loaded capacitor. Then, switching frequency of the inverter is controlled by feedback voltage and current in order to have constant output power even when load is varied.