Protection circuit to prevent a transition from ZVS mode to ZCS mode under variable frequency operation

a simple protection circuit for resonant power converters using soft switching topologies is proposed in this paper. The proposed protection circuit can protect the power MOSFET of bridge converter from abnormal condition. The circuit is designed to provide protection to a power supply for a gas discharge lamp by a sudden transition from zero voltage switching (ZVS) mode to zero current switching (ZCS) mode under variable frequency operation. Using this protection circuit, the operating frequency of the lamp driving inverter system is kept close to and on the right side of the resonant frequency and the inverter is always operated in the ZVS condition. The validity and effectiveness of the proposed circuits are verified thought experimental results.

[1]  Fred C. Lee,et al.  Radial mode piezoelectric transformer design for fluorescent lamp ballast applications , 2002, 2002 IEEE 33rd Annual IEEE Power Electronics Specialists Conference. Proceedings (Cat. No.02CH37289).

[2]  Jong Tae Hwang,et al.  Intelligent high-voltage high-power ballast IC , 2007, 2007 7th Internatonal Conference on Power Electronics.

[3]  E. M. Baker,et al.  Design of Radial Mode Piezoelectric Transformers for Lamp Ballast Applications , 2002 .

[4]  Ray-Lee Lin,et al.  LLC DC/DC Resonant Converter with PLL Control Scheme , 2007, APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition.

[5]  Aiguo Patrick Hu,et al.  ZVS frequency analysis of a current-fed resonant converter , 2000, 7th IEEE International Power Electronics Congress. Technical Proceedings. CIEP 2000 (Cat. No.00TH8529).

[6]  Bishwajit Saha,et al.  Single Reverse Blocking Switch Type Pulse Density Modulation Controlled ZVS Inverter with Boost Transformer for Dielectric Barrier Discharge Lamp Dimmer , 2006, 2006 CES/IEEE 5th International Power Electronics and Motion Control Conference.

[7]  Ray-Lee Lin,et al.  Inductor phase feedback for phase-locked loop control of electronic ballasts , 2005, Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference, 2005..

[8]  Chien-Ming Wang,et al.  A Novel Zero-Voltage-Switching Single-Stage High-Power-Factor Electronic Ballast , 2007, 2007 7th International Conference on Power Electronics and Drive Systems.