• The Transactions of the Korean Institute of Power Electronics
• /
• v.19 no.1
• /
• pp.57-63
• /
• 2014

In this paper a bidirectional DC-DC converter is proposed for renewable energy systems, eco-friendly vehicles, energy storage systems, uninterruptible power supply(UPS) systems and battery test equipments. The two-stage bidirectional converter employing a fixed-frequency series loaded resonant converter is designed to be capable of operating under zero-current-switching turn on and turn off regardless of voltage and load variation, and hence its magnetic components and EMI filters can be optimized. And efficiencies and volumes of the two-stage bidirectional converters are compared according to configuration of isolated and non-isolated parts and a two-stage topology suitable for low voltage and high current applications is proposed. A 12kW(12V, 1000A) prototype of the proposed converter has been built and tested to verify the validity of the proposed operation.

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

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.53 no.8
• /
• pp.517-524
• /
• 2004

In this paper, a novel zero-voltage-switching(ZVS) resonant DC-DC converter is proposed. It is composed of two symmetrical active-clamped circuits, the converter can be achieve ZVS in each switches. Also, active clamp capacitor ratios($\alpha$) of proposed circuit can be reduce a peak stress of switching voltage for each main switch. Simulation results using Pspice 9.2 ver and $C^{++}$ characteristic analysis show a provement for the validity of theoretical analysis. The analysis of the proposed Current-Fed Push Pull type DC-DC converter is generally described by using normalized parameter, and achieved an evaluated characteristic values which is needed to design a circuit. We confirm a rightfulness theoretical analysis by comparing a theoretical values and experimental values obtained from experiment using MOSFET as switching devices.

• Proceedings of the KIPE Conference
• /
• 2015.07a
• /
• pp.319-320
• /
• 2015

A hybrid converter for the on-board charger consisting of a soft switching full bridge (SSFB) and a half bridge (HB) LLC resonant converter is proposed. The proposed topology adopts an additional switch and a diode at the secondary side of SSFB converter to guarantee the wide ZVS range of primary side switches and to eliminate the circulating current. The output voltage is regulated by controlling the duty cycle of secondary side switch. The effectiveness of the proposed converter was experimentally verified using a 10-kW prototype circuit. The experimental results show 96.8% peak efficiency.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.2
• /
• pp.383-392
• /
• 2016

This paper proposes the design considerations of resonant network and transformer magnetics for 500 kHz high switching frequency LLC resonant converter. The high power density can be effectively achieved by adopting high switching frequency which allows small size passive components in the converter. The design methodology of magnetizing inductance is derived for zero voltage switching (ZVS) condition, and the design methodology of the transformer and output capacitance is derived to achieve high power density at high operating frequency. Moreover, the structure of transformer is analyzed to obtain the proper inductance value for high switching operation. To verify the proposed design methodology, simulation and experimental results will be presented including temperature of passive and active components, and power conversion efficiency to evaluate dominant power loss. In addition, the validity of magnetics design will be evaluated with operating waveforms of the prototype converter.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.60 no.4
• /
• pp.246-252
• /
• 2011

In this paper proposes the soft-switching boost converter and MPPT control for improving the efficiency of PV system. The proposed converter designed H-bridge auxiliary resonant circuit. By this circuit, all of the switching devices perform the soft switching under the zero voltage and zero current condition. Therefore the periodic switching losses can be decreased at turn on, off. The soft switching boost converter designs for 1.5[kW] solar module of the power conversion. Thus, this soft switching boost converter is simulated by MATLAB simulation using Newton-Method algorithm. As a result, Proposed Soft Switching Converter compared to a typical boost converter switching loss was reduced about 61%. And the overall system efficiency was verified to increase about 3.3%.

• Proceedings of the KIEE Conference
• /
• 1999.07g
• /
• pp.3129-3131
• /
• 1999

The electronic ballast for MHD lamp was studied for automotive headlight application. Its basic principle is the Current Sourcing Push-Pull Resonant Inverter with DC I2Volt input Voltage. By changing the switching frequency according to the lamp state, the automotive requirement of very fast warm-up and the zero voltage switching condition were shown by the simulation of the ballast circuit.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.18 no.5
• /
• pp.458-465
• /
• 2013

This paper proposes a novel soft-switched auxiliary resonant circuit to provide a Zero-Voltage-Transition at turn-on for a conventional PWM boost converter in a PFC application. The proposed auxiliary circuit enables a main switch of the boost converter to turn on under a zero voltage switching condition and simultaneously achieves both soft-switched turn-on and turn-off. Moreover, for the purpose of an intelligent multi-chip power module fabrication, the proposed circuit is designed to satisfy several design constraints including space saving, low cost, and easy fabrication. As a result, the circuit is easily realized by a low rated MOSFET and a small inductor. Detail operation and the circuit waveform are theoretically explained and then simulation and experimental results are provided based on a 1.8 kW prototype PFC converter in order to verify the effectiveness of the proposed circuit.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.2B no.3
• /
• pp.133-139
• /
• 2002

In this paper, a prototype of an active auxiliary quasi-resonant DC link (QRDCL) snubber assisted voltage source bidirectional power converter (AC to DC and DC to AC) operating at zero voltage soft-switching (BVS) PWM nlode is presented for a Battery Energy Storage System (BESS). The operating principle of this QRDCL circuit and multifunctional control-based converter system, including PWM inverter mode in which energy flows from the battery bank to the three-phase utility-grid in addition to an active PWM converter mode in which energy flows from the utility-grid to the battery banks are described respectively by the control implementation on the basis of d-q coordinate plane transformation. The multifunctional operation characteristics of this three-phase ZVS PWM bi-directional converter with QRDCL is demonstrated fer a BESS under the power conditioning and processing schemes of energy supply mode and energy storage mode, and compared with a conventional three-phase hard switching PWM bi-directional converter for a BESS. The effectiveness of the three-phase ZVS PWM hi-directional converter with QRDCL is proven via the simulation analysis.

• Proceedings of the KIPE Conference
• /
• 1998.07a
• /
• pp.14-19
• /
• 1998

This paper has described about principle and form of proposed circuit made use of soft switching technology ZVS(Zero-Voltage-Switching) to reduce turn on and off loss at switching. also, the analysis of the proposed circuit has described by using normalized parameter and operating characteristics have been evaluated as to switching frequency and parameters. In addition, this paper proves the propriety of theoretical analysis in terms of the experiments.