Research On The Energy Self-capture Technology Of Micro Sensor System

Nowadays, the micro sensor systems mainly powered by batteries. Some works as long as three to five years, others work as short as3-5months. After the battery is depleted, most of the sensors will be abandoned. Even those replace the battery that will work in a certain time before the power off. To alleviate this problem, a variety of low-power technologies have researched. However, scholars have been looking for a way to solve it. Energy self-capture technology has become hot. At the beginning of this paper, it shows the analysis of the power feature of micro sensor system. By studying the principle and design, this paper put forward a set of Energy self-capture system that combines vibration energy harvesting systems, thermoelectric energy harvesting systems and RF energy harvesting systems to each other.Firstly, the power consumption characteristics of the micro sensor system were analyzed, and three typical low-power workflow of STM32W108microcontroller were proposed. By the testing of collection-transmit workflow, the average power consumption of the system is only117.81mW.Secondly, the piezoelectric material properties and structural characteristics of piezoelectric energy harvesting mathematical model system were analyzed. The simulation model of unimorph cantilever structure is also tested by using the software of COMSOL. The structural parameters of the piezoelectric single-chip group cantilever beam model, such as the ratio of width to length, ratio of the length of the piezoelectric to beam, the thickness of the base beams and the piezoelectric material, were tested. The study found that these structural parameters affect only the characteristic frequency of the system, and the smaller to the output characteristics of the system. By studying the material of the piezoelectric unimorph cantilever beam model, the elastic modulus and density of these materials are large impact on the characteristic frequency of the system. Only the piezoelectric constant and the dielectric constant of piezoelectric will affect the output characteristics of the system.Then, by studying the heat source of the thermoelectric energy collection system, the most suitable source is natural heat for the micro sensors system. The analysis of resistance matching and the thermal resistance matching of the model is given. According to the design requirements, the thermoelectric element has550thermocouples. The height of the element is10mm. the area to0.45mm2. The resistance is0.68Ω, and matching resistance is92.4Ω. In theory, the output power is116.9mW.Finally, through the analysis of the spatial distribution of the radio wave characteristics, the design of collect relevant antenna for RF energy harvesting system is proposed. Based on the mathematical model of the antenna, this paper puts forward the eight million broadband microstrip antennas as a collection of antennas. According to the test of RF energy harvesting, in the wavelength range of900MHz, such as mobile phone signals, the system can output up to about7.8V and17pW.