Segmented stator electrical machine

1. An arrangement for an electrical machine having fractional slot topology, comprising:

a plurality of stator segments, each stator segment having teeth alternating with slots in a circumferential direction, each stator segment having at both circumferential ends a tooth portion; and

for each phase of a plurality of phases a conductor wound in coils around the teeth, wherein a number of coils of any phase in any stator segment is the same as a number of coils of any other phase in the stator segment;

wherein the fractional slot topology is given by combining a first fractional topology times a number of stator segments and a second fractional topology being different from the first fractional topology.

2. The arrangement according to claim 1 , further comprising:

a rotor having a plurality of permanent magnets and rotationally supported to be rotatable around the stator segments, the permanent magnets being magnetically coupled to the coils.

3. The arrangement according to claim 1 , wherein the first fractional topology and/or the second fractional topology is given by:

Ns=Np +/−1

or

Ns=Np +/−2,

wherein

Np is the total number of poles,

Ns is the total number of slots.

4. The arrangement according to claim 1 , wherein the number of stator segments is three,

Np≠ 3 * k− 2, wherein k is a positive integer,

Ns /( m*GCD ( Ns,Np/ 2)))= n , wherein n is positive integer,

Np is the total number of poles,

Ns is the total number of slots,

m is the number of phases,

GCD(x,y) is the greatest common denominator of x and y.

5. The arrangement according to claim 1 , wherein the number of stator segments is three and

wherein the first fractional topology is nine slots and eight poles and the second fractional topology is three slots and two poles or

wherein the first fractional topology is 12 slots and 10 poles and the second fractional topology is three slots and two poles.

6. The arrangement according to claim 1 , wherein:

the number of stator segments is six,

Np≠3* k 1, wherein k is a positive integer,

Ns/(GCD(Ns, Np/2)))≠2* n−1, wherein n is a positive integer,

Np is a total number of poles and

Ns is a total number of slots, and

GCD(x,y) is a greatest common denominator of x and y,

further wherein the number of phases is any positive integer number.

7. The arrangement according to claim 1 , wherein the number of stator segments is six and

wherein the first fractional topology is 12 slots and 10 poles and the second fractional topology is six slots and two poles.

8. The arrangement according to claim 1 , wherein a number of phases is three or larger than three.

9. A generator, comprising:

an arrangement according to claim 1 .

10. A wind turbine, comprising:

a turbine rotor with a plurality of blades;

a generator according to claim 1 coupled to the turbine rotor; and

a converter coupled to an output terminal of the generator.

11. A method of manufacturing an arrangement for an electrical machine having fractional slot topology, the method comprising:

providing a plurality of stator segments, each stator segment having teeth alternating with slots in a circumferential direction, each stator segment having at both circumferential ends a tooth portion;

assembling the stator segments by connecting the stator segments at circumferential ends of the stator segments; and

arranging, for each phase of a plurality of phases a conductor in coils around the teeth, wherein a number of coils of any phase in any stator segment is the same as a number of coils of any other phase in the stator segment;

wherein the fractional slot topology is given by combining a first fractional topology times a number of stator segments and a second fractional topology being different from the first fractional topology.

12. The method according to claim 11 , further comprising:

arranging a rotor having plural permanent magnets and being rotationally supported to be rotatable around the assembled stator segments, such that the permanent magnets are magnetically coupled to the coils.