Novel brushless slip-ring-free winding type rotor asynchronous motor

Abstract

The invention provides a novel brushless slip-ring-free winding type rotor asynchronous motor, and relates to the technical field of motor technology development and manufacturing, the novel brushless slip-ring-free winding type rotor asynchronous motor comprises a fan and a motor shell, and a motor output shaft is arranged in the motor shell. The temperature rise of the motor is lower, and the operation is more stable. The stator side is directly connected to a power frequency power grid, the voltage and the frequency are constant, the iron loss (in direct proportion to the square of the frequency) and the copper loss (in direct proportion to the square of the current) of the stator are basically stabilized near the rated working condition, and no extra harmonic loss exists. And at the rotor side, the slip power is controlled through an electromagnetic coupler and a chopper, the rotor current is determined by the load demand, no higher harmonic injection exists, the rotor copper loss is only the loss corresponding to the rated slip, the slip power can be partially fed back, and the rotor heating is further reduced. On the whole, the loss of each part of the motor is close to a rated running state, the temperature rise is generally 5-10K lower than the rated temperature rise, and the motor is particularly suitable for long-term low-speed and heavy-load running scenes.

Description

Technical Field

[0001] This invention relates to the field of electric motor technology development and manufacturing technology, and in particular to a novel brushless, slip-free, spiral-rotor asynchronous motor. Background Technology

[0002] Existing brushless doubly-fed motors, lacking an output path for rotor induced electromotive force, require a dedicated frequency converter to control the stator feedback winding for speed regulation. This dedicated frequency converter speed regulation system (1 / 3 to 1 / 2 of the motor power) introduces some grid pollution. The frequency converter supplies power to the motor via AC-DC-AC conversion (or AC-AC conversion), and its front-end rectifier bridge (diodes or IGBTs) generates numerous characteristic harmonics (such as the 5th, 7th, and 11th harmonics), leading to grid current distortion. Even with a conventional two-level frequency converter, without an input filter or reactor, the grid current THD is typically 10%–20%. If the load fluctuates significantly or the frequency converter has a high power rating (approaching 1 / 2 of the motor power), harmonic pollution will be more pronounced, potentially affecting the normal operation of other sensitive equipment in the grid (such as instruments and PLCs). Furthermore, the dedicated frequency converter speed regulation of brushless doubly-fed motors generates high-energy harmonics, which can affect the air gap magnetic flux coupling during speed regulation.

[0003] Harmonic magnetic fields cause magnetic circuit saturation: The non-sinusoidal voltage output by the frequency converter introduces harmonics into the motor current. These harmonics increase slot current and slot magnetomotive force, leading to leakage magnetic circuit saturation, reducing stator leakage reactance, and affecting the distribution and coupling of air gap flux. Harmonic torque is generated: The interaction between harmonic flux in the air gap and the induced harmonic current in the rotor produces asynchronous harmonic torque. Although its value is constant, it is very small and its impact is negligible. Furthermore, harmonic magnetic fields of different orders, mainly the 5th and 7th harmonics with the largest amplitudes, interact with the fundamental magnetic field to generate sixth-harmonic torque. This is a pulsating torque with an average value of zero, but the pulsation amplitude is large at low speeds and low frequencies, causing noise and vibration, and affecting the stability of air gap flux coupling. Power factor is affected: Current harmonics increase the effective current value, improve magnetic circuit saturation, and increase excitation current, thereby reducing the power factor. This also indirectly has an adverse effect on air gap flux coupling, leading to a decrease in motor operating performance. The rectifier stage of a frequency converter can lead to a low input power factor (potentially as low as 0.6-0.7 under light load), requiring an additional power factor compensation device. Otherwise, it will increase reactive power losses in the power grid. Furthermore, dedicated frequency converter speed control systems are prone to high temperature rise when operating at low speeds or high frequencies. Stator side: The inverter output voltage is a PWM (Pulse Width Modulation) waveform, containing a large number of high-order harmonics, which will generate additional harmonic copper losses in the stator windings. At the same time, the cooling effect of the motor fan decreases at low speeds, and if the inverter is not equipped with forced cooling measures, it will aggravate the temperature rise. Core losses: The high-order harmonics in the PWM waveform will increase the eddy current losses and hysteresis losses in the core (especially during high-frequency speed regulation), resulting in higher core temperature rise.

