• Journal of Electrical Engineering and Technology
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• v.1 no.2
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• pp.216-225
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• 2006

This paper presents a new circuit topology of DC busline switch and snubbing capacitor-assisted full-bridge soft-switching PWM inverter type DC-DC power converter with a high frequency link for low voltage large current applications as DC feeding systems, telecommunication power plants, automotive DC bus converters, plasma generator, electro plating plants, fuel cell interfaced power conditioner and arc welding power supplies. The proposed power converter circuit is based upon a voltage source-fed H type full-bridge high frequency PWM inverter with a high frequency transformer link. The conventional type high frequency inverter circuit is modified by adding a single power semiconductor switching device in series with DC rail and snubbing lossless capacitor in parallel with the inverter bridge legs. All the active power switches in the full-bridge inverter arms and DC busline can achieve ZVS/ZVT turn-off and ZCS turn-on commutation operation. Therefore, the total switching losses at turn-off and turn-on switching transitions of these power semiconductor devices can be reduced even in the high switching frequency bands ranging from 20 kHz to 100 kHz. The switching frequency of this DC-DC power converter using IGBT power modules is selected to be 60 kHz. It is proved experimentally by the power loss analysis that the more the switching frequency increases, the more the proposed DC-DC converter can achieve high performance, lighter in weight, lower power losses and miniaturization in size as compared to the conventional hard switching one. The principle of operation, operation modes, practical and inherent effectiveness of this novel DC-DC power converter topology is proved for a low voltage and large current DC-DC power supplies of arc welder applications in industry.

• 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 Power Electronics
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• v.22 no.3
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• pp.256-262
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• 2017

This paper presents the control algorithm of a single-phase AC/DC/AC PWM converter for the linear compressor of a refrigerator. The AC/DC/AC converter consists of a full-bridge PWM converter for the control of the input power factor and a half-bridge PWM inverter for the control of the single-phase linear compressor. At the DC-link of this topology, two capacitors are connected in series. These DC-link voltages must be balanced for safe operation. Thus, a new control method of DC voltage balancing for the half-bridge PWM inverter is proposed. The balancing algorithm uses the Integral-Proportional controller and inserts the DC-offset current at the Proportional-Resonant current controller of the inverter to solve the DC-link unbalanced voltages between the two capacitors. The proposed algorithm can be easily implemented without much computation and additional hardware circuit. The usefulness of the proposed algorithm is verified through several experiments.

• Journal of Power Electronics
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• v.2 no.2
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• pp.112-123
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• 2002

This paper presents a novel prototype of the utility AC power interfaced soft-switching sinewave pulse modulated inverter using the high-frequency flyback for the small scale distributed renewable energy power conditioner. The proposed cricuit with a high-frequency isolation link has a funtion of electrical isolation, which is more cost-effective and reliable for the small-scale distributed renwal energy utilization system from a safety point of riew. The discontinuous conduction mode(DCM) operation of the high-frequency flyback transformer is adopted to establish a simple and low-cost circuit configuration and control scheme. For the simplicity, the circuit operating principle is described on the basis of the modified conventional full bridge inverter, whitch is the typical conventional high-frequency full-bridge inverter employing the high requency flyback transformer to eanble the effictive function of the electrical isolation. Than, the new circuit topology of the unility-interfaced soft-switching sinewave pulse modulated inverter using IGBTs is proposed. The proposed cricuit topology is additionally composed of the auxiliary power regenerating snubber cricuits, which are also mathematically analyzed for the parameter desigen settings. Finally, the performance of the propose inverter is evaluated on the basis of computer-aid simulation. It is noted that the sinewave pulse modulated output current of the inverter is synchronous to the AC main voltage.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.260-264
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• 2004

In this paper the novel converter topology for the switched reluctance motor drives is proposed, which is composed of the minimum switch per phase and is connected to the single-phase voltage inverter for ac voltage source. The proposed converter topology is divided into two types according to the voltage source inverter of half bridge type and full bridge type. Proposed converters of two types are proposed, analyzed and compared with each other. The SRM using proposed converter maintain the hi인 efficiency though the power switches are reduced.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.2
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• pp.68-74
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• 2004

This paper presents a novel hybrid multilevel inverter using DC-Link voltage combination in order to improve the waveshape of output voltage and reduce harmonics. The proposed multilevel inverter can generate an 11-level output voltage. It employs three H-bridge cell, which consists of single phase full-bridge inverter module. Among them, two modules are used for level generation, and one module performs PWM switching. Nine levels are synthesised by the level inverter, and two levels are added to output by the PWM inverter. As a result, it generates an 11-level. The operational principles are explained in depth, and the validity of the proposed system is verified through the PSpice simulation and experimental results based on a prototype.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.372-375
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• 2021

A three-leg inverter-type isolated DC-DC Converter that can use 220 and 440 V grid input voltages is introduced. The secondary circuit structure of the proposed topology is center-tap, which is the same as the conventional phase-shifted full-bridge converter. However, the primary circuit structure is composed of a three-leg inverter structure and a transformer, in which two primary windings are connected in series. The proposed circuit structure has a wider input voltage range than the conventional phase-shifted full-bridge converter, and the circulating-current on the primary-side is reduced. In addition, the voltage stress at the secondary rectifier is greatly improved, and high efficiency can be achieved at a high input voltage by removing the snubber circuit added to the conventional converter. Prototype converters with input DC of 311 V, output of 622 V, and 50 V and 6 kW class specifications were designed and manufactured to verify the validity of the proposed topology; the experimental results are presented.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.2
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• pp.114-122
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• 2004

This paper presents a novel single-stage active-clamp type high frequency resonant inverter. The proposed topology is integrated full-bridge boost rectifier as power factor corrector and active-clamp type high frequency resonant inverter into a single-stage. The input stage of the full-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. By adding additional active-clamp circuit to conventional class-E high frequency resonant inverter, main switch of inverter part operates not only at Zero-Voltage-Switching mode but also reduces the switching voltage stress of main switch. Simulation results have demonstrated the feasibility of the proposed high frequency resonant inverter. Characteristics values based on characteristics estimation through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter will be able to be practically used as a power supply in the fields of induction heating applications, fluorescent lamp and DC-DC converter etc.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.1-4
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• 2003

This paper proposes a method of voltage control for three-phase multilevel H-bridge inverters with selective harmonic elimination (SHE) PWM The full-bridge configuration of H-bridge inverter cells enables voltage control with a fixed PWM pattern by means of phase shifting between the legs, which greatly simplifies the control while maintaining the harmonic elimination characteristics. The series combination of the cells in multilevel configuration can be exploited to further improve the hormonic elimination characteristics with proper phase shifting between the ceil volitage. A complexor-based control method is introduced to control the magnitude and phase angle of cell voltages that form three-phase multilevel output voltages. Simulation results show that the proposed method along with SHE PWM would provide satisfactory performance in spite of its simplicity.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.3
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• pp.57-66
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• 1993

This research proposes a high frequency series resonant inverter consisting of equivalent half - bridge model in combination with two L-C linked full-bridge inverter circuits using MOSFET. As a output power control strategy, the sequential gate control method is applied. Also, analysis of operating MODE and state equation is described. From the computer simulation results, the inverters and devices can be shared properly voltage and current rating of the system in accordance with series and parallel operations. And it is confirmed that the proposed system has very stable performance.