Stator excitation winding capable of bearing large current
By designing a stator excitation winding using parallel branch shunt excitation current, the problems of heating and insulating medium aging caused by high current density and large copper loss in the stator excitation winding in the prior art are solved, and the effect of reducing heat generation and improving motor reliability is achieved.
Patent Information
- Application Number
- CN202421361383.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-14
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-06-14
AI Technical Summary
When starting a high-power APU, the stator excitation winding of existing DC series excitation motors is prone to severe heat generation and high temperature due to high current density and high copper loss, which accelerates the aging of the insulation medium, causing the excitation winding to be short-circuited to the ground, the motor fails and causes safety accidents.
A stator excitation winding that can withstand high current is designed, and the excitation current shunt design of two parallel branches is used to wind the excitation coils on the four stator poles in a specific order through the same enameled wire, and the conductive connection between the wiring terminals and the enameled wire is formed to form a conductive connection to divert the excitation current.
It effectively reduces the heating of the excitation winding, avoids the risk of insulating medium aging and the short circuit of the excitation winding to the ground, and improves the reliability and safety of the motor.
Smart Images
Figure CN222654911U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of direct current motors, in particular to a stator excitation winding capable of bearing large currents, which is used for starting direct current motors of aviation auxiliary power devices. Background Art
[0002] Modern large and medium-sized military and civilian aircraft are generally equipped with aviation auxiliary power units, referred to as APUs. When the aircraft's turbofan engine stops in the air, it is necessary to start the APU to provide power and air to the aircraft to provide power for starting the turbofan engine. Therefore, the APU is an important device to ensure that the turbofan engine can be restarted after it stops in the air, and the DC motor that drives the APU ignition and starting is a low-voltage, high-current DC motor that uses the onboard battery as power source.
[0003] DC motors are mainly divided into permanent magnet motors and electrically excited motors. Currently, electrically excited DC series motors are mostly used to start high-power APUs. This is because the hundreds of amperes of current generated by permanent magnet motors when starting high-power APUs may cause permanent demagnetization of permanent magnets and motor failure. The stator magnetic poles of electrically excited motors are equipped with excitation windings (coils). When the excitation windings are energized, a magnetic field is generated. The stator excitation windings and rotor windings are connected in series to form a DC series motor.
[0004] The coil winding of the stator excitation winding of the existing DC series motor is as follows: Figure 1 As shown, the stator excitation winding has four stator poles, which are wound with the same enameled wire, and a coil is formed at each stator pole. The coil head is connected to the positive pole of the DC power supply, and the coil tail is connected to the negative pole of the DC power supply. When the existing DC series motor is used to ignite and start the APU, a large current of hundreds of amperes will be passed through the stator excitation winding. The excitation winding has a high current density and large copper loss, which causes the excitation winding to heat up severely and generate high temperature. When the APU fails to start once, the APU will be started repeatedly. At this time, the excitation winding temperature of the DC series motor rises sharply. When the temperature exceeds the temperature resistance level of the insulating medium between the excitation winding and the pole (C-level insulation 220℃), it will accelerate the aging of the insulating medium and reduce the insulation strength, causing the excitation winding to short-circuit to the ground, and the motor failure will cause a safety accident. How to avoid overheating of the excitation winding is an urgent problem to be solved. Utility Model Content
[0005] The main purpose of the utility model is to provide a stator excitation winding capable of bearing large current, aiming at reducing the temperature of the excitation winding and preventing the excitation winding from overheating.
[0006] To achieve the above-mentioned purpose, the utility model proposes a stator excitation winding capable of withstanding large current, comprising a stator housing and four stator poles evenly distributed inside the stator housing; along the counterclockwise direction, the four stator poles are the first pole, the second pole, the third pole and the fourth pole in sequence; the inner ends of the first pole and the third pole are N poles; the inner ends of the second pole and the fourth pole are S poles; the same enameled wire is wound in sequence according to the fourth pole, the second pole, the first pole and the third pole, and excitation coils are formed on the four stator poles respectively; one end of the enameled wire is the coil head and the other end is the coil tail; the coil head and the coil tail are connected to the negative pole of a DC power supply; a wiring terminal is connected to the enameled wire between the second pole and the first pole, and the wiring terminal is conductively connected to the enameled wire, and the wiring terminal is connected to the positive pole of the DC power supply.
