Composition Structure Of Electric Vehicle Motor

1. Permanent magnet DC motor:
It consists of stator poles, rotors, brushes, casings, etc.
The stator poles are made of permanent magnets (permanent magnet steel), made of ferrite, alnico, neodymium iron boron and other materials. According to its structural form, it can be divided into several types such as cylindrical type and tile type.
The rotor is generally made of laminated silicon steel sheets, and the enameled wire is wound between the two slots of the rotor core (there are three windings in three slots), and the joints are respectively welded on the metal sheets of the commutator.
The brush is a conductive part that connects the power supply and the rotor winding, and has two properties of conductivity and wear resistance. The brushes of permanent magnet motors use single-sex metal sheets or metal graphite brushes, and electrochemical graphite brushes.
2. Brushless DC motor:
It is composed of permanent magnet rotor, multi-pole winding stator, position sensor and so on. The brushless DC motor is characterized by being brushless, and uses semiconductor switching devices (such as Hall elements) to realize electronic commutation, that is, electronic switching devices are used to replace traditional contact commutators and brushes. It has the advantages of high reliability, no commutation spark, and low mechanical noise. As shown in Figure 1.
The position sensor commutates the current of the stator winding in a certain order according to the change of the rotor position (that is, detects the position of the rotor magnetic pole relative to the stator winding, and generates a position sensing signal at the determined position, which is processed by the signal conversion circuit and then removed. Control the power switch circuit, and switch the winding current according to a certain logic relationship).
3. High-speed permanent magnet brushless motor:
It is composed of stator core, magnetic steel rotor, sun gear, deceleration clutch, hub shell and so on.
A Hall sensor can be mounted on the motor cover for speed measurement.
There are three types of position sensors: magnetic sensitive, photoelectric and electromagnetic.
A brushless DC motor using a magneto-sensitive position sensor, its magneto-sensitive sensor devices (such as Hall elements, magneto-sensitive diodes, magneto-sensitive pole tubes, magneto-resistors or application-specific integrated circuits, etc.) are installed on the stator assembly. To detect changes in the magnetic field generated when the permanent magnet and the rotor rotate. Hall elements are mostly used in electric vehicles.
A brushless DC motor using a photoelectric position sensor, a photoelectric sensor device is arranged on the stator assembly at a certain position, a light shield is installed on the rotor, and the light source is a light-emitting diode or a small light bulb. When the rotor rotates, due to the function of the shading plate, the photosensitive components on the stator will intermittently generate pulse signals at a certain frequency.
The brushless DC motor with electromagnetic position sensor is equipped with electromagnetic sensor components (such as coupling transformer, proximity switch, LC resonant circuit, etc.) on the stator assembly. When the position of the permanent magnet rotor changes, the electromagnetic effect will make the electromagnetic sensor Generates a high frequency modulated signal (whose amplitude varies with rotor position).
The working voltage of the stator winding is provided by the electronic switching circuit controlled by the output of the position sensor.