The variation of of output power and capacitor voltage with dimming is illustrated in Figure.14. From figure.14, it can be concluded that output power increases along with Vc with increase in diming. The efficiency versus dimming is plotted and illustrated in figure.15. From figure.15 it clearly indicates the efficiency of proposed converter is almost same throughout the operation of dimming from 20% to 100%. Further the efficiency of the driver circuit is achieved 92.6% at 100% dimming. The major advantages of the proposed converter are reduced switching loss, achieves high efficiency, reduced component count, and reduction of output electrolytic capacitor. Further, comparative study of the single input LC series resonant converter with similar researchers is summarized in Table II. It can be noticed from Table II that the single input LC series resonant converter requires fewer switching devices. Also, single input LC series resonant converter provides several advantages, such as dimming control, compact size, soft switching, and increased overall efficiency.
4 CONCLUSION
This work proposes a single input full-bridge LC series resonant converter based high brightness light emitting diode driver with ZVS. This work presents the detailed analysis, design guidelines and simulation results in order to study the effectiveness of the proposed single input full-bridge series resonant converter. The proposed converter is designed to operate with zero-voltage-switching, which resulted in reduction of switching losses. Owing to the reduction of switching losses, the overall efficiency of proposed converter is achieved 92.6% at 100% dimming. Further the converter is operated with DC bus voltage, therefore the filter capacitor is sufficient to eliminate switching ripples, which results in elimination of filter capacitors and enhance the lifespan of LED driver. Moreover, the proposed converter is tested with dimming level from 20% to 100% to study the effectiveness of DPWM dimming control. For an input DC bus voltage of 24 V, the efficiency higher than 92.6% has been achieved owing to less power processing by the converter and presence of ZVS throughout the operating range. An efficient power factor correction converter may be included in the configuration and different control techniques for better dimming may be studied as future work.