Power control device for high-frequency induced heating cooker

• US 4,764,652 A
• Filed: 04/22/1987
• Issued: 08/16/1988
• Est. Priority Date: 04/23/1986
• Status: Expired due to Term

• Current Assignee: Gold Star Co., Ltd. (LG Corporation)
• Original Assignee: Gold Star Co., Ltd. (LG Corporation)
• Inventors: Lee, Min K.
• Primary Examiner(s): Leung, Philip H.
• Application Number:
  US07/041,351
• Time in Patent Office: 482 Days
• Field of Search: 219/10.77, 219/10.75, 219/10.49 R, 363/97, 363/21, 363/131
• US Class Current: 219/627
• CPC Class Codes: H05B 6/062 for cooking plates or the like

Abstract

A power control device for high-frequency induced heating cooker is designed to supply a constant power to the work coil regardless of any change in the input current and voltage. The control device compares the voltage detected at the input current sensor detecting the input current of the full-wave rectifier with the set voltage of the user selector and applies a control voltage to the pulse oscillator and applies the pulse oscillating signal of the pulse oscillator to the driver and makes the switching transistor rapidly turn on and off to generate a high-frequency current through the work coil. It includes a voltage sensor to detect the input and output voltages of the coil, a comparator to compare both detector voltages and to determine the drive starting point of the oscillator, a subtractor to subtract the voltage on the input side of the work coil from the set voltage of the user selector, a comparator to compare the voltage detected at the input current sensor with the normal vessel reference voltage, a transistor to cut off the control voltage applied to the pulse oscillator, a search control voltage part to produce a search control voltage of a constant level and a starting circuit part to generate an oscillation signal of a constant cycle, and a transistor turned on and off by the oscillation signal and supplies the search control voltage to the pulse oscillator in a constant period.

Claims

1. A power control device for a high-frequency induced heating cooker having a work coil driven by inverter means comprising:

rectifier means for rectifying AC power supplied to the inverter means;

input current sensor means for detecting the input current from the AC power supplied to said rectifier means;

first comparator means for comparing the detected input current of the input current sensor means with a manually selectable reference voltage;

pulse oscillator means for generating a rectangular pulse signal;

driver means for applying the rectangular pulse signal to said inverter means to turn said inverter means ON to thereby apply a high frequency current through said work coil;

voltage sensor means for detecting the voltages on both the input and output sides of the work coil;

second comparator means for comparing both detected voltages of the voltage sensor means and determining whether the output of said first comparator means will drive said pulse oscillator means;

means for substracting the voltage detected at the voltage sensor means on the input side of the work coil from the manually selected reference voltage;

third comparator means for comparing the detected voltage of the input current sensor means with a reference voltage which would be generated by the presence of a normal sized cooking vessel on the work coil;

semiconductor switch means for cutting OFF a high potential output signal of the third comparator means;

search control voltage means for generating an oscillating signal during a predetermined period;

starting circuit means for generating an oscillating signal during the predetermined period; and

transistor means turned ON and OFF by the oscillating signal of the starting circuit means for cutting OFF the supply of the search control voltage to said pulse oscillator means at a predetermined time.

2. A power control device for a high-frequency induced heating cooker as claimed in claim 1, further including temperature sensing circuit means for detecting the ambient temperature of the cooking vessel connected to the transistor means for cutting OFF the supply of the search control voltage.

3. A power control device for a high-frequency induced heating cooker as claimed in claim 1, further including fourth comparator means for comparing the output of said first comparator means with a predetermined reference voltage, said fourth comparator means generating a high-potential signal when the removal of a normal cooking vessel is detected by the output of said first comparator means exceeding an additional reference voltage.

4. A power control device for a high-frequency induced heating cooker as claimed in claim 1, further including indication circuit means for indicating a low-potential output signal from the third comparator means.