基于压电谐振频率的PM2.5监测系统

基于压电谐振频率法采用模块化设计思想，设计了压电谐振式PM2.5监测系统，对系统的采样单元、谐振单元、频率测试与显示单元、控制单元等部件进行设计，并对系统进行集成与性能评价。为实现对PM2.5颗粒物的有效采样，并减小温度等环境因素对压电晶体检测性能的影响，系统采用惯性冲击式分粒原理结合静电沉降的采样方案，以2个相同的石英晶体振荡电路来构建双石英晶体谐振器，建立压电谐振频率与压电晶片质量间的关系，实现根据压电谐振频率的变化来确定PM2.5的质量浓度。系统测试结果表明，PM2.5测试数据与官方公布的数据相近，数据变化趋势一致。该PM2.5监测系统能反映被测区域PM2.5质量浓度的变化情况，满足PM25监测需求。

PM2.5 Monitoring System Based on Piezoelectric Resonant Frequency

Based on piezoelectric resonant frequency method,a piezoelectric resonant PM2.5 monitoring system is designed with the modular design concept.The sampling unit,resonant unit,frequency test and display unit,control unit and other components of the system are designed,and the integration and performance evaluation of the system are carried out.For this system,the sampling scheme of inertial impact particle principle integrated with electrostatic precipitation is adopted to realize the effective sampling of PM2.5 particles and reduce the effect of the environmental factor on the piezoelectric crystal detection performance.Two identical quartz crystal oscillator circuits are used to construct a dual quartz crystal resonator,and the relationship between the piezoelectric resonant frequency and the piezoelectric wafer quality is established,and the mass concentration of PM2.5 is determined based on the change of the piezoelectric resonant frequency.The system test results show that the PM2.5 test data are close to the official standard data, and the trend of data changes is consistent.The PM2.5 monitoring system can reflect the change of PM2.5 mass concentration in the measured area and meet PM2.5 monitoring requirements.