Methods and apparatus for a permanent magnet machine with a direct liquid cooled stator
A permanent magnetic machine includes a stator body having a first end, a second end, and a plurality of generally radial slots formed therein for accepting a set of windings having a first set of end-turns at the first end and a second set of end-turns at the second end. The stator body has a plurality of channels adjacent to the slots and extending from the first end of the stator body to the second end of the stator body, wherein the channels are configured to allow the flow of a cooling fluid therethrough. A plurality of nozzles in fluid communication with the plurality of channels are configured to spray the cooling fluid onto the first and second set of end turns.
1. A permanent magnet machine comprising:
a stator body having a first end and a second end, and having a plurality of generally radial slots formed therein for accepting a set of windings having a first set of end-turns at the first end and a second set of end-turns at the second end;
the stator body having a plurality of channels adjacent to the slots and extending from the first end of the stator body to the second end of the stator body, the channels configured to allow the flow of a cooling fluid therethrough; and
a plurality of nozzles in fluid communication with the plurality of channels and configured to spray the cooling fluid onto the first and second set of end turns;
a first end ring having a first set of ring cavities provided therein and configured to house a first set of the nozzles, the first end ring attached to the first end of the stator body such that the channels are in fluid communication with the first set of ring cavities;
a second end ring having a second set of ring cavities provided therein and configured to house a second set of the nozzles, the second end ring attached to the second end of the stator body such that the channels are in fluid communication with the second set of ring cavities; and
an inlet coupled to one of the first set of ring cavities, and an outlet coupled to one of the first or second set of ring cavities, wherein the cooling fluid is configured to flow from the inlet, through the channels, to the outlet;
wherein the channels, the first set of ring cavities, and the second set of ring cavities are configured such that the cooling fluid may flow in a cylindrical serpentine pattern from the inlet to the outlet.
2. The permanent magnet machine of claim 1 , wherein the first set of cavities includes cavities housing approximately four to eight of the first set of nozzles, and the second set of cavities includes cavities housing approximately four to eight of the second set of nozzles.
3. The permanent magnet machine of claim 1 , wherein each of the first and second sets of nozzles includes nozzles spaced circumferentially and facing radially inward.
4. The permanent magnet machine of claim 1 , wherein each of the first and second set of cavities are generally arcuate.
5. The permanent magnet machine of claim 1 , wherein the channels are longitudinal and parallel to the axis of the stator.
6. The permanent magnet machine of claim 5 , wherein the stator body includes between 10 and 20 channels.
7. The permanent magnet machine of claim 1 , wherein the channels extend to the outer perimeter of the stator body to form a plurality of longitudinal fins.
8. A method for cooling a permanent magnet machine, comprising:
providing a stator body having a plurality of channels adjacent to a plurality of winding slots and extending from a first end of the stator body to a second end of the stator body;
providing a plurality of windings within the winding slots, the windings having a first set of end turns and second set of end turns; and
causing a cooling fluid to flow through the channels during operation of the permanent magnet machine;
providing a plurality of nozzles in fluid communication with the plurality of channels;
attaching to the first end of the stator body a first end ring having a first set of ring cavities provided therein and configured to house a first set of the nozzles;
attaching to the second end of the stator body a second end ring having a second set of ring cavities provided therein and configured to house a second set of the nozzles, such that the channels, the first set of ring cavities, and the second set of ring cavities are configured such that the cooling fluid flows in a cylindrical serpentine pattern from the inlet to the outlet; and
spraying the cooling fluid onto the first and second set of end turns.
9. The method of claim 8 , wherein the first set of cavities includes cavities housing approximately four to eight of the first set of nozzles, and the second set of cavities includes cavities housing approximately four to eight of the second set of nozzles.
10. The method of claim 8 , including spacing the first and second sets of nozzles circumferentially and facing them radially inward.
11. The method of claim 8 , wherein the channels are longitudinal and parallel to the axis of the stator.