[0004] In actual operation, if the motor runs at less than 50% of its rated speed for a long time and the frequency converter does not use vector control or optimized PWM strategy, the motor temperature rise may be 10-15K higher than the rated temperature, and the energy saving rate of low speed and high torque load is not ideal. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems existing in the prior art, and to propose a novel brushless, slip-free, wound-rotor asynchronous motor.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a novel brushless, slip-free, wound-rotor asynchronous motor, comprising a fan and a motor housing, wherein a motor output shaft is disposed inside the motor housing, a motor rotor core is disposed on the side of the motor output shaft, a motor rotor shaft is disposed on the motor output shaft, and 8.5 mm thick electromagnetic isolation discs are symmetrically connected to the side of the motor output shaft, with electromagnetic isolation disc fixing bolts threaded onto the 8.5 mm thick electromagnetic isolation discs, a motor stator winding is connected to the side of the motor rotor core, a motor stator core is connected to the side of the motor stator winding, and motor rotor windings are connected to both ends of the motor rotor core, a three-phase electromagnetic coupler rotor core is disposed inside the motor housing, a three-phase electromagnetic coupler rotor winding is disposed on the three-phase electromagnetic coupler rotor core, and a three-phase electromagnetic coupler stator core is symmetrically disposed inside the motor housing, with three-phase electromagnetic coupler stator windings connected to both ends of the three-phase electromagnetic coupler stator core.

[0007] Preferably, a second bearing is provided on the outer side of the motor output shaft, and one end of the second bearing is connected to a motor output shaft end bearing cover, the motor output shaft end bearing cover being internally threaded with bolts.

[0008] Preferably, the fan is provided with a motor fan cover on the outside, and a motor base is provided at the bottom of the motor fan cover.

[0009] Preferably, the motor fan cover is connected to a fan cover fixing bolt, and the side of the motor housing is connected to a motor end cover fixing bolt.

[0010] Preferably, the outer side of the motor housing is provided with motor housing heat dissipation fins, and the top of the motor fan cover is provided with a lifting ring.

[0011] Preferably, the fan has a first bearing inside, an inner bearing cover is connected to the side of the first bearing, an outer bearing cover is provided outside the inner bearing cover, the outer bearing cover is provided with inner and outer bearing cover fixing bolts, and a motor end cover is connected to the side of the outer bearing cover, the motor end cover is connected to the motor housing.

[0012] Compared with the prior art, the advantages and positive effects of the present invention are as follows: 1. In this invention, the motor temperature rise is lower and the operation is more stable. Stator side: Directly connected to the power grid, with constant voltage and frequency, stator iron losses (proportional to the square of the frequency) and copper losses (proportional to the square of the current) remain relatively stable near rated operating conditions, with no additional harmonic losses. Rotor side: Slip power is controlled through an electromagnetic coupler and chopper. The rotor current is determined by load demand, with no high-order harmonic injection. Rotor copper losses are only the losses corresponding to the rated slip, and the slip power can be partially fed back, further reducing rotor heating. Overall, the losses of each component of the motor are close to the rated operating state, and the temperature rise is typically 5-10K lower than the rated temperature rise, making it particularly suitable for long-term low-speed, heavy-load operation scenarios.

[0013] 2. In this invention, the brushless, slip-ring-free cascade speed control system (rotor side + 1 / 10 power electromagnetic coupler + high-frequency chopper) has extremely low grid pollution. The system only performs power conversion on the rotor side through a low-power (1 / 10 of the motor power) high-frequency chopper, while the main stator remains directly connected to the power frequency grid, avoiding direct disturbance to the grid by high-power power electronic devices. The rotor-side chopper has low power, and the harmonic current it generates is isolated by the electromagnetic coupler and attenuated by the motor stator impedance, resulting in extremely low harmonic content fed back to the grid. Typically, the grid current THD can be controlled within 5% (meeting the requirements of national standard GB / T 14549-1993). Cascade speed control, through feedback slip power, can improve the overall system power factor (usually close to 1), not only without consuming grid reactive power but also improving the grid power factor and reducing the investment in reactive power compensation equipment.

