Inductive Sensor for Temperature Measurement in Induction Heating Applications

A new inductive sensor for temperature measurement in domestic induction hobs and results of its applications are presented. It consists of a coil and a resonant electronic circuit which measures the impedance variation of ferromagnetic pots when their temperature changes. This sensor has promising applicability in induction hobs because it has instantaneous response, it is cheap, and contactless. The performance of the sensor is tested in the cooking range from 20°C to 220° C with pots of different materials, revealing a measurement error lower than 6°C. This error is much lower than that obtained from measurements with current sensing systems installed in induction hobs, namely a thermistor measuring the temperature of the glass in the cooking zone. The proposed sensor will allow fire prevention in cooking processes with a cost comparable to that of conventional measurement systems.