[0007] Preferably, the enameled wire is an enameled copper flat wire, and along the radial direction, the enameled copper flat wires on each excitation coil are arranged in a stacked manner.
[0008] Preferably, the number of layers of enameled rectangular copper wire on each excitation coil is not less than 5 layers.
[0009] Preferably, the connection between the terminal and the enameled wire is by welding.
[0010] Preferably, the connection terminal and the enameled wire are connected by resistance brazing with silver or copper solder.
[0011] Preferably, the connecting terminal is formed by bending a plate; one end of the connecting terminal is provided with a first bending portion and a second bending portion; a slot is formed between the first bending portion and the second bending portion; and the enameled wire is clamped in the slot.
[0012] Preferably, the other end of the connection terminal has a third bending portion, and a connection clip in the form of a U-shaped opening is provided on the third bending portion.
[0013] Preferably, the connecting terminal is formed by bending a copper plate.
[0014] Preferably, when the four excitation coils are unfolded, each excitation coil is wound clockwise.
[0015] Preferably, the enameled wire between the fourth magnetic pole and the second magnetic pole is adhered to the inner wall of the stator housing; the enameled wire between the first magnetic pole and the third magnetic pole is adhered to the inner wall of the stator housing.
[0016] Due to the adoption of the above technical solution, the beneficial effects of the utility model are as follows:
[0017] (1) The stator excitation winding provided by the utility model has two parallel branches, which can effectively reduce the heating of the excitation winding and avoid the high temperature generated by the excitation winding causing aging of the insulating medium, resulting in the risk of the excitation winding short-circuiting to the ground and the failure of the motor causing a safety accident.
[0018] (2) In the present invention, a slot is formed between the first bent portion and the second bent portion on the terminal block, which facilitates the enameled wire to be clamped into the slot. At the same time, a U-shaped opening-shaped wiring clamp is provided on the terminal block, which facilitates the connection between the terminal block and the terminal post on the positive pole of the DC power supply. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.
[0020] Figure 1 The figure is a schematic diagram of the winding direction and polarity distribution of the stator excitation winding of the existing DC series motor;
[0021] Figure 2 A schematic diagram of a stator excitation winding provided in the utility model;
[0022] Figure 3 It is a schematic diagram of the positional relationship between the wiring terminals and each excitation coil in the utility model;
[0023] Figure 4 It is a schematic diagram of the winding direction of each excitation coil in the utility model;
[0024] Figure 5 A schematic diagram of the winding direction of each excitation coil in the utility model;
[0025] Figure 6 It is a three-view drawing of the wiring terminal in the utility model;
[0026] Figure 7 The diagram is a schematic diagram of the current direction and magnetic pole direction in the stator excitation winding provided in the utility model.
[0027] Explanation of the accompanying drawings: 1a, first coil; 1b, second coil; 1c, third coil; 1d, fourth coil; 2a, first magnetic pole; 2b, second magnetic pole; 2c, third magnetic pole; 2d, fourth magnetic pole; 3, stator housing; 4, terminal; 4a, first bending portion; 4b, second bending portion; 4c, slot; 4d, third bending portion; 4e, wiring bayonet; 5, coil head; 6, coil tail. DETAILED DESCRIPTION
[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0029] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0030] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.
[0031] Combination Figure 1 As shown, in the stator excitation winding of the existing DC series motor, there are four stator poles, which are wound with the same enameled wire, and a coil is formed at each stator pole, the coil head is connected to the positive pole of the DC power supply, and the coil tail is connected to the negative pole of the DC power supply. Figure 1 The winding direction and current direction in the magnet can be determined according to the right-hand screw rule to form N, S, N, S poles alternately. In the existing field winding, there is a branch from the positive pole to the negative pole. The field winding has a high current density and large copper loss, which causes the field winding to heat up severely and generate high temperature.
[0032] Combination Figures 2 to 7As shown, it is a specific embodiment of a stator excitation winding capable of withstanding large current provided by the utility model, and the stator excitation winding comprises a stator housing 3 and four stator magnetic poles evenly distributed inside the stator housing 3. Figure 2 As shown, along the counterclockwise direction, the four stator poles are the first pole 2a, the second pole 2b, the third pole 2c and the fourth pole 2d, wherein the first pole 2a and the third pole 2c are placed 180° apart on the circumference, and the inner ends of the two are N poles. The second pole 2b and the fourth pole 2d are placed 180° apart on the circumference, and the inner ends of the two are S poles.
