MX2012009505A - Polyphase dynamoelectric machines and stators with phase windings formed of different conductor material(s). - Google Patents

Abstract

A stator for a polyphase dynamoelectric machine includes a stator core and windings positioned about the stator core. The windings include at least a first phase winding and a second phase winding. The first phase winding is formed of at least one electrical conductor material that is not present in the second phase winding.

Description

POLYPHASIC DYNAMOELECTRIC MACHINES AND STATORS WITH DEVANCED IN PHASE FORMED OF DIFFERENT (S) MATERIAL (S) DRIVER (S) CROSS REFERENCE TO RELATED REQUESTS This application claims the benefit of the Chinese Application of the Invention Patent No. 201110240191.5 filed on August 19, 2011 and of the Chinese Application for Utility Model No. 201120305050.2 filed on August 19, 2011, the complete descriptions of which are incorporated in the present by reference.

FIELD OF THE INVENTION The present disclosure relates to polyphase dynamoelectric machines and stators with phase windings formed from one or more different electrical conductive materials.

BACKGROUND This section provides background information related to the present description that are not necessarily the prior art.

Dynamoelectric machines such as electric motors and generators convert electrical energy into mechanical energy, or vice versa.

Electric motors can be classified into two types: single-phase motors and polyphase motors. Single-phase motors are driven by a single-phase AC power source, while polyphase motors are driven by a polyphase source of AC power, which is typically a three-phase AC power source. For the purposes of this description, a motor driven by a single-phase AC power source is a single-phase motor, even if the motor includes multiple windings such as a main winding and an auxiliary / start winding.

Polyphase motors and generators have multiple (typically three) in-phase windings. Conventionally, phase windings are formed of copper (including copper alloys). More recently, phased windings have been formed of aluminum (including aluminum alloys) to reduce the cost of polyphase motors. This is due to the relatively higher cost of copper compared to aluminum. The formation of each phase winding of both copper and aluminum is also known to achieve the desired performance characteristics while minimizing the amount of copper used in each phase winding. Again, this is done to reduce the total cost of the engine due to the relatively higher cost of copper compared to aluminum.

SUMMARY This section provides a general summary of the description, and is not an exhaustive description of its total scope or of all its characteristics.

In accordance with one aspect of the present disclosure, a stator. for a polyphase dynamoelectric machine it includes a stator core and windings placed around the stator core. The windings include at least a first phase winding and a second phase winding. The first phase winding is formed of at least one electrical conductive material that is not present in the second phase winding.

Aspects and areas of additional applicability will become apparent from the description provided herein. The description and the specific examples provided below are intended for illustrative purposes only and are not intended to limit the scope of the present disclosure.

DRAWINGS The drawings described herein are for illustrative purposes only of the selected embodiments and not of all possible implementations, and are not intended to limit the scope of the present disclosure.

Figure 1 is a plan view of a stator for a polyphase dynamoelectric machine according to an exemplary embodiment of the present disclosure.

Figures 2A and 2B are circuit diagrams for exemplary stators having only one electrical conductor per phase.

Figures 3A and 3B are circuit diagrams for exemplary stators having the same number of electrical conductors per phase.

Figures 4A to 4C are circuit diagrams for exemplary stators having different numbers of electrical conductors per phase.

Figure 5 is a plan view of a polyphase motor according to another exemplary embodiment of the present disclosure.

Figure 6 is a block diagram of a compressor according to another exemplary embodiment of this description.

Corresponding reference numbers indicate corresponding parts throughout all the various views of the drawings.

DETAILED DESCRIPTION The exemplary embodiments will now be more fully described with reference to the accompanying drawings.

Exemplary modalities are provided so that this description is exhaustive, and fully transfers the scope to those skilled in the art. Numerous specific details are set forth such as examples of specific components, devices and methods to provide a full understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that it is not necessary to employ specific details, that exemplary embodiments can be incorporated in many different forms and that none should be construed as limiting the scope of the description. In some exemplary embodiments, well-known processes, well-known device structures and well-known technologies are not described in detail.

