Transformer Apparatus

Abstract

Systems, apparatuses, and methods are described for a transformer designed for supporting two or more sets of windings referenced to different voltage levels. Use of semiconductive shields may direct electrical fields caused by the different voltage levels to have a first amplitude in a first region of the transformer and a second amplitude in a second region of the transformer, and may enable efficient and cost-effective use of insulating materials and transformer design.

1 . An apparatus comprising:
 a transformer comprising:
 a core comprising at least a first core leg, 
 first windings disposed around the first core leg, 
 a first semiconductive shield disposed around the first windings, 
 a second semiconductive shield disposed around the first semiconductive shield, 
 second windings disposed around the second semiconductive shield. 
   
     
     
         2 . The apparatus of  claim 1 , further comprising a first bobbin disposed around the first core leg, wherein the first windings are wound around the first bobbin. 
     
     
         3 . The apparatus of  claim 1 , wherein the first windings comprise at least two voltage taps, and a first voltage tap of the first windings is electrically connected to the first semiconductive shield. 
     
     
         4 . The apparatus of  claim 1 , wherein the second windings comprise at least two voltage taps, and a first voltage tap of the second windings is electrically connected to the second semiconductive shield. 
     
     
         5 . The apparatus of  claim 1 , wherein the first windings comprise at least two voltage taps,
 wherein a first voltage tap of the first windings is electrically connected to the first semiconductive shield,   the second windings comprise at least two voltage taps, wherein a first voltage tap of the second windings is electrically connected to the second semiconductive shield,   wherein the first voltage tap of the first windings is connected to a first reference electrical potential, and the first voltage tap of the second windings is connected to a second reference electrical potential.   
     
     
         6 . The apparatus of  claim 5 , wherein a voltage difference between the first reference electrical potential and the second reference electrical potential is above 100V. 
     
     
         7 . The apparatus of  claim 5 , wherein a voltage difference between the first reference electrical potential and the second reference electrical potential varies sinusoidally.
 The apparatus of  claim 7 , wherein a voltage difference between the first reference electrical potential and the second reference electrical potential varies according to a sine wave having an amplitude of 10 kV or higher.   
     
     
         8 . The apparatus of  claim 5 , wherein the first reference electrical potential is electrical ground. 
     
     
         9 . The apparatus of  claim 15 , wherein the second reference electrical potential is electrical ground. 
     
     
         10 . The apparatus of  claim 1 , wherein the core comprises a second core leg, the transformer further comprising:
 third windings disposed around the second core leg,   a third semiconductive shield disposed around the third windings,   a fourth semiconductive shield disposed around the third semiconductive shield,   fourth windings disposed around the fourth semiconductive shield.   
     
     
         11 . The apparatus of  claim 10 , wherein the first windings and the third windings are connected to a first electrical potential, and the second windings and the fourth windings are connected to a second electrical potential. 
     
     
         12 . The apparatus of  claim 1 , further comprising a conductive case, wherein the transformer is placed in the conductive case. 
     
     
         13 . The apparatus of  claim 12 , wherein the conductive case is grounded. 
     
     
         14 . The method of  claim 11 , further comprising insulating material disposed between the first semiconductive shield and the second semiconductive shield. 
     
     
         15 . A method comprising:
 winding a first winding around a first leg of a magnetic core,   disposing a first cylindrical shield around the first winding,   disposing a second cylindrical shield around the first shield,   disposing a second winding around the second shield,   electrically connecting the first winding to the first shield, and   electrically connecting the second winding to the second shield.   
     
     
         16 . The method of  claim 15 , further comprising injecting insulating material between the first shield and the second shield. 
     
     
         17 . The method of  claim 15 , further comprising encompassing the magnetic core, the first and second windings and the first and second shields in a case. 
     
     
         18 . The method of  claim 15 , wherein the case is a resin epoxy case. 
     
     
         19 . The method of  claim 15 , further comprising voltage terminals of the first winding to a voltage source. 
     
     
         20 . The method of  claim 15 , further comprising voltage terminals of the second winding to a voltage source. 
     
     
         21 . The method of  claim 15 , further comprising connecting the first winding to a first electrical potential, and connecting the second winding to a second electrical potential that is different form the first electrical potential.