Advantages of permanent magnet synchronous motor compared to AC asynchronous motor
High efficiency and more power saving:
(1) Since the magnetic field of the permanent magnet synchronous motor is generated by a permanent magnet, the excitation loss (copper loss) caused by the magnetic field generated by the excitation current is avoided;
(2), permanent Compared with the asynchronous motor, the external characteristic efficiency curve of the magnetic synchronous motor is much higher at light load, which is the biggest advantage of the permanent magnet synchronous motor compared with the asynchronous motor in terms of energy saving. Because usually when the motor is driving the load, it rarely runs at full power. This is because: on the one hand, when the user selects the motor, the motor power is generally determined according to the limit working condition of the load, and the limit working condition occurs. The chances are very few. At the same time, in order to prevent the motor from burning under abnormal conditions, the user will further leave a margin for the power of the motor; on the other hand, when designing the motor, in order to ensure the reliability of the motor, the designer usually On the basis of the power required by the user, a certain power margin will be further reserved, so that more than 90% of the motor in actual operation is working below 70% of the rated power, especially when driving fans or pumps. Motors usually work in the light load region. For the asynchronous motor, its efficiency is very low at light load, while the permanent magnet synchronous motor can still maintain a high efficiency in the light load area, and its efficiency is more than 20% higher than that of the asynchronous motor.
(3) Due to the high power factor of the permanent magnet synchronous motor, the motor current of the permanent magnet synchronous motor is smaller than that of the asynchronous motor, and the stator copper consumption of the motor is correspondingly smaller and the efficiency is higher.