[0014] 3. In this invention, the brushless slip-ring-free cascade speed control system (rotor side + 1 / 10 power electromagnetic coupler + high frequency chopper) consumes less than one percent of its own power and does not pollute the power grid. Therefore, its power saving rate is higher than that of frequency converter speed control and dedicated frequency converter speed control for brushless doubly fed motors. Attached Figure Description

[0015] Figure 1 This invention presents a schematic diagram of the overall structure of a novel brushless, slip-free, spiral-rotor asynchronous motor.

[0016] Legend: 1. Motor fan cover; 2. Fan; 3. Motor end cover; 4. Bearing inner cover; 5. Bearing outer cover; 6. First bearing; 7. Bearing inner and outer cover fixing bolts; 8. Fan cover fixing bolts; 9. Motor end cover fixing bolts; 10. Motor housing; 11. Motor housing heat dissipation fins; 12. Lifting ring; 13. Motor stator core; 14. Motor rotor core; 15. Motor stator winding; 16. Motor rotor winding; 17. Motor rotor shaft; 18. 8.5 mm thick electromagnetic isolation disc; 19. Electromagnetic isolation disc fixing bolts; 20. Three-phase electromagnetic coupler stator winding; 21. Three-phase electromagnetic coupler rotor winding; 22. Three-phase electromagnetic coupler stator core; 23. Three-phase electromagnetic coupler rotor core; 24. Motor output shaft end bearing cover; 25. Bolt; 26. Motor output shaft; 27. Second bearing; 28. Motor base. Detailed Implementation

[0017] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0018] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways than those described herein, and therefore the invention is not limited to the specific embodiments disclosed in the following specification.

[0019] Example 1: As Figure 1As shown, the present invention provides a technical solution: a novel brushless, slip-free, wound-rotor asynchronous motor, comprising a fan 2 and a motor housing 10. An output shaft 26 is disposed inside the motor housing 10. A motor rotor core 14 is disposed on the side of the output shaft 26. A motor rotor shaft 17 is disposed on the output shaft 26. An 8.5 mm thick electromagnetic isolation disc 18 is symmetrically connected to the side of the output shaft 26. Electromagnetic isolation disc fixing bolts 19 are threaded onto the 8.5 mm thick electromagnetic isolation disc 18. A motor stator winding 15 is connected to the side of the motor rotor core 14. A motor stator core 13 is connected to the side of the motor stator winding 15. Motor rotor windings 16 are connected to both ends of the motor rotor core 14. A three-phase electromagnetic coupler rotor core 23 is disposed inside the motor housing 10. A three-phase electromagnetic coupler rotor winding 21 is disposed on the three-phase electromagnetic coupler rotor core 23. Three-phase electromagnetic coupler stator cores are symmetrically disposed inside the motor housing 10. 22. The stator core 22 of the three-phase electromagnetic coupler is connected to the stator winding 20 of the three-phase electromagnetic coupler at both ends. A second bearing 27 is provided on the outside of the motor output shaft 26. One end of the second bearing 27 is connected to the motor output shaft end bearing cover 24. The internal thread of the motor output shaft end bearing cover 24 is connected to the bolt 25. A motor fan cover 1 is provided on the outside of the fan 2. A motor base 28 is provided at the bottom of the motor fan cover 1. A fan cover fixing bolt 8 is connected to the motor fan cover 1. A motor end cover fixing bolt 9 is connected to the side of the motor housing 10. A motor housing heat dissipation fin 11 is provided on the outside of the motor housing 10. A lifting ring 12 is provided on the top of the motor fan cover 1. A first bearing 6 is provided inside the fan 2. A bearing inner cover 4 is connected to the side of the first bearing 6. A bearing outer cover 5 is provided on the outside of the bearing inner cover 4. A bearing inner and outer cover fixing bolt 7 is provided on the bearing outer cover 5. A motor end cover 3 is connected to the side of the bearing outer cover 5. The motor end cover 3 is connected to the motor housing 10.

