CN104201849A - Separable transformer type double-stator brushless double-fed motor - Google Patents

Abstract

The invention discloses a separable transformer-type double-stator brushless double-fed motor. A separable transformer-type double-stator brushless double-fed motor comprises an outer stator, a cup-shaped rotor, an inner stator and a rotating shaft in sequence from outside to inside; The outer stator, the cup-shaped rotor and the inner stator are coaxial and independent of each other, and the rotor is fixed on the rotating shaft; an outer air gap is provided between the outer stator and the cup-shaped rotor, and an inner air gap is provided between the rotor and the inner stator; the present invention Separable transformer double-stator brushless double-fed motor is a new type of motor structure based on the operating principle of brushed double-fed motor through structural equivalence. The separable transformer composed of the inner layer of the rotor and the inner stator transmits the rotor current and voltage of the doubly-fed motor to the inner stator side in a non-contact manner, thereby fully realizing the function of the brush doubly-fed motor, but canceling the brush doubly-fed motor It is a brush slip ring with low reliability and needs regular maintenance, so it has a good application value in high reliability, maintenance-free, low-cost frequency conversion speed regulation occasions.

Description

A separable transformer-type double-stator brushless double-fed motor

technical field

The invention relates to the field of brushless motors, in particular to a double-stator brushless double-fed motor with separable transformers.

Background technique

The traditional doubly-fed motor is a wound-rotor asynchronous motor, and the rotor winding rotates with the rotor. The voltage and current in the rotating winding must be led out by conduction through the use of brush slip rings. Therefore, the doubly-fed motor has two electrical ports and one mechanical port, has good frequency conversion and speed regulation performance, and is widely used in megawatt-level wind power generation systems and high-performance drives. However, the existence of the brush slip ring leads to poor reliability of the motor and high maintenance costs. The de-energization and brushing of brushed doubly-fed motors has always been the focus of people's research.

Patent Publication No. CN102163896A provides a brushless doubly-fed motor, the surface of the stator and the rotor core close to the air gap are punched with slots along the axial direction and the circumferential direction. The power winding is placed in the slot parallel to the axis, and the control winding is placed in the slot parallel to the circumferential direction. The stator power winding and the rotor power winding constitute the winding asynchronous motor subsystem to realize electromechanical energy conversion; the stator control winding and the rotor control winding constitute the transformer subsystem to realize the brushless adjustment function of the frequency and amplitude of the excitation power supply applied to the rotor power winding. However, since the stator core and the rotor core are multiplexed by the power winding magnetic field and the control winding magnetic field, the iron core is easily saturated. Once the iron core is saturated, the power winding and the control winding will be coupled to each other, increasing the difficulty of control. Secondly, due to the existence of slots parallel to the axial direction, the distribution of the magnetic field of the control winding along the circumferential direction is no longer uniform, but is related to the relative position between the rotor and the stator. As the rotor spins, the transformer subsystem generates a periodic torque component that degrades the motor's torque output. At the same time, the axial slot will increase the equivalent air gap length and reduce the transmission capacity of the transformer subsystem.

Contents of the invention

Purpose of the invention: In order to solve the problem of brush slip rings in traditional doubly-fed motors, a separable transformer in the field of non-contact power transmission is introduced into doubly-fed motors, and a separable transformer-type double-stator brushless doubly-fed motor is proposed. The deficiencies of the prior art are solved.

Technical solution: A separable transformer-type double-stator brushless double-fed motor, which is characterized in that it includes an outer stator, a cup-shaped rotor, an inner stator, and a rotating shaft from the outside to the inside; the outer stator, the cup-shaped rotor, and the inner stator are coaxial And independent of each other, the rotor is fixed on the rotating shaft; an outer air gap is provided between the outer stator and the cup-shaped rotor, and an inner air gap is provided between the rotor and the inner stator;

The outer stator includes the outer stator core and the outer stator winding from the outside to the inside;

The cup-shaped rotor includes the outer core of the rotor, the axial support of the rotor and the inner core of the rotor in sequence from the outside to the inside; the outer core of the rotor includes the outer winding of the rotor embedded in the outer rotor core; the inner core of the rotor includes The rotor inner winding;

The inner stator includes the inner stator winding and the inner stator core sequentially from outside to inside;

Among them, the outer stator winding and the outer winding of the rotor are arranged along the axial direction, which is a 2p pole distributed winding; the inner stator winding and the inner winding of the rotor are annular concentrated windings, arranged along the circumferential direction; the outer stator winding and the inner stator winding are respectively The two feed ports of the motor; the outer stator core and rotor outer core are evenly slotted along the axial direction, and the inner stator core and rotor inner core are evenly slotted along the circumferential direction, and the slots are concentric with the shaft.

