Suyong Chae

Digital Predictive Feed-Forward Controller for a DC–DC Converter in Plasma Display Panel

This paper describes a new digital control method to enhance the dynamic performance of a dc-dc converter used in Plasma Display Panels (PDP). A simple digital PID compensator with duty ratio feed-forward control is proposed to minimize the output voltage variation for continuously changing load current. The duty ratio feed-forward is calculated using a noise-free load current information, which is predicted by the available video data of the PDP. No separate current sensing circuit is required. A small signal z-domain feed-forward model is derived for the performance analysis and controller design. The proposed control method is experimentally verified on an Asymmetrical Half Bridge (AHB) dc-dc converter, which supplies power to a 42 inch PDP.

Digital load current feed-forward control method for a dc-dc converter

This paper describes a new digital feed-forward control method to enhance the dynamic performance of a dc-dc converter. The feed-forward duty ratio is calculated based on the charge balance of the output capacitor using the load current, and it is combined with the output of the digital PED feedback compensator. The feed-forward duty ratio propagates to the consecutive switching cycles during the load transient interval to immediately supply the required energy. The propagation length is decided by comparing the feed-forward duty ratio with the switching period. The performance improvement of the proposed digital control method is experimentally verified on a 200 W buck dc-dc converter.

A Cost Effective PDP Sustainer using Two-Winding Transformer with Hybrid Operation

In this paper, a new PDP sustainer using transformer energy recovery networks is proposed. The two-winding transformer gives the proposed topology several merits, such as a lower number of devices, simple gate driver, ZVS-on of the main switches, ZCS-off of the resonant switches and diodes and high energy recovery efficiency. The turns ratio realizes the voltage-applied overdriving technique as well as the current-injected overdriving technique. The hybrid driving technique using both methods is researched, which is useful for a faster transition time, hence providing higher contrast ratio and luminous efficiency. The proposed circuit is verified with simulation and experimental results of a 42-inch PDP.

P-114: A New Energy Recovery Circuit for the PDP Sustainer using the Auxiliary Transformer

A new PDP sustainer is proposed to improve the demerits of prior approaches — imperfections in ZVS switching and large number of devices. Auxiliary transformer (AT) provides additional resonant energy to operate main full-bridge switches with ZVS and resonant switches and diodes with ZCS. Experimental results verify the proposed circuit.

Off-line buck LED driver for series connected LED segments

This paper proposes an offline light-emitting diode (LED) driver which is based on inverted buck topology. The proposed circuit consists of control circuit, bridge diode and inverted buck converter which has multiple switches connected to LED segments in parallel. While the conventional buck LED driver regulates fixed LED forward voltage, the proposed driver regulates variable LED forward voltage according to input voltage level. By the capability to adjust the LED forward voltage, it can reduce the current ripple while using same inductance. In addition, it enables to operate wide voltage range of LED lamp, simultaneously achieving high power factor. The basic operation principle and the control scheme are described. The proposed offline LED driver has been demonstrated in a 7 W, 110 Vrms experimental prototype, which provides high efficiency and low LED current ripple with high power factor.

IGBT based high voltage converter with integrated magnetics

In this paper, a half-bridge LCC high voltage converter with integrated magnetics is proposed. The resonant tank is formed with high conversion ratio transformer in one core, resulting in cost effectiveness. Using IGBT, operation in below resonant frequency with hybrid soft start method are suggested. The design guideline of the integrated magnetic component and controller in below resonant frequency operation is described. 13kV prototype hardware verifies the proposed converter operation.

An Integrated AC-DC Converter with Tight Output Voltage Regulation

This paper introduces an integrated ac-dc converter based on the parallel-series structure. The parallel structure is composed of two converters operate in continuous conduction mode. The parallel structure enhances the conversion efficiency and extends the power processing capability. The series connection of the output capacitors makes the output dc voltage to be regulated tightly. The operation principle and the control method with the small signal model are described. The operation of the proposed converter is experimentally verified by a 400W prototype hardware.

P-113: An Efficient and Cost-Effective Novel Driving Scheme for AC - PDP Sustain Driver

A new concept of an efficient energy recovery for plasma display panel (PDP) is proposed. Using a transformer in parallel with the panel capacitance, resonant current through the auxiliary switches can be reduced which results in a higher energy recovery efficiency. The validity of the proposed sustain driver established through experimental results at 200 kHz.