A three‐leg resonant converter for two output LED lighting application with independent control

Abstract

A three-leg resonant converter is proposed to drive two light emitting diode (LED) lamps of different power ratings. This may be required when both main and local lighting are essential. The proposed converter is operated simultaneously at two different frequencies. Two series resonant circuits are used to allow two different frequency currents. Each lamp is powered through a series resonant circuit and is controlled independently. LED lamp currents are regulated at the desired operating current by using phase-modulation control and asymmetrical duty ratio control. In addition, pulse-width modulation (PWM) dimming control is implemented for two LED lamps independently. The proposed topology has advantages of zero-voltage switching (ZVS), regulation of lamp currents, independent illumination control, and high efficiency. A 126-W prototype has been developed experimentally to confirm its working principle, performance, and validity.

A buck‐boost integrated high gain non‐isolated half‐bridge series resonant converter for solar PV/battery fed multiple load LED lighting applications

“…20,[24][25][26][27][28][29] LED drivers in previous works 20,25,26 use transformers, suitable for isolated applications but have limitations like more number of transformers, secondary windings, inductors, and capacitors. Non-isolated LED drivers with multiple loads, reported in previous studies, 24,[27][28][29] suffer from drawbacks like no independent dimming, less reliable, unequal output voltage gains, unable to drive loads with equal or unequal wattages/voltages. Further, LED driver in Ramakrishnareddy et al 28 requires one extra switch that increases cost and power losses as compared with the proposed configuration.…”

“…Many multiple load LED drivers are available in the literature. 20,[24][25][26][27][28][29] In Alonso et al, 20 the number of transformers increases as the LED loads increase. In Liu et al, 25 the number of secondary windings of transformer increases as the LED loads increase.…”

“…Several non-isolated LED drivers for multiple loads are reported in previous studies. 24,[27][28][29] In Reddy and Narasimharaju, 29 the second load is driven from the leakage energy of coupled inductor used with the first load. Thus, the wattage of the second load must be less than that of the first load and hence unable to drive equal loads.…”

“…But this configuration can drive only loads with equal voltages and also independent dimming control is not possible. In Ramakrishnareddy et al, 28 the LED driver provides unequal gains for multiple loads, thus driving only loads with unequal voltages, and ZVS is achieved partially across the switching devices.In this paper, a new buck-boost integrated high gain non-isolated symmetrical half-bridge resonant converter-based LED driver for multiple loads is proposed. As shown in Figure 1, the proposed configuration is the integration of synchronous buck-boost converter and half-bridge series LC resonant converter, which provides the same voltage gain as that of the full-bridge converter with less number of switches, effective utilization of switching devices and input voltage.…”

“…But this configuration can drive only loads with equal voltages and also independent dimming control is not possible. In Ramakrishnareddy et al, 28 the LED driver provides unequal gains for multiple loads, thus driving only loads with unequal voltages, and ZVS is achieved partially across the switching devices.…”