Bi-directional isolated DC-DC converter for the electrification of transportation
A topology for an isolated, bi-directional, DC-DC converter, that provides step-up and step-down functionality, with a reduced transformer turns ratio, allows a simplified transformer design with reduced cost and increased efficiency. This topology also has a very small level of re-circulating current, relative to other topologies regarding cost and performance.
1. A bi-directional DC-DC converter ( 50 ) comprising:
a first stage ( 30 ) comprising:
a first port ( 22 ) connected between a first node (N 1 ) and ground;
the first port ( 22 ) being bi-directionally operable as an output or an input;
the first port ( 22 ) being operatively connected to a primary winding ( 80 ) of a first transformer (Tr 1 );
a second stage ( 40 ) comprising:
a second port ( 24 ) connected between seventh and eighth nodes (N 7 , N 8 );
the second port ( 24 ) being bi-directionally operable as an output or an input;
the second port ( 24 ) being operatively connected to a secondary winding ( 82 ) of the first transformer (Tr 1 );
the secondary winding of the first transformer having first and second terminals;
a third stage ( 60 ) comprising:
a second resonant inductor (Lr 2 ) having first and second terminals,
a fifth resonant capacitor (Cr 5 ) having first and second terminals;
a primary winding ( 90 ) of a second transformer (Tr 2 ),
the primary winding of the second transformer having first and second terminals;
a secondary winding ( 92 ) of the second transformer (Tr 2 ),
the secondary winding of the second transformer having first and second terminals;
a rectifier ( 70 ) having an input comprising first and second terminals;
the rectifier ( 70 ) having an output comprising first and second terminals;
the first terminal of the second resonant inductor (Lr 2 ) being connected to a third node (N 3 );
the second terminal of the second resonant inductor (Lr 2 ) being connected to a thirteenth node (N 13 );
the first terminal of the fifth resonant capacitor (Cr 5 ) being connected to a fourth node (N 4 );
the second terminal of the fifth resonant capacitor (Cr 5 ) being connected to an eighteenth node (N 18 );
the first terminal of the input of the rectifier ( 70 ) being connected to a fourteenth node (N 14 );
the second terminal of the input of the rectifier ( 70 ) being connected to a seventeenth node (N 17 );
the first terminal of the output of the rectifier ( 70 ) being connected to a sixteenth node (N 16 );
the second terminal of the output of the rectifier ( 70 ) being connected to a fifteenth node (N 15 );
the primary winding ( 90 ) of the second transformer (Tr 2 ) being connected between the second resonant inductor (Lr 2 ) and the fifth resonant capacitor (Cr 5 );
the fourth and thirteenth nodes not always being at the same electrical potential.
2. A bi-directional DC-DC converter ( 50 ) comprising:
a first stage ( 30 ) comprising:
a first port ( 22 ) connected between a first node (N 1 ) and ground;
the first port ( 22 ) being bi-directionally operable as an output or an input;
the first port ( 22 ) being operatively connected to a primary winding ( 80 ) of a first transformer (Tr 1 );
a second stage ( 40 ) comprising:
a second port ( 24 ) connected between seventh and eighth nodes (N 7 , N 8 );
the second port ( 24 ) being bi-directionally operable as an output or an input;
the second port ( 24 ) being operatively connected to a secondary winding ( 82 ) of the first transformer (Tr 1 );
the secondary winding of the first transformer having first and second terminals;
a third stage ( 60 ) comprising:
a second resonant inductor (Lr 2 ) having first and second terminals,
a fifth resonant capacitor (Cr 5 ) having first and second terminals;
a primary winding ( 90 ) of a second transformer (Tr 2 ),
the primary winding of the second transformer having first and second terminals;
a secondary winding ( 92 ) of the second transformer (Tr 2 ),
the secondary winding of the second transformer having first and second terminals;
a rectifier ( 70 ) having an input comprising first and second terminals;
the rectifier ( 70 ) having an output comprising first and second terminals;
the first terminal of the second resonant inductor (Lr 2 ) being connected to a third node (N 3 );
the second terminal of the second resonant inductor (Lr 2 ) being connected to a thirteenth node (N 13 );
the first terminal of the fifth resonant capacitor (Cr 5 ) being connected to a fourth node (N 4 );
the second terminal of the fifth resonant capacitor (Cr 5 ) being connected to an eighteenth node (N 18 );
the first terminal of the primary winding ( 90 ) of the second transformer (Tr 2 ) being connected to the thirteenth node (N 13 );
the second terminal of the primary winding ( 90 ) of the second transformer (Tr 2 ) being connected to the eighteenth node (N 18 );
the first terminal of the secondary winding ( 92 ) of the second transformer (Tr 2 ) being connected to a fourteenth node (N 14 );
the second terminal of the secondary winding ( 92 ) of the second transformer (Tr 2 ) being connected to a seventeenth node (N 17 );
the first terminal of the input of the rectifier ( 70 ) being connected to the fourteenth node (N 14 );
the second terminal of the input of the rectifier ( 70 ) being connected to the seventeenth node (N 17 );
the first terminal of the output of the rectifier ( 70 ) being connected to a sixteenth node (N 16 );
the second terminal of the output of the rectifier ( 70 ) being connected to a fifteenth node (N 15 ).
3. The bi-directional DC-DC converter ( 50 ) of claim 2 further comprising a third voltage source (V 3 ) being connected between the fifteenth and sixteenth nodes (N 15 , N 16 ).
4. The bi-directional DC-DC converter ( 50 ) of claim 2 further comprising a third load (RL 3 ) being connected between the fifteenth and sixteenth nodes (N 15 , N 16 ).