Application of brushless motor in electric automatic vehicle

The brushless DC motor used in electric bicycles is usually made into a disc motor, which is installed in the wheel hub. The wheel hub is connected with the rim by spokes, which directly drives the wheel to rotate. The stator is composed of stator core, armature winding and its outgoing line, sensing element and its outgoing line, stator support, shaft and other parts. The stator core is generally made into many to many slots to meet the requirements of large torque and low speed. The form of stator winding is similar to that of polyphase permanent magnet synchronous motor, which plays an important role in the process of energy conversion. The number of winding phases is three-phase, and Y-type connection is adopted. The three-phase windings are respectively connected with the corresponding power switching devices in the electronic switch circuit, that is, the three-phase half control drive pipeline. Another kind of permanent magnet brushless DC motor with outer rotor is widely used in electric bicycles. At present, the outer rotor permanent magnet brushless DC motor developed in the circle mostly adopts multi pole, multi slot and flat structure. Compared with the brush DC motor, brushless DC motor has the following advantages when applied to electric bicycles: (1) long service life, maintenance free and high reliability. In brush DC motors, the brush and commutator wear faster. Generally, the brush needs to be replaced after working for about 1000 hours. In addition, the technology of the reduction gearbox is difficult, especially the lubrication of the transmission gear, which is a big problem in the current brush scheme. Therefore, the brush motor has the problems of high noise, low efficiency and easy to cause faults. (2) High efficiency and energy saving. Generally speaking, because brushless DC motor has no friction loss of mechanical commutation, consumption of gearbox and consumption of speed regulating circuit, the efficiency can usually be higher than 85%. However, considering the highest cost performance in the actual design, in order to reduce data consumption, it is generally designed to be 76%, while the efficiency of brush DC motor is usually about 70% due to the consumption of gearbox and overrunning clutch. Therefore, brushless DC motor has obvious advantages.