The Study Of Controlling The Output Characteristics Of Triboelectric Nanogenerator And Passive Power Management Circuit

In the Internet of Things(IoT),there are a large number of sensors that are widely distributed.The traditional battery-powered approach shows more and more drawbacks,such as limited life,complex maintenance,difficult to recycle and easy to cause environmental pollution.Collecting mechanical energy from the location of the sensor and developing a self-powered energy supply system is an effective energy solution.As a new way to obtain energy,triboelectric nanogenerator(TENG)can collect mechanical energy generated by the environment or human motion and directly convert it into electricity.Compared with electromagnetic induction generators,TENG has great advantages in collecting low frequency mechanical energy.In the future development and popularization of IoT,TENG can be used as a power source for microelectronic devices,and self-powered systems can be developed in combination with electronic devices.In addition,TENGs can be used as self-powered sensor for environmental monitoring,human-computer interaction,biosensing,etc.However,the high impedance characteristics of TENG make it difficult for directly powering small electronic devices.A power management circuit(PMC)is necessary to efficiently store the energy generated by TENG in a battery or a capacitor.TENG has high output impedance,generally in the range from 1 to 10 MΩ.However,the input impedance of common PMCs is only several kΩ.So the energy of TENG can’t be input into PMC effectively.In this paper,based on our privious work on pulsed triboelectric nanogenerator(Pulsed-TENG),we studied the output control and power management of TENG,aimed to solve the impedance matching problem between TENG and PMC,and developed two new passive PMCs,which can achieve high energy storage efficiency and drive the work of electronic devices.In chapter 2,a passive PMC based on triboelectric nanogenerator with a unidirectional switch(TENG-UDS)was designed.The output characteristics of TENG are regulated by switches,which greatly reduces the internal impedance of TENG and achieves impedance matching between TENG and PMC.TENG-UDS can maximize the output voltage and energy in the load range of 1 kΩ to 1 GΩ.And because of the design of the two contacts in the unidirectional switch,the unidirectional pulse output can be realized without rectification,which eliminates the energy loss caused by the rectification and reduces the complexity of the circuit.At the same time,the incorporation of TENG-UDS into the PMC greatly increases the charging rate and energy storage efficiency of the capacitor or battery.Theoretical calculations show that the energy storage efficiency of the passive PMC can reach 75.8%.In the actual charging process of a capacitor,its energy storage efficiency is 48.0%.In addition,to maintain a low frequency of motion,this passive PMC can be used to drive commercial electronic meters to work properly.Compared to the active PMC,the operation of the unidirectional switch in the above passive PMC does not require additional power supply,reducing the energy loss while decreasing the circuit complexity.The work of the unidirectional switch is relatively restricted by the environment,which imposes great limitations on its practical application.In chapter 3,based on the previously reported triboelectric nanogenerator with an electrostatic vibrator switch(TENG-EVS),we designed a new universal passive PMC.TENG-EVS can maintain high frequency energy output and can be applied to the collection of mechanical energy in different environments.Firstly,based on TENG-EVS,the relationship between output characteristics of Pulsed-TENG and load resistance is studied.It is found that the maximum output voltage and energy can be maintained even the matching impedance is 0.001 Ω.This proves that the output voltage and energy of the Pulsed-TENG can be maximized without the influence of load resistance.Then we applied TENG-EVS to PMC and developed a new type of passive PMC.Its energy storage efficiency was studied by simulation and actual test.The simulation results show that the total energy storage efficiency can reach 83.6%.In the actual charging experiment,the total energy storage efficiency is 57.8%,which achieves a significant increase in charging rate and energy storage efficiency.In addition,the energy stored in this passive PMC can drive the calculator and the temperature hygrometer.Through the research of this paper,we have realized the impedance matching between TENG and PMCs based on two different Pulsed-TENGs,and designed two new passive PMCs.Moreover,the passive PMC can achieve high energy storage efficiency and drive the small electronic devices to work normally.It lays a solid foundation for the application of TENG in the IoT and wearable electronic devices.