The terminology used herein is for the sole purpose of describing particular exemplary modalities and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" may be intended to also include the plural forms, unless the context clearly dictates otherwise. The terms "comprises", "comprising", "including" and "having" are inclusive and consequently specify the presence of features, integers, stages, operations, elements, and / or established components, but do not exclude the presence or addition of one or more characteristics, integers, stages, operations, elements, components and / or different groups thereof. It should not be construed that the steps of the method, processes and operations described herein necessarily require performance in the particular order treated or illustrated, unless specifically identified as a performance order. It should also be understood that additional or alternative steps may be employed.

When an element or layer is referred to as being "on", "engaged to", "connected to" or "coupled to", another element or layer, this may be directly on, engaged, connected or coupled to the other element or layer, or intermediate elements or layers may be present . In contrast, when an element is referred to as being "directly on", "directly engaged", "directly connected to" or "directly coupled to" another element or layer, there may be no intermediate elements or layers present. Other words used to describe the relationship between the elements should be interpreted similarly (eg, "between" against "directly between", "adjacent" against "directly adjacent", etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed elements.

Although the terms, first, second, third, etc., may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first", "second" and other numeric terms, when used herein, do not imply a sequence or order unless clearly indicated by the context. Therefore, a first element, component, region, layer or section discussed below can be referred to as a second element, component, region, layer or section without departing from the teachings of the exemplary embodiments.

Spatially relative terms, such as "interior", "exterior", "below", "under", "bottom", "top", "top" and the like, can be used herein to facilitate the description to describe the relationship of an element or characteristic with another element (s) or characteristic (s) as illustrated in the figures. The spatially relative terms may be used to cover the different operations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures is inverted, the elements described as "low" or "below" other elements or characteristics would then be "above" the other elements or characteristics. Thus, the exemplary term "low" may encompass an orientation both above and below. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatially relative descriptions used herein to be interpreted accordingly.

A stator for a three-phase dynamoelectric machine according to an exemplary embodiment of the present disclosure is illustrated in Figure 1 and is generally indicated by the reference number 100. As shown in Figure 1, the stator 100 includes a core of stator 102 and several in-phase windings placed around the stator core 102, including a first phase winding 104, a second phase winding 106 and a third phase winding 108. The first phase winding 104 is formed of at least one material electrical conductor that is not present in the second phase winding 106. For example, the first phase winding 104 may include copper, and the second phase winding 106 may be formed from one or more other electrical conductive materials that do not include copper.

By employing an electrically conductive material in the first phase winding that is not present in the second phase winding, the stator 100 - or a dynamoelectric machine incorporating the stator 100 - can have the desired combination of attributes (such as efficiency and material cost) that may not be achieved with a conventional stator that employs the same (s) electrical conductive material (s) in each phase winding.

In the exemplary embodiment of Figure 1, the stator core 102 is illustrated only with three projecting poles. In other embodiments, additional poles (and preferably are employed) may be employed. In that case, each phase winding 104-108 may include two or more coils wound around two or more projecting poles. In addition, the electrically conductive material (s) used for a particular phase winding may depend on the number and / or position of its coils around the stator core 102. Each coil includes one or more turns, and the number of turns for each coil can be the same or different from that of the other coils.

In some embodiments, the windings in step 104-108 each include only one electrical conductor. For example, as shown in Figure 2A, the first phase winding 104 may be formed only from an electrical conductor that includes copper (eg, a copper wire), while the second phase winding 106 and the third phase winding 108 may each be formed only of an electrical conductor that includes aluminum (eg, an aluminum wire). Figure 2B illustrates another exemplary configuration, wherein the first phase winding 104 and the third phase winding 108 may each be formed only of one electrical conductor including copper, while the second phase winding 106 may be formed only of one electrical conductor that includes aluminum. In Figures 2A and 2B, the first phase winding 104 includes at least one electrical conductive material (i.e., copper) that is not present in the second phase winding 106.

