Induction heating cooking device
View Patent ↗An induction heating cooking device has an inverter including a resonant circuit, and a heating output control part. The resonant circuit has a resonant capacitor and a heating coil that is magnetically coupled to a load. The inverter has first and second switching elements. The heating output control part performs control by inverting the rate values of the driving periods of the first and second switching elements. The driving of the inverter is thus controlled so that substantially the same heating output is obtained to average the losses of the first and second switching elements.
1. An induction heating cooking device comprising:
an inverter including
a series circuit of a first switching element and a second switching element that are connected to ends of a smoothing capacitor,
a first diode connected to the first switching element in anti-parallel,
a second diode connected to the second switching element in anti-parallel, and
a resonant circuit that has a heating coil and a resonant capacitor, and is connected to one of the first switching element and the second switching element in parallel;
a heating output control part that alternately drives the first switching element and the second switching element, and controls a heating output used when the heating coil induction-heats a load; and
a switching element temperature detecting part for detecting temperature of the switching element;
wherein the heating output control part sets driving frequency of the first switching element and the second switching element to be substantially 1/n (where, n is an integer of 2 or more) times higher than resonance frequency of the resonant circuit in heating the load; and
wherein the heating output control part switches driving duty defined by rates of a driving period of the first switching element and a driving period of the second switching element, based on a detection output of the switching element temperature detecting part, so that the driving period of the first switching element and the driving period of the second switching element are inverted in length, and switches and controls the driving duty so that substantially the same heating output is obtained.
2. The induction heating cooking device according to claim 1 , wherein the load is made of nonmagnetic metal with low resistivity.