Magnetically controlled transformer apparatus for controlling power delivered to a load with current transformer feedback

• US 7,274,574 B1
• Filed: 05/15/2006
• Issued: 09/25/2007
• Est. Priority Date: 05/15/2006
• Status: Expired due to Fees

• Current Assignee: George E. Biegel
• Original Assignee: George E. Biegel
• Inventors: Biegel, George E.
• Primary Examiner(s): HAN, YOUNGHUIE JESSICA
• Application Number:
  US11/433,869
• Time in Patent Office: 498 Days
• Field of Search: 363/16, 363/21.08, 363/21.09, 363/21.16, 363/21.17, 363/24, 363/25, 363/133, 323/250, 323/355, 323/358, 315/306, 315/307, 315/308, 315/224, 315/209.R
• US Class Current: 363/16
• CPC Class Codes: H02M 3/338 in a self-oscillating arrangement H02M3/337 takes precedence
• CPC Class Codes: H05B 41/2827 using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
• CPC Class Codes: H05B 41/391 using saturable magnetic devices

Abstract

A circuit with a magnetically variable transformer having primary and secondary windings wound on a magnetic core wherein the transformer core with associated windings is placed in close proximity to an independently wound control coil. The transformer core is placed within the bore of the control coil and an optional focusing armature concentrates the magnetic field at the poles. Application of a control current forms poles at the control coil extremities and causes a change in permeability of the transformer core thereby altering the power output of the transformer inversely to the magnitude of the control current. The control current from the output of the secondary coil of a current transformer in series with the load and conditioned by a feedback conditioning circuit modulates the level of the control current. The magnetically variable transformer controls a D.C. to A.C. inverter circuit, which is useful in supplying power to a fluorescent lamp and other A.C. receptive loads. Additionally, a microprocessor optionally modulates the feedback from the secondary of the current transformer while receiving inputs from manual and automatic environmental controls.

Claims

1. A circuit having a variable transformer, a current transformer, and a feedback circuit for supplying a feedback controlled current to a load wherein;

said variable transformer consists of;

a magnetic core upon which is wound at least one primary coil for receiving an input voltage;

said magnetic core additionally having at least one secondary coil for supplying an output voltage proportional to a turns ratio defined by the number of turns of the secondary coil in the numerator to the number of turns of the primary coil in the denominator and a primary current;

said magnetic core being fabricated from a magnetically soft material;

a control coil proximate to and physically isolated from the magnetic core of said variable transformer wherein said physical isolation of said control coil beneficially assures electrical isolation from said primary coil and said secondary coil of said variable transformer;

said control coil receiving a control current from said feedback circuit wherein said control current generates a magnetic field;

said magnetic field causing a change in permeability of the magnetic core of said variable transformer in a physically non-coupled manner wherein said permeability in said magnetic core is increased as said control current in said control coil increases;

said output voltage of said variable transformer decreases with the increase of said permeability;

said current transformer having at least one primary winding and a plurality of secondary windings;

said primary winding of the current transformer receiving a current from the secondary coil of the variable transformer;

wherein

a first secondary winding serving to provide a feedback current to the control coil of said variable transformer;

additional secondary windings being optionally provided for input to one of the group consisting of an external controller, a microprocessor, and a monitoring system; and

said feedback circuit useful for conditioning said feedback current from said current transformer and being chosen from the group consisting of a DC coupled feedback and control circuit, an AC coupled feedback and control circuit, and an optically coupled microprocessor feedback and control circuit.

2. The load of claim 1 being chosen from the group consisting of fluorescent lamps, Cold Cathode Fluorescent lamps, and electro-luminescent panels, halogen lamps, H.I.D. lamps, Metal Halide lamps, and switching power supplies.

3. The variable transformer of claim 1 having one primary coil for receiving an input voltage and said at least one secondary coil is a first secondary coil and a second secondary coil each supplying said output voltage and current;

said first secondary coil and said second secondary coil being wound on said core of magnetic material common to said primary coil to produce voltages out of phase from one another;

said first secondary coil and said second secondary coil each communicatingly control an inverter circuit for producing a high voltage high frequency A.C. power source;

a first end of said first secondary coil is communicatingly attached to a base of a first inverter transistor and second end of said first secondary coil is attached to a ground voltage and a collector of a second inverter transistor;

a first end of said second secondary coil is communicatingly attached to a base of said second inverter transistor and a second end of said second secondary coil is attached to an emitter of said second inverter transistor;

a positive D.C. voltage being supplied to a collector of said first inverter transistor and a ground voltage being supplied to a junction of an emitter of said first inverter transistor and a collector of said second inverter transistor;

said collector of said first inverter transistor is communicatingly attached to a first terminal of a series resonant inductor having a second terminal attached to a first terminal of a load;

a second terminal of said load is attached to a first terminal of a series resonant capacitor while a second terminal is attached to a first terminal of the primary of said variable transformer;

a second terminal of the primary of said variable transformer is attached to said ground voltage;

said inverter circuit for producing a high voltage high frequency A.C. power source is controlled through the application of said control current from one of the group of a D.C. source and a low frequency A.C. source to a pair of input terminals of said control coil;

said control current creating a magnetic field for controlling the permeability of said magnetic core wherein an output power of said inverter circuit is controlled;

said A.C. power source providing said output power inversely proportional to said control current of said variable transformer; and

said A.C. power source in series with the primary of said current transformer being suitable for supplying a controllable power level to an A.C. receptive load.

4. The inverter circuit of claim 3 wherein said control current supplied to the control coil of said variable transformer is fed back from a secondary winding of said current transformer interposed by said feedback circuit.

5. The circuit of claim 1 wherein said optically coupled microprocessor feedback and control circuit has a sensor and control element input wherein said sensor and control element input is either singular or in the plurality;

said sensor and control element input chosen from a group consisting of a temperature controller, an ambient light controller, a manual controller, scheduled controller, and sensory and control elements; and

said sensory and control elements chosen from a group consisting of a resistive control, a light sensor, a temperature sensor and other devices required by the application to control or maintain the light level.

6. The microprocessor feedback and control circuit of claim 1 wherein it is used alone or in combination with a feedback circuit chosen from the group consisting of a DC coupled feedback and control circuit, an AC coupled feedback and control circuit.

7. The variable transformer of claim 3 having a winding serving as a current source for an inverter circuit and also having a primary winding and at least two secondary windings for supplying a pair of inverter transistor base currents;

a series resonant inverter circuit for producing a high voltage high frequency A.C. power source is controlled through the application of said control current from one of the group of a D.C. source and a low frequency A.C. source to a pair of input terminals of said control coil;

said control current creating said magnetic field for controlling the permeability of said magnetic core wherein an output power of said series resonant inverter circuit is controlled; and

said A.C. power source providing said output power inversely proportional to said control current of said variable transformer.

8. The inverter circuit of claim 7 wherein said control current supplied to the control coil of said variable transformer is controllably modulated by said feedback circuit.