Page - 135 - in Adaptive and Intelligent Temperature Control of Microwave Heating Systems with Multiple Sources

5.1. Verification inHEPHAISTOS Step1: Heatingpatternsofsinglefeedingsource The heating stability verified in the experiment refers to two parts. Thefirstpart is toseehowtheheatingpatternchangeswithtime,and the other one is to test if the heating patterns are equivalent when the same source is switched on and off multiple times. If a feeding source hasthesameheatingpatternatdifferenttrialsandthispatternisstable over time, then it is guaranteed that this source can provide a stable poweroutputaswellasastableEMfielddistribution. Foralldifferentheatingsources j in thefirst twomodules (seefigure 2.13,1≤ j≤12): repeat repeat 1 Waituntil the temperatureof theworkpiece iscooleddown to30◦C∼32◦C; 2 Switch theheatingsource j for10s; 3 Recordtheheatingpattern fromthe infraredcameraat time t= 0,2,4,6,8,10s. until for three times; untilall sourcesare tested; Figure 5.2. Procedures to test theheatingpatternsofsinglesource. The procedures for the experiment are described in figure 5.2. For individual sources, the typical results are illustrated as in figure 5.3 and 5.4. The numbers within figures 5.3 represent the temperature changes of this point at this time compared with the initial tempera- ture in the first figure at t= 0 s. For example, the number +0.60◦C in location 3 at time t= 2 s represents that the temperature of this lo- cation increases0.60◦Cduring the last 2 s. Although the temperature increasings are not entirely linear, the whole temperature distribution (thermal pattern) stays the same during the 10 s, which indicates a stableheatingpattern fromthissource. Compared with this heating stability of time, what is more important is the stability of the heating patterns at different trials. Because in 135