• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.425-429
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• 2002

In this paper, a single-phase inverter using a diode bridge-type resonant circuit to implement ZVT(Zero Voltage Transition) switching is presented. The current control algorithm is analyzed about how to design the circuit with auxiliary switch which can ZVT operation for the main power switch. The simulation and experimental results would be shown to verify the proposed current algorithm, because the main power switch is turn on with ZVT and the hi-directional inverter is operated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.62-69
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• 2005

This paper presents the improved AC/DC PFC(Power-Factor-Correction) ZVT(Zero-Voltage-Transition) Boost Converter. The conventional AC/DC PFC ZVT Boost Converter minimizes the switching loss of the main switch within all of the load range. That is because AC/DC PFC ZVT Boost converter makes the main switch and the auxiliary switch turn on simultaneously so that it makes ZVS (Zero-Voltage-Switching) possible at the light load. However, it has two problems that ale large loss of the auxiliary switch and the increasing of the reverse current of the main switch. Therefore this research presents high efficiency to reduce the current stress of the auxiliary switch and the reverse current of main switch by adding a diode to the conventional ZVT converter. The prototype of 640[W], 100[kHz] system using MOSFET is implemented for this experimental verification.

• 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

• Journal of Power Electronics
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• v.8 no.1
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• pp.35-50
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• 2008

A zero-voltage-transition (ZVT) pulse width modulated (PWM) converter is a PWM converter with a single main power switch that has an auxiliary circuit to help it turn on with zero-voltage switching (ZVS). There have been many ZVT-PWM converters proposed in the literature as they are the most popular type of ZVS-PWM converters. In this paper, the properties and characteristics of several types of ZVT-PWM converters are reviewed. A new type of ZVT-PWM converter is then introduced, and the operation of a sample converter of this type is explained and analyzed in detail. A procedure for the design of the converter is presented and demonstrated experimentally. The feasibility of the new converter is confirmed with results obtained from an experimental prototype. Conclusions on the performance of ZVT-PWM converters in general are made based on the efficiency results obtained from the experimental prototypes of various ZVT-PWM converters of different types.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.324-328
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• 2001

This paper presents parallel operation and control loop design of ZVT(Zero Voltage Transition) Full Bridge DC/DC Converter. At parallel operation of ZVT Full Bridge Converter, dynamic current shared inductor devides the same current of unit converter and ZVT circuit and aids to high efficiency in the system. Base on the modeling of ZVT. Full Bridge Converter, the control loop is designed using a simple two-pole, one-zero compensation circuit. To show the validity of the design procedures, the small signal analysis of the closed loop system and open loop system is carried out and the superiority of the dynamic characteristics is verified through the experiment with a 2kW, 50kHz prototype converter.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.9
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• pp.473-478
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• 2001

In this paper a soft switching ZVT(Zero Voltage Transition) power factor converter using active snubbers is designed to improve efficiency and reduce voltage spike and parasitic ringing. The main switch achieves ZVT and the auxiliary switch operates with ZCS. A 2KW soft switching ZVT converter is designed with switching frequency 100kHz, output voltage 400VDC. Then the designed system is realized and experimental results show that the measured efficiency and power factor are over 97.45% and 0.997 respectively with an input current THD less than 3%.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.3
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• pp.209-214
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• 2000

In this paper, we propose a FB ZVT(full bridge zero voltage transition) PWM OC~OC converter which uses a a saturable reactor, instead of two additional switches, to achieve zero voltage switching. The conventional h high frequency phase shifted FB ZVT PWM OC-OC converter has a disadvantage that a circulating current f flows through high frequency transformer and switching devices during the free-wheeling interval. Due to this c circulating current, conduction loss increases. In order to reduce such the loss as this, we propose circuit of r reducing conduction loss at the secondary side of transformer. The operation principles are explained in detail a and the several interesting simulations and experimental results verify the validity of the proposed circuit.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.265-268
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• 1998

This paper presents a soft-switching average current control PWM high power factor boost converter. Conventional boost ZVT-PWM converter has a disadvantage of hard-switching for auxiliary switch at turn-off. A soft switched auxiliary switch is proposed to achieve a high performance ZVT-PWM boost rectifier. The simulation and experimental results show that soft switching operation can be maintained for wide line and load range, which in turn improves the converter performance in terms of efficiency, switching noise and circuit reliability.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.10-13
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• 1998

In this paper, a control strategy of the three phase ZVT inverter for ac motor drives is proposed. The topology of ZVT inverter analyzed with a description of the control conditions dependent on the load current and MSVM(Modified Space Vector Modulation). The detailed simulation results indicate that zero-voltage operation during transition of the MSVM algorithm can be achieved.

• Advances in environmental research
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• v.1 no.1
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• pp.37-55
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• 2012

Here we show that perchlorate reduction during pitting corrosion of zero-valent titanium (ZVT) is likely caused by dissolved titanium species, especially Ti(II). Several possible mechanisms were suggested based on the literature and were evaluated based on experimental observations. Direct reduction of perchlorate on the bare metal of the ZVT electrode was thermodynamically infeasible due to the high anodic potential that was applied. Other potential mechanisms were considered such as reduction by small ZVT metal particles released from the electrode and direct reduction on the oxide layer of the electrode where potential was sufficiently reduced by a high ohmic potential drop. However, these mechanisms were not supported by experimental results. The most likely mechanism for perchlorate reduction was that during pitting corrosion, in which ZVT is partially oxidized to form dissolved ions such as Ti(II), which diffuse from the electrode surface and react with perchlorate in solution. This mechanism is supported by measurements of the dissolution valence and the molar ratio of ZVT consumed to perchlorate reduced (${\Delta}Ti(0)/{\Delta}ClO_4{^-}$). The results shown in this study demonstrate that ZVT undergoing pitting corrosion has the capability to chemically reduce perchlorate by producing dissolved Ti(II) and therefore, it has the potential to be applied in treatment systems. On the other hand, the results of this research imply that the application of ZVT undergoing pitting corrosion in treatment systems may not be feasible now due to several factors, including material and electricity costs and possible chloride oxidation.