A Wireless Dimmable Lighting System Using Variable-Power Variable-Frequency Control

This article proposes and implements a wireless dimmable lighting system using variable-power variable-frequency (VPVF) control, which can eliminate the use of secondary converters via wireless power transfer (WPT). The proposed scheme integrates the secondary T-LCL circuit into a sealed antiparallel light-emitting diode (LED) lamp, which takes the key merits of safety, flexibility, maintenance free, and convenience for manufacturing. Moreover, it can effectively widen the LED dimming range and reduce the starting voltage requirements, which inherently improve the output fluctuation insensitivity and voltage deviation tolerance. In contrast to phase shift control, a WPT-inherent VPVF control is proposed to realize effective reductions in both the switching frequency and switching losses, while maintaining the regulation accuracy and output fluctuation suppression by up to 48.45% as compared with burst firing control. The system electrical efficiency can reach 88.08% with 20-cm transfer distance and it is improved by 3.35% during power control. Both theoretical analysis and practical experimentation are given to verify the feasibility of proposed VPVF-modulated wireless dimmable lighting system.