Woosup Kim

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.

Design and analysis of high-voltage transformer for HID lamp igniter

In this paper, requirements for the HID lamp igniter transformer capable of hot strike are described. A small size high voltage (HV) transformer composed of a ferrite core and an outer wall is designed. The characteristics such as flux linkage, current density and inductance are simulated with finite element methodology. The design guideline of the HV transformer that produces an output voltage with a peak value of 25 kV and a pulse width of larger than 100 nS for a 35 W automotive HID ballast prototype is discussed as an illustrative example

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.

Cost-effective sustain driver employing a new four-quadrant switch cell for AC plasma display

A new energy-recovery circuit (ERC) for the plasma display panel (PDP) using a switched transformer is proposed. The proposed ERC is very cost effective due to the reduction of device count and circuit complexity such as highside gate drivers and diodes in the resonant path. Also, the leakage inductances of the transformers are used as resonant inductors for soft-switching operation of the main switches. The operation and performance of the proposed energy recovery circuit were validated through waveform and power efficiency measurement tests with prototype hardware in 200 kHz switching frequency.

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.

A new energy-recovery circuit for the plasma display panel using the switched transformer

A new energy-recovery circuit (ERC) for the plasma display panel (PDP) using a switched transformer is proposed. It is intended mainly for the cost effectiveness by the reduction of device count and circuit complexity. The proposed ERC eliminates high-side gate drivers and diodes in the resonant path. Also, the leakage inductances of the transformers are utilized as the resonant inductors for ZVS operation of the main switches. To confirm the validity of the proposed circuit, its operation and performance were verified through experimental tests with prototype hardware.

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.

A novel transformer coupled efficient AC-PDP sustain driver

The novel concept of a transformer coupled energy recovery sustain-driver (TERSD) for plasma display panels (PDP) is proposed. The two windings of the transformer greatly boost up the displacement current flowing through the panel capacitance during the transition time and hence enable a fast inversion of the voltage polarity with practical values of resonant inductance. The resonant inductance can be increased by a factor of (n+1) 2 as compared to prior approaches. Increased inductance results in lower peak and rms current stresses and hence reduced conduction losses both in the resonant inductor and the energy recovery (auxiliary) switches. The proposed circuit can achieve zero-voltage-switching (ZVS) of the sustain switches and zero-current-switching (ZCS) of the auxiliary switches. The operational principle and design procedure of the proposed circuit are presented with theoretical analysis. The validity of the proposed sustain driver is established through simulation and experimental results at 200 kHz. The test results with a transition time of 400 ns are also presented to demonstrate the potential of TERSD to be used as a high frequency sustain-driver, thus increasing the brightness of PDPs.

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.