[0033] Combination Figure 2 and Figure 3 As shown, the same enameled wire is wound in the order of the fourth magnetic pole 2d, the second magnetic pole 2b, the first magnetic pole 2a, and the third magnetic pole 2c, and excitation coils are formed on the four stator magnetic poles respectively; specifically, the excitation coil includes a fourth coil 1d formed on the fourth magnetic pole 2d, a second coil 1b formed on the second magnetic pole 2b, a first coil 1a formed on the first magnetic pole 2a, and a third coil 1c formed on the third magnetic pole 2c. One end of the enameled wire is a coil head 5, and the other end is a coil tail 6; the coil head 5 and the coil tail 6 are connected to the negative pole of the DC power supply; the enameled wire between the second magnetic pole 2b and the first magnetic pole 2a is connected with a terminal 4, and the terminal 4 is connected to the positive pole of the DC power supply. When the terminal 4 is connected to the enameled wire, the paint at the connection position on the enameled wire is removed, so that a conductive connection is formed between the terminal 4 and the enameled wire.
[0034] Combination Figures 2 to 4 As shown, the enameled wire is an enameled copper flat wire, and the enameled copper flat wires on each excitation coil are stacked in the radial direction. Specifically, according to the rated speed and rated torque of the DC motor, it is calculated that the number of layers of the enameled copper flat wire on each excitation coil is not less than 5 layers. The enameled copper flat wire is a pure copper wire as a base material, which is tinned, flattened and then enameled and insulated. Due to the special treatment of pure copper and enameled insulation layer, the enameled copper flat wire has good conductivity and electrical insulation properties. Enameled copper flat wire is one of the common materials for making electromagnetic coils, which will not be described here.
[0035] In order to ensure the firmness of the connection between the terminal 4 and the enameled wire, the connection between the terminal 4 and the enameled wire is welding. Specifically, the connection between the terminal 4 and the enameled wire is resistance brazing with silver or copper solder. Silver soldering has the characteristics of low melting point, good wettability, high strength, etc. Copper soldering has the characteristics of low cost and good electrical conductivity, etc.
[0036] Combination Figure 6As shown, the terminal block 4 is formed by bending a plate; one end of the terminal block 4 has a first bending portion 4a and a second bending portion 4b; a slot 4c is formed between the first bending portion 4a and the second bending portion 4b; after the enameled wire is clamped in the slot 4c, welding is convenient.
[0037] Combination Figure 6 As shown, the other end of the terminal block 4 has a third bent portion 4d, and a U-shaped opening-shaped connection bayonet 4e is provided on the third bent portion 4d. The purpose of providing the connection bayonet 4e is to facilitate connection with the terminal on the positive pole of the DC power supply, and then the third bent portion 4d is compressed by the terminal nut.
[0038] In this embodiment, the connection terminal 4 is formed by bending a copper plate T2-M, which has excellent electrical conductivity, thermal conductivity, corrosion resistance and processing performance, and can be welded and brazed.
[0039] Combination Figure 2 and Figure 3 As shown, Figure 3 This is an expanded view before the four excitation coils are installed in the stator housing 3. Each coil is wound clockwise. Looking radially outward from the inside of the stator housing 3, the four excitation coils are installed on the stator poles in the stator housing 3 on the circumference according to the following requirements. Specifically, the first coil 1a is installed on the first pole 2a, the second coil 1b is installed on the second pole 2b, the fourth coil 1d is flipped 180° to be installed on the fourth pole 2d opposite the second coil 1b, and the third coil 1c is flipped 180° to be installed on the first pole 2a opposite the first coil 1a.
[0040] Combination Figure 1 As shown, since the span between the fourth magnetic pole 2d and the second magnetic pole 2b is large, in order to ensure the regularity of the enameled wire inside the stator casing 3 and avoid interference between the enameled wire and the rotor, the enameled wire between the fourth magnetic pole 2d and the second magnetic pole 2b is pasted on the inner wall of the stator casing 3; similarly, the enameled wire between the first magnetic pole 2a and the third magnetic pole 2c is also pasted on the inner wall of the stator casing 3.
