CN100345358C

CN100345358C - Permanent magnet synchronous motor for shielded pump

Info

Publication number: CN100345358C
Application number: CNB2005100469354A
Authority: CN
Inventors: 唐任远; 安忠良; 马鑫; 赵清
Original assignee: Shenyang University of Technology
Current assignee: Shenyang University of Technology
Priority date: 2005-07-27
Filing date: 2005-07-27
Publication date: 2007-10-24
Anticipated expiration: 2025-07-27
Also published as: CN1734884A

Abstract

The present invention relates to a permanent magnet synchronous motor for shielding a pump, which belongs to the technical field of a motor. The present invention comprises a front and a back bearing chambers, bearings arranged in the front and the back bearing chambers, bearing sleeves, a shaft, a rotor and a stator, wherein the rotor comprises a rotor shielded sleeve, a rotor core, a rotor baffle plate, an auxiliary impeller, a permanent magnet and a permanent magnet baffle plate; a permanent magnet slot is arranged in the rotor core along the tangential direction of a rotating shaft, and the permanent magnet is embedded in the permanent magnet slot and is fixed by the permanent magnet baffle plate; the permanent magnet slot is positioned inside a rotor slot, and a magnetism separation magnetic bridge is arranged between the permanent magnet slot and the rotor slot. The present invention overcomes the shortcoming of low efficiency of the existing induction motor, and has the characteristics of simple structure, high motor efficiency, high power factor, large power density, high overload capacity, low temperature rise, little noise, high reliability during long high-temperature operation, no leakage, explosion resistance, corrosion resistance, corrosion prevention, etc.

Description

The permanent magnet synchronous motor that is used for canned pump

Technical field

The present invention relates to the motor technology field, particularly a kind of permanent magnet synchronous motor that is used for canned pump.

Background technology

At present, be widely used in oil, chemical industry, light industry, the induction motor of medical industry, its structure comprises front and back bearings chamber and inner bearing and bearing holder (housing, cover) thereof, axle, rotor and rotor shielding sleeve, stator and stator can, though realized the effect of shielding, make and have corrosivity, hypertoxicity, radioactivity, inflammable and explosive, materials such as volatile and high-temp liquid do not expose fully, but because there is housing in motor internal, thereby the air gap of motor is bigger, all the induction motor than same specification is low to make the power factor of motor and efficient, rated current is big, thereby does not reach energy-conservation effect.And industrial used permanent magnet synchronous motor, the patent No. is the permanent magnet synchronous motor that ZL00252880.0 discloses a kind of high ability of pulling in, its architectural feature is: radially-arranged permanent magnet embeds in the permanent magnet trough of rotor core, permanent magnet trough is positioned at the rotor below, has every the magnetic magnetic bridge between two grooves.The ability of pulling in of this motor is strong, and its power factor and efficient all increase, but there is not housing in motor internal, can not realize the effect that shields.

Summary of the invention

In order to solve the problem of above-mentioned existence, the object of the present invention is to provide a kind of permanent magnet synchronous motor that is used for canned pump, it will shield the architectural feature of induction motor and the architectural feature of permanent magnet synchronous motor combines, on the shielding induction motor, increase permanent magnet, the efficient of motor and power factor are improved.

The present invention is used for the permanent magnet synchronous motor of canned pump, comprise front and back bearings chamber and inner bearing thereof and bearing holder (housing, cover), axle, rotor, stator, rotor portion comprises rotor shielding sleeve, rotor core, rotor baffle plate, accessory impeller, also comprise permanent magnet and permanent magnet baffle plate, tangentially have a permanent magnet trough in rotor core inside along rotating shaft, permanent magnet embeds in the permanent magnet trough, fixes with the permanent magnet baffle plate; Permanent magnet trough is positioned at rotor inside, has between two grooves every the magnetic magnetic bridge; Periphery in rotor core is provided with rotor shielding sleeve, in rotor core and end, permanent magnet two ends the rotor baffle plate is set.In order to improve the utilance of permanent magnet, reduce leakage field, on the width of rotor notch, make corresponding change, the width br0 that makes the rotor notch is 1.4～1.9mm; Size every magnetic magnetic bridge length c should guarantee to consider mechanical strength simultaneously that between 1.15～1.2mm the distance b between permanent magnet trough should guarantee between 1.5～1.75mm; If the wide a of rotor bottom land can not guarantee certain size in addition, even the size of d is littler, also will significantly descending of magnetic bridge every the magnetic effect, but after a reaches a certain size, no longer include significant change every the magnetic effect, and excessive a will make the mechanical strength of rotor descend, so the size of a is comparatively suitable between 2.5～4.5mm, satisfies the motor performance requirement.

