Single-material-substrated triboelectric–electromagnetic hybrid generator for self-powered multifunctional sensing in intelligent greenhouse

The environmental micro-energy harvested by the triboelectric–electromagnetic hybrid generator(TEHG)can power sensors and Internet of Things(IoT)nodes in smart agriculture.However,the separation structure of traditional TEHG raises the complexity of form and material,which is harmful to the miniaturization of the device.Herein,a single-material-substrated triboelectric–electromagnetic hybrid generator(SMS-TEHG)based on the flexible magnets is designed to achieve the structural integration of triboelectric nanogenerator(TENG)and electromagnetic generator(EMG).The flexible magnets serve as the electropositive triboelectric materials for TENG and the magnetic materials for EMG,simplifying the structural complexity of TEHG.The open-circuit voltage(VOC)of the TENG and EMG are 187.2 and 9.0 V at 300 rpm,respectively.After 30,000 cycles of stability testing,the VOC of the TENG and EMG retain about 95.6%and 99.3%,respectively.Additionally,the self-powered applications driven by SMS-TEHG in intelligent greenhouse have been successfully demonstrated,such as crop light supplementation,rain monitoring,and wireless temperature and humidity sensing.This work provides a new design for TEHG and possibilities for applying TEHG and IoT in smart agriculture.

Triboelectric nanogenerator with mechanical switch and clamp circuit for low ripple output

For new renewable clean energy,triboelectric nanogenerators(TENGs)have shown great potential in response to the world energy crisis.Nevertheless,the alternating-current signal generated by a TENG needs to be converted into a direct-current signal to be effective in applications.Therefore,a power management circuit,comprising a clamp rectifier circuit and a mechanical switch,is proposed for the conversion and produces a signal having a low ripple coefficient.The power management circuit adopts a clamp circuit as the rectifier circuit to increase the rectified voltage,and reduces the loss resulted from the components by reducing the use of discrete components;the electronic switch in the buck regulator circuit is replaced with a mechanical switch to reduce cost and complexity.In a series of experiments,this power management circuit displayed a stable output voltage with a ripple voltage of 0.07 V,crest factor of 1.01,and ripple coefficient of 2.2%.The TENG provides a feasible method to generate stable electric energy and to supply power to low-consumption electronic devices.