• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1235-1244
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• 2017

This paper proposes a fuzzy logic controlled new topology of high voltage gain zero voltage switching (ZVS) asymmetrical PWM full-bridge DC-DC boost converter for constant load and high power applications. The APWM full-bridge stage provides high voltage gain and soft-switching characteristics increase the efficiency and reduce the switching losses. Fuzzy logic controller (FLC) improves the performance and dynamic characteristics of the proposed converter. A comparison with a classical proportional-integral (PI) controller demonstrates the high performances of the proposed technique in terms of effective output voltage regulation under different operating conditions. Simulation is done by integrating two different simulation platforms $PSIM^{(R)}$ and $Matlab^{(R)}/Simulink^{(R)}$ by using SimCoupler tool of $PSIM^{(R)}$. Experimental results using 120W load have been provided to validate the results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.3
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• pp.65-72
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• 2016

This paper discussed the LCL-type & Isolated bidirectional dc-dc converter(BDC) with dual full bridge inverter. In order to verify the analysis of the BDC, Experimental prototype has been designed and implemented to supply constant voltage regardless of loads and proposed a method to select switching frequency that depended on two inductors' inductance ratio and transformer parameters. The proposed converter has been composed of LCL resonant network with unit inductance ratio ($L_r/L_f$=1) and then operated with fixed duty, 50% duty ratio and fixed frequency. There are some characteristics that input voltage and output voltage of the BDC is nearly identical and zero voltage turn-on switching is possible in forward and reverse mode. Finally, it has been showed that BDC is possible to commutate operating mode normally and provide constant output voltage in selected switching frequency.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.226-228
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• 2006

This paper presents the two lossless auxiliary inducors-assisted voltage source type half bridge(single ended push pull:SEPP) series resonant high frequency inverter for induction heated fixing roller in copy and printing machines. The simple high-frequency inverter treated here can completely achieve stable zero current soft switching (ZCS) commutation forwide its output power regulation ranges and load variations under constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operatprinciple is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZCS operation commutation, together with its output effective power regulation charactertics-based on the high frequency PDM strategy. The experimenoperating performances of this voltage source SEPP ZCS-PDM series resonant high frequency inverter using IGBTs are illustrated as compared with computer simulation results and experimenones. Its power losses analysis and actual efficiency are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliimplemented here is proved from the practical point of view.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.227-230
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• 2003

In this paper, a full bridge edge-resonant zero voltage mode based soft-switching PWM DC-DC power converter with a high frequency center tapped transformer link stage is presented from a practical point of view. The power MOSFETS operating as synchronous rectifier devices are implemented in the rectifier center tapped stage to reduce conduction power losses and also to extend the transformer primary side power MOSFETS ZVS commutation area from the rated to zero-load without a requirement of a magnetizing current. The steady-state operation of this phase-shift PWM controlled power converter is described in comparison with a conventional ZVS phase-shift PWM DC-DC converter using the diodes rectifier. Moreover, the experimental results of the switching power losses analysis are evaluated and discussed in this paper. The practical effectiveness of the ZVS phase-shift PWM DC-DC power converter treated here is actually proved by using 2.5kW-32kHz breadboard circuit. An actual efficiency of this converter is estimated in experiment and is achieved as 97$\%$ at maximum.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.564-570
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• 2010

Last train of the vehicle for eht energy saving and improved performance PWM converters ares widely used. In the case of PWM converters by the zero detection system performance depends on whether it can be argued. Zero voltage detectio method of the hardware and software approach is to in this paper, the zero detection methods for hardware and software problems that have occured as a complemnetary technique was expained.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.409-412
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• 1998

In this paper, an improved soft switching forward dc/dc converter is proposed. The proposed converter is constructed by using non-dissipate snubbers in parallel with the main switch and output diode of the conventional forward converter. Due to use of the non-dissipative snubbers, the proposed converter achieves zero-voltage switching for all switching devices and output diodes without switching losses. The complete operating principles and experimental results will be presented.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2145-2147
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• 1998

This paper presents a Class-D type switched mode audio power amplifier employing ZVT(Zero-Voltage-Transition) soft switching technique. In order to obtain a wide bandwidth and lower distortion for an audio amplifier a high switching frequency is essential. The ZVT switching scheme enables a high frequency switching without sacrificing the efficiency much as in a hard switching. A prototype amplifier is built to demonstrate the feasibility of this technique for the audio power amplifier.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.484-488
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• 2001

The grid voltage of commercial utility power source hi Japan and USA is 100rms, but in China and European countries, it is 200rms. In recent years, In Japan 200Vrms out putted single phase three wire system begins to be used for high power applications. In 100Vrms utility AC power applications and systems, an active voltage clamped quasi-resonant Inverter circuit topology using IGBTs has been effectively used so far for the consumer microwave oven. In this paper, presented is a half bridge type voltage-clamped high-frequency Inverter type AC-DC converter using which is designed for consumer magnetron drive used as the consumer microwave oven in 200V utility AC power system. This zero voltage soft switching Inverter can use the same power rated switching semiconductor devices and three-winding high frequency transformer as those of the active voltage clamped quasi-resonant Inverter using the IGBTs that has already been used for 100V utility AC power source. The operating performances of the voltage source single ended push pull type Inverter are evaluated and discussed for consumer microwave oven. The harmonic line current components In the utility AC power side of the AC-DC power converter operating at ZVS­PWM strategy reduced and improved on the basis of sine wave like pulse frequency modulation and sine wave like pulse width modulation for the utility AC voltage source.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1646-1654
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• 2015

In this paper, a single-switch ZVZCS quasi-resonant CLL isolated DC-DC converter for driving a low-power (less than 100 W) 32'' LED backlighting liquid crystal display television (LCD TV) is proposed. The proposed converter exhibits both forward and flyback operational characteristics. All semiconductors are activated and deactivated under the soft switching conditions during the switching transition without additional active devices. The switching frequency varies less than about 10 kHz for load variations, leading to minimizing the efficiency reduction under light load. Furthermore, the low di/dt and dv/dt by soft switching enhance the electromagnetic interference (EMI) performance above 1 MHz. A theoretical analysis is described in detail, and a 72-W prototype converter verifies the validity of the analysis.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.3
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• pp.115-124
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• 2002

This paper presents an active auxiliary edge-resonant DC link snubber with a ringing surge damper and a three-phase voltage source type zero voltage soft-switching inverter with the resonat snubber treated here for the AC servo motor driver applications. The operation of the active auxiliary edge-resonant DC link snubber circuit with PWM voltage is described, together with the practical design method to select its circuit parameters. The three-phase voltage source type soft-switching inverter with a single edge-resonant DC link snubber treated here is evaluated and discussed for the small-scale permanent magnet (PM) type-AC servo motor driver from an experimental point of view. In addition to these, the AC motor stator current and its motor speed response for the proposed three-phase soft-switching inverter employing Intelligent Power Module(IPM) based on IGBTS are compared with those of the conventional three-phase hard-switching inverter using IPM. The practical effectiveness of the three-phase soft-switching inverter-fed permanent magnet type AC motor speed tracking servo driver is proven on the basis of the common mode current in a novel type three-phase soft-switching inverter-fed AC motor side and the conductive noise on the mains terminal interface voltage as compared with those of the conventional three-phase hard-switching inverter-fed permanent magnet type AC servo motor driver for the speed tracking applications.