Abstract: A heater unit is provided, the heater unit equipped with an induction heating coil and an electric heater selectively operated based on kind and state of a load of a cooking vessel placed on the heater unit. The kind is determined by an input current inputted when a load-type determination unit causes the induction heating coil to be operated and a resonance current flowing into the induction heating coil. The state is determined by a temperature change of the heater unit when a load-state determination unit allows the electric heater to generate heat, and the induction heating coil and the electric heater are selectively operated based on the determined kind and state of the load. Accordingly, a user needs not to scrupulously determine the kind of the cooking vessel and the electric cooker is not operated under a no-load state to prevent occurrence of safety accidents.

Abstract: A heater unit comprises: a hot wire heating unit; an induction heating unit provided adjacent to the hot wire heating unit and operated by induction heating; and connectors each for connecting the hot wire heating unit to the induction heating unit. A cooker comprises: a casing; a heating plate provided on an upper surface of the casing; a hot wire heating unit provided on a bottom surface of the heating plate for generating heat according to application of an electric power; an induction heating unit provided on the bottom surface of the heating plate for being adjacent to the hot wire heating unit and operated by induction heating; connectors each for connecting the hot wire heating unit to the induction heating unit; and support members each provided on the bottom surface of the hot wire heating unit and for supporting the hot wire heating unit.

Abstract: An induction-heating cooking apparatus and a method for operating the same are disclosed. Upon receiving a low-voltage signal in a high-output level state, the apparatus controls an output signal to allow an inverter to be operated only in a ZVS (Zero Voltage Switching) area. If an input voltage applied to a circuit is a low voltage, the apparatus compensates for the input voltage using a smaller one between a blocking voltage and an output control signal generated from the microprocessor, thereby limiting a compensation component. Therefore, the apparatus prevents the occurrence of a power loss caused by an excessive switching operation, and also prevents a switch from receiving a high instantaneous current, resulting in increased endurance of cooking appliances.

Abstract: An induction-heating cooking apparatus, operation of which is interrupted by container eccentricity is disclosed. Upon receiving an input signal varying with the degree of eccentricity of a container, the apparatus changes a reference signal for determining the presence or absence of a small load in proportion to a pulse-width control signal controlling the width of an inverter driving pulse. Although the eccentricity of the container occurs in a normal heating operation and completely escapes from a cook zone, the apparatus determines the occurrence of a no-load state, and interrupts an operation of an inverter circuit, resulting in increased stability of a circuit and a product.

Abstract: An induction heating cooker capable of accurately discriminating whether the material of a cooking container placed in the induction heating cooker is magnetic or non-magnetic, using a phase change in a resonant capacitor voltage of an inverter circuit and a switching pulse signal of the inverter circuit, irrespective of the load of the cooking container, and a method for operating the induction heating cooker.