System and method for detecting changes in food load characteristics using coefficient of variation of efficiency

摘要

An electromagnetic cooker is provided that has a controller and a plurality of RF supplies configured to introduce electromagnetic radiation into the closed cavity to heat a food load. The controller (a) causes the generation of RF excitation to occur at a specified frequency and phase shift from each of the plurality of RF sources for a predetermined period of time, and (b) during the predetermined period of time, the plurality of RF sources (C) Variation to measure the reverse power at and analyze to calculate the efficiency, determine the coefficient of variation of efficiency, and monitor the coefficient of variation to identify expected changes in the characteristics of the food load. It is configured to repeat steps (a) and (b) until an expected change in the food load profile is identified based on the change in the coefficient. This property may be food load volume.