Design and Analysis of Wireless Direct-Drive High-Intensity Discharge Lamp

The wireless power transfer (WPT) for directly driving the high-intensity discharge (HID) lamp is proposed and implemented. In this article, the HID lamp is ignited and operated solely on the resonator without using any ignitor, ballast, or additional LC tank. Meanwhile, the key characteristics in the ignition and running phases are generally analyzed with the consideration of compensation schemes and number of coils. The even-coil series-series (SS) and odd-coil series-parallel (SP) WPT are identified to be more competent for wireless lighting with short and long transfer distances, respectively. In addition, the resonant frequency of 400 kHz is chosen to improve the luminous efficacy up to 150 lm/W. For exemplification, two-coil SS, three-coil SP, four-coil SS, and five-coil SP wireless HID lamps have been built and developed with the overall distances of 20, 40, 68, and 100 cm, and the transfer efficiencies are 94.1%, 89.6%, 83.1%, and 69.2%, respectively. Both the theoretical and experimental results are given to validate the feasibility and flexibility of the proposed system.