Intermittent control switch characteristics of triboelectric electric hybrid energy harvesting devices and power management circuits†

Abstract

Renewable energy sources such as wind, vibration, and tidal energy are widely available in everyday life, with scenarios where multiple renewable energy sources coexist. If multiple energy sources are collected efficiently, energy collection utilization and power generation will be increased. In this study, a triboelectric electric hybrid energy harvesting device (HEH-TENG) capable of harvesting rotational and vibrational mechanical energy is proposed in addition to a hybrid energy harvesting circuit (HEH-PMC) with intermittent control switches. The HEH-TENG is divided into a rotational triboelectric nanogenerator (R-TENG), which collects rotational mechanical energy, and a vibrational triboelectric nanogenerator (V-TENG), which collects vibrational mechanical energy. The HEH-PMC includes a rectifier module, energy storage module, comparison and detection module, switching module, and filtering module. The comparison and detection module includes a PNP-type triode and a detection capacitor, and the detection capacitor is connected to the emitter of the triode. The TENG is charged for the detection capacitor. When the voltage of the detection capacitor reaches a certain value, the triode is turned on. The thyristor SCR of the switching module is triggered after the transistor conducts, thus transferring the electrical energy in the storage capacitor to the back-end circuit. A new charging process is generated once the discharge of the storage capacitor is completed, thus realising intermittent control of switching conductivity. The HEH-PMC achieves stable power output, and the charging efficiency of the HEH-PMC is improved by 892% compared to a normal charging circuit when the R-TENG and V-TENG are operated simultaneously under the condition of charging a filter capacitor with a capacitance of 22 μF to 5 V without a load. The circuit was tested for its ability to carry a load. To simulate a micropower sensor, resistors with resistance values ranging from 100 kΩ to 3 MΩ were selected as loads for testing. A comparison of the back-end load voltages of the HEH-TENG and general-purpose power supply circuits under the same conditions shows that the output voltage of the HEH-PMC is higher than that of the general-purpose power supply circuit. When a 220 kΩ resistor is used as the load, the voltage increases from 0.53 V to 3.9 V, which is 7.36 times the voltage of the general power supply circuit and 54.15 times its power, indicating that the HEH-PMC has higher load capacity. Thus, this study provides a strategy for a hybrid energy harvesting approach for TENGs as well as hybrid energy harvesting power management circuits, and the approach is expected to expand the practical applications of TENGs.