Alternatively, one or more of the windings in step 104 to 108 may include two or more electrical conductors connected in parallel. In addition, the first phase winding 104 can have the same number of electrical conductors as the second and third windings in phase 106, 108. For example, Figure 3A illustrates an exemplary embodiment in which each phase winding 104 to 108 includes two electrical conductors connected in parallel. In particular, the first phase winding 104 is formed of two electrical conductors including copper, while the second and third phase windings 106, 108 are each formed of two electrical conductors including aluminum. Similarly, in the example shown in Figure 3B, each phase winding 104 to 108 includes three electrical conductors connected in parallel. In particular, the first and third windings in phase 104, 108 are each formed of three electrical conductors including copper, while the second phase winding 106 is formed of three electrical conductors including aluminum. In Figures 3A and 3B, the first phase winding 104 includes at least one electrical conductive material (i.e., copper) that is not present in the second phase winding 106.

In the exemplary modalities shown in Figures 2 and 3, the first phase winding 104 is formed exclusively with a first conductive material. electrical (e.g., copper wire) and second phase winding 106 is formed exclusively with a second electrical conductive material that is different from the first electrically conductive material (e.g., aluminum wire).

Figures 4A to 4C illustrate further exemplary embodiments in which the first phase winding 104 has a number of electrical conductors different from that of the second or third windings in phase 106, 108. In the exemplary embodiment of Figure 4A, the first winding of Phase 104 is formed of two electrical conductors connected in parallel, including a first electrical conductor that includes copper and a second electrical conductor that includes aluminum. In contrast, the second and third windings in phase 106, 108 are each formed of a single electrical conductor including aluminum. Figure 4B illustrates another exemplary embodiment having the same configuration as in the example of Figure 4A, except that the third phase winding 108 in Figure 4B is formed of a conductor that includes aluminum rather than copper. In the exemplary embodiment of Figure 4C, the first and third windings in phase 104, 108 are each formed of two electrical conductors connected in parallel, including a first electrical conductor including copper and a second electrical conductor including aluminum. In contrast, the second phase winding 106 is formed of a single electrical conductor that includes copper. In Figures 4A to 4C, the first phase winding 104 includes at least one electrical conductive material (ie, copper in Figures 4A and 4B, and aluminum in Figure 4C) that is not present in the second phase winding 106. .

The third phase winding 108 (when employed) can have the same configuration (ie, the same number and type of electrical conductors) as the first phase winding 104 or the second phase winding 106. Alternatively the third phase winding 108 it may have a unique configuration different from that of the first phase winding 104 and the second phase winding 106. Figure 4B is an example of a third phase winding 108 having a unique configuration.

In any given embodiment, the size or gauge of the wire of each electrical conductor may be the same as or different from the size or gauge of the wire of other electrical conductors in the same phase winding (if applicable) or of the other windings in phase. Generally, the size or size of the. wire of any particular driver. it can depend on the desired resistance and / or impedance of the conductor and its associated phase winding, on the position of the conductor in the stator core, on the "stacked height" of the stator laminations stacked (when applicable), on the design of the stator laminations (when used), the size of the machine, the intended application and / or other considerations. In many embodiments, the size of each electrical conductor will vary between approximately 19 AWG and approximately 14 AWG.

With further reference to Figure 1, the stator core 102 can be formed in any suitable manner using any suitable material. For example, the stator core 102 may employ a segmented or non-segmented construction, and may include multiple laminations stacked together. The laminations may be formed of steel, cast iron, aluminum, or other suitable materials.

The dimensions of the stator 100 may be selected as appropriate for any given application. In some embodiments, the stator 100 has a diameter of between about 5.3 inches (13.5 cm) and about 7.1 inches (18 cm). In a particular embodiment, the stator 100 has a diameter of approximately 6.3 inches (16 cm).

Although the exemplary embodiments described above employ electrical conductors including copper or aluminum, it should be understood that other known electrical conductive materials can be employed including silver, gold, calcium, beryllium, tungsten, etc. In addition, the teachings of this description can also be applied using future electrical conductive materials (i.e., currently unknown).

