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.

Abstract: A variable-frequency inverter microwave oven and a method for controlling the same. The inverter microwave oven comprises a magnetron for generating electromagnetic waves, a direct current (DC) voltage generator for rectifying and smoothing a commercial alternating current (AC) voltage, which is an inverter drive voltage, to generate a DC voltage, and a switching device for performing a switching operation based on the DC voltage from the DC voltage generator to generate an AC voltage for the driving of the magnetron. The switching device includes a plurality of switches turned on/off in response to the DC voltage from the DC voltage generator.

Abstract: An inverter circuit of a microwave oven is disclosed, in which it is possible to decrease the unit manufacturing cost of production, and to control an output of a magnetron correctly. The inverter circuit of the microwave oven according to the present invention is provided with a micom outputting a reference voltage preset by a user; an input current detector converting a current provided from the power source to a voltage level; a comparator comparing an output signal of the input current detector with the reference voltage; an integrator increasing or decreasing a level of an output signal of the comparator; a trigger circuit connected to the high voltage transformer, and generating a trigger signal; and a PWM controller receiving an output signal of the integrator and an output signal of the trigger circuit, for controlling drive of the magnetron.

Abstract: A variable-frequency inverter microwave oven and a method for controlling the same. The inverter microwave oven comprises a magnetron for generating electromagnetic waves, a direct current (DC) voltage generator for rectifying and smoothing a commercial alternating current (AC) voltage, which is an inverter drive voltage, to generate a DC voltage, and a switching device for performing a switching operation based on the DC voltage from the DC voltage generator to generate an AC voltage for the driving of the magnetron. The switching device includes a plurality of switches turned on/off in response to the DC voltage from the DC voltage generator.

Abstract: The present invention relates to a polypropylene resin composition and more particularly, to the polypropylene resin composition comprising a high crystalline polypropylene, a polypropylene or polyethylene having low molecular weight, an inorganic filler and an anti-additive. The polypropylene resin of the present invention provides improved heat resistance, impact resistance and scratch resistance, so that it is suitable for substituting conventional polypropylenes used for automotive interior materials having several tens of grades, and further lowers manufacturing cost along with improving productivity and reclamation of used materials.