Chung-Wook Roh

Multilevel voltage wave-shaping display driver for AC plasma display panel application

A new sustainer circuit with multilevel voltage wave-shaping characteristics for an AC plasma display panel (AC-PDP) drive is proposed. The proposed circuit features half the device voltage stresses and significantly reduced power losses compared with those of the conventional ones. This circuit, realizable without much increased cost of the semiconductor devices, gives a significant improvement in the power efficiency, essential for the design of a drive circuit for the AC-PDP. A comparative analysis and experimental results are presented to show the validity of the proposed sustainer circuit.

Novel plasma display driver with low voltage/current device stresses

A new energy-recovery-sustain circuit suitable for a plasma display panel (PDP) application is proposed. The proposed circuit features the low device voltage/current stresses, and the inherent circulating current elimination characteristics, essential to design a power efficient and low cost plasma display driver circuit. The proposed circuit is demonstrated experimentally for driving a 42 inches plasma display panel. It is best suited in a low cost and power efficient plasma display.

Dual-coupled inductor-fed DC/DC converter for battery drive applications

A new isolated boost DC/DC converter suitable for a low-input-voltage application is introduced. The proposed converter features low switch current stresses, wide range of input voltage, and inherent inrush current protection, essential for the design of a low-to-high-voltage conversion circuit. A comparative analysis and experimental results are presented to show the validity of the proposed converter.

P‐19: Multi‐Level Voltage‐Fed Power Efficient Sustain Circuit for AC Plasma Display Panel Drive

A new sustain circuit based on the three-level converter topologies for an AC plasma display panel (AC-PDP) drive, is proposed. The proposed circuit features half the device voltage stresses and the significantly reduced power losses, compared to those of the conventional ones. This circuit, realizable without much increased cost of the semiconductor devices, gives a significant improvement in the power efficiency, essential for the design of a drive circuit for the AC-PDP. A comparative analysis and experimental results are presented to show the validity of the proposed sustain circuit.

Current sourced power efficient sustainer circuit for AC plasma display drive

A new sustain circuit for an AC plasma display drive is proposed. The proposed circuit uses the instantaneous peak current flowing through the inductor during charging and discharging a plasma display panel (PDP), to mainly recover the energy lost by the capacitive displacement current. This circuit can be realized with a small number of part counts, and gives the zero voltage switching characteristics to all the switches even in the presence of a parasitic resistance, essential for the design of a sustain circuit for the AC plasma display. The capacitive displacement current and the required reactive power are greatly reduced in the proposed circuit. A comparative analysis and experimental results are presented to show the validity of the proposed energy recovery circuit.

Magnetic-coupled high power factor converter with low line current harmonic distortions for power factor correction and fast output response

A new magnetic-coupled high power factor converter (MCHPFC) with a single switch/single stage is proposed. The proposed converter gives good power factor correction, low current harmonic distortions, and tight output voltage regulation. The prototype shows that the IEC555-2 requirements are met satisfactorily with nearly unity power factor. A proposed MCHPFC is particularly suited for low-power-level power supply applications.

Boost Converter Embedded Battery Charging Function for Application of E-bike

In the conventional E-bike, a 42 V/10 A Li-ion battery drives a 24 V/10 A BLDC motor via a 6-switch PWM DC/AC inverter. The major problems of the conventional battery-fed motor drive systems are listed as follows. To charge the battery, an external battery charger (adapter) is required, which degrades the portability of E-bike users. In addition, given the high-frequency operation of the motor drive inverter, the switching losses are significant, which degrades the whole power efficiency. High-voltage batteries (42 V) require a complex battery management system (BMS), which degrades the reliability of the battery pack. In this paper, an embedded boost-converter battery charger for E-bikes is proposed. The variable output boost converter, which converts 16.8 V battery voltage to the required variable voltage of the inverter input, can use a low-voltage battery and thus improve the reliability of batteries. By varying the inverter input voltage via boost converter, a DC link voltage control method can be applied to reduce the switching frequency of the inverter, which improves the whole power efficiency. Given that the function of a flyback charger is integrated in the proposed boost converter, the portability of the E-bike user can be maximized by excluding an external adapter. The validity of the proposed circuit will be confirmed by operation mode analysis and simulation. Moreover, experimental results of integrative charger using Li-ion battery and 200 W motor test will be showed with a prototype sample as well.

Universal Single-Phase Line Compatible High Power AC/DC Converter

A conventional single-phase high-power system typically generates a large AC line input current at universal 90 VAC condition. Sometimes, this phenomenon can block the Earth Leakage Circuit Breaker (ELCB), which causes problems. Replacing power facilities is essential to ensure smooth operations. Thus, this paper proposes a method that can drive higher power than the limit of conventional power facilities. The proposed method can reduce the large AC line input current by limiting the input power of Power Factor Correction (PFC). An additional battery circuit can supplement the power deficiency. Specifically, a bidirectional converter with charging and discharging functions was adopted for the battery circuit. Finally, the validity of the proposed system could be confirmed by modal analysis and simulation, and an experiment in 2 KW condition was implemented with a prototype sample as well.

Resonant Step-Down DC/DC Converter to Reduce Voltage Stresses of Motor Driving Inverter under 3-phase AC Utility Line Condition

This paper presents a resonant step-down DC/DC converter to reduce the voltage stresses of a 3-phase inverter module under the three-phase AC utility line condition. Under this condition, a conventional 3-phase inverter module suffers from high voltage stresses as a result of the high rectified DC link voltage; hence, a high-cost high-voltage-rating inverter module must be used. However, using the proposed converter, a low-cost low-voltage-rating inverter module may be adopted to drive the motor even under the 3-phase AC line condition. The proposed converter, which can be realized with small size inductor and low-voltage-rating semiconductor devices, operates at a high-efficiency mode because of the zero-current switching operations of all the semiconductor devices. The operational principles are explained and a design example is provided in the study. Experimental results demonstrate the validity of the proposed converter.

Coupled nondissipative snubber fed single-stage AC/DC converter for simple low power level power supply application

This paper presents a new single-stage forward converter with a magnetic coupled nondissipative snubber, which gives good power factor correction (PFC), low current harmonic distortion and tight output voltage regulation. The proposed converter features the low switch current stress and the low switch voltage stress, essential for the design of a single-stage power factor correction converter. The prototype shows the IEC 1000-3-2 requirements are met satisfactorily with nearly unity power factor. This proposed converter with magnetic coupled nondissipative snubber is particularly suited for low power level power supply applications.