In the exemplary modalities shown in Figures 2 to 4, the windings in phase 104 to 108 are connected in a Star configuration. Alternatively, the phased windings may be connected in a Delta configuration.

It should also be understood that although Figures 1 to 4 illustrate stators for three-phase machines, the teachings of this description are applicable to any polyphase machine having more or less in-phase windings, including stators having only biphasic windings (e.g., for two-phase motors).

In any given embodiment of this disclosure, the electrical resistance of the first phase winding may be substantially different from the electrical resistance of the second phase winding and / or the electrical resistance of the third phase winding. For example, the resistance of the first phase winding may differ from the resistance of the second phase winding by more than ten percent (10%). In other words, the resistance of the first phase winding may be less than ninety percent (90%) or greater than one hundred and ten percent (110%) of the resistance of the second phase winding. However, preferably, the electrical impedance of the first phase winding will be substantially the same (eg, within 10 percent (10%) of) as the electrical impedance of the second phase winding and / or the electrical impedance of the third winding of phase. In other words, the impedance of the first phase winding is preferably equal to the impedance of the second phase winding or to the impedance of the third phase winding, plus or minus 10 percent (± 10%). As a result, the current imbalance between any of the two phases will be no more than ten percent (10%) when the stator is used, for example, in a motor activated by a balanced power source.

Figure 5 illustrates a polyphase electric motor 200 according to another exemplary embodiment of this description. The electric motor 200 includes a stator 202 and a rotor 204 coupled to a motor shaft 206. The rotor 204 can have any suitable configuration. For example, the rotor 204 may employ a squirrel cage, slip ring, solid core, or other suitable construction.

Additionally, the rotor 204 may be surrounded by the stator 202 as shown in Figure 5. Alternatively, the rotor may be configured to extend around the stator (ie, sometimes referred to as an "outer rotor" or "flipped" motor) .

The stator 202 may employ any of the configurations mentioned above and / or illustrated in Figures 1 to 4. Preferably, the stator includes three-phase windings each having an electrical impedance that is within ten percent (10%) of the impedances. electrical from other windings in phase. As a result, the current imbalance between any of the biphasic windings will be no more than ten percent (10%) when the polyphase motor is activated with a balanced power source.

In a presently preferred embodiment, the polyphase motor 200 of Figure 5 includes a stator 202 having the winding configuration shown in Figure 2A. Based on the performance measurements of the fixed rotor, the line-to-line inductance between the first phase winding 104 and the second phase winding 106 is 56.4 mH, the line-to-line inductance between the first phase winding 104 and the third phase winding 108 is 62.7 mH, and the line-to-line inductance between the second phase winding 106 and the third phase winding 108 is 69.2 mH. Consequently, the average line-to-line inductance is 62.8 mH. Additionally, the maximum deviation between any of two line-to-line inductances is only about ten percent (10%), although the first phase winding 104 is formed of a different material (ie, copper) than that of the second and third windings in phase 106, 108. In addition, the deviation between the line-to-line inductances can be attributed to an uneven air gap within the motor, rather than to the different electrical conductor materials.

To calculate the average phase inductance, the average line-to-line inductance can be used in the following formula (1), where Lph is the average phase inductance and Liinea is the average line-to-line inductance. (1) Lph = Llinea / 1.5 Therefore, for the particular modality under discussion, the average phase inductance is 42 mH.

The phase reactance can be calculated using formula (2) below, where X is the phase reactance, f is the operating frequency and Lph is the average phase inductance (calculated above). (2) X = 2 * n * f * Lph Assuming an operating frequency of 50 Hz, the reactance for each phase is 13.2 ohms.

The impedance of each phase can be calculated using formula (3) below, where Z is the phase impedance, R is the phase resistance and X is the phase reactance. (3) Z = V (R2 + X2) In this exemplary embodiment, the second phase winding 106 and the third phase winding 108 (both formed of aluminum) each have a resistance of 1727 ohms, while the first phase winding 104 (formed of copper) has a resistance of 1,146 ohms. Therefore, the impedance for each aluminum phase winding is 13.31 ohms, while the impedance for the copper phase winding is 13.25 ohms.

