Induction heating device and method of controlling the same

A method of controlling an induction heating device, the method comprising:

• determining, by a control circuit, a driving scheme and duty cycle of a first working coil according to a required power value for the first working coil;
• determining, by the control circuit, a driving scheme and duty cycle of a second working coil according to a required power value for the second working coil;
• determining, by the control circuit, a driving start time of the first working coil and a driving start time of the second working coil based on the driving scheme of the first working coil, the driving scheme of the second working coil, and a predetermined driving period of the first working coil and the second working coil;
• determining, by the control circuit, an eccentricity determination period of the first working coil and an eccentricity determination period of the second working coil based on the driving scheme of the first working coil, the driving scheme of the second working coil, the driving period, the duty cycle of the first working coil, and the duty cycle of the second working coil;
• driving each of the first working coil and the second working coil according to the driving scheme and the driving start times, wherein the driving each of the first working coil and the second working coil includes the control circuit providing control signals to a driving circuit, and based on the control signals, driving signals are output from the driving circuit for providing on-times and off-times of the first working coil and the second working coil;
• while the first and second working coils are driven based on the control signals from the control circuit, obtaining voltage values from at least one voltage sensor at the first working coil and the second working coil or obtaining current values from at least one current sensor at the first working coil and the second working coil;
• receiving, at the control circuit, the obtained voltage values from the at least one voltage sensor or the obtained current values from the at least one current sensor of each of the first and second working coils;
• determining, at the control circuit, input power values of the first working coil and the second working coil based on the received voltage values or the received current values;
• determining, by the control circuit, eccentricity of a vessel placed on the first working coil according to the eccentricity determination period of the first working coil, wherein the determining of eccentricity of the vessel placed on the first working coil includes the control circuit comparing the determined input power value of the first working coil with a predetermined reference value;
• and
• determining eccentricity of a vessel placed on the second working coil according to the eccentricity determination period of the second working coil, wherein the determining of eccentricity of the vessel placed on the second working coil includes the control circuit comparing the determined input power value of the second working coil with a predetermined reference value,
• wherein if the driving scheme of the first working coil is a duty driving scheme and the driving scheme of the second working coil is a duty driving scheme, the eccentricity determination period of the first working coil and the eccentricity determination period of the second working coil are set based on a result of comparing the on-time of the first working coil and the on-time of the second working coil with ½ of the driving period, and
• wherein when one of the first working coil and the second working coil is a target for determining eccentricity of the vessel, driving of another one of the first working coil and the second working coil is stopped.