Electric machine with integrated electromagnetic pumping system for direct cooled windings

Abstract

To provide an electric machine with an integrated electromagnetic pumping system for direct cooled windings.SOLUTION: The integrated electric machine includes a stator, a rotor positioned within the stator, and an electromagnetic pumping system in communication with the stator.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application and the resulting patent relate generally to electric machines, such as motors and generators, used in the production of electrical power, and more particularly to electric machines with an integral electromagnetic pump system for flowing an electrically conductive fluid coolant therethrough. [Background technology]

[0002] Generally, electric machines, such as motors and generators, used to produce electrical power may include a rotor with wound coils or permanent magnets that act as a magnetic flux source. The rotor rotates within a fixed stator, in which rotation induces an alternating current. The overall power output of the electric machine may be limited by heat buildup in the rotor and / or stator components. Such heat buildup may be reduced, at least in part, by using different types of coolant flows. However, such coolants generally require the use of separate pumps, blowers, and other types of equipment that may affect the overall efficiency of the electric machine. Summary of the Invention

[0003] Accordingly, the present application and resultant patent provide an integrated electric machine that includes a stator, a rotor disposed within the stator, and an electromagnetic pump system in communication with the stator.

[0004] This application and the resulting patent may further provide a method for cooling an integrated electric machine having a rotor and a stator, the method including pumping an electrically conductive fluid through direct cooling windings of the stator with a plurality of electromagnetic pump windings, absorbing heat from the electrically conductive fluid from the direct cooling windings of the stator, pumping the electrically conductive fluid to a heat exchanger, and cooling the electrically conductive fluid in the heat exchanger, which cycle may be repeated.

[0005] The present application and the resulting patent may further provide an integrated electric machine that may include a stator having a plurality of directly cooled windings, a rotor disposed within the stator, and an electromagnetic pump system in communication with the directly cooled windings of the stator. The electromagnetic pump system includes an electrically conductive fluid flowing therethrough.

[0006] These and other features and improvements of the present application and any resulting patent will become apparent to those skilled in the art upon review of the following detailed description when considered in conjunction with the several drawing figures and the appended claims. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram of an electric machine with a stator and a rotor; [Figure 2] 1 is a schematic diagram of an example integrated electric machine with an electromagnetic pump system as may be described herein. [Figure 3] 3 is a further schematic diagram of the integrated electric machine with the electromagnetic pump system of FIG. 2; DETAILED DESCRIPTION OF THE INVENTION

[0008] Referring now to the drawings, wherein like numerals refer to like elements throughout the several views, FIG. 1 is a schematic diagram of an example electric machine 100. In general, electric machine 100 may be a motor 110 or a generator 120. Electric machine 100 may include a stator 130 and a rotor 140. Stator 130 may include a stator frame 150 and a body 160, which may include conductive windings 170 around a magnetic core. (Alternatively, rotor 140 may include conductive windings around a magnetic core.) Rotor 140 may include a shaft 180 having a rotational axis RA. Stator 130 is disposed around rotor 140. Shaft 180 may be driven to rotate about rotational axis RA by, for example, a gas turbine, a steam turbine, a wind turbine, a hydroelectric turbine, an internal combustion engine, or any other suitable device configured to provide a rotational output. Shaft 180 is coupled to a substantially cylindrical body 190. Rotor 140 is disposed within stator 130 and configured to provide a stationary magnetic field. As described above, rotation of rotor 140 within stator 130 generates current in conductive windings 170, which may generate electrical output from electric machine 100. The electric machines described herein are for illustrative purposes only; many different components and configurations may be used.

[0009] 2 and 3 are schematic diagrams of an example integrated electric machine 200 as may be described herein. Integrated electric machine 200 may include some of the components of electric machine 100 described above, including rotor 140 rotating within stator 130 having conductive windings 170. In this example, these components of electric machine 100 are integrated with electromagnetic pumping system 210. For example, conductive windings 170 may be direct-cooled windings 220 used in liquid cooling. Direct-cooled windings 220 may have coolant passages 230 with conductive fluid 240 flowing therethrough. Typically, conductive fluid 240 may be a metal powder-filled fluid. Examples of conductive fluids include liquid sodium, sodium-potassium alloys, lithium, mercury, cesium, gallium, potassium, Field's metal (bismuth, indium, tin alloy), Rose's metal (bismuth, lead, tin alloy), Wood's metal (bismuth, lead, tin, cadmium alloy), Cerrosafe (bismuth, lead, tin, cadmium alloy), Cerrolow 136 (bismuth, lead, indium, tin alloy) and Examples of conductive fluids include aluminum, aluminum alloys, and the like. Molten salts and brines are also conductive. Higher conductivity suspensions may provide greater efficiency herein. Other types of conductive fluids 240 may also be used. In certain embodiments, coolant passages may be provided within the rotor 140.

