A MICROCONTROLLER-BASED, FEEDBACK POWER CONTROL SYSTEM FOR MICROWAVE DRYING PROCESSES

Abstract

Microwave drying is an energy-efficient method, resulting in large energy savings. Microwave power andtemperature of the products during drying process have significant influence on the quality of final products. To provide anautomatically controlled microwave power and stabilize temperature variations during a drying process, amicrocontroller-based, temperature-feedback power control system was developed. Two temperature sensors, a thermocoupleprobe, and an infrared sensor, were used and compared. A fiber-optic thermometer was also used for temperature calibration.Within 180 min, a carrot sample was dried to 14.63% moisture content (wet basis) and no carrot was burned.