This article demonstrates a fiber-based power-bylight system that is capable of delivering up to 6.2 W of continuous electrical power at common voltages of 3.3 and 5 V. This optical link includes bidirectional optical communication, for which the data stream from the base to the remote unit is realized by amplitude modulation of the laser beam over the same fiber. At the remote unit, a gallium arsenide-based photovoltaic (PV) laser power converter receives and converts the light. The data are demodulated with a dedicated electric circuit, while the power is forwarded to a dc-dc boost converter. The optical data uplink is realized over a separate optical fiber. In operation, a PV conversion efficiency of above 50% has been measured. For downlink data rates up to 115.2 kb/s, unperturbed signal integrities are demonstrated, at higher data rates, the signal integrity deteriorates. An assessment of power budget and power losses in the overall system is presented. Finally, a smart power management concept is introduced, which controls the laser output power with respect to changing electrical load, optimizes the operating point of the PV cell, and, thus, increases system efficiency for varying load operation. Thereby, it also minimizes laser and PV cell operating temperatures, and eventually prolongs the lifetime of the system.
In this work a demonstrator with a switching frequency up to 2.5 MHz is shown. These comparatively high frequencies reduce the weight and the system costs of the resonant 3-kW-DC-DC-converter. The electrical properties of the implemented Gallium Nitride (GaN) power transistors enable high switching frequencies while maintaining high efficiency. The presented converter has a power density of approximately 3 W/cm3. The total efficiency of the converter is higher than 90 % for all operation points above 1/5 of the nominal load. Exceptionally high efficiency of 94.5 % can be reached at half of the nominal load and a switching frequency of 2 MHz. Possible improvements are defined and could be reached by adding a continuous dead time control as well as adapting the driver circuit of the synchronous rectification
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.