The selected permanent magnetic material of the present invention is a Nd-Fe-Bo permanent magnet material, the maximum degaussing of permanent magnet working point is the working point of motor permanent magnet under maximum degaussing working condition, in the design of electrical motor process, the scope of this working point should be used Nd-Fe-Bo permanent magnet material demagnetization curve flex point a when maximum operating temperature _Mk110%～150%, otherwise permanent magnet may demagnetize, motor can't operate as normal.

Advantage of the present invention is that magnetic circuit is a radial structure, and this is simple in structure, leakage field is less, because the restriction in space, it is special in the magnetic mode to take, reduce to increase magnetic resistance, leakage field is reduced, use less Nd-Fe-B permanent magnet can provide motor required air gap flux density every the size of magnetic bridge.The present invention improves the whole efficiency of electric pump, utilize Nd-Fe-Bo permanent magnet material, make electric efficiency height, power factor height and power density is big, overload capacity is strong, and temperature rise is low, noise is little, long term high temperature when operation reliability height do not have characteristics such as reveal, explosion-proof, anti-corrosion, anticorrosion, and the present invention can be 200 ℃ of normal down operation.

Description of drawings

Fig. 1 is rotor punching figure of the present invention;

Fig. 2 is a rotor structural representation of the present invention;

Fig. 3 is of the present invention every magnetic magnetic bridge structural representation, and wherein a is a rotor bottom land width, and b is the distance between permanent magnet trough, and c is every magnetic magnetic bridge length;

Fig. 4 is an overall structure schematic diagram of the present invention;

Working point coordinate schematic diagram when Fig. 5 is permanent magnet zero load of the present invention, fully loaded and maximum degaussing, magnetic field intensity when wherein e is nominal load, magnetic field intensity when f produces the permanent magnet degaussing, transverse axis is the magnetic field intensity (H) of permanent magnet, the longitudinal axis is the magnetic flux density (B) of permanent magnet;

Fore bearing chamber 1 among the figure, 2 reinforcing rings, 3 stator winding, 4,5 stator cans, 6 rotor shielding sleeves, 7 stator cores, 8 supports, 9 rotor cores, 10 permanent magnets, 11 permanent magnet baffle plates, 12 rotor baffle plates, 13 accessory impellers, 14 terminal boxes, 15 bearings, 16 bearing holder (housing, cover)s, 17 flanges,

rear bearing chambers

18,19 permanent magnet trough, α _MkBe the flex point of permanent magnet, α _MhBe maximum degaussing working point, α _MNBe fully loaded working point, α _M0Be the unloaded operation point.

Embodiment

Further narrate content of the present invention below in conjunction with drawings and Examples:

Mechanical structure rotor core of the present invention 9 inside are provided with outside the permanent magnet 10, and all the other structures are identical with squirrel-cage induction motor.As shown in Figure 3: comprise fore bearing chamber 1, rear bearing chamber 18 and inner bearing 15 thereof and bearing holder (housing, cover) 16, axle 4, rotor, stator, the periphery of axle 4 is provided with rotor, stator successively, rotor portion comprises rotor shielding sleeve 6, rotor core 9, rotor baffle plate 12, accessory impeller 13, also comprise permanent magnet 10, permanent magnet baffle plate 11, radially have permanent magnet trough 19 in rotor core 9 inside, permanent magnet 10 embeds in the permanent magnet trough 19 (rotor punching figure as shown in Figure 1), and is fixing with permanent magnet baffle plate 11; Permanent magnet trough 19 is positioned at rotor inside, has every the magnetic magnetic bridge between two grooves.Permanent magnet 10 adopts Nd-Fe-Bo permanent magnet material.The periphery of rotor core 9 is provided with rotor shielding sleeve 6, and rotor core 9 and end, permanent magnet 10 two ends are provided with rotor baffle plate 12, and

rotor shielding sleeve

6 and 12 girth weldings of rotor baffle plate are provided with accessory impeller 13 between the bearing of rotor baffle plate 12 and rear bearing chamber 18.The housing material of rotor, stator is non-magnetic stainless steel 1Cr18Ni9Ti, and its thickness is 0.5mm, and utilizes inferior welding technology, rotor, the stator coil of motor is shielded, to satisfy the requirement of motor to shielding.Low in order to solve motor efficiency, adopt the Nd-Fe-B permanent magnetic rotor.For reducing cost, rotor adopts the mode of cast aluminium.Stator is formed and is comprised stator core 7, stator winding 3, stator can 5, flange 17, support 8.The shaft of motor material is the round steel of 1Cr17Ni2, and bearing 15 and bearing holder (housing, cover) 16 adopt artificial synthetic Inorganic Non-metallic Materials SiC; In design process, the draw ratio of motor is got bigger, reduces housing loss that the stator and rotor housing brought and the sassafras loss that rubs that is brought by liquid thus.

