Electrical transformer having a controlled distribution of leakage inductance

1. An electrical transformer comprising a magnetic core and a primary coil, a primary circuit, a secondary coil, and a secondary circuit, the electrical transformer configured such that:

a first inductance value L 1so measured on the primary circuit with the secondary circuit open,

a second inductance value L 1ss measured on the primary circuit with the secondary circuit short-circuited, and

a third inductance value L 2po measured on the secondary circuit with the primary circuit open,

satisfy the following condition:

L

2

⁢

PO

-

1

n

2

⁢

L

M

<

(

1

A

)

·

(

L

1

⁢

SO

-

L

M

)

with

L M =√{square root over (( L 1SO −L 1SS )× L 1SO ·N 2 )}

where A is a real number greater than 10 and less than or equal to 100; and

where N is a transformation ratio of the transformer.

2. The electrical transformer according to claim 1 , wherein A is a real number greater than or equal to 50.

3. A method for producing the electrical transformer of claim 1 , said method comprising the following steps:

a selection of a magnetic core geometry for the electrical transformer to produce;

a determination of a thickness of an air gap corresponding to a desired magnetising inductance value of the electrical transformer to produce;

secondary windings on the magnetic core having the selected magnetic core geometry and a thickness of the air gap so as to cover said air gap;

a determination of a leakage reluctance value of the electrical transformer as a function of a ratio between a desired leakage inductance value on the primary circuit of the electrical transformer to produce and the desired magnetising inductance value of the electrical transformer to produce;

a determination of a distance h between the primary windings, configured to form the primary circuit of the electrical transformer to produce and the secondary windings, as a function of said leakage reluctance value; and

a winding of the primary windings on the magnetic core of the electrical transformer at said distance h from the secondary windings.

4. The method according to claim 3 , wherein the magnetic core is selected from type E or type EI.

5. The method according to claim 4 , wherein the following equation is implemented:

L

M

=

N

1

2

*

μ

0

⁢

S

e

where N 1 is the number of windings on the primary circuit, μ 0 is the electromagnetic permeability of air and S is the effective magnetic cross section area of the electrical transformer,

to determine the value of the required thickness e of the air gap, corresponding to the desired magnetising inductance value L M .

6. The method according to claim 4 , wherein the following equations are implemented:

Rgap

=

1

μ

0

*

e

S

where R gap is the air gap reluctance of the electrical transformer, μ 0 is the electromagnetic permeability of air, e is the thickness of the air gap of the electrical transformer and S is the effective magnetic cross section area of the electrical transformer and

Rgap

Rleakage

=

Lf

⁢

1

L

M

where Rleakage is the leakage reluctance of the electrical transformer, Lf 1 is the leakage inductance on the primary circuit of the electrical transformer and L M is the magnetising inductance of the electrical transformer, to determine the leakage reluctance value of the electrical transformer.

7. The method according to claim 4 , wherein the following equation is implemented:

Rleakage

=

1

2

⁢

μ

0

*

l

h

*

m

where Rleakage is the leakage reluctance of the electrical transformer, μ 0 is the electromagnetic permeability of air, m is the magnetic core depth of the electrical transformer and 1 is the width of an electromagnetic leakage zone between the primary windings and the secondary windings, corresponding to the distance separating an outer leg and a central leg of the magnetic core of type E or of type EI,

to determine the value of the distance h between the primary windings and the secondary windings.