Light-Energy-Harvesting System and Its Test Environmental Setup

Abstract

Mobile devices and wireless sensor nodes (WSNs) have been rapidly developed in recent years and will get used much more widely in the future To extend battery usage time of mobile devices and WSNs and to meet their strict load demand high-efficiency and fast-transient power management IC is needed Light-energy harvesting is an elegant solution by integrating photovoltaic (PV) devices into such applications to further extend battery usage time or even make them autonomous forming a light-energy-harvesting system To examine the performance of the light-energy-harvesting system both PV devices and light-energy harvesters should be tested and measured Solar array simulator (SAS) and solar simulators are widely used instruments with accurate and multifunctional feature Still they are expensive and hard to carry In this thesis test environmental setup is proposed using a demonstration box with peripheral components to setup both outdoor- and indoor-light environment with controllable power density of the light sources within wide application range The demonstration box can be used to test and measure PV devices and light-energy harvesters with enough accuracy lower cost and better portability To verify its availability measurement result of PV devices and light-energy harvester using different ways are compared to each other with elaborated reasons for measurement differences The proposed demonstration box models outdoor-light condition with power density from 0 to 1 999W/m2 and models indoor-light condition with power density from 0 to 20 000 lux with enough uniformity In addition it only occupies size of 20cm × 20cm × 20cm with very-light weight featuring great portability On the other hand the light-energy-harvesting system in this thesis contains a light-energy harvester and a DC-DC buck converter The adopted light-energy harvester from previous work features high efficiency and fast-transient response under fast-irradiance-changing condition The DC-DC buck converter employing current-mode control and fast load-transient technique is re-designed with lower inductance to further improve the load-transient response

Date of Award	2017 Feb 3
Original language	English
Supervisor	Tai-Haur Kuo (Supervisor)