CN1050955A

CN1050955A - High-performance rare-earth permanent-magnetic synchronous motor

Info

Publication number: CN1050955A
Application number: CN 89102453
Authority: CN
Inventors: 朱震莲
Original assignee: NANJING COLLEGE OF AERONAUTICS
Current assignee: NANJING COLLEGE OF AERONAUTICS
Priority date: 1989-10-07
Filing date: 1989-10-07
Publication date: 1991-04-24

Abstract

A kind of high-performance rare-earth permanent-magnetic synchronous motor since at the permanent magnet outside device magnetic pole pole shoe, the permanent magnet both sides are provided with permanent magnet degaussing winding, and heterogeneous bridge rectifier is set, make motor in starting process, weaken the moment of resistance that the permanent magnet magnetic place produces, overcome the difficulty of electric motor starting.When motor pulled in speed, the demagnetizing effect of degaussing winding for permanent magnet disappeared, and has guaranteed working performance of permanent magnet.This motor volume is little, and is in light weight, no excitation loss, and the general asynchronous motor of power ratio is high by 4～10%, and cos  is connected to 1, and stabilization of speed, alternative existing partial asynchronous motor.

Description

High-performance rare-earth permanent-magnetic synchronous motor

High-performance rare-earth permanent-magnetic synchronous motor belongs to electrical field.

Permanent magnet synchronous motor has energy index (efficiency eta, power factor cos ψ) height, and characteristics simple in structure, easy to maintenance are a kind of usefulness height, broad-spectrum energy-saving motor.

Because rare earth permanent-magnetic material has high remanent magnetism Br, three high characteristics of high-coercive force Hc and high energy product (BH), the ratio, efficiency eta and the power factor cos ψ that make the power of motor and weight are all than general asynchronous machine height, and stabilization of speed, and be only relevant with mains frequency.But this STARTING OF PERMANENT MAGNET SYNCHRONOUS MOTORS poor performance.All adopt squirrel-cage bar or magnetic hysteresis asynchronous starting at present, pull in then.In starting process, before synchronous speed, the moment that permanent magnetic field produces is opposite with the asynchronous moment direction of asynchronous starting, becomes the starting reactance square.Permanent magnetic field is stronger, and its moment of resistance is bigger, has a strong impact on the starting of motor, even makes starting torque have depressed phenomenon.Thereby become the emphasis of domestic and international vast scholar's research.But research up to now by way of mainly being by optimal selection squirrel-cage bar and magnetic structure size, improve asynchronous moment, but just all improve to starting performance, solve as yet at all.

The objective of the invention is to make permanent magnet motor in starting process, weaken the moment of resistance that permanent magnetic field produced, when pulling in, make this weakening effect Lock-out again, recover permanent magnetic field, enter synchronous operation, thereby obtain high starting performance, fundamentally solve the problem that the across-the-line starting of permanent magnet synchronous motor electrical network exists.

Characteristics of the present invention are that rotor permanent magnet (magnet steel) embeds the built-in type structure in the rotor core, and outside device main pole pole shoe constitutes the armature rotor iron core, has groove above, installing polyphase ac winding, i.e. asynchronous starting winding.Asynchronous starting and permanent magnet degaussing winding is set between each magnetic pole magnet steel.The inboard of magnet steel is magnetic pole yoke and rotating shaft, on this rotor and heterogeneous bridge rectifier is housed, with the rotor rotation, also can be described as rotating rectifier, and it is the rotor AC Windings is connected with permanent magnetism degaussing winding and constitutes rectification circuit.

Its operation principle is, after stator winding connects power supply, just form rotating magnetic field in the air gap, in its rotor AC Windings, produce induced potential, be rectified into direct current through heterogeneous bridge rectifier and supply with rotor permanent magnet degaussing winding, form the rotor-exciting magnetic potential, the direction of this magnetic potential is opposite with permanent magnet magnetic potential direction, is demagnetizing effect.Because alternating current that flows through in the rotor AC Windings and stator rotating magnetic field interact, generate electromagnetic torque, be asynchronous moment, make the electric motor starting rotation, before motor speed does not reach synchronously, the demagnetizing effect of demagnetization magnetic potential exists all the time in this nonsynchronous starting torque and the degaussing winding, and asynchronous slip is bigger, and stronger to the demagnetizing effect of permanent magnet, the moment of resistance of permanent magnetic field weakens greatly in the starting process thereby make, starting torque is improved, overcomes the shortcoming of magneto starting difficulty.After motor pulls in speed, induced potential in the rotor AC Windings is zero, excitation-free current exists in its degaussing winding, permanent magnet there is not demagnetizing effect, guaranteed the permanent magnet synchronous motor self characteristics, during synchronous operation, asynchronous starting winding and direct current winding just become the damping winding of synchronous motor, and the service behaviour of motor is improved.Its efficient is higher by 4～10% than general different machine of step, and power factor makes motor have remarkable energy saving effect near 1.

