交流同步电动机已成为交流可调传动中的一颗新星，特别是永磁同步电动机，电

The AC synchronous motor has become a new star in the AC adjustable transmission, especially the permanent magnet synchronous motor. The motor has a brushless structure, high power factor, high efficiency, and the rotor speed is strictly synchronized with the power frequency. There are two types of synchronous motor frequency conversion speed control system: other control frequency conversion and automatic control frequency conversion. In principle, the automatic control frequency conversion synchronous motor is very similar to the DC motor. The mechanical commutator of the DC motor is replaced with a power electronic converter. Or "Brushless DC Motor (BLDC)". The traditional automatic frequency conversion synchronous machine speed control system has a rotor position sensor, and a system without a rotor position sensor is currently being developed. Vector control can also be used for the other control frequency conversion method of synchronous motor, which is simpler than the asynchronous motor in the vector control oriented by the rotor magnetic field. Switched reluctance motor (SR) is a special type of synchronous motor. The fixed rotor has a double-salient pole structure, strong brushless, and large output torque. Since the winding of the SR motor only needs a unidirectional current, it is powered. The only need is a unipolar power converter, the circuit is simple. The traditional SR motor speed control system also requires a position detector, and is currently developing a sensorless SR speed control system. SR motors have outstanding advantages, and their application fields are expanding day by day. What is slightly inferior is that: SR motor power converters output irregular current pulses