• Journal of Power Electronics
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• v.15 no.6
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• pp.1508-1516
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• 2015

A single phase H-bridge inverter is employed in conventional Inductive Power Transfer (IPT) systems as the primary side power supply. These systems may not be suitable for some high power applications, due to the constraints of the power electronic devices and the cost. A high-frequency cascaded multi-level inverter employed in IPT systems, which is suitable for high power applications, is presented in this paper. The Phase Shift Pulse Width Modulation (PS-PWM) method is proposed to realize power regulation and selective harmonic elimination. Explicit solutions against phase shift angle and pulse width are given according to the constraints of the selective harmonic elimination equation and the required voltage to avoid solving non-linear transcendental equations. The validity of the proposed control approach is verified by the experimental results obtained with a 2kW prototype system. This approach is expected to be useful for high power IPT applications, and the output power of each H-bridge unit is identical by the proposed approach.

• Journal of Power Electronics
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• v.17 no.1
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• pp.76-87
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• 2017

Finite-set predictive current control (FS-PCC) is advantageous for power converters due to its high dynamic performance and has received increasing interest in multilevel inverters. Among multilevel inverter topologies, the cascaded H-bridge (CHB) inverter is popular and mature in the industry. However, a main drawback of FS-PCC is its large computational burden, especially for the application of CHB inverters. In this paper, an FS-PCC method based on a deadbeat solution for three-phase zero-common-mode-voltage CHB inverters is proposed. In the proposed method, an inverse model of the load is utilized to calculate the reference voltage based on the reference current. In addition, a cost function is directly expressed in the terms of the voltage errors. An optimal control actuation is selected by minimizing the cost function. In the proposed method, only three instead of all of the control actuations are used for the calculations in one sampling period. This leads to a significant reduction in computations. The proposed method is tested on a three-phase 5-level CHB inverter. Simulation and experimental results show a very similar and comparable control performance from the proposed method compared with the traditional FS-PCC method which evaluates the cost function for all of the control actuations.

• Journal of Power Electronics
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• v.19 no.4
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• pp.989-999
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• 2019

This paper proposes a fault-tolerant control strategy with finite control set model predictive control (FCS-MPC) based on hierarchical optimization for five-level H-bridge neutral-point-clamped (5L-HNPC) inverter-fed induction motor drives. Fault-tolerant operation is analyzed, and the fault-tolerant control algorithm is improved. Adopting FCS-MPC based on hierarchical optimization, where the voltage is used as the controlled objective, called model predictive voltage control (MPVC), the postfault controller is simplified as a two layer control. The first layer is the voltage jump limit, and the second layer is the voltage following control, which adopts the optimal control strategy to ensure the current following performance and uniqueness of the optimal solution. Finally, simulation and experimental results verify that 5L-HNPC inverter-fed induction motor drives have strong fault tolerant capability and that the FCS-MPVC based on hierarchical optimization is feasible.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.160-161
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• 2007

This paper describes the development of a single-phase DVR(Dynamic voltage Restorer), which is composed of H-bridge inverter and super-capacitors. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental works with 3kVA prototype. The developed system can compensates the input voltage sag and interruption within 2ms, in which the maximum allowable duration of voltage interruption is 1.5 seconds. It can be effectively used to compensate the voltage interruption in the sensitive load, such as computer, communication equipment, automation equipment, and medical equipment. The developed system has a simple structure to be easily implemented with commercially available components and to be highly reliable in operation.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.981-986
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• 2003

Recently, a fuel cell is remarkable for new generation system. The fuel cell generation system converts the chemical energy of a fuel directly into electrical energy. The fuel cell generation is characterized by low voltage and high current. For connecting to utility, it needs both a step up converter and an inverter. The step up converter makes DC link and the inverter changes D.C to A.C. In this paper, full bridge converter and the single phase inverter are designed and installed for fuel cell. Simulation and experiment verify that fuel cell generation system could be applied for the distributed generation.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.309-313
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• 2001

A single-phase bi-directional inverter with a diode bridge-type resonant circuit to implement ZVT(Zero Voltage Transition) switching is proposed. It is shown that the polarized ramptime current control algorithm, a method that belongs to the family of ZACE(Zero Average Current Error) methods, is a suitable technique to integrate with a typical single-phase ZVT inverter. The proposed current control algorithm is analyzed to design the circuit with auxiliary switch which can operate with ZVT for the main power switch. The simulation results would be shown to verify the proposed current algorithm to turn the main power switch on with ZVT and to operate the inverter bi-directionally

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.433-434
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• 2013

본 논문에서는 절연타입의 Half-bridge 구조를 이용하여 입력단을 구성하고 출력단에 5레벨의 출력전압을 생성할 수 있는 새로운 구조의 멀티레벨 PWM 인버터를 제안한다. 기존의 Cascaded H-bridge 멀티레벨 인버터는 두 대의 H-Bridge 인버터 모듈을 직렬 결합하여 5레벨의 출력전압을 생성하는 방식이며, 제안하는 방식은 기존 멀티레벨 인버터의 기본 모듈인 H-bridge의 전원을 절연타입의 Half-bridge 구조를 이용하여 구성하고 스위칭 소자 1개와 다이오드 1개를 추가한 구조이다. 동일한 5레벨의 출력전압 생성 시 기존 방식은 2차 측에 8개의 스위칭 소자가 사용되는 반면 제안된 방식은 5개의 스위칭 소자와 1개의 다이오드가 사용되기 때문에 스위칭 손실 및 부피를 줄일 수 있으며 입력단과 출력단 사이의 절연으로 인한 시스템의 안정성을 확보할 수 있다. PSIM 기반의 컴퓨터 시뮬레이션을 통해 제안된 멀티레벨 인버터의 타당성을 검증한다.

• 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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• 2014.07a
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• pp.81-82
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• 2014

H-bridge 타입의 고압인버터는 낮은 DC링크 전압을 이용하여 높은 출력 AC전압을 얻을 수 있는 멀티레벨 인버터 토폴로지로서 다양한 분야에서 실증, 적용 되어왔다. 본 논문에서는 고속철도의 피크전력 보상을 위한 단상 H-bridge 멀티레벨 인버터를 사용한 PCS의 적용을 검토하였고, DC링크 전압을 각각의 배터리 전원을 사용함으로서 발생될 수 있는 배터리 불평형에 대한 PWM제어 알고리즘을 개발하였다. 제안된 알고리즘은 H-bridge타입에서 적용되고 있는 PWM제어방법 중 THD 특성에서 가장 우수한 PD방식을 배터리 상태에 따라 각 H-bridge에서 회전시켜 DC전압 불균형을 해결 할 수 있도록 구성하였다. 제안된 알고리즘은 PSIM을 사용하여 시뮬레이션을 수행함으로서 제안된 기법의 타당성을 검증하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.47-50
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• 2005

In this paper, we investigate a filtering technique to reduce the adverse effect of long motor leads on H-bridge cascaded 7-level inverter fed ac motor drive. The switching surge voltage becomes the major cause to occur the insulation failure by serious voltage stress in the stator winding of high voltage induction motor. However, the effect of switching surge appears un seriousin high voltage induction motor than low voltage induction motor. Consequently, we demonstrated that the filter connected to the motor terminals greatly reduces the transient voltage stress and ringing, moreover we show lowers the dv/dt of the inverter switching pulse. The results of simulation show the suppression of dv/dt and the reduced peak voltage at the motor end of a long cable.