Accordingly, although the resistance of the first phase winding differs from the resistance of each of the second and third phase windings by more than thirty percent (30%), the impedance of the first phase winding 104 is approximately the same as that of the first phase winding. the impedance of the second phase winding 106 and the third phase winding 108. Thus, the current through each phase winding will be approximately the same when the motor 200 is energized by a balanced power source, although the first Phase winding 104 is formed of a different material (ie, copper) to that of the second and third windings in phase 106, 108.

The teachings of this disclosure can be applied to a wide variety of polyphase motors and generators of various configurations (e.g., size, shape, horsepower, etc.), including induction motors, synchronous motors, etc. Such engines can be used in a wide variety of applications including pumps, fans, heaters, compressors, appliances, transmitters, electric vehicles and any other polyphase motor application.

Figure 6 illustrates a compressor 300 according to another exemplary embodiment of this description. As shown in Figure 6, the compressor 300 includes a polyphase motor 302. The polyphase motor 302 includes a stator (not shown). The stator can employ any of the configurations mentioned above and / or illustrated in Figures 1 to 5. The compressor 300 is preferably a hermetically sealed displacement compressor. Alternatively, another suitable type of compressor can be used including oscillating, rotary screw and rotary vane compressors.

The above description of the modalities has been provided for purposes of illustration and description. This does not pretend to be exhaustive or limit the description. The individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, when applicable, are interchangeable and may be used in a selected embodiment, even if it is not specifically displayed or described. They can also vary in many ways. Such variations should not be considered apart from the description, and all such modifications are intended to be included within the scope of the description.

Claims (18)

1. A stator for a polyphase dynamoelectric machine, the stator comprising a stator core and windings placed around the stator core, the windings including at least a first phase winding and a second phase winding, the first phase winding being formed less an electrical conductive material that is not present in the second phase winding.

2. The stator of claim 1, wherein the at least one conductive material comprises copper.

3. The stator of any preceding claim wherein the second phase winding comprises aluminum.

4. The stator of any preceding claim wherein the first phase winding includes only one electrical conductor.

5. The stator of claim 1, 2 or 3, wherein the first phase winding includes a first electrical conductor and a second electrical conductor connected in parallel with the first electrical conductor.

6. The stator of claim 5, wherein the first electrical conductor and the second electrical conductor each comprise copper.

7. The stator of claim 5, wherein the first electrical conductor comprises copper and the second electrical conductor comprises aluminum.

8. The stator of any preceding claim, wherein the second phase winding includes only one electrical conductor.

9. The stator of any preceding claim, wherein the first phase winding has a resistance, the second phase winding has a resistance, and the difference between the resistance of the first phase winding and the resistance of the second phase winding is greater than the resistance of the second phase winding. ten percent (10%) of the resistance of the second phase winding.

10. The stator of > any preceding claim wherein the first phase winding has an impedance, the second phase winding has an impedance, and the impedance of the first phase winding is within 10 percent (10%) of the impedance of the second phase winding .

11. The stator of any preceding claim, further comprising a third phase winding.

12. The stator of claim 11, wherein the third phase winding comprises copper.

13. The stator of claim 11, wherein the third phase winding comprises aluminum.

14. The stator of claim 11, 12 or 13, wherein the third phase winding includes only one electrical conductor.

15. A polyphase dynamoelectric machine comprising the stator of any preceding claim.

16. The polyphase dynamoelectric machine of claim 15, wherein the machine is a polyphase motor.

17. The polyphase dynamoelectric machine of claim 16, wherein the current differences between any of the biphasic windings are not greater than ten percent (10%) of one of any of said biphasic windings when the polyphase motor is activated with a source of balanced energy

18. A hermetic compressor comprising the polyphase dynamoelectric machine of claim J.6.