Electric machine with concentrated windings
The electrical machine ( 1 ) has a stator ( 2 ), which has slots ( 6 ) distributed about the periphery, between which a tooth ( 7, 8 ) is placed, and in which a winding system ( 9 ) with at least one winding phase is placed. Each winding phase contains at least one coil group. Each coil group contains a first single coil ( 10 ) and at least one additional coil ( 11 ). All single coils ( 10, 11 ) of each coil group are electrically connected in series. Each of the additional single coils ( 11 ) is arranged in an offset manner with an offset angle (φm k,i ) in relation to the first single coil ( 10 ). The respective offset angle (φm k,i ) is calculated according to: formula (I) in which k ε {1, 2, . . . (n−I, i ε {0, 1, . . . (6−p N −1)}, n being a group coil number of all single coils ( 10, 11 ) of the respective coil group, k being a coil index of the additional single coils ( 11 ), i being a position index, and p N being an effective pole number. The teeth ( 7, 8 ) at least partially differ from one another in their respective shape or in their respective extension in the peripheral direction.
1. An electric machine comprising:
a rotor,
a stator having a circumference, with a predetermined plurality of slots and a predetermined plurality of teeth distributed about the circumference in alternating arrangement, wherein a shape or dimension of the teeth of at least a subset of the predetermined plurality of teeth is different from a shape or dimension of other teeth that do not belong to the subset, and
a winding system having at least one winding phase arranged in the slots, wherein each winding phase comprises at least one coil group, and each coil group comprises a first single coil and at least one additional single coil, with the first single coil and the at least one additional single coil of each coil group surrounding a tooth of the subset and being electrically connected in series, and with the other teeth that do not belong to the subset lacking coils,
wherein each of the at least one additional single coil of a coil group is arranged relative to a corresponding first single coil with a mechanical offset angle of:
φ
m
ki
=
(
i
+
k
n
)
·
60
°
p
N
with
k
∈
{
1
,
2
,
…
(
n
-
1
)
}
i
∈
{
0
,
1
,
…
(
6
·
p
N
-
1
)
}
as measured in a circumferential direction of the stator,
wherein n is an index common to a all single coils of a coil group, k is a coil index of the at least one additional single coil, i is a running integer indicating a position of a coil about the circumference of the stator, and p N a number of pole pairs of the rotor.
2. The electric machine of claim 1 , wherein the first single coil and the at least one additional single coil are formed as tooth coils.
3. The electric machine of claim 1 , wherein the rotor comprises permanent magnets.
4. The electric machine of claim 1 , wherein each winding phase comprises at least two coil groups and the at least two coil groups associated with a winding phase are electrically connected in series.
5. The electric machine of claim 1 , wherein each winding phase comprises at least two coil groups and the at least two coil groups associated with a winding phase are electrically connected in parallel.
6. The electric machine of claim 3 , wherein the rotor is implemented as an external rotor.
7. The electric machine of claim 3 , wherein the rotor is implemented as an internal rotor.