Accompanying drawing of the present invention is as follows:

Accompanying drawing 1. permanent magnet synchronous motor structure schematic diagrames of the present invention.

Accompanying drawing 2. permanent magnets (magnet steel) are the schematic diagram of rectangle.

Accompanying drawing 3. permanent magnets are the schematic diagram of watt shape.

Accompanying drawing 4. heterogeneous bridge rectifier circuit figure of the present invention.

Accompanying drawing 5.a) squirrel-cage bar or magnetic hysteresis nonsynchronous starting torque figure.

B) nonsynchronous starting torque figure of the present invention.

By accompanying drawing 1 as can be known, high-performance rare-earth permanent-magnetic synchronous motor of the present invention is by stator core (1), casing (2,11), permanent magnet (3), armature rotor iron core are that magnetic pole pole shoe (4), stator winding (5), rotor asynchronous starting winding (6), starting degaussing winding (7), heterogeneous bridge rectifier (8), support (9), end cap (10,12), bearing (13), rotating shaft (14) and rotor-end pressing plate (15) constitute.Wherein permanent magnet (3) can be made into as accompanying drawing 1 and the rectangle shown in the accompanying drawing 2, also can be made into as shown in Figure 3 watt shape or other forms, embeds within its rotor core.The magnetic pole pole shoe (4) that is installed in permanent magnet (3) outside is formed by punching silicon-steel, forms armature core, and there is groove on its surface, and settling the rotor polyphase ac winding (6) of symmetry is phase-wound rotor.Number of poles is identical with the permanent magnet pole number of poles.The permanent magnet inboard is magnetic pole yoke (16) (being (5) in accompanying drawing 2 and 3) and rotating shaft (14) (being (6) in accompanying drawing 2 and 3), leave enough gaps between the magnetic pole of magnet steel (3) and magnet steel (3), constituting vat, is rotor direct current winding (7) so that place starting degaussing winding.Heterogeneous bridge rectifier (8) can adopt dedicated block, is directly installed in the rotating shaft (14), near permanent magnet (3), makes simple and reliable for structurely, and fan can be set, and improves the radiating effect of stator.Stator is the same with general motor, is made up of stator armature iron core and stator polyphase ac winding, and the number of phases of winding is all identical with rotor with number of poles, and polyphase windings must symmetry.

Accompanying drawing 3 is the heterogeneous bridge rectifier of rotating rectifier (8), and it is rectified into the starting degaussing winding (7) that direct current is supplied with rotor permanent magnet (3) interpolar with the induced potential in the rotor AC Windings, forms the excitation magnetic potential (N of rotor _i, S _i), its direction and permanent magnet magnetic potential (N _m, S _m) direction opposite, permanent magnet is played demagnetizing effect, the moment of resistance that makes magneto weaken permanent magnetic field greatly in starting process to be produced is as accompanying drawing 4(b) M ₂Shown in.M among the figure ₁Be nonsynchronous starting torque, M is synthetic starting torque.Accompanying drawing 4(a) shown in is to adopt squirrel-cage bar or magnetic hysteresis nonsynchronous starting torque figure.(a) of comparative drawings figs 4 and (b) clearly finds out the moment of resistance M that permanent magnetic field produced of Fig. 4 (a) ₂Very big, not only weakened starting torque M, and make M recessed phenomenon occur, and the starting torque M shown in Fig. 4 (b) is with respect to Fig. 4 (a), obtained tangible improvement, not only improve starting torque M, and eliminated recessed phenomenon basically, thereby solved the difficulty that magneto is difficult to start.After motor pulls in speed, because induced potential is zero in the rotor AC Windings, degaussing winding excitation-free current exists, demagnetizing effect Lock-out to permanent magnet, interact by permanent magnetic field and stator rotating magnetic field fully, constitute permanent magnet synchronous motor work, guaranteed the performance of magneto.

Because the magneto volume is little, in light weight, need not consume exciting power, no excitation loss, its efficient is higher by 4～10% than general asynchronous motor, and cos ψ approaches 1, and with the leg speed operation, stabilization of speed is widely used, alternative most existing asynchronous motor.

Claims

1, a kind of high-performance rare-earth permanent-magnetic synchronous motor is made of stator core (1), casing (2), permanent magnet (3), stator winding (5), asynchronous starting winding (6), support (9), end cap (10,12), bearing (13), rotating shaft (14), rotor-end pressing plate (15), it is characterized in that permanent magnet (3) is for embedding the interior structure of rotor core, outside dress main pole pole shoe (4), constitute armature rotor, the asynchronous starting winding is set, permanent magnetism starting degaussing winding (7) is set between the magnetic pole of permanent magnet (3), and heterogeneous bridge rectifier (8) is housed on rotor.