Firstly, the advantages of permanent magnet motor (PMSM) are high efficiency, high torque density, wide speed range and small size.
Because of the use of permanent magnets, there is no need for excitation current, thus reducing reactive power loss and improving the efficiency and power density of the motor.
The magnetic field strength of permanent magnet motor has nothing to do with the motor speed, which makes its speed regulation range very wide and can provide large torque at low speed.
The disadvantages of permanent magnet motor are high cost and difficult maintenance. Due to the use of expensive rare earth permanent magnet materials, the manufacturing cost of permanent magnet motors is high.
At the same time, the temperature characteristics of permanent magnets are poor, and they may demagnetize at high temperature, so special attention should be paid to maintenance.
The advantages of induction motor are high reliability, low cost and strong fault tolerance.
The induction motor has simple structure, low manufacturing cost and convenient maintenance.
Because the rotor of induction motor is a squirrel-cage structure with self-protection function, it has high reliability.
In case of fault, induction motor can maintain a certain output torque by changing rotor resistance, so it has strong fault tolerance.
The disadvantages of induction motor are low efficiency and poor speed regulation performance.
Because of asynchronous operation mode, the efficiency of induction motor is usually lower than that of permanent magnet motor.
At the same time, the speed regulation performance of induction motor is not as good as that of permanent magnet motor, so it is necessary to install frequency converter and other control devices to realize speed regulation.