[Shenzhen Meanstone Intelligent Technology] Switch (synchronous) reluctance motor
2021-09-08 17:23:46
Shenzhen Meanstone Intelligent Technology Co., Ltd
A switched reluctance motor is a type of synchronous motor whose torque is caused by the unequal permeability (permeability) of the orthogonal and straight axes of the rotor, without field windings or permanent magnets.
The structure of synchronous reluctance motor
The stator of synchronous reluctance motor can be distributed winding and concentrated winding, consisting of a winding frame and an iron core, the three main types of reluctance motor rotor are: salient pole rotor, axial laminated rotor and transverse laminated rotor.
The structure of synchronous reluctance motor
The stator of synchronous reluctance motor can be distributed winding and concentrated winding, consisting of a winding frame and an iron core, the three main types of reluctance motor rotor are: salient pole rotor, axial laminated rotor and transverse laminated rotor.
Working principle of synchronous reluctance motor
The alternating current through the stator winding creates a rotating magnetic field in the air gap of the motor, the synchronization between the magnetic field generated by the stator and the internal magnetic field generated by the rotor, and when the external magnetic field generated by the stator is generated through the rotor, the rotor will tend to shift the direction of its internal magnetic flux and generate minimum magnetoresistance.
The alternating current through the stator winding creates a rotating magnetic field in the air gap of the motor, the synchronization between the magnetic field generated by the stator and the internal magnetic field generated by the rotor, and when the external magnetic field generated by the stator is generated through the rotor, the rotor will tend to shift the direction of its internal magnetic flux and generate minimum magnetoresistance.
When the rotor attempts to establish its most conductive axis (d-axis) with the applied magnetic field, torque is created to minimize magnetoresistance (magnetoresistance) in the magnetic circuit, and the amplitude of the torque is proportional to the difference between the orthogonal inductors of the Ld and Lq, so that the greater the difference, the greater the torque generated.
The working principle can be explained as follows: an object a composed of anisotropic materials has different electrical conductivity along the d and q axes, while the isotropic magnetic material of object b has the same electrical conductivity in all directions, and if there is an Angle between the d axis and the field line, the magnetic field applied to the anisotropic object a produces torque. If the D-axis of object a does not coincide with the magnetic field line, the object will introduce a distortion in the magnetic field. In this case, the direction of the distorted magnetic field line will reunite with the q axis of the object.
The working principle can be explained as follows: an object a composed of anisotropic materials has different electrical conductivity along the d and q axes, while the isotropic magnetic material of object b has the same electrical conductivity in all directions, and if there is an Angle between the d axis and the field line, the magnetic field applied to the anisotropic object a produces torque. If the D-axis of object a does not coincide with the magnetic field line, the object will introduce a distortion in the magnetic field. In this case, the direction of the distorted magnetic field line will reunite with the q axis of the object.
In a synchronous reluctance motor, the magnetic field is generated by a sinusoidal distribution of stator windings, the magnetic field rotates at a synchronous speed, in which case there is always a torque, the purpose of which is to reduce the overall system potential energy by reducing the field distortion along the Q-axis (delta-0). If the Angle δ remains constant, for example by controlling the magnetic field, the electromagnetic energy will be continuously converted into mechanical energy. The stator current is responsible for magnetizing and generating a torque in an attempt to reduce magnetic field distortion. Torque is controlled by controlling the current Angle, that is, the Angle between the current vector of the stator winding and the rotor d axis in the rotating coordinate system.
Characteristics of synchronous reluctance motor
Advantages: Simple and strong rotor structure, rotor structure is simple, composed of electrical steel sheet, no magnet and short circuit winding. Since there is no current in the rotor, it will not heat up during operation, thus extending the service life of the motor. Because rare earth metals are not used in production, the final price of electric motors is lower. In the absence of magnetic force, the maintenance of the motor is simplified. Because there are no windings and magnets on the rotor, the rotor has a low moment of inertia, which enables the motor to accelerate faster and save energy. Since the operation of synchronous reluctance motor requires frequency converter, the speed of the reluctance motor can be controlled in a wide speed range.
Advantages: Simple and strong rotor structure, rotor structure is simple, composed of electrical steel sheet, no magnet and short circuit winding. Since there is no current in the rotor, it will not heat up during operation, thus extending the service life of the motor. Because rare earth metals are not used in production, the final price of electric motors is lower. In the absence of magnetic force, the maintenance of the motor is simplified. Because there are no windings and magnets on the rotor, the rotor has a low moment of inertia, which enables the motor to accelerate faster and save energy. Since the operation of synchronous reluctance motor requires frequency converter, the speed of the reluctance motor can be controlled in a wide speed range.
Disadvantages: Work requires a variable frequency driver because the magnetic flux is generated by current and needs to be solved by using a variable frequency driver with power correction.