Patent ID: 9006624
Filing Date: 2015-04-14
Classification: H05B

Abstract:
1. An induction heating, system comprising: an induction heating coil operable to inductively heat a load with a magnetic field; a switching device coupled between the induction heating coil and a power source, the switching device being configured to provide power to the load; a detector for generating a current feedback signal at an output of the switching device corresponding to a current flowing through the induction heating coil, the detector comprising a shunt resistor in series with a return path of current flowing through the induction heating coil to ground; and a controller for detecting, a switching transient in the current feedback signal and determining a resonant frequency of the system based on a characteristic of the switching transient, the controller being configured to determine whether the switching transient is positive or negative in magnitude and identify that the system is operating at or below the resonant frequency when it is determined that the switching transient is positive in magnitude and that the system is operating above the resonant frequency when the switching transient is negative in magnitude.