[0010] The conductive fluid 240 can be pumped through the direct cooling windings 220 via a push-pull action by multiple electromagnetic pump windings 250 positioned about the stator 130. In an electromagnetic pump, a magnetic field is oriented perpendicular to the direction of fluid movement while an electric current is passed through it. This generates an electromagnetic force that moves the fluid. Electromagnetic pumps are generally categorized into three types: conduction pumps, induction pumps, and thermoelectric pumps. AC or DC conduction pumps pass electric current directly through electrodes into the fluid. During induction pump operation, a moving magnetic field induces an electric current in the conductive fluid. Thermoelectric pumps extract electricity from the thermal energy contained in the heated liquid metal flow to power the electric current. Advantageously, electromagnetic pumps have no moving parts or vibrations, so wear and tear are generally not an issue. This reduces overall maintenance.

[0011] The coolant passages 230 of the direct-cooled winding 220 may be in communication with a heat exchanger 260. While a counter-flow configuration with cooling flow 280 is shown herein, the heat exchanger 260 may be of conventional design with any type and direction of flow paths. The coolant passages 230 and the heat exchanger 260 may have an electrical isolator 270 disposed therebetween due to the nature of the electrically conductive fluid 240. The electrical isolator 270 may be of conventional design. Other components and configurations may be used herein.

[0012] In use, electromagnetic pumping system 210 circulates electrically conductive fluid 240 through coolant passages 230 to cool direct-cooled windings 220 of stator 130, exchanging heat with cooling stream 280 in heat exchanger 260 before repeating the cycle. In this manner, integrated electric machine 200 combines the nonmoving aspects of electromagnetic pumping system 210 to circulate electrically conductive fluid 240 through hollow coolant passages 230 of direct-cooled windings 220. Specifically, integrated electric machine 200 combines elements of electric machine 100 and electromagnetic pumping system 210.

[0013] Electromagnetic pump system 210 eliminates the need for separate, conventional mechanical pumps that would otherwise move coolant to and from the direct-cooled windings, filters, heat exchangers, and other components of electric machine 100. Integrated electric machine 200 eliminates rotating mechanical pump components that are typically subject to standard maintenance cycles and that can prematurely fail due to wear and other external factors. Additionally, because electromagnetic pump system 210 is integrated within the overall frame 150 of electric machine 100, the interfaces through which coolant enters and exits the windings (and housing) are also eliminated, limiting the potential for loss-of-coolant accidents (LOCAs) and leaks.

[0014] For applications requiring high power density, the elimination of the mechanical pump along with all associated ancillary components (pipes, fittings, etc.) would be a significant advantage in increasing the motor / generator power density. The electromagnetic pump system 210 also allows for more effective and efficient use of coolant.

[0015] It will be apparent that the foregoing relates only to certain embodiments of this application and the resulting patent. Numerous changes and modifications may be made herein by those skilled in the art without departing from the general spirit and scope of the invention as defined by the following claims and their equivalents.

