Abstract: The present invention relates to an induction heating cooker for supplying a predetermined resonant current to a heating coil to thereby carry out a cooking operation, the induction heating cooker including: a rectifying unit for full wave rectifying a commercial alternating current, a zero voltage detecting unit for detecting a zero potential of the commercial alternating current, a control unit for synchronizing with the zero potential of the commercial alternating current detected by the zero voltage detecting unit to thereby control the overall operations of the induction heating cooker, a variable frequency oscillating unit for receiving a control signal generated by the control unit to thereby generate an oscillating frequency, an inverter driving unit for generating a driving signal to thereby drive the switching element according to the oscillating frequency generated by the variable frequency oscillating unit, an inverter for receiving the direct current voltage generated from the rectifying unit acc

Abstract: An induction cooking heater includes at least one inductor, a high-frequency current generator and a magnetic circuit located beneath the inductor. The reluctance of the magnetic circuit is calibrated so that the magnetic circuit gets saturated from a predetermined temperature lower than the maximum permissible temperature for the inductor. A plate made of non-magnetic, electrically conductive material located beneath the magnetic circuit, gives rise to an increase in current in the inductor when the magnetic circuit starts getting saturated. The generator is then controlled by a regulator for limiting the value of the current in the inductor to deliver lower power to the inductor.

Abstract: The load balancer incorporates link coil circuits that inductively couple to induction heating coils, which are connected in parallel across a power source. A capacitor is electrically connected in the link coil circuit. By varying degree to which the link coil is inductively coupled to the heating coil or by changing the capacitance, either using a variable capacitor or switching among different capacitors, changes in the amount of reactance coupled into the heating coil are effected. Thus, the current in the corresponding heating coil can be varied, enabling adjustment of the heating of the workpiece. Accordingly, the resulting system is efficient since only a single coil rather than multiple series coils are used. This aspect can be enhanced when litz cable is used in coil construction. Further, the system is compatible with active control.

Abstract: An automatic burner assembly is disclosed, which assembly is adapted to be automatically and selectively actuatable upon the placement of a given vessel thereon or in close proximity thereto, this assembly comprising a heating element operably coupled to a sensor assembly, where this assembly is capable of detecting the presence of a given vessel on or proximate to the heating element.

Abstract: An induction cooking apparatus and method for inductively heating cookware is provided. An analog/digital circuit, including a microprocessor, generates a plurality of gating pulses for operating the power inverter circuit and monitors the operation of the power inverter circuit. The microprocessor provides signals to start and stop the inverter circuit, and determines a period of uninterrupted power inverter circuit operation corresponding to a desired cooking temperature. Analog circuitry is provided for sustaining operation of the power inverter circuit after the power inverter circuit is started, and for compensating for variations in cookware materials.

Abstract: A process for induction hardening a part to a desired depth with an AC signal applied to the part from a closely coupled induction coil includes measuring the voltage of the AC signal at the coil and the current passing through the coil; and controlling the depth of hardening of the part from the measured voltage and current. The control system determines parameters of the part that are functions of applied voltage and current to the induction coil, and uses a neural network to control the application of the AC signal based on the detected functions for each part.

Abstract: This invention relates to a process and a device for controlling power for a circuit comprising a resonant inverter intended to supply a variable impedance load comprising an inductive component. The invention renders the active power consumed by the load independent of the nature of the load by producing an error signal that is a function of an average value of a current passing through power transistors of the inverter, this error signal being used to control a power modulator controlling the switching of the power transistors. Such a process and device finds particular application to a circuit for controlling power supplied to an inducer and a cooking utensil.

Abstract: In order to determine the contents of solids in a heated elongated slug of thixotropic metal having a longitudinal axis, there is an apparatus comprising an inductive heating coil with electrical winding. Moreover, a sensor includes at least one measuring coil arranged between the heating coil and the slug. This sensor provides an output signal which corresponds to the contents of solids demanded.

Abstract: In a switching device of an induction heating cooker, an oppositely poled diode for conducting a reverse current is coupled across the collector-emitter portion of a switching element provided in the first switching device, and turn-ON operation of the switching devices does not OCCUR in normal operation of the DUTY FACTOR T.sub.2 /T.sub.1 .apprxeq.0.5.

Abstract: An induction heater comprises a coupled pair of inverters and an induction head for generating heat, coupled to the second inverter. The output signal of the first inverter which operates at a fixed frequency, is controlled by feedback indicative of the heat output of the induction head. A control circuit processes the feedback information to compensate for power losses in the induction head. The output of the first inverter is electrically coupled to the input of the second inverter, which operates at an adjustable frequency which is selected by the user to optimize heating. The power delivered to the induction head is dependent on the output voltage of the second inverter, which is dependent on the output signal of the first inverter.