[0020] In this embodiment, the three output terminals of the rotor winding of the wound-rotor motor are directly connected to the rotor winding 21 of the three-phase electromagnetic coupler. The output of the stator winding 20 of the three-phase electromagnetic coupler is modulated by the PLC to control the high-frequency chopper. The brushless slip-ring cascade speed control system (rotor side + 1 / 10 power electromagnetic coupler + high-frequency chopper) uses the high-frequency chopper to inverter control the feedback winding of the motor. Since its self-consumption is less than one percent and does not pollute the power grid, its energy saving rate is higher than that of frequency converter speed control and brushless doubly fed motor speed control using a dedicated frequency converter. Main motor: 15kW asynchronous motor (stator includes main winding + feedback winding, rotor is wound-rotor, no slip rings); Rotor side: The rotor slip electromotive force / current is converted into a feedback electrical signal through the electromagnetic coupler; Feedback loop: The output terminal of the electromagnetic coupler is rectified, modulated by the PLC, and then controls the high-frequency chopper. The output of the high-frequency chopper is connected to the stator feedback winding to realize slip power internal feedback.

[0021] The main parameters of the motor body are set as follows: rated power P_N=15kW, rated voltage U_{1N}=380V (stator main winding, Y connection), rated speed n_N≈1460r / min (slip s_N≈0.027); rated current I_{1N}≈30A (main winding), efficiency eta_N≈88%, power factor cos phi_N≈0.85; number of pole pairs p=2 (4 poles), stator core outer diameter D_1≈290mm, core length L≈150mm (compatible with the previous electromagnetic coupler); stator winding design (main winding + feedback winding) main winding (responsible for output) (Rated power input): Number of turns per phase in series N_1: According to the induced electromotive force formula U_{1ph}≈4.44fN_1K_{dp1}\Phi_m, f=50Hz,\Phi_m≈0.012Wb (magnetic flux), K_{dp1}=0.95 (winding coefficient), we get N_1≈180 turns; Conductor specifications: Current density J=3A / mm², current per phase I_{1ph}=30 / \sqrt{3}≈17.3A, conductor cross-sectional area A_1=17.3 / 3≈5.8mm², select\Phi2.8mm enameled wire (cross-sectional area 6.15mm²). Feedback winding (receiving slip power): The maximum feedback power is P_{s.max}=s_{max}P_N, and the speed range is taken as s_{max}=0.3 (minimum speed ≈1050r / min), therefore P_{s.max}=0.3×15=4.5kW, and the feedback winding power is designed accordingly; Voltage: Independent winding, Y-connected, line voltage U_{2N}=110V (low voltage adaptation feedback loop), phase voltage U_{2ph}≈63V; Number of turns N_ 2: Based on the voltage ratio U_{1ph} / U_{2ph}=N_1 / N_2, 220 / 63≈180 / N_2, we can solve for N_2≈52 turns; Wire specifications: Feedback current I_2=P_{s.max} / (\sqrt{3}U_{2N})≈4500 / (1.732×110)≈23.7A, cross-sectional area A_2=23.7 / 3≈7.9mm², select Phi3.2mm enameled wire (cross-sectional area 8.04mm²).Winding arrangement: The main winding and feedback winding adopt a "concentric slot arrangement" (the same stator slot is divided into upper and lower layers, with the main winding at the bottom and the feedback winding at the top), and the number of stator slots Z_1=36 (12 slots per phase, evenly distributed); Rotor winding design (brushless adaptation): The rotor is a wound type, star connection, connected to the previously designed electromagnetic coupler rotor winding (no slip rings, current is transmitted through electromagnetic induction); Rotor induced electromotive force (at rest) E_{20}≈200V (matching the electromagnetic coupler rotor input voltage), rotor rated current I_2≈35A (balanced with the main winding current); Number of turns N_2'≈60 turns (estimated based on the current ratio I_1N_1≈I_2N_2'), conductor specifications are the same as the feedback winding (\Phi3.2mm, or 2\Phi2.2mm wires wound in parallel).

