Back-wound winding high-speed motor with low-loss stator structure

Abstract

The invention discloses a back-wound winding high-speed motor with a low-loss stator structure. The back-wound winding high-speed motor comprises a shell, an outer shielding layer, an outer winding bracket, a motor stator, a back-wound winding and a motor rotor, the casing, the outer shielding layer, the outer winding support and the motor stator are sequentially and coaxially arranged from outside to inside. Tooth grooves are formed in the outer surface of the outer winding support and the inner surface of the motor stator. The number of the tooth grooves of the stator outer winding support is the same as that of the tooth grooves in the motor stator. The back-wound winding is wound in tooth grooves of the motor stator and the outer side winding support in a back-wound winding mode. The outer winding bracket is made of a non-magnetic insulating material; the outer shielding layer is of an annular structure, is installed between the stator outer side winding support and the outermost side machine shell, and is used for ensuring that the internal magnetic induction intensity is in an unsaturated state. The motor efficiency is improved, and the electromagnetic compatibility of the motor is improved.

Description

Technical Field

[0001] This invention belongs to the field of high-speed motor body structure design, and in particular to a low-loss stator structure back-wound high-speed motor. Background Technology

[0002] High-speed motors, characterized by high power density, high efficiency, and compact structure, are widely used in centrifugal air compressors, micro gas turbine generators, flywheel energy storage, and many other applications. However, if the rotor of a high-speed motor is too long, its rated operating speed will approach the critical speed range, leading to increased shaft vibration and even equipment damage. Back-wound windings significantly reduce the length of the winding ends, thereby shortening the rotor span and mitigating rotor dynamics problems caused by slender shafts to some extent. Therefore, they are widely used.

[0003] Existing technology combines back-wound windings with slotless motors. Patent CN111431301A adds non-magnetic slots to the inner side of the stator of the slotless motor. The purpose is to avoid high-frequency harmonics in the air gap magnetic field caused by stator core slotting, reduce rotor eddy current losses, and solve the problem of difficult winding fixation in slotless motors, thus protecting the winding insulation performance. However, the use of non-magnetic slots on the inner side of the stator increases the equivalent air gap length and reduces the power density of the motor. Especially in the back-wound winding configuration, the outer winding of the back-wound winding is wound on the silicon steel stator. The magnetic field generates leakage flux through the stator slots where the outer winding is wound, and the proportion of leakage flux relative to the main magnetic field is greatly increased. The patent CN213461269U adds non-magnetic support structures to both the inner and outer sides of the stator of the slotless motor to avoid high-frequency harmonics in the air gap magnetic field caused by the slotting of the stator core, thereby reducing rotor eddy current losses. While solving the problem of difficult winding fixation in slotless motors, it also reduces the weight of the motor. Although the addition of non-magnetic support structures to the outer side of the stator in patent CN213461269U reduces the proportion of leakage flux relative to the main magnetic field to some extent, the main magnetic field uses a slotless structure, resulting in a large equivalent air gap length and low power density of the motor. In addition, it does not consider the problem of induced current and losses caused by the back-wound outer winding on the motor housing and other structures.

[0004] In back-wound motors, to reduce the length of the end windings, the windings are wound around the outside of the stator. However, because current flows through the outer windings, invalid magnetic fields unrelated to the motor's main magnetic field are generated in the stator yoke, stator external teeth, housing, and the space where the outer windings are located, causing unnecessary losses in these structures. On the one hand, since back-wound motors are mostly used in high-speed motors, the internal electromagnetic field frequency of high-speed motors is higher than that of medium- and low-speed motors, so the losses caused by invalid magnetic fields cannot be ignored. On the other hand, during motor operation, the magnetic field generated by the outer windings on the housing can interfere with external measuring equipment. Summary of the Invention

[0005] The purpose of this invention is to provide a high-speed motor with a low-loss stator structure and back-wound windings, which can reduce the overall loss caused by ineffective magnetic fields, improve motor efficiency, shield the magnetic field of the outer windings on the housing, avoid the generation of induced current on the housing, and significantly improve the electromagnetic compatibility of the motor.

[0006] The technical solution to achieve the purpose of this invention is as follows: A low-loss stator structure with back-wound high-speed motor includes a housing, an outer shielding layer, an outer winding support, a motor stator, back-wound windings, and a motor rotor. The housing, outer shielding layer, outer winding bracket, and motor stator are arranged coaxially from the outside to the inside. The outer surface of the outer winding bracket and the inner surface of the motor stator are both provided with toothed slots, and the number of toothed slots on the outer winding bracket of the stator is the same as the number of toothed slots on the motor stator; the back-wound winding is wound in the toothed slots of the motor stator and the outer winding bracket by a back-wound winding method; the outer winding bracket is made of non-magnetic insulating material. The outer shielding layer is a ring-shaped structure, installed between the outer winding support of the stator and the outermost housing, to ensure that the internal magnetic induction intensity is in an unsaturated state.

