Simple
permanent magnet synchronous motor having the structure, small size, high efficiency, power factor advantages. Currently, the permanent magnet synchronous motor has been in the metallurgical industry (ironworks sintering plant and the like), ceramic industry (ball), the rubber industry (mixer), the oil industry (pumping), the textile industry (Twister, spun yarn medium and low voltage motors machine) and other industries in obtaining results, and the gradual accumulation of experience in design and operation. .
1 PMSM Category
according to permanent structural classification thereof: surface permanent magnet synchronous motor (SPMSM), interior permanent magnet synchronous motor (an IPMSM).
An induction electric potential waveform classification stator winding: sine-wave permanent magnet synchronous motors, brushless permanent magnet DC motor.
2 magnet synchronous motor structure
Permanent Magnet Synchronous Motor (English name for the permanent mag⁃net synchronous motor, referred to as PMSM) it is mainly composed of various components of the rotor, the stator cover and other components. Permanent magnet synchronous motor stator structure with a general induction motor structure is very similar, the biggest difference asynchronous motor rotor structure is placed on the rotor with a permanent magnet pole of a high quality, depending on the position of the permanent magnet mounted on the rotor, permanent magnet synchronous motors are generally classified into a surface structure and built-in type rotor rotor structure.
a great influence on the placement of the permanent magnet motor performance. Surface of the rotor structure – the outer surface of the rotor core of the permanent magnet, the rotor structure is simple, but produces very little torque asynchronous, start only suitable for less demanding applications, is rarely used. Built-rotor structure – a permanent magnet positioned between the core shaft and squirrel cage bars, the startup performance, the vast majority of the current permanent magnet synchronous motor have such a structure.
3 magnet synchronous motor works
permanent magnet synchronous motor is up and running of the magnetic field generated by the interaction of the stator windings, and a permanent magnet rotor squirrel cage and the three form. ElectricityWhen the mover stationary, into a three phase stator winding current, the stator generates a rotating magnetic field, a rotating magnetic field of the stator relative to the rotor to rotate within the cage winding generates a current, a rotating magnetic field is formed a rotor, a stator and a rotor rotating magnetic field rotating magnetic field produced by the interaction asynchronous torque to accelerate rotation of the rotor started from rest. In this process, the permanent magnetic field of the stator and the rotor rotational speed different field, will generate an alternating torque. When the rotor is accelerated to speeds approaching synchronous speed, when the permanent magnet rotor and the stator magnetic field rotational speed nearly equal, slightly greater than the speed of the rotating stator magnetic field of the rotor permanent magnet field, which interact to generate a torque to the rotor synchronization pull-in operation. In the synchronous operation state, no current is generated inside the rotor winding. At this time, only the permanent magnet rotor generates a magnetic field, rotating magnetic field which interacts with the stator, generating a driving torque. It can be seen, by the permanent magnet synchronous motor is asynchronous torque of the rotor windings realization started. After startup, the rotor winding is no longer functioning, the magnetic field generated by the permanent magnets and stator windings interaction drive torque.
4 magnet synchronous motor operating mode
the generator excitation current obtained in several ways 1, dynamo generator excitation mode excitation mode power supply having such a specific direct current electrical generating machine, which is called a dedicated DC exciter DC generator, generally coaxial with the generator exciter field winding of the generator through slip rings mounted on the shaft and the fixed brush large direct current obtained from the exciter. This excitation mode with the excitation current independent and work more reliable and reduce electricity consumption from the advantages of the past few decades is the main generator excitation mode, with a more mature operating experience.The disadvantage is slower excitation regulator, maintenance workload, it is rarely used in the above 10MW Unit.
2, AC exciter excitation mode power supply some modern high-capacity AC exciter generator excitation current. AC exciter shaft is also mounted on the large generator, which outputs the rectified AC current flows through the rotor excitation generator is supplied, at this time, he genus excitation mode excitation mode, and because the use of the stationary rectifying means, it is also known is excited static excitation, AC pilot exciter provides excitation current. AC pilot exciter machine may be a permanent device or measuring apparatus having a self-excited alternator constant pressure. In order to increase the speed of excitation regulator, AC exciter usually 100–200HZ frequency generator, while the sub-exciter AC frequency generator is used to 400–500HZ. And three-phase alternating current excitation winding such a generator winding are wound in the stator slots, only the teeth and the groove rotor without windings, like gears, so that it does not contact member rotatable brush, slip ring or the like, having a reliable , simple structure and easy manufacturing process and so on. The disadvantage is noisy, the harmonic component is large AC potential.
3, no exciter field excitation mode is not provided in the special mode exciter, acquired from the excitation power generator itself, by itself and then supplied to the generator field rectifier, said self-excited static excitation. Static excitation can be divided into a self-excited and self-excitation and compound excitation from two ways. It is made from the shunt field current manner through the outlet of the generator connected rectifier transformer, the rectifier supplied to the generator excitation, excitation mode having a junction that is simple, less equipment, less maintenance, and low investment advantages. From the complex excitation voltage regulating means other features, also connected in series with the circuit power generator stator current transformer. This transformer is in effect a short circuit occurs, to provide a larger exciting current generator, rectifier transformer to compensate for the lack of output. This embodiment has two exciter field supply obtained by rectifying the current transformer and the voltage supply source obtained by the series transformer.