Because permanent magnet is neighbouring every the existence of magnetic magnetic bridge and the influence of magnetic groove, interaction between the permanent magnet and the magnetomotive effect of friendship armature axis, armature magnetomotive force is uneven to the demagnetizing effect of permanent magnet, so the working point of each several part permanent magnet is also inequality in the motor.Local loss of excitation may take place down in maximum armature magnetomotive force effect, the reduction motor properties, thus further cause the whole loss of excitation of motor, make the motor can't operate as normal.Working point when being the zero load of permanent magnet, fully loaded and maximum degaussing as Fig. 5 will guarantee that motor does not cause the irreversible demagnetization of permanent magnet under maximum armature magnetomotive force effect, will guarantee the maximum degaussing working point 150%a of permanent magnet in design process _Mk＞a _Mh＞110%a _Mk

Definite method of the maximum degaussing of permanent magnet working point may further comprise the steps:

(1), obtains maximum demagnetizing current I when disregarding winding resistance _h(A)

I_{h} = \frac{E_{0} + U}{X_{d}}

E in the formula ₀-unloaded back electromotive force per unit value, U-input voltage per unit value, X _d-d-axis reactance, A-is the current unit ampere;

(2), obtain when taking into account winding resistance stator current (A)

I_{h} = \frac{E_{0} X_{d} + \sqrt{E_{0}^{2} X_{d}^{2} - (R_{1}^{2} + X_{d}^{2}) (E_{0}^{2} - U^{2})}}{R_{1}^{2} + X_{d}^{}}

E in the formula ₀-unloaded back electromotive force per unit value, U-input voltage per unit value, X _d-d-axis reactance, R ₁-stator resistance, A-are the current unit ampere;

(3) with (2) step gained stator current I _bThe direct-axis current I that replacement is used in electromagnetism calculates _d, the permanent magnet working point that draws thus is the maximum degaussing working point of permanent magnet, in conjunction with the electromagnetic field numerical algorithm, directly obtains the distribution situation of permanent magnet working point:

The maximum degaussing working point b of permanent magnet _Mk:

b_{mh} = \frac{λ_{n} (1 - {f^{'}}_{adh})}{λ_{n} + 1}

{f^{'}}_{adh} = \frac{0.45 m K_{dp} {NI}_{h}}{P σ_{0} H_{c} h_{M} \times 10}

I_{h} = \frac{E_{0} X_{d} + \sqrt{{E_{0}}^{2} {X_{d}}^{2} - ({R_{1}}^{2} + {X_{d}}^{2}) ({E_{0}}^{2} - U^{2})}}{{R_{1}}^{2} + {X_{d}}^{2}}

In the formula: λ _nThe total magnetic conductance per unit value of-external magnetic circuit, f ' _Abh-maximum demagnetization magnetic potential per unit value, the m-number of phases, K _Dp-winding factor, the N-number of turn that whenever is in series, I _hStator current per unit value during-starting, p-number of pole-pairs, σ ₀-magnetic leakage factor, H _c-calculating coercive force, h _M-permanent magnet magnetization direction thickness, E ₀-unloaded back electromotive force per unit value, U-input voltage per unit value, X _d-d-axis reactance, R ₁-stator resistance.

Claims

1, a kind of permanent magnet synchronous motor that is used for canned pump, comprise front and back bearings chamber and inner bearing thereof and bearing holder (housing, cover), axle, rotor, stator, rotor portion comprises rotor shielding sleeve, rotor core, rotor baffle plate, accessory impeller, it is characterized in that rotor portion also comprises permanent magnet and permanent magnet baffle plate, tangentially have a permanent magnet trough in rotor core inside along rotating shaft, permanent magnet embeds in the permanent magnet trough, fixes with the permanent magnet baffle plate; Permanent magnet trough is positioned at the rotor bottom, has between two grooves every the magnetic magnetic bridge; Periphery in rotor core is provided with rotor shielding sleeve, in rotor core and end, permanent magnet two ends the rotor baffle plate is set.

2, the permanent magnet synchronous motor that is used for canned pump according to claim 1 and 2, the width that it is characterized in that described rotor notch is 1.4～1.9mm.

3, the permanent magnet synchronous motor that is used for canned pump according to claim 1, it is characterized in that described size range every the magnetic magnetic bridge: rotor bottom land wide (a) is 2.5～4.5mm, distance between permanent magnet trough (b) is 1.5～1.75mm, is 1.15～1.2mm every magnetic magnetic bridge length (c).

4, the permanent magnet synchronous motor that is used for canned pump according to claim 1 is characterized in that described permanent magnetic material is a Nd-Fe-Bo permanent magnet material.

5, the permanent magnet synchronous motor that is used for canned pump according to claim 1, the scope that it is characterized in that the maximum degaussing of described permanent magnet working point be used Nd-Fe-Bo permanent magnet material when maximum operating temperature the demagnetization curve flex point 110%～150%.