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Power control device for the magnetron of microwave oven

  • US 4,816,986 A
  • Filed: 02/08/1988
  • Issued: 03/28/1989
  • Est. Priority Date: 02/08/1988
  • Status: Expired due to Fees
First Claim
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1. A power control device for the magnetron of a microwave cooking oven, comprising:

  • a mains voltage rectifier having an input serving as the input of said device, and an output;

    a starting current limiter having a power input connected to said output of said mains voltage rectifier, a control input and an output;

    a capacitance filter having an input connected to said output of said starting current limiter, and an output;

    a choke having an input connected to said output of said capacitance filter, and an output;

    a master control of the operating modes of said microwave oven, having an output;

    an anode voltage regulator having a power input connected to said output of said choke, a control input connected to said output of said master control, a first output adapted for connection to the anode circuit of said magnetron, and a second output;

    a heater voltage source for said magnetron, having an input connected to said second output of said anode voltage regulator, and an output adapted for connection to the heater filament of said magnetron;

    said anode voltage regulator including;

    a bridge-type d.c. voltage to a.c. voltage converter having a power input connected to said power input of said regulator, control inputs, and an output;

    a transformer having a primary winding with terminals connected with said output of said bridge-type converter, and a secondary winding with terminals;

    a rectifier having an input connected to said terminals of said secondary winding of said transformer, and an output;

    a filter having an input connected to said output of said rectifier and an output connected to said first output of said anode voltage regulator;

    a generator of control pulse sequences for said anode voltage regulator, having an input connected to said control input of said regulator and outputs connected to said respective outputs of said bridge-type converter;

    a d.c. voltage source having an output;

    a current amplitude shaper having a power input connected to said output of said d.c. voltage source, a control input connected to said anode circuit of said magnetron, and an output;

    a saturable magnetic element having an input connected to said output of said current amplitude shaper, and an output connected to said terminals of said primary winding of said transformer;

    a diode having an input connected to said power input of said regulator and an output connected to said second output of said regulator;

    said heater voltage source including;

    a half-bridge d.c. voltage to a.c. voltage converter having a power input connected to said input of said heater voltage source, control inputs and an output;

    a transformer having a primary winding with terminals connected to said input of said half-bridge converter, first, second and third secondary windings with their respective terminals;

    said first secondary winding having its terminals connected to said output of said heater voltage source;

    a generator of sequences of heater voltage stabilizing pulses, having an input connected to said terminals of said second secondary winding and outputs connected to said respective control inputs of said half-bridge converter;

    an auxiliary rectifier having an input connected to said terminals of said third secondary winding, and an output connected to said control input of said starting current limiter.

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