• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.3
• /
• pp.302-311
• /
• 2005

We propose an improved active forward converter by adding a non-dissipative snubber circuit to the secondary of the conventional active clamp forward converter in this paper. The snubber circuit is composed of a tapped inductor, a snubber capacitor, and two diodes. Comparing with the conventional one, the proposed one makes it possible ZVS to operate in a smaller magnetizing current condition. The operational principles and the equivalent mode analysis of an improved active forward converter are mentioned in this paper. In conclusion, we constructed the prototype of the modified active forward converter with 300W output capacity and verified higher efficiency compared to the conventional one.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.65 no.2
• /
• pp.114-121
• /
• 2016

This paper is Instant space vector PWM(Pulse Width Modulation)power conversion devices in switching power semiconductors from my generation to losses and switching when the voltage surge and current surge of electronic noise(EMI: Electro Magnetic Interference / RFI: Radio Frequency Interference)to effectively minimize the power soft-switching power conversion circuit topologies of auxiliary resonant DC tank for the purpose of high performance realization of the electric power conversion system by the high-speed switching of a semiconductor device(AQRDCT simultaneously : an active auxiliary resonance using auxiliary Quasi-resonant DC tank)DC link snubber switch has adopted a three-phase voltage inverter. AQRDCL proposed in this paper can reduce the effective and current peak stress of the power semiconductors of the auxiliary resonant snubber circuit compared to the conventional active-resonant DC link snubber, it is not necessary to install the clamp switch of the auxiliary resonant DC link, DC the peak current and power loss of the bus line can be reduced.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.3
• /
• pp.40-51
• /
• 2008

This research presents a new active auxiliary resonant snubber with for induction heating PWM high frequency inverter solving the problem of induction heating PWM 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 active auxiliary resonant snubber with for induction heating PWM high frequency inverter. The inverter circuit which is attempted by the on-off operation of a switch has the effect of reducing the power loss due to soft switching and high frequency switching. This confirms that power regulation is possible on a continuous basis from 0.25[kW] to 2.84[kW] where the duty factor(D) changes from 0.08 to 0.3 under zero current switching which operates by an asymmetrical pulse width modulating control. The power conversion efficiency is 95[%]. Due to these results, the active auxiliary resonant snubber for an induction heating PWM high frequency inverter is considered effective as a source of induction heating.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.4B no.3
• /
• pp.127-133
• /
• 2004

This paper presents a prototype of three-phase current source zero voltage soft-switching PWM controlled PFC rectifier with Single Active Auxiliary Resonant Commutated Snubber (ARCS) circuit topology. The proposed three-phase PFC rectifier with sinewave current shaping and unity power factor scheme can operate under a condition of Zero Voltage Soft Switching (ZVS) in the main three phase rectifier circuit and zero current soft switching (ZCS) in auxiliary snubber circuits. The operating principle and steady-state performances of the proposed three-phase current source soft-switching PWM controlled PFC rectifier controlled by the DSP control implementation are evaluated and discussed on the basis of the experimental results of this active rectifier setup.

• Proceedings of the KIPE Conference
• /
• 1997.07a
• /
• pp.417-422
• /
• 1997

This paper proposed that a AC-DC Converter topology of high power factor with soft switching mode operates with four chopper connecting a number of parallel circuit. To improve these, a large number of soft switching topologies included a resonant circuit have been proposed. And, some simulative results on computer is included to confirm the validity of the analytical results. The partial resonant circuit makes use of a inductor using step up and a condenser of loss-less snubber. The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in partial resonant circuit makes charging engergy regenerated at input power source for resonant operation. The proposed conversion system is deemed the most suitable for high power applications where the power switching devices are used.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.920-927
• /
• 1998

This paper proposed that an Analysis of a partial resonant AC-DC converter for high power and power factor operates with four choppers connecting to a number of parallel circuit. To improve these, a large number of soft switching topologies included a resonant circuit have been proposed. And, some simulative results on computer are included to confirm the validity of the analytical results. The partial resonant circuit makes use of an inductor using step-down and a condenser of lose-less snubber. The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in a partial resonant circuit makes charging energy regenerated at input power source for resonant operation. The proposed conversion system is deemed the most suitable for high power applications where the power switching devices are used

• Journal of Electrical Engineering and Technology
• /
• v.5 no.3
• /
• pp.477-483
• /
• 2010

This paper is studied on a novel buck-boost isolated converter for high efficiency and high power factor. The switching devices in the proposed converter are operated by soft switching technique using a new quasi-resonant circuit, and are driven with discontinuous conduction mode (DCM) according to pulse width modulation (PWM). The quasi-resonant circuit makes use of a step up-down inductor and a loss-less snubber capacitor. The proposed converter with DCM also simplifies the requirement of control circuit and reduces a number of control components. The input ac current waveform in the proposed converter becomes a quasi sinusoidal waveform in proportion to the magnitude of input ac voltage under constant switching frequency. As a result, it is obtained by the proposed converter that the switching power losses are low, the efficiency of the converter is high, and the input power factor is nearly unity. The validity of analytical results is confirmed by some simulation results on computer and experimental results.

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

• The Transactions of the Korean Institute of Power Electronics
• /
• v.21 no.4
• /
• pp.351-355
• /
• 2016

Welding machines are high-capacity systems used in a low-frequency range using IGBT. As their system is similar to a large transformer, most welding machines suffer a great loss because of hard switching and vast leakage inductance. A voltage-balancing circuit is designed to overcome these shortcomings. This circuit can reduce the transformer size by making it into a high frequency and reducing the input voltage by half and by adopting a serial structure that connects two full-bridges in a series to use a MOSFET with a good property at high frequency. In addition, a Schottky diode is used in the primary rectifier to overcome the low efficiency of most welding machines. To use the Schottky diode with a reliably relatively low withstanding voltage, an active snubber is adopted to effectively limit the ringing voltage of the diode cut-off voltage.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.9 no.6
• /
• pp.560-567
• /
• 2004

In this paper, the design and implementation of a high power(300W) forward converter using a planar transformer is presented. The overall size and volume of the converter is decreased by replacing a planar transformer in stead of using a conventional winding transformer. Due to the decreased size and volume, power density of the applied forward converter is increased. Also, in this paper, the 300W ZVS forward converter with active clamp snubber circuit is compared to the 300W hard switching forward converter planar transformer, the decreased size and volume, the 300W ZVS forward converter with active clamp snubber circuit, 30W hard switching forward converter.