[0016] Further aspects of the invention are provided by the subject matter of the following clauses. [Embodiment 1] An integrated electric machine including a stator, a rotor positioned within the stator, and an electromagnetic pumping system in communication with the stator. [Embodiment 2] 10. The integrated electric machine of any preceding embodiment, wherein the stator comprises direct cooled windings. [Embodiment 3] 10. The integrated electric machine of any preceding embodiment, wherein the direct cooled windings comprise coolant pathways therethrough. [Embodiment 4] 10. The integrated electric machine of any preceding embodiment, wherein the electromagnetic pumping system comprises a conductive fluid. [Embodiment 5] 10. The integrated electric machine of any preceding embodiment, wherein the conductive fluid flows through the coolant pathways of the direct cooled windings. [Embodiment 6] 10. The integrated electric machine of any preceding embodiment, wherein the conductive fluid comprises liquid sodium, sodium-potassium alloys, or lithium. [Embodiment 7] 10. The integrated electric machine of any preceding embodiment, wherein the conductive fluid comprises aluminum or aluminum alloys. [Embodiment 8] 10. The integrated electric machine of any preceding embodiment, wherein the conductive fluid comprises molten salts or brine. [Embodiment 9] 10. The integrated electric machine of any preceding embodiment, wherein the electromagnetic pumping system comprises a plurality of electromagnetic pump windings to pump the conductive fluid through the coolant pathways of the direct cooled windings. [Embodiment 10] 10. The integrated electric machine of any preceding embodiment, wherein the electromagnetic pump windings operate via conduction, induction, or thermoelectric. [Embodiment 11] 10. The integrated electric machine of any preceding embodiment, wherein the electromagnetic pumping system comprises a heat exchanger in communication with the coolant pathways of the direct cooled windings. [Embodiment 12] 10. The integrated electric machine of any preceding embodiment, further comprising an electrical isolator positioned about the coolant pathways and the heat exchanger. [Embodiment 13] 10. The integrated electric machine of any preceding embodiment, wherein the heat exchanger comprises a counter-flow heat exchanger with a cooling fluid. [Embodiment 14] 10. The integrated electric machine of any preceding embodiment, wherein the integrated electric machine comprises a motor or a generator. [Embodiment 15] A method of cooling an integrated electric machine having a rotor and a stator, the method including: pumping a conductive fluid through direct cooled windings of the stator by a plurality of electromagnetic pump windings; absorbing heat in the conductive fluid from the direct cooled windings of the stator; pumping the conductive fluid to a heat exchanger; and cooling the conductive fluid in the heat exchanger. [Embodiment 16] 1. An integrated electric machine comprising: a stator with a plurality of direct cooled windings; a rotor positioned within the stator; and an electromagnetic pumping system in communication with the plurality of direct cooled windings of the stator, the electromagnetic pumping system comprising a conductive fluid flowing therethrough. [Embodiment 17] 10. The integrated electric machine of any preceding embodiment, wherein the direct cooled windings comprise coolant pathways therethrough. [Embodiment 18] 10. The integrated electric machine of any preceding embodiment, wherein the electromagnetic pumping system comprises a plurality of electromagnetic pump windings to pump the conductive fluid through the direct cooled windings. [Embodiment 19] 10. The integrated electric machine of any preceding embodiment, wherein the electromagnetic pumping system comprises a heat exchanger in communication with the coolant pathways of the direct cooled windings. [Embodiment 20] 10. The integrated electric machine of any preceding embodiment, further comprising an electrical isolator positioned about the coolant pathways and the heat exchanger. [Explanation of symbols]

[0017] 100: Electric machine 110: Motor 120: Generator 130: Stator 140: Rotor 150: Stator frame 160: Body 170: Conductive windings 180: Shaft 190: Substantially cylindrical body 200: Integrated electric machine 210: Electromagnetic pump system 220: Direct cooling windings 230: Coolant passages 240: Conductive fluid 250: Electromagnetic pump windings 260: Heat exchanger 270: Electrical isolator 280: Cooling flow RA: Rotating shaft

Claims

1. a stator; a rotor disposed within the stator; an electromagnetic pump system in communication with the stator.

2. The integrated electric machine of claim 1 , wherein the stator includes directly cooled windings.

3. The integrated electric machine of claim 2 , wherein the direct cooled winding includes a coolant passage therethrough.

4. The integrated electric machine of claim 3 , wherein the electromagnetic pump system contains an electrically conductive fluid.

5. The integrated electric machine of claim 4 , wherein the electrically conductive fluid flows through the cooling passages of the directly cooled windings.

6. The integrated electric machine of claim 4 , wherein the conductive fluid comprises liquid sodium, a sodium-potassium alloy, or lithium.

7. The integrated electric machine of claim 4 , wherein the conductive fluid comprises aluminum or an aluminum alloy.

8. The integrated electric machine of claim 4 , wherein the conductive fluid comprises a molten salt or a saline solution.

9. The integrated electric machine of claim 4 , wherein the electromagnetic pump system includes a plurality of electromagnetic pump windings that pump the electrically conductive fluid through the coolant passages of the direct cooled windings.

10. The integrated electric machine of claim 9 , wherein the electromagnetic pump windings are powered by conduction, induction, or thermoelectric.

11. The integrated electric machine of claim 4 , wherein the electromagnetic pump system includes a heat exchanger in communication with the coolant passages of the direct cooled winding.

12. The integrated electric machine of claim 11 further comprising an electrical isolator disposed about the coolant passages and the heat exchanger.

13. The integrated electric machine of claim 11 , wherein the heat exchanger comprises a counterflow heat exchanger with a cooling fluid.

14. The integrated electric machine of claim 1 , wherein the integrated electric machine comprises a motor or a generator.

15. a stator having a plurality of directly cooled windings; a rotor disposed within the stator; an electromagnetic pump system in communication with the plurality of direct cooling windings of the stator; wherein the electromagnetic pump system includes an electrically conductive fluid flowing therethrough.

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