[0022] The rotor winding output is not connected to a slip ring and is directly mechanically connected to the rotor winding of the electromagnetic coupler (rotating on the same axis). The slip electromotive force output from the stator winding of the electromagnetic coupler (rectified to DC) is adjusted by a high-frequency chopper (controlled by a PLC) to regulate the feedback power, and then converted into AC power (50Hz ± slip frequency) matching the frequency of the stator feedback winding by an inverter circuit, and fed into the feedback winding. Chopper frequency: 20kHz (high frequency reduces harmonics), duty cycle adjusted from 0-100%, corresponding to slip rate 0-0.35 (speed range 1460-949r / min). Rectifier / inverter module: 600V / 50A thyristor (or IGBT) is selected to adapt to a maximum feedback power of 4.5kW. Energy flow: rotor slip power → electromagnetic coupler → chopper / inverter → stator feedback winding → superimposed with the input power of the main winding to drive the motor (slip power is not wasted, improving efficiency).

[0023] Speed ​​range: Slip 0.027-0.35, corresponding to speeds of 1460-949 r / min (meets the speed control needs of most industries); Efficiency: Due to internal feedback of slip power (rather than resistive energy consumption), efficiency at low speeds is ≥80% (traditional series resistance speed control is only 50%-60%); Brushless reliability: Eliminating slip rings avoids brush wear and sparking problems, adapting to harsh environments such as dust and vibration. Main motor specifications: 15kW, 4 poles, 380V, Y-connection, rated speed 1460 r / min, stator main winding: 180 turns per phase, enameled wire, current 30A, stator feedback winding: 52 turns per phase, enameled wire, voltage 110V, maximum short-term feedback power 4.5kW. Rotor winding: 60 turns per phase, enameled wire, current 35A, no slip rings (connected to electromagnetic coupler). Speed ​​range: 949-1460 r / min (slip 0-0.35), efficiency ≥80% (low speed). This design achieves brushless slip power internal feedback through "stator dual winding + rotor electromagnetic coupling," retaining the high efficiency of cascade speed regulation while solving the slip ring maintenance problem of traditional wound-rotor motors. It is suitable for industrial speed regulation scenarios of 15kW motors. The three-phase electromagnetic coupler has a power of 1.8kW and a three-phase design. Assuming the stator core diameter, rotor core, and air gap are consistent with the motor, the stator core outer diameter D_1 is 280-320mm (take 290mm); the stator core inner diameter D_{i1} is 180-200mm. mm (take 190mm); Rotor core outer diameter D_2: consistent with the motor rotor, twice the size of the stator inner diameter in terms of air gap (air gap delta=0.3-0.5mm, take 0.4mm), so D_2=190-2×0.4=189.2mm; Core length L: 120-150mm (take 130mm); Stator slot number Z_1: 36 slots (three-phase, 12 slots per phase); Rotor slot number Z_2: 30 slots (conventional matching); Power supply frequency: because the coupler transmits the rotor slip electromotive force, the frequency varies with the slip rate (when the maximum s≤0.35, the frequency≤15Hz), designed for a low frequency of 15Hz.

[0024] Core material: Same as the motor, using silicon steel sheets (e.g., 50W250, low iron loss, suitable for low frequency), 0.5mm thick; Stator core: Tooth width b_{t1}: Calculated from the number of slots and inner diameter, b_{t1}=\frac{\pi D_{i1}}{Z_1}-b_{s1} (b_{s1} is the slot width, taken as 8-10mm), according to Z_1=36, D_{i1}=190mm, b_{t1}≈\frac{3.14×190}{36}-9≈16.5-9=7.5mm; yoke height h_{j1}:\frac{D_1-D_{i1}-2h_{s1}}{2} (h_{s1} is the slot height, taken as 25mm), h_{j1}≈\frac{290-190-2×25}{2}=15mm; rotor core: tooth width b_{t2}:\frac{\pi D_2}{Z_2}-b_{s2} (b_{s2} is the rotor slot width, taken as 7mm), when Z_2=30, b_{t2}≈\frac{3.14×189.2}{30}-7≈19.7-7=12.7, yoke height h_{j2}:\frac{D_2-D_{i2}}{2} (D_{i2} is the rotor inner diameter, taken as 100mm), h_{j2}≈\frac{189.2-100}{2}=44.6mm; magnetic flux density verification: at low frequency, the core magnetic flux density B_{Fe} can be slightly higher, taken as 1.4-1.6T (the motor is usually 1.2-1.4T). Because the coupler power is low and the magnetic flux is small, the existing core size (consistent with the motor) is fully satisfied and no adjustment is required.

