Research On Wearable Device Power Supply System Based On The Power Generation By Human Body Movement

The appearance and development of wearable devices facilitate people’s lives.At the same time,the continuous power supply of wearable devices becomes the bottleneck of its further development.Batteries are currently the main source of power for wearable devices,but it is inconvenient to replace batteries frequently or to find power interfaces to charge them.Therefore,it is considered that if there is no negative impact on the daily activities of the human body,a power supply system based on human motion can be created by using the appropriate device to collect energy and be assisted by an efficient micro-power management system.In view of the current theory and technology,the more valuable energy based on the human body is:(1)the motion energy of the human body;(2)the heat energy of the human body itself;(3)the biological energy and chemical energy of the human body itself.In this thesis,piezoelectric vibration power generation method is used to collect human motion energy,specifically,first of all,in the aspect of structure design,piezoelectric vibrator is made according to the structure characteristics and generation performance of piezoelectric film,and 2D and 3D structure diagrams of all kinds of devices are drawn on AutoCAD and SolidWorks platforms.The device is made by 3D printer,and then the piezoelectric oscillator based on PVDF thin film is placed on the device object.Secondly,in the aspect of hardware design the rectifier and filter circuit are designed,the circuit of charging lithium-ion battery controlled by MSP430 single chip microcomputer and the external power supply circuit of USB interface are also designed in the first power conversion system.In the second power conversion system,the AC/DC conversion part and the super capacitor energy storage part are the same as system one.The difference is that the integrated linear charging chip TP4057 for lithium-ion battery is adopted.Thirdly,in the aspect of software design,the modular programming method is used,which is mainly to program,debug and burn the charge and discharge process of lithium-ion battery controlled by MSP430 single chip microcomputer in the power conversion system one.The important segments include ADC conversion module,PWM output module,the temperature,voltage,charging current detection module of lithium-ion battery and the process control module for each charging stage and the alarm module,etc.Finally,the AC/DC circuit and the Buck circuit are simulated on Multisim and MATLAB platform respectively,and the whole system object is put onto the human body for wearable and actual test,the data is recorded.The experimental results show that the power supply system which uses the human body motion to drive the piezoelectric device to generate electricity then converts the electric energy and outputs the DC 5V with the USB interface can meet the requirements for the power supply of the wearable equipment in this thesis,and the combined energy storage method of the super capacitor and the lithium-ion battery is adopted,the whole system is easy to carry,so it has good practical value.