Introduction to the electric motor of electric bicycle


At present, all electric bicycles use DC rotary motors. […]

At present, all electric bicycles use DC rotary motors. According to the different ways in which the magnetic field is generated, there are two types of magnetic motors. The magnetic field of the DC excitation motor is generated by the coil winding, which is characterized by strong overload capacity and large output power. It is commonly used in high-power equipment such as electric tricycles: the magnetic field of the DC permanent magnet motor is generated by permanent magnets, because there is no need for winding excitation. In this way, the electric energy consumed when the field winding is working is eliminated, and the conversion efficiency of the motor is improved. Therefore, DC permanent magnet motors are commonly used by electric bicycles, and they are also our first choice for refitting small wind turbines.
In order to keep the motor rotating in one direction, the direction of the current must be changed when the DC motor passes through the balance point. There are usually two methods: one is to use a mechanical commutator (brush) to change the armature coil when it passes the balance position. The direction of current, the second is to switch the direction of current when the armature coil passes through the equilibrium position through an electronic switch circuit. The former is usually called a DC brushed motor, and the latter is called a DC brushless motor. In the DC brushed motor, the magnetic steel is used as the stator, the coil winding is used as the rotor, and a commutator is installed on the rotor. The coil winding is connected to the commutator. The commutator is connected to the external power supply through the brush. When rotating, the winding coils of the motor are alternately connected with the positive and negative poles of the power supply, thereby completing the commutation of the winding coil current and making the motor continue to rotate in one direction. In the DC brushless motor, the magnetic steel is the rotor, and the coil winding is the stator. The stator coil is composed of three windings evenly distributed in space. When the current flowing into the coil is switched in sequence under the interaction of the position sensor and the electronic switch , It will generate a rotating magnetic field, which drives the rotor to rotate in one direction.