[0025] Coupler power P = 1.8kW, three-phase apparent power S = P cos phi (cos phi is taken as 0.85), therefore S ≈ 1800 0.85 ≈ 2118VA; stator winding output voltage U_1: needs to match PLC input signal and chopper requirements, take low voltage signal level, let U_1 = 36V (three-phase line voltage), then phase voltage U_1ph = 36 ≈20.8V; Stator rated current I_1: I_1=\frac{S}{\sqrt{3}U_1}≈\frac{2118}{\sqrt{3}×36}≈34A; Rotor winding current I_2: Matches the motor rotor current (15kW motor rotor rated current I_{2N}≈30-40A), since the coupler rotor is connected to the motor rotor, take I_2=35A (to balance with I_1). Calculation of winding turns (derived from the stator side): Number of turns in series per phase N_1: According to the induced electromotive force formula U_{1ph}≈4.44fN_1K_{dp1}\Phi_m (K_{dp1} is the winding coefficient, taken as 0.95; \Phi_m is the magnetic flux per pole); First, calculate Phi_m: Given the core magnetic flux density B_{Fe} = 1.5T, and the area per pole A = \frac{\pi D_{i1}L}{2p} (assuming the number of pole pairs p = 2, i.e., 4 poles), A ≈ \frac{3.14×190×130}{2×2} ≈ 19428mm² = 0.0194m²; Phi_m = B_{Fe} × A = 1.5 × 0.0194 ≈ 0.0291Wb; Substituting into the voltage formula: 20.8 ≈ 4.44 × 15 × N_1 × 0.95 × 0.0291, we get N_1 ≈ \frac{20.8}{4.44 × 15 × 0.95 × 0.0291} ≈ \frac{20.8}{1.81} ≈ 11.5, take 12 turns / phase (number of turns per coil); Rotor winding turns N_2: Based on the current ratio (I_1N_1≈I_2N_2 under ideal coupling), N_2≈\frac{I_1N_1}{I_2}≈\frac{34×12}{35}≈11.6, take 12 turns / phase (symmetric to the stator, simplifying the design).

[0026] Stator winding: Connection: Star (Y connection), phase voltage 20.8V matched with 36V line voltage; winding type: short-pitch distributed winding (consistent with the motor, slot pitch angle alpha=20°, take pitch y=8 / 9, increase K_{dp1}); Conductor specifications: Current density J = 2.5-3 A / mm² (slightly lower at low frequencies), stator conductor cross-sectional area A_1 = I_1 J ≈ 342.5 = 13.6 mm², select multi-strand copper conductor (e.g., 2 × Φ2.9 mm, cross-sectional area 2 × 6.6 = 13.2 mm², close to the calculated value), number of conductors per slot = 2N_1 / Z_1 × 3 = 2 × 12 / 12 = 2 (12 slots per phase, 2 conductors per slot); Rotor winding: Connection method: Same as the motor rotor winding (usually star connection), directly connected to the motor rotor winding; Wire specifications: A_2=\frac{I_2}{J}≈\frac{35}{2.5}=14mm², select Φ3.0mm single-strand copper wire (cross-sectional area 7.07mm², if the current is 35A, 2 wires are needed to be wound in parallel, with a total cross-sectional area of ​​14.14mm²), the number of conductors per slot matches the stator (take 2). Core material: 50W250 silicon steel sheet, thickness 0.5mm.

[0027] Stator core dimensions: outer diameter 290mm, inner diameter 190mm, length 130mm, 36 slots. Rotor core dimensions: outer diameter 189.2mm, inner diameter 100mm, length 130mm, 30 slots. Air gap 0.4mm (consistent with the motor). Stator windings are Y-connected, 12 turns per phase, short-pitch distributed windings, 2×Φ2.9mm copper wires, 2 conductors per slot. Rotor windings are Y-connected, 12 turns per phase, connected to the motor rotor windings, 2×Φ3.0mm copper wires (parallel winding), 2 conductors per slot. Rated power / voltage / current: 1.8kW, stator line voltage 36V, stator current 34A, rotor current 35A.

