The Study Of Pyroelectric Energy Harvesting Measure System Based On PWM Temperature Control Principle

With the deep research application of pyroelectric materials,utilizing the pyroelectric materials for energy harvesting has become a research hot topic,the research on the testing system of pyroelectric energy harvesting has important effect on the development of pyroelectric materials and devices.At present,most of the relevant measurement system evaluate the performance of pyroelectric materials by measuring the pyroelectric coefficient.There are few reports on the pyroelectric energy harvesting measurement system related to device structure and external excitation conditions,and there are some shortcomings,such as complex operation,and poor automation.Based on above background,in order to realize the energy harvesting performance characterization of the pyroeletric materials,this work studied automatic measurement technology of pyroelectric energy harvesting.Firstly,the hardware circuit of the testing system was designed.The hardware circuit part took the USB6002 data acquisition card as the core,including temperature control module,voltage and temperature acquisition module and power supply module.The temperature control module which consisted of a data acquisition card,a semiconductor cooling chip,a solid state relay and a radiator,based on the PWM control principle,could generates a periodic variable temperature field with adjustable rate of temperature change.Voltage and temperature acquisition module collected the real time voltage signal generated by pyroelectric samples,and the real time temperature signal generated by the LM35 temperature sensor.The power supply module offered power to the chip and semiconductor cooling chip.In order to make the temperature field distribution more uniform and make the system more convenient and reliable,the sample cavity similar to the drawer and the shell of the test system were designed and fabricated.Secondly,the software of the test system based on LABVIEW platform was designed.The software part included function selection module,data acquisition module,data processing and display module.The data acquisition module collected the voltage and temperature value in real time and simultaneously displayed the temperature-time curve.The data processing and display module calculated and processed the data collected by the acquisition module,and displayed the relevant curve and the test data on the front panel.Function selection module obtained the data preservation and removal,test system exiting and other operations,to realize the automaticl test function.Finally,the test system was debugged and tested.The temperature range of the test system is from 20? to 80 ?,the temperature change frequency is from 13.98 mHz to 34.11 mHz,the maximum measurement deviation of the test system is 3.8% compared with the oscilloscope.The PZT-5H pyroelectric ceramic discs are tested at different heating rates using the test system,and the corresponding peak voltages are 2.508 V,2.907 V,3.374 V,3.724 V respectively.