Patent ID: 8901466

Claim:
A method for operating an induction heating device, the induction heating device including, an induction coil, a capacitor connected in parallel to the induction coil, the induction coil and the capacitor forming a parallel resonant circuit, and a controllable switching element connected between an intermediate circuit voltage generated from an alternating supply voltage and a reference potential in series with the parallel resonant circuit and controlled in such a way that an oscillation of the parallel resonant circuit is caused during a heating operation, the method comprising the steps of: determining a low point of an oscillation cycle at a connection node of the parallel resonant circuit and the switching element; determining a low point voltage at the low point of the oscillation cycle; switching on the switching element, in the low point of the oscillation cycle, for an on period determined as a function of the low point voltage in such a way that at least one low point voltage in one or more following oscillation cycles does not exceed a predetermined maximum value; comparing the low point voltage with a reference voltage and a comparison signal is generated as a function of the comparison result indicating whether the low point voltage is higher or lower than the reference voltage; increasing the on period in an instance in which the comparison signal indicates that the low point voltage is higher than the reference voltage; and generating the reference voltage as a function of the switching state of the switching element.