Stator for rotating electric machine
A stator core with a plurality of slots circumferentially arranged therearound has a stator winding including three (UVW) phase windings, each phase winding having 4n parallel windings. The stator winding is formed of U-shaped conductor segments inserted in the slots from one axial end, a pair of open end portions of each conductor segment extending axially from of the stator core and being bent toward circumferentially opposite directions, the bent portions being star connected together. The plurality of slots have, for each phase winding, pairs of circumferentially adjacent slots, each slot having an even number of slot-received portions of the phase winding radially aligned in a column, and for each circumferential slot pairs, the slot-received portion in an m-th layer of each slot of the pair is electrically connected to the portion inserted in an (m+1)-th layer of a slot of a circumferentially adjacent slot.
1. A stator for a rotating electric machine, the stator comprising:
a stator core having a plurality of slots circumferentially arranged around the core; and
a stator winding including three (U-phase, V-phase, W-phase) out-of-phase phase windings wound around the stator core, each of the phase windings being a parallel connection of 4×n (n being a positive integer) parallel windings, the stator winding being formed of a plurality of U-shaped conductor segments inserted in the slots from one axial end of the stator core, a pair of open end portions of each conductor segment extending axially outside of the stator core on the other axial end being bent toward circumferentially opposite directions, ends of given bent portions of the conductor segments are welded to each other such that the phase windings are electrically star connected to each other in a predetermined electrical connection pattern, wherein
the plurality of slots comprise, for each of the phase windings, pairs of circumferentially adjacent slots, in each slot of which an even number of slot-received portions of the phase winding are radially aligned in a column, and for each pair of the circumferentially adjacent slots for the phase winding, the slot-received portion inserted in an m-th layer (m being a positive integer) of each slot of the pair of circumferentially adjacent slots being electrically connected to the slot-received portion inserted in an (m+1)-th layer of one of slots of an adjacent pair of circumferentially adjacent slots,
each pair of circumferentially adjacent slots includes a first slot and a second slot, the second slot being circumferentially adjacent in a clockwise direction as view from a turn portion side of the stator winding,
a first slot group comprises the first slots of the respective pairs of circumferentially adjacent slots,
a second slot group comprises the second slots of the respective pairs of circumferentially adjacent slots,
in a portion of the stator winding at an axial coil end of the stator winding opposite a portion of the stator winding formed of a plurality of bent portions, each of the parallel windings of each of the phase windings revolves circumferentially while alternating the first and second slot groups in the circumferential direction through a combination of five and seven slot pitch based switchings.
2. The stator of claim 1 , wherein
each of the conductor segments comprises a pair of parallel straight portions, and a turn portion connecting the pair of straight portions, and
in a portion of the stator winding formed of a plurality of turn portions of the conductor segments at one axial coil end of the stator winding, the turn portion of each of the conductor segments axially straddles up to one of the turn portions of the other conductor segments.
3. The stator of claim 1 , wherein
each of the parallel windings comprises transition lines having a six slot pitch and providing transition between an E-th layer, from a winding starting end, of one slot and an (E+1)-th layer (E being a positive even number) of another slot that is six slots away from the one slot, all the transition lines being located within a given circumferential section of a portion of the stator winding formed of a plurality of turn portions of the conductor segments at one axial coil end of the stator winding, and
a winding starting end and a winding terminating end of each of the parallel windings are within the given circumferential section.
4. The stator of claim 2 , wherein
each of the parallel windings comprises transition lines having a six slot pitch and providing transition between an E-th layer, from a winding starting end, of one slot and an (E+1)-th layer (E being a positive even number) of another slot that is six slots away from the one slot, all the transition lines being located within a given circumferential section of a portion of the stator winding formed of a plurality of turn portions of the conductor segments at one axial coil end of the stator winding, and
a winding starting end and a winding terminating end of each of the parallel windings are within the given circumferential section.