Ferroresonant voltage regulator stabilized for light load conditions

Claim 2

A regulator device comprising a transformer structure having magnetic core means which has at least a first and second magnetic path, primary winding means wound on said magnetic core means including means for connecting said primary winding means to an alternating current source, secondary winding means on said magnetic core means including load winding means for providing an output voltage to a load which is proportional to the rate of change of flux in said first and second magnetic paths, means for decoupling said source from said load winding means, a first corE winding for said first magnetic path and a second core winding for said second magnetic path, capacitor means coupled across said first and second core windings, inductance means for altering the slope at the half cycle boundaries of the output voltage waveform, and switching means operative at a selected time im a first half cycle of the load voltage to connect the inductance of said inductance means across said first core winding, and operative at a selected time in a second half cycle of the load voltage to connect the inductance of the said inductance means across said second core winding, to effect resonant discharge and reverse charging of said capacitor in each half cycle.

Claim 3

A regulator device as set forth in claim 1, wherein the impedance of said inductance means is small compared to the effective primary inductance.

Claim 4

A regulator device as set forth in claim 1, wherein said switching means comprises first and second thyristors, each having anode, cathode, and gate electrodes, means connecting the anode electrodes of said first and second thyristors respectively to one end of said first and second core windings, and in which said inductance means comprises an inductor connected between the cathode electrodes of said first and second thyristors and the other ends of said first and second core windings.

Claim 5

A regulator device as set forth in claim 3, wherein said capacitor means is a capacitor connected directly between said anode electrodes.

Claim 6

A regulator device as set forth in claim 1, wherein said switching means comprises first and second thyristors, each having anode, cathode and gate electrodes, means connecting the cathode electrodes of said first and second thyristors to one end of each of said first and second core windings, and in which said inductance means comprises first and second inductor windings connected respectively between the anode electrodes of said second and first thyristors and the other ends of said second and first core windings.

Claim 7

A regulator device as set forth in claim 5, wherein said first and second inductor windings are wound on separate cores.

Claim 8

A regulator device as set forth in claim 5, wherein said first and second inductor windings are wound on the same core.

Claim 9

In a regulator device comprising a transformer structure having a magnetic core which has a center leg over which first and second magnetic paths are established, primary winding means wound on said center leg of the magnetic core including means for connecting said primary winding to an alternating current source, secondary winding means including load winding means wound on said center leg of said core for providing an output voltage proportional to the rate of change of flux in said first and second paths, a first core winding wound on said center leg for said first magnetic path and a second core winding wound on said center leg for said second magnetic path, magnetic shunt means for decoupling said source from said secondary windings, capacitor means coupled across said first and second core windings, switching means including a first switch means in a first path coupled across said first core winding to control current conduction from said capacitor over the second core path to drive said second magnetic core path into hard magnetic saturation and to substantially clamp the flux in said first magnetic core path at a selected level which varies with and is determined by the time in a first half cycle of the output voltage at which said first switch means is enabled, and a second switch means in a second path coupled across said second winding to control current conduction from said capacitor over said first core path and to substantially clamp the flux level in said second core path at a selected level which is determined by and varies with the time in a second half cycle of the output voltage at which said second switch means is enabled, and control means for selectively enabling said first and second switch means in alternate half cyCles; inductor means for altering the slope of the half cycle boundaries of the output voltage waveform, said inductor means connected in series with said first switch means in said first path and in series with said second switch means in said second path, to thereby add impedance for said current conduction from said capacitor in each half cycle after the switching means is enabled.

Claim 10

In a regulator device comprising a transformer structure having a magnetic core which has a center leg over which first and second magnetic paths are established, primary winding means wound on said center leg of the magnetic core including means for connecting said primary winding to an alternating current source, secondary winding means including load winding means wound on said center leg of said core for providing an output voltage proportional to the rate of change of flux in said first and second paths, a first core winding wound on said center leg for said first magnetic path and a second core winding wound on said center leg for said second magnetic path, magnetic shunt means for decoupling said source from said secondary windings, capacitor means coupled across said first and second core windings, switching means including a first switch means in a first path coupled across said first core winding to control current conduction from said capacitor over the second core path to drive said second magnetic core path into hard magnetic saturation and to substantially clamp the flux in said first magnetic core path at a selected level which varies with and is determined by the time in a first half cycle of the output voltage at which said first switch means is enabled, and a second switch means in a second path coupled across said second winding to control current conduction from said capacitor over said first core path and to substantially clamp the flux level in said second core path at a selected level which is determined by and varies with the time in a second half cycle of the output voltage at which said second switch means is enabled, and control means for selectively enabling said first and second switch means in alternate half cyCles; inductor means for altering the slope of the half cycle boundaries of the output voltage waveform, said inductor means connected in series with said first switch means in said first path and in series with said second switch means in said second path, to thereby add impedance for said current conduction from said capacitor in each half cycle after the switching means is enabled.

Claim 11

A regulator device as set forth in claim 8, wherein the impedance of said inductance means is small compared to the effective primary inductance.

Claim 12

A regulator device as set forth in claim 8, wherein said switch means comprises first and second thyristors, each having anode, cathode, and gate electrodes, means connecting the anode electrodes of said first and second thyristors respectively to one end of said first and second core windings; and in which said inductance means comprises an inductor connected between the cathode electrodes of said first and second thyristors and the other ends of said first and second core windings.

Claim 13

A regulator device as set forth in claim 8, wherein said switch means comprises first and second thyristors, each having anode, cathode and gate electrodes, means connecting the cathode electrodes of said first and second thyristors to one end of each of said first and second core windings, and in which said inductance means comprises first and second inductor windings connected respectively between the anode electrodes of said second and first thyristors and the other ends of said second and first core windings.

Claim 14

A regulator device as set forth in claim 11, wherein said first and second inductor windings are wound on separate cores.

Claim 15

A regulator device as set forth in claim 11, wherein said first and said second inductor windings are wound on the same core.