Abstract: An inverter cooker with a high voltage/low voltage separating device, which can protect the user from accident and prevents the inverter cooker from malfunctioning by separating a low voltage circuit portion from high voltage circuit portion regardless of the performance of signal transmission. According to the inverter cooker, the signal intercommunicating between the high voltage circuit portion such as an inverter controller or a current detector and the low voltage circuit portion such as a function key input device or a system controller is performed through the high voltage/low voltage separating device which has a plurality of photo-couplers.

Abstract: A monitor device for creating a current signal having a voltage representative of the instantaneous alternating current in an induction heating coil connected to an alternating current supply by two closely spaced, parallel input conductors separated by a narrow gap or flux package through which flows the flux created by the alternating current in the parallel conductors. The monitor device comprising: a multiturn sensing winding, means for securing the winding between said parallel conductors and over the flux passage whereby the flux flowing through flux passage intersects the turns of the sensing winding, and means for creating the current signal by the induced voltage in the winding.

Abstract: An apparatus for sensing a small object in a high-frequency induction heating cooker, comprising a rectifying/smoothing circuit for rectifying and smoothing an AC voltage from a power source to convert it into a DC voltage, an inverter for converting the DC voltage into a high frequency of AC voltage, a heating coil for generating an induced current according to the AC voltage from the inverter, a synchronization detector for detecting a synchronization signal, a current detector for detecting an amount of current through the rectifying/smoothing circuit, a voltage detector for detecting a voltage from a desired position of the inverter, a small object sensing circuit for discriminating presence of the small object in a cooking container in response to output voltages from the current detector and the voltage detector, a clock generator for generating a clock signal for system synchronization, a pulse generator for generating a pulse signal in response to output signals from the clock generator and the small

Abstract: A high frequency induction heating appliance comprising a working coil for generating a high frequency signal, a switching device for switching a drive voltage to the working coil, a low voltage transformer for lowering an AC power voltage, an input current detector for detecting current of the AC power, an output adjusting device for providing an output adjusting signal, a differential amplifier for amplifying a difference between output signals from the input current detector and output adjusting device, a first comparator for comparing the output signal from the input current detector with a reference voltage, an integrator for integrating an output signal from the differential amplifier, a start signal generating circuit, a zero crossing detecting circuit, a delay circuit for delaying a zero crossing detect signal by a time period, an AND logic operating circuit for AND logic-operating a start signal and the delayed zero crossing detect signal, a synchronizing signal generator, a reference signal generato

Abstract: An induction heating device includes an induction heating gun which includes a housing, a U-shaped pole piece having two spaced apart opposite ends defining a gap therebetween, the U-shaped pole piece being mounted in one end of the housing, and a tank circuit including an induction coil wrapped around the pole piece and a capacitor connected to the induction coil. A power source is connected to the tank circuit. A pull test machine is provided having a stationary chuck and a movable chuck, the two chucks holding two test pieces bonded together at a bond region. The heating gun is mounted on the pull test machine in close proximity to the bond region of the two test pieces, whereby when the tank circuit is energized, the two test pieces are heated by induction heating while a tension load is applied to the two test pieces by the pull test machine to determine separation strength of the bond region.

Abstract: An induction heater comprises a coupled pair of inverters and an induction head for generating heat, coupled to the second inverter. The first inverter operates at a constant frequency, but the total output current is controlled through pulse width modulation. The output current is rectified and provided as a DC input voltage, proportional to the total output current of the first inverter, to the second inverter. The second inverter operates at an adjustable frequency which is selected by the user to optimize heating. The power delivered to the induction heater is dependent on the output voltage of the second inverter, which is dependent on the input voltage to the second inverter, and the output current of the first inverter.

Abstract: A circuit for compensating for the output of a high frequency induction heating cooker, comprising a rectifying circuit for rectifying an external AC input power into a DC power and applying the DC power to a working coil, an output regulation signal generating circuit for generating an output regulation signal as a result of the comparison of an input voltage and an output regulation voltage, a start driving circuit for generating a start drive voltage, a triangular wave generating circuit being triggered in response to a driven state of the working coil to generate a triangular wave signal, a switching circuit for start-driving the working coil in response to the start drive voltage, comparing the output regulation signal with the triangular wave signal and switching the driving of the working coil in accordance with the compared result, a voltage detecting circuit for detecting a voltage being applied from the rectifying circuit to the working coil and inversion-amplifying the detected voltage, an output c