[0028] The working principle of this embodiment is as follows: During use, the output end of the rotor winding is not connected to the slip ring, but is directly mechanically connected to the rotor winding of the electromagnetic coupler (rotating on the same axis); the slip electromotive force output by the stator winding of the electromagnetic coupler (which is rectified to DC) is adjusted by a high-frequency chopper (controlled by PLC) to adjust the feedback power, and then converted into AC power (50Hz ± slip frequency) that matches the frequency of the stator feedback winding by the inverter circuit, and sent to the feedback winding. The stator winding 15 of the motor is designed with two sets of windings. The main winding and the feedback winding are arranged in a concentric slot (the same stator slot is divided into upper and lower layers, with the main winding below and the feedback winding above). An insulating layer is placed between the main winding and the feedback winding. The three-phase output terminal of the motor rotor winding 16 is directly connected to the input terminal of the three-phase electromagnetic coupler rotor winding 21. The low-voltage AC electromotive force output by the three-phase electromagnetic coupler stator winding 20, which is in the same frequency as the induced electromotive force of the motor rotor, is rectified and fed to the PLC to control the high-frequency chopper. The modulated power output from the high-frequency chopper is then inverted into AC power and input to the motor feedback winding, realizing the closed-loop control of the brushless, slip-free, wound-rotor asynchronous motor with high-frequency chopper series pole stepless speed regulation. A carbon fiber disk with an electromagnetic isolation layer is installed on the motor rotor shaft 17.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A new type of brushless, slip-ring-free, wound rotor asynchronous motor comprising a fan (2) and a motor housing (10), characterized in that: The inside of the motor shell (10) is provided with a motor output shaft (26), the side of the motor output shaft (26) is provided with a motor rotor core (14), the motor output shaft (26) is provided with a motor rotor shaft (17), the side of the motor output shaft (26) is symmetrically connected with an 8.5mm thick electromagnetic isolation disc (18), the 8.5mm thick electromagnetic isolation disc (18) is threadedly connected with an electromagnetic isolation disc fixing bolt (19), the side of the motor rotor core (14) is connected with a motor stator winding (15), the side of the motor stator winding (15) is connected with a motor stator core (13), the both ends of the motor rotor core (14) are connected with a motor rotor winding (16), the inside of the motor shell (10) is provided with a three-phase electromagnetic coupler rotor core (23), the three-phase electromagnetic coupler rotor core (23) is provided with a three-phase electromagnetic coupler rotor winding (21), the inside of the motor shell (10) is symmetrically provided with a three-phase electromagnetic coupler stator core (22), the both ends of the three-phase electromagnetic coupler stator core (22) are connected with a three-phase electromagnetic coupler stator winding (20).

2. A novel brushless, slip-ringless, wound rotor asynchronous electric motor according to claim 1, characterized in that: The outside of the motor output shaft (26) is provided with a second bearing (27), one end of the second bearing (27) is connected with a motor output shaft end bearing gland (24), the inside of the motor output shaft end bearing gland (24) is threadedly connected with a bolt (25).

3. The novel brushless, slip-ringless, wound rotor asynchronous electric motor as claimed in claim 1, wherein: The outside of the fan (2) is provided with a motor fan cover (1), the bottom of the motor fan cover (1) is provided with a motor base (28).

4. A novel brushless, slip-ringless, wound rotor asynchronous electric motor according to claim 3, characterized in that: The motor fan cover (1) is connected with a fan cover fixing bolt (8), the side of the motor shell (10) is connected with a motor end cover fixing bolt (9).

5. The novel brushless, slip-ringless, wound rotor asynchronous electric motor as claimed in claim 3, wherein: The outside of the motor shell (10) is provided with a motor shell heat dissipation rib (11), the top of the motor fan cover (1) is provided with a lifting ring (12).

6. The novel brushless, slip-ringless, wound rotor induction motor of claim 1, wherein: The inside of the fan (2) is provided with a first bearing (6), the side of the first bearing (6) is connected with a bearing inner cover (4), the outside of the bearing inner cover (4) is provided with a bearing outer cover (5), the bearing outer cover (5) is provided with a bearing inner and outer cover fixing bolt (7), the side of the bearing outer cover (5) is connected with a motor end cover (3), the motor end cover (3) is connected with the motor shell (10).

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