[0041] The stator excitation winding provided in this embodiment, when in use, when the terminal 4 is connected to the positive pole of the DC power supply, and the coil head 5 and the coil tail 6 are connected to the negative pole of the DC power supply, the stator excitation winding is divided into two parallel branches, and the excitation current passes through the two branches from the positive pole of the power supply to the negative pole of the power supply. The two parallel branches play a role of shunting. The magnetic flux direction of each magnetic pole can be determined according to the right-hand screw rule. The excitation winding circuit is as follows Figure 7 As shown, press Figure 2 The excitation coil is placed to alternately form N, S, N, S magnetic poles in the inner circle of the stator. Figure 1 Compared with the stator excitation winding, under the same excitation current, the current density is reduced by 50% due to the two parallel branches that play the role of current shunting, which can effectively reduce the heating of the stator excitation winding.
[0042] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made under the concept of the present invention using the contents of the specification and drawings of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.
Claims
1. A stator excitation winding capable of withstanding large currents, characterized in that: It comprises a stator casing (3) and four stator magnetic poles evenly distributed inside the stator casing (3); In the counterclockwise direction, the four stator magnetic poles are the first magnetic pole (2a), the second magnetic pole (2b), the third magnetic pole (2c) and the fourth magnetic pole (2d). The inner ends of the first magnetic pole (2a) and the third magnetic pole (2c) are N poles; the inner ends of the second magnetic pole (2b) and the fourth magnetic pole (2d) are S poles; The same enameled wire is wound in sequence in the order of the fourth magnetic pole (2d), the second magnetic pole (2b), the first magnetic pole (2a), and the third magnetic pole (2c), and excitation coils are formed on the four stator magnetic poles respectively; One end of the enameled wire is a coil head (5), and the other end is a coil tail (6); the coil head (5) and the coil tail (6) are connected to the negative pole of a DC power supply; A connection terminal (4) is connected to the enameled wire between the second magnetic pole (2b) and the first magnetic pole (2a), and the connection terminal (4) and the enameled wire are electrically connected, and the connection terminal (4) is connected to the positive pole of a DC power supply.
2. A stator excitation winding capable of withstanding large current as claimed in claim 1, characterized in that: The enameled wire is an enameled copper flat wire, and the enameled copper flat wires on each excitation coil are arranged in layers along the radial direction.
3. A stator excitation winding capable of withstanding large current as claimed in claim 2, characterized in that: The number of layers of enameled copper flat wire on each excitation coil shall not be less than 5.
4. A stator excitation winding capable of withstanding large current as claimed in claim 1, characterized in that: The connection method between the wiring terminal (4) and the enameled wire is welding.
5. A stator excitation winding capable of withstanding large current as claimed in claim 4, characterized in that: The connection method of the connection terminal (4) and the enameled wire is resistance brazing with silver or copper solder.
6. A stator excitation winding capable of withstanding large current as claimed in claim 1, characterized in that: The connecting terminal (4) is formed by bending a plate; one end of the connecting terminal (4) is provided with a first bending portion (4a) and a second bending portion (4b); a clamping groove (4c) is formed between the first bending portion (4a) and the second bending portion (4b); and the enameled wire is clamped in the clamping groove (4c).
7. A stator excitation winding capable of withstanding large current as claimed in claim 6, characterized in that: The other end of the connecting terminal (4) is provided with a third bending portion (4d), and a connecting clamping opening (4e) in the form of a U-shaped opening is arranged on the third bending portion (4d).
8. A stator excitation winding capable of withstanding large current as claimed in claim 6, characterized in that: The connecting terminal (4) is formed by bending a copper plate.
9. A stator excitation winding capable of withstanding large current as claimed in claim 1, characterized in that: When the four excitation coils are unfolded, each excitation coil is wound clockwise.
10. The stator excitation winding capable of withstanding large current as claimed in claim 1, characterized in that: The enameled wire between the fourth magnetic pole (2d) and the second magnetic pole (2b) is adhered to the inner wall of the stator housing (3); The enameled wire between the first magnetic pole (2a) and the third magnetic pole (2c) is adhered to the inner wall of the stator housing (3).