• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.9
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• pp.843-848
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• 2006

This paper explains the design and fabrication of an inverter for LCD backlight using a multilayer piezoelectric transformer. That inverter is operated by the burst dimming method whose dimming signal is controlled by the duty ratio of rectangular switching signal to a PWM controller. The brightness of CCFL's are investigated according to the various dimming signals, and when those CCFL's are turned on, the temperature distributions on the piezoelectric transformer and circuit components of the inverter are also investigated by a thermo-camera.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.169-171
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• 2005

In this paper, a novel type of auxiliary switched capacitor assisted edge resonant soft switching PWM series load resonant high frequency inverter with two auxiliary edge resonant lossless inductor snubbers is proposed for small consumer induction heating appliances. The operation principle of this high frequency inverter is described using the switching mode equivalent circuits. The practical effectiveness of the newly proposed soft switching inverter are discussed as compared with the conventional soft switching high frequency inverters based on simulation and experimental results from an application point of view.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.77-85
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• 2009

With the advent of power semiconductor switching devices, power electronics relating to high frequency electromagnetic eddy current based induction heating technology have become more suitable and acceptable. This paper presents high-frequency induction heating cooking appliance circuit based on the zero current switching-PWM single ended push-pull(ZCS-PWM SEPP) resonant inverter added AC-DC converter. This inverter uses pulse-width-modulation(PWM) control method with active auxiliary quasi-resonant lossless inductor snubbers and a switched capacitor. To improved the transient performance, the PI controller is applied for this system. For the systematic parameter optimization of the PI controller, the gradient-based optimization algorithm is applied. The performance of optimized parameters is evaluated using simulation and experimental test. These results show that the proposed systematic optimal tuning method improve the transient performances of this system.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.144-146
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• 2007

본 논문에서는 고효율 LCD Backlight 구동을 위해 주로 사용하던 Phase shift Full bridge 방식을 대신할 수 있는 Dual Half Bridge Inverter를 제안하였다. 제안된 회로는 일반적인 Push-Pull 인버터 구동용 제어 IC의 출력 신호 2개로 스위치 4개를 제어할 수 있으며 넓은 범위의 ZVS(zero voltage switching)을 보장하여 소자 발열 및 효율 상승의 이점을 가진다. 제안된 Inverter Topology를 소개하며 동작모드 해석과 시뮬레이션 및 실험을 통한 검증결과를 제시 한다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.1
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• pp.33-38
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• 2003

This paper describes control principles of the piezoelectric ultrasonic motor which is operated by the ultrasonic vibration generated by the piezoelectric element. The piezoelectric ultrasonic motor has excellent characteristics such as compact size, noiseless motion, low speed, high torque and controllability, and has been recently applied for the practical utilization in industrial, consumer, medical and automotive fields. In this paper, the design of two-phase push-pull inverter for driving the piezoelectric ultrasonic motor is described, and a new control method of automatic resonant frequency tracking using PLL(Phase-Locked Loop) technique is mainly presented. the experimental results by this inverter system for driving the piezoelectric ultrasonic motor are illustrated herein. The inverter system with PLL technique improved the speed stability of the piezoelectric ultrasonic motor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.350-357
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• 2006

In this paper, a PSPICE model of piezoelectric transformer and CCFL using an electrical equivalent circuit was presented. The parameters of CCFL for PSPICE were derived by the least square method. The computer simulations were performed and the results are compared on the PSIPCE model of piezoelectric transformer driven by push-pull inverter and CCFL.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3129-3131
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• 1999

The electronic ballast for MHD lamp was studied for automotive headlight application. Its basic principle is the Current Sourcing Push-Pull Resonant Inverter with DC I2Volt input Voltage. By changing the switching frequency according to the lamp state, the automotive requirement of very fast warm-up and the zero voltage switching condition were shown by the simulation of the ballast circuit.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.166-167
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• 2007

본 논문은 고주파 IH(Induction Heating) 조리기기의 전원으로 사용되는 인버터를 PI 제어기를 사용하여 듀티비를 가변시켜 출력을 최적 제어하는 회로를 제시하였다. 분석에 사용된 기본 인버터 회로는 Single-Ended Push-Pull (SEPP) 영전류 스위칭 공진인버터이며 실제 IH 조리기기의 동작을 구현하기 위해 입력단의 전원으로 220V 60Hz 정현파와 브리지 정류기, 평활 콘덴서를 사용하였다. 회로의 해석과 시뮬레이션을 위해 범용 시뮬레이션 툴인 Pspice를 이용하여 분석하였다. 향후, 제안된 제어방법은 유사한 IH 기기, DC-DC 컨버터, 인덕션 모터등의 시스템에 활용되리라 기대된다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.236-241
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• 2017

This paper presents a single-phase grid connected voltage-ed inverter with a power decoupling circuit. In the single-phase grid connected voltage-ed inverter, it is well known that a power pulsation with twice the grid frequency is contained in the input power. In a conventional voltage type inverter, electrolytic capacitors with large capacitance have been used in order to smooth the DC voltage. However, lifetime of those capacitors is shortened by the power pulsation with twice grid frequency. The authors have been studied a active power decoupling(APD) method that reduce the pulsating power on the input DC bus line, this enables to transfer the ripple energy appeared on the input DC capacitors into the energy in a small film capacitor on the additional circuit. Hence, extension of the lifetime of the inverter can be expected because the small film capacitor substitutes for the large electrolytic capacitors. Finally, simulation and experimental results are discussed.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.133-135
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• 2007

This research presented the new zero-current switching pulse width modulation SEPP(Single Ended Push-Pull)high frequency inverter for solving the problem of the zero-current SEPP high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the zero-current switching pulse width modulation SEPP high frequency inverter. The inverter circuit which is attempted by on-off operation of a switch has the reduction effect of the power loss due to a soft switching and a high frequency switching. And it confirmed that the power regulation is possible continuously from 0.25[kW] until 2.84[kW] in the case the duty rate(D) changes from 0.08 to 0.3 under zero-current switching operating by a dissymmetry pulse width modulating control and the power conversion efficiency comes true the efficiency of 95[%]. Due to the result above, the ZCS PWM SEPP high frequency inverter will be effective as sources of an induction heating apparatus.