REGULATING AND FILTERING TRANSFORMER

• US 3,708,744 A
• Filed: 08/18/1971
• Issued: 01/02/1973
• Est. Priority Date: 08/18/1971
• Status: Expired due to Term

• Current Assignee: ABB Power T&D Limited (ABB Limited)
• Original Assignee: Donald S. Stephens, James M. Banic Jr
• Inventors: Stephens, Donald S., Banic, James M. Jr.
• Primary Examiner(s): Goldberg, Gerald
• Application Number:
  US05/172,683
• Time in Patent Office: 503 Days
• Field of Search: 323/6,48,50,56,60,61,81,78 336/155,160,165,178,214
• US Class Current: 323/307
• CPC Class Codes: G05F 3/06 using combinations of saturated and unsaturated inductive devices, e.g. combined with resonant circuit

Abstract

Transformer for providing a regulated and filtered output voltage. Input voltage is applied to an input winding which is wound around two magnetic cores. One magnetic core saturates for part of each half-cycle of the induced alternating flux during normal operation. The other magnetic core does not saturate during normal operation and includes air gaps in the legs thereof. An output winding is positioned around the nonsaturating core and connected in parallel with a capacitor to form an output tank circuit resonant at the operating frequency of the transformer.

Claims

1. A regulating and filtering transformer comprising a first magnetic core having first and second regions, a second magnetic core having first and second regions, an input winding having a plurality of turns with each of said turns wound around the second region of said first magnetic core and the first region of said second magnetic core to induce alternating flux therein, an output winding which links the flux in the second region of said second magnetic core and which is connected in parallel circuit relationship with a capacitor to provide a resonant tank circuit, said first magnetic core being constructed and dimensioned to cause it to saturate during a portion of each half-cycle of the alternating flux therein, said second magnetic core being constructed and dimensioned to provide a higher reluctance path for the alternating flux induced by said input winding than the path provided by said first magnetic core when said first magnetic core is not saturated, and said second magnetic core being constructed and dimensioned to provide a lower reluctance path for the alternating flux produced by said input winding than the path provided by said first magnetic core when said first magnetic core is saturated.

2. The regulating and filtering transformer of claim 1 wherein the second magnetic core includes an air gap for increasing the reluctance of the magnetic core.

3. The regulating transformer of claim 1 wherein the second magnetic core includes two air gaps for increasing the reluctance of the magnetic core, one of the air gaps being positioned in the first region of said second magnetic core and the other of said air gaps being positioned in the second region of said second magnetic core.

4. The regulating and filtering transformer of claim 3 wherein the two air gaps have equal gap distances.

5. The regulating and filtering transformer of claim 1 wherein the magnetic cores are constructed of layers of laminations.

6. The regulating and filtering transformer of claim 1 wherein the magnetic cores are of the wound type.

7. A regulating and filtering transformer comprising a first wound magnetic core having first and second regions, a second wound magnetic core havinG first and second regions, and an input winding having a plurality of turns with each of said turns wound around the second region of said first wound magnetic core and the first region of said second wound magnetic core, said input winding inducing alternating flux into said first and second wound magnetic cores, an output winding positioned around the second region of said second magnetic core and connected in parallel circuit relationship with a capacitor to provide a resonant tank circuit, said first magnetic core being constructed and dimensioned to cause it to saturate during a portion of each half-cycle of the alternating flux therein, said second wound magnetic core being dimensioned and containing air gaps to provide, when said first wound magnetic core is not saturated, a higher reluctance path for the alternating flux provided by said input winding than the path provided by said first wound magnetic core, said second wound magnetic core providing, when said first wound magnetic core is saturated, a lower reluctance path for the alternating flux induced by said input winding than the path provided by said first wound magnetic core, a first of said air gaps being positioned in the first region of said second wound magnetic core, a second of said air gaps being positioned in the second region of said wound magnetic core, with the gap distances of said first and second air gaps being substantially equal.