[0007] The significant advantages of this invention compared to existing technologies are: This invention designs a stator structure that, on the one hand, can shield the magnetic field generated by the outer winding in the housing, avoiding induced current in the housing. This reduces the risk of housing leakage and significantly improves electromagnetic compatibility, reducing interference to external measuring equipment during motor operation. On the other hand, it can reduce overall losses caused by ineffective magnetic fields and provide support space for the outer winding, facilitating the fixing and winding of the back-wound outer winding and achieving phase-to-phase physical isolation of the outer winding. Attached Figure Description

[0008] Figure 1 This is a cross-sectional view of a back-wound motor. Detailed Implementation

[0009] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0010] The present invention provides a low-loss stator structure for a back-wound high-speed motor, such as... Figure 1 As shown, it includes a housing 1, an outer shielding layer 2, an outer winding bracket 3, a motor stator 4, a back-wound winding 5, and a motor rotor 6, wherein the back-wound winding 5 is wound on the motor stator 4 and the outer winding bracket 3 by a back-wound winding method.

[0011] The outer winding support 3 is made of non-magnetic insulating material, and its outer surface is machined with grooves. The number of grooves is the same as the number of grooves on the motor stator 4, and they are evenly distributed on the outer surface and are circumferentially positioned to correspond one-to-one with the grooves on the motor stator 4. The outer shielding layer 2 is a ring structure installed between the outer winding support 3 and the outermost housing 1. It is made of silicon steel sheets stacked axially, and its thickness must ensure that the internal magnetic induction intensity is not saturated.

[0012] The inner surface of the motor stator 4 is uniformly slotted. The back-wound winding 5 uses Litz wire and is wound in the slots of the motor stator 4 and the outer stator winding bracket 3 in a back-wound manner. The motor stator 4 is made of laminated silicon steel sheets. When inserting the wire, insulating paper needs to be placed between the slots and the back-wound winding 5. The outer stator winding bracket 3 is made of non-magnetic insulating material. When inserting the wire, no insulating paper is needed between its slots and the back-wound winding 5. The height of the slots of the motor stator 4 and the outer stator winding bracket 3 must be greater than the height of the inner back-wound winding 5 to ensure the embedding of the back-wound winding 5.

[0013] This invention designs a stator structure that, on the one hand, can shield the magnetic field generated by the outer winding in the housing, avoiding induced current in the housing. This reduces the risk of housing leakage and significantly improves electromagnetic compatibility, reducing interference to external measuring equipment during motor operation. On the other hand, it can reduce overall losses caused by ineffective magnetic fields and provide support space for the outer winding, facilitating the fixing and winding of the back-wound outer winding and achieving phase-to-phase physical isolation of the outer winding.

Claims

1. A high-speed motor with a low-loss stator structure and back-wound windings, characterized in that, It includes the housing, outer shielding layer, outer winding support, motor stator, back-wound winding, and motor rotor; The housing, outer shielding layer, outer winding bracket, and motor stator are arranged coaxially from the outside to the inside. The outer surface of the outer winding bracket and the inner surface of the motor stator are both provided with toothed slots, and the number of toothed slots on the outer winding bracket of the stator is the same as the number of toothed slots on the motor stator; the back-wound winding is wound in the toothed slots of the motor stator and the outer winding bracket by a back-wound winding method; the outer winding bracket is made of non-magnetic insulating material. The outer shielding layer is a ring-shaped structure, installed between the outer winding support of the stator and the outermost housing, to ensure that the internal magnetic induction intensity is in an unsaturated state.

2. The low-loss stator structure back-wound high-speed motor according to claim 1, characterized in that, The outer shielding layer is made of silicon steel sheets stacked axially, and the thickness must ensure that the internal magnetic induction intensity is not saturated.

3. The low-loss stator structure of the back-wound high-speed motor according to claim 1, characterized in that, The motor stator is made of stacked silicon steel sheets.

4. The low-loss stator structure of the back-wound high-speed motor according to claim 3, characterized in that, When winding the motor stator, insulating paper needs to be placed between the slots and the back-wound winding.

5. The low-loss stator structure of the back-wound high-speed motor according to claim 1, characterized in that, The tooth groove height of both the motor stator and the outer winding bracket must be greater than the height of the inner back-wound winding to ensure the embedding of the back-wound winding.

6. The low-loss stator structure of the back-wound high-speed motor according to claim 1, characterized in that, The back-wound winding uses Litz wire.

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