10351

9550

كارشناسي ارشد

الكترونيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1394

سيزده، 85ص.: مصور، جدول، نمودار

وحيد غفاري نيا

1394/05/19

مسعود سيدي، اصغر غلامي

1396/10/03

كتابنامه

برق و كامپيوتر

مهندسي برق و كامپيوتر

ID9550

به فارسي و انگليسي

Optimization of Temperature Modulation for High Speed and Low Power Gas Analysis Using Metal Oxide Gas Sensors Mohammad Ebrahim Ariani me ariani@ec iut ac ir Data of Submission 2014 04 29 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan Iran 84156 83111Degree Master of Science Language PersianSupervisors Dr Vahid Ghafarinia ghafarinia@cc iut ac irAbstract Metal oxide gas sensors are widely used in gas detection applications due to their lowcost and high sensitivity These sensors also respond to a wide range of chemicalcompounds However lack of selectivity and their operation at elevated temperatures are themain limiting factors preventing their use in portable gas analysis instruments Temperaturemodulation is an effective method to overcome these drawbacks In this method theoperating temperature of the sensor is not constant instead it is varied according to atemporal pattern Here the transient responses of a generic metal oxide are analyzed to findan optimum pattern for temperature modulation Gas recognition time power consumptionand discriminability are the main three criteria used for pattern optimization First the resultsof experiments on thermal measurements were used to model the thermal behavior of thesensing pallet Using the inverse model the appropriate heater voltage patterns required forgenerating the desired temperature patterns were derived The three basic patterns of interestare ramp exponential and step functions The sensor was thermally excited using the basictemperature patterns Experiments were repeated with different combination ofcharacteristic parameters e g amplitude time constant and slope The discriminability ofthe resulted transient responses were compared based on their spatial variation in the PCAfeature space Those resulted from step modulation were the best for optimized gasidentification It was also shown that normalized transient responses can be successfullyemployed for quantitative analysis of the target gases The results of basic patterns were alsoused as a reference to generate combinational temperature modulation patterns Keywords metal oxide gas sensors temperature modulation thermal transient 1response gas analysis

وحيد غفاري نيا

مسعود سيدي، اصغر غلامي