Induction cooking power converter with improved coil position

Claim 2

An induction cooking appliance for use with a single phase, three-wire alternating voltage source comprising an induction heating coil mounted adjacent a utensil support and producing an alternating magnetic field for heating a cooking utensil, a solid state power supply having three input terminals including a grounded power distribution system neutral terminal, said power supply comprising full wave rectifying means and filter means for producing a desired unidirectional voltage between said grounded neutral terminal and a second output terminal, and a solid state inverter energized by said unidirectional voltage and generating an ultrasonic frequency wave that drives said induction heating coil, said induction heating coil being connected directly to said grounded neutral terminal.

Claim 3

A cooking appliance according to claim 1 wherein said induction heating coil is a nominally flat coil with the outer turn thereof connected to said grounded neutral terminal.

Claim 4

A cooking appliance according to claim 2 wherein said inverter is a series resonant inverter controlled by a single thyristor device, said thyristor device also being connected directly to said grounded neutral terminal.

Claim 5

A cooking appliance according to claim 1 wherein said full wave rectifying means comprises a pair of alternately conducting solid state rectifier devices respectively connected between the other two input terminals and a common input to said filter means.

Claim 6

A cooking appliance according to claim 1 wherein said full wave rectifying means comprises a pair of alternately conducting phase controlled thyristor devices respectively connected between the other two input terminals and a common input to said filter means, and a freewheeling diode connected between said grounded neutral terminal and said common input to said filter means.

Claim 7

A cooking appliance according to claim 1 wherein said full wave rectifying means comprises a pair of alternately conducting solid state rectifier devices respectively connected between the other two input terminals and a common input to said filter means, and a freewheeling diode connected between said grounded neutral terminal and said common input to said filter means, said inverter being a series resonant inverter controlled by a single thyristor device that is also connected directly to said grounded neutral terminal.

Claim 8

An induction cooking appliance for use with a single phase, three-wire alternating voltage source comprising a nominally flat induction heating coil mounted adjacent a substantially unbroken non-metallic utensil support and producing an alternating magnetic field for heating a cooking utensil, a solid state power supply having three input terminals including a grounded power distribution system neutral terminal, said power supply comprising full wave rectifying means and filter means for producing a desired unidirectional voltage between said grounded neutral terminal and a second output terminal, and a solid state inverter energized by said unidirectional voltage and generating an ultrasonic frequency wave that drives said induction heating coil, said inverter comprising a capacitor and said induction heating coil coupled together as a series resonant circuit that is operated by a single thyristor device, said induction heating coil and thyristor device being connected directly to said grounded neutral terminal.

Claim 9

An induction cooking appliance for use with a single phase, three-wire alternating voltage source comprising a nominally flat induction heating coil mounted adjacent a substantially unbroken non-metallic utensil support and producing an alternating magnetic field for heating a cooking utensil, a solid state power supply having three input terminals including a grounded power distribution system neutral terminal, said power supply comprising full wave rectifying means and filter means for producing a desired unidirectional voltage between said grounded neutral terminal and a second output terminal, and a solid state inverter energized by said unidirectional voltage and generating an ultrasonic frequency wave that drives said induction heating coil, said inverter comprising a capacitor and said induction heating coil coupled together as a series resonant circuit that is operated by a single thyristor device, said induction heating coil and thyristor device being connected directly to said grounded neutral terminal.

Claim 10

A cooking appliance according to claim 7 wherein the outer turn of said induction heating coil is connected directly to said grounded neutral terminal, and said inverter is operated at a variable repetition rate and further includes a reversely poled diode connected across said thyristor device and reset inductor means for recharging said capacitor to sustain circuit oscillation.

Claim 11

A cooking appliance according to claim 7 wherein the outer turn of said induction heating coil is connected directly to said grounded neutral terminal, and said full wave rectifying means comprises a pair of alternately conducting solid state rectifier devices respectively connected between the other two input terminals and a common input to said filter means.

Claim 12

A cooking appliance according to claim 7 wherein the outer turn of said induction heating coil is connected directly to said grounded neutral terminal, said full wave rectifying means comprises a pair of alternately conducting phase controlled thyristors respectively connected between the other two input terminals and a common input to said filter means, said filter means comprises a series filter inductor and shunt filter capacitor, and said power supply further includes a freewheeling diode connected between the common input to said filter means and said grounded neutral terminal.

Claim 13

A cooking appliance according to claim 7 wherein the outer turn of said induction heating coil is connected directly to said grounded neutral terminal, said full wave rectifying means comprises a pair of alternately conducting power diodes respectively connected between the other two input terminals and a common input to said filter means, said filter means comprises a series filter inductor and shunt filter capacitor, and said power supply further includes a freewheeling diode connected between the common input to said filter means and said grounded neutral terminal.