Ferroresonant power supply and method
First Claim
1. A power supply, comprising:
- a ferroresonant circuit, including a transformer with a core of magnetic material, a primary winding, a secondary winding and reactive means coupled with at least one of said windings;
said transformers having a pair of bias windings;
means for applying an alternating voltage to said ferroresonant circuit, said alternating voltage having a frequency that is approximately equal to a resonant frequency of said ferroresonant circuit;
an output circuit coupled to said secondary winding; and
means for sensing a signal in said output circuit and for applying a feedback signal to said bias windings in accordance with the sensed signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A power supply is disclosed which comprises a ferroresonant circuit, the ferroresonant circuit including a transformer with a core of magnetic material, a primary winding, a secondary winding, and reactive means coupled with at least one of the windings. The transformer also has at least one bias winding. An alternating voltage is applied to the ferroresonant circuit, the alternating voltage having a frequency that is approximately equal to a resonant frequency of the ferroresonant circuit. An output circuit is coupled to the secondary winding. A signal from the output circuit is applied as a feedback signal to the bias winding to control DC flux bias of the core. In an illustrated embodiment, the means for applying an alternating voltage signal to the ferroresonant circuit includes an oscillator for generating alternating voltage control signals, and a switching circuit responsive to an input power source for generating the alternating voltage signals under control of the oscillator. The switching circuit is preferably adapted to provide zero-current switching. The disclosed ferroresonant power supply can operate at relatively high frequencies, for example above 20 KHz and up to about 1 MHz, using standard core materials and without unacceptable losses. Control of the output is obtained by the ferroresonant circuit and without the need for frequency modulation or other circuit complications that are often used with zero-current switching techniques. Also, the disclosed power supply can operate over a wide range of input voltages.
-
Citations
42 Claims
-
1. A power supply, comprising:
-
a ferroresonant circuit, including a transformer with a core of magnetic material, a primary winding, a secondary winding and reactive means coupled with at least one of said windings; said transformers having a pair of bias windings; means for applying an alternating voltage to said ferroresonant circuit, said alternating voltage having a frequency that is approximately equal to a resonant frequency of said ferroresonant circuit; an output circuit coupled to said secondary winding; and means for sensing a signal in said output circuit and for applying a feedback signal to said bias windings in accordance with the sensed signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
-
18. A power supply, comprising:
-
a ferroresonant circuit, including a transformer with a core of magnetic material, a primary winding, a secondary winding and reactive means coupled with at least one of said windings; controllable means for flux biasing the transformer core; means for applying a zero current switched alternating voltage to said ferroresonant circuit, said alternating voltage having a frequency that is greater than 20 KHz and is approximately equal to a resonant frequency of said ferroresonant circuit; an output circuit coupled to said secondary winding; and means for sensing a signal in said output circuit and for applying a feedback signal to said controllable flux biasing means in accordance with the sensed signal. - View Dependent Claims (19, 20)
-
-
21. A power supply, comprising:
-
a ferroresonant circuit, including a transformer with a core of magnetic material, a primary winding, a secondary winding, a capacitor coupled across said primary winding, and an inductor coupled to said capacitor; said transformer having a pair of bias windings; means for coupling an alternating voltage across said inductor and capacitor, said alternating voltage having a frequency that is approximately equal to the resonant frequency of the circuit including said inductor and capacitor; an output circuit coupled to said secondary winding, said output circuit including rectifier means for generating a DC output; and means for sensing the DC output and for applying a feedback signal to said bias windings in accordance with the sensed signal. - View Dependent Claims (22, 23, 24, 25, 26, 27)
-
-
28. A method for generating a DC voltage supply, comprising the steps of:
-
providing a ferroresonant circuit, including a transformer with a core of magnetic material, a primary winding, a secondary winding and reactive means coupled with at least one of said windings, said transformer having a bias winding; providing an oscillator for generating alternating voltage control signals and a switching circuit, under control of said oscillator, for generating said alternating voltage signals at a frequency that is approximately equal to a resonant frequency of said ferroresonant circuit; switching the switching circuit at substantially zero current; applying said alternating voltage to said ferroresonant circuit; rectifying and smoothing the signal from the secondary winding to obtain a DC output voltage; and sensing the output voltage, and applying a feedback signal to said bias winding in accordance with the sensed voltage. - View Dependent Claims (29, 30, 31)
-
-
32. A power supply, comprising:
-
a ferroresonant circuit, including a transformer with a core of magnetic material, a primary winding, a secondary winding and reactive means coupled with at least one of said windings; said transformer having a bias winding and a further bias winding; means for applying an alternating voltage to said ferroresonant circuit, said alternating voltage having a frequency that is approximately equal to a resonant frequency of said ferroresonant circuit; an output circuit coupled to said secondary winding; means for sensing a DC voltage level of said output circuit and for applying a feedback signal to said bias winding in accordance with the sensed DC voltage level; and means for sensing a current in said output circuit and for applying a feedback signal to said further bias winding in accordance with the sensed current. - View Dependent Claims (33)
-
-
34. A method for generating a DC voltage supply, comprising the steps of:
-
providing a ferroresonant circuit, including a transformer with a core of magnetic material, a primary winding, a secondary winding and reactive means coupled with at least one of said windings, said transformer having a bias winding; applying an alternating voltage to said ferroresonant circuit, said alternating voltage having a frequency that is greater than 20 KHz and is approximately equal to a resonant frequency of said ferroresonant circuit; rectifying and smoothing the signal from the secondary winding to obtain a DC output voltage; and sensing the output voltage, and applying a feedback signal to said bias winding in accordance with the sensed voltage. - View Dependent Claims (35)
-
-
36. A power supply, comprising:
-
a ferroresonant circuit, including a transformer with a core of magnetic material, a primary winding, a secondary winding and reactive means coupled with at least one of said windings; said transformer having a bias winding; an oscillator for generating alternating voltage control signals; a zero current switching circuit, under control of said oscillator, for applying an alternating voltage to said ferroresonant circuit, said alternating voltage having a frequency that is approximately equal to a resonant frequency of said ferroresonant circuit; an output circuit coupled to said secondary winding; and means for sensing a signal in said output circuit and for applying a feedback signal to said bias winding in accordance with the sensed signal. - View Dependent Claims (37, 38, 40)
-
-
39. The power supply as defined by claim 50, wherein said means for sensing a signal in said output circuit comprises means for sensing the DC output level of said output circuit.
-
41. A power supply, comprising:
-
a ferroresonant circuit, including a transformer with a core of magnetic material, a primary winding, a secondary winding, a capacitor coupled across said primary winding, and an inductor coupled to said capacitor; said transformer having a bias winding; means for coupling a zero current switched alternating voltage across said inductor and capacitor, said alternating voltage having a fraquency that is at least 20 KHz and is approximately equal to the resonant frequency of the circuit including said inductor and capacitor; an output circuit coupled to said secondary winding, said output circuit including rectifier means for generating a DC output, and means for sensing the DC output and for applying a feedback signal to said bias winding in accordance with the sensed signal. - View Dependent Claims (42)
-
Specification