Specifically, the speed of the brushless doubly-fed motor is jointly determined by the electrical frequency and the number of pole pairs of the two sets of stator windings. The two sets of stator windings are respectively the inner stator winding and the outer stator winding; Electric frequency realizes motor speed adjustment.

Specifically, the speed n _r of the separable transformer-type double-stator brushless doubly-fed motor, the frequency f _p of the current in the inner stator winding, and the frequency f _q of the outer stator winding and the middle current satisfy the relationship:

${\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; p</span>}}$

In the formula, p is the number of magnetic pole pairs.

Specifically, the axial support of the rotor is a cup-shaped mechanical support device.

Beneficial effect:

The separable transformer-type double-stator brushless doubly-fed motor of the present invention is a novel motor structure based on the operation principle of the brushed doubly-fed motor and proposed through structural equivalence. The separable transformer in the field of non-contact power transmission is introduced into the doubly-fed motor, and the separable transformer composed of the inner layer of the rotor and the inner stator transmits the rotor current and voltage of the doubly-fed motor to the inner stator side in a non-contact manner, thereby It fully realizes the functions of the brush double-fed motor, but cancels the brush slip ring in the brush double-fed motor which has low reliability and needs regular maintenance, and the motor speed can be adjusted flexibly only by changing the electrical frequency of the stator winding. Therefore, it has good application value in the occasions of high reliability, maintenance-free, and low-cost frequency conversion speed regulation.

The slots on the traditional inner stator core and rotor inner core are axial slots, and the silicon steel sheets need to be stamped or wire-cut into laminations that are evenly slotted along the circumferential direction, and then laminated along the axial direction with a fixed length or a fixed number into iron heart. At the same time, the axial slot will increase the equivalent air gap length and reduce the transmission capacity of the transformer subsystem. However, the present invention adopts slotting along the circumferential direction, and only needs to stamp or wire-cut the silicon steel sheets into rings with different inner diameters, and then stack them along the axial direction to form iron cores, and the process is simple. Moreover, the tangential force between the transformer primary and secondary is zero, and no additional torque ripple will be generated.

The axial support of the rotor is located between the outer core and the inner core of the rotor. It is made of materials with poor magnetic and conductive properties but high mechanical strength, such as austenitic stainless steel. It also supports and isolates the magnetic field. Therefore, the power The winding magnetic field and the control winding magnetic field are spatially isolated from each other and functionally independent of each other. At the same time, due to the double air gap structure, the width of the two air gaps can be designed separately, because the outer air gap is used for electromechanical energy conversion and needs to be appropriately larger (0.5-0.7mm) to reduce torque ripple; while the inner layer The air gap is used for non-contact energy transmission, and it needs to be as small as possible (0.3-0.5mm) to increase the coupling inductance between the primary and secondary and improve the energy transmission efficiency.

Description of drawings

Fig. 1 is a schematic cross-sectional view of the present invention.

Fig. 2 is a schematic diagram of the structure of the rotor of the present invention.

Fig. 3 is a schematic diagram of the structure of the inner stator of the present invention.

In the figure, 1 is the outer stator core, 2 is the outer stator winding, 3 is the outer core of the rotor, 4 is the outer winding of the rotor, 5 is the axial support of the rotor, 6 is the inner core of the rotor, and 7 is the inner winding of the rotor. 8 is the rotor radial air duct, 9 is the inner stator core, 10 is the inner stator winding, and 11 is the inner stator radial air duct.

Detailed ways

The present invention will be further explained below in conjunction with the accompanying drawings.

As shown in Figure 1, a separable transformer-type double-stator brushless double-fed motor includes an outer stator, a cup-shaped rotor, an inner stator, and a rotating shaft from the outside to the inside; the outer stator, the cup-shaped rotor, and the inner stator are coaxial and Independent of each other, the rotor is fixed on the rotating shaft as the only mechanical port of the motor; there is an outer air gap between the outer stator and the cup-shaped rotor, and an inner air gap between the rotor and the inner stator;

The outer stator includes the outer stator core 1 and the outer stator winding 2 from the outside to the inside, and the outer stator core is made of laminated silicon steel sheets;

As shown in Figure 2, the cup-shaped rotor includes the rotor outer core 3, the rotor axial support 5 and the rotor inner core 6 from the outside to the inside; the rotor outer core 3 includes the rotor outer winding 4 embedded in the outer rotor core ; The rotor inner layer iron core 6 includes the rotor inner layer winding 7 embedded in the outer rotor iron core; the rotor outer layer winding 4 and the rotor inner layer winding 7 are correspondingly connected. The rotor axial support 5 is a cup-shaped mechanical support device. The inner and outer cores of the rotor are made of laminated silicon steel sheets. The axial support of the rotor is made of materials with poor electrical and magnetic properties but high mechanical strength, such as austenitic stainless steel.

As shown in Fig. 3, the inner stator includes an inner stator core 9, an inner stator winding 10 is embedded in the inner stator core 9, and the inner stator core is formed by laminating silicon steel sheets;

As shown in FIG. 2 , there are two rotor radial air passages 8 passing through the rotor inner iron core 6 on the rotor inner iron core 6 , and the rotor radial air passages 8 are perpendicular to the axial direction.

As shown in FIG. 3 , there are two inner stator radial ventilation passages 11 passing through the inner stator core 9 on the inner stator core 9 , and the inner stator radial ventilation passages 11 are perpendicular to the axial direction.

Among them, the outer stator winding 2 and the rotor outer winding 4 are arranged axially, which are 2p pole distributed windings; the inner stator winding 10 and the rotor inner winding 7 are annular concentrated windings, arranged along the circumferential direction; the outer stator winding 2 and The inner stator windings 10 are respectively the two feed ports of the motor; the outer stator core 1 and the rotor outer core 3 are evenly slotted along the axial direction, and the inner stator core 9 and the rotor inner layer iron core 6 are evenly slotted along the circumferential direction. Concentric with axis.

The speed of the brushless double-fed motor is determined by the electrical frequency and the number of pole pairs of the two sets of stator windings. The two sets of stator windings are the inner stator winding 10 and the outer stator winding 2; Realize motor speed regulation. The rotational speed n _r of the motor and the frequency f _p of the current in the inner stator winding 10, and the frequency f _q of the outer stator winding 2 and the middle current satisfy the relationship:

${\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; p</span>}}$

In the formula, p is the number of magnetic pole pairs.

This speed formula is similar to the speed formula of doubly-fed motor, the difference is that the separable transformer can only transmit AC voltage and current, but cannot work at synchronous speed When the motor rotates,

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (4)

1. A separable transformer-type dual-stator brushless doubly-fed motor, characterized in that it comprises an outer stator, a cup-shaped rotor, an inner stator and a rotating shaft from outside to inside; the outer stator, the cup-shaped rotor and the inner stator are coaxial and Independent of each other, the rotors are fixed on the rotating shaft; an outer air gap is provided between the outer stator and the cup-shaped rotor, and an inner air gap is provided between the rotor and the inner stator; The outer stator includes the outer stator core and the outer stator winding from the outside to the inside; The cup-shaped rotor includes the outer core of the rotor, the axial support of the rotor and the inner core of the rotor in sequence from the outside to the inside; the outer core of the rotor includes the outer winding of the rotor embedded in the outer rotor core; the inner core of the rotor includes The rotor inner winding; The inner stator includes the inner stator winding and the inner stator core sequentially from outside to inside; Among them, the outer stator winding and the outer winding of the rotor are arranged along the axial direction, which is a 2p pole distributed winding; the inner stator winding and the inner winding of the rotor are annular concentrated windings, arranged along the circumferential direction; the outer stator winding and the inner stator winding are respectively The two feed ports of the motor; the outer stator core and rotor outer core are evenly slotted along the axial direction, and the inner stator core and rotor inner core are evenly slotted along the circumferential direction, and the slots are concentric with the shaft. 2. A separable transformer-type dual-stator brushless doubly-fed motor as claimed in claim 1, wherein the speed of the brushless doubly-fed motor is determined jointly by the electric frequency and the number of pole pairs of the two sets of stator windings, The two sets of stator windings are the inner stator winding and the outer stator winding respectively; the motor speed adjustment is realized by changing the electrical frequency of one or both sets of windings. 3. A kind of separable transformer-type double-stator brushless doubly-fed motor as claimed in claim 2, characterized in that, the rotational speed nr of said separable transformer-type double-stator brushless doubly-fed motor is related to the current in the inner stator winding The frequency f _p , the frequency f _q of the outer stator winding and the medium current satisfy the relationship: ${\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; p</span>}}$ In the formula, p is the number of magnetic pole pairs. 4. A separable transformer-type double-stator brushless doubly-fed motor as claimed in claim 1, wherein the axial support of the rotor is a cup-shaped mechanical support device.