Wind and solar energy are important ubiquitous energy sources for Internet of Things nodes operating long-term in the field.It is essential to determine the boundary conditions of energy harvesting and storage under varying wind speeds and solar intensities to improve the efficient utilization of ubiquitous energy.A wind-solar hybrid energy harvester design and an intelligent charging-discharging scheme are proposed.It consists of a drag-type wind energy harvester

a solar panel array

logic circuits

and an energy storage unit.The wind harvester utilizes the principles of torque determined by the windward angle and air pressure

and achieves low-wind-speed capture capability by overcoming the start-up torque threshold.To solve the problems of environmental volatility and system power supply stability

a dual lithium battery master-standby intelligent charging and discharging strategy is adopted

enabling dynamic adjustment of charging and discharging cycles based on power thresholds.Experimental results show that the starting wind speed of the energy harvester is only 1.4m/s

reaching the light air starting level.The energy conversion efficiency is at least 37.13% in the wind speed range of 1.4~10m/s.Under natural wind-solar conditions

a 950mAh lithium battery can be charged to 70% within 7 hours

meeting the requirement for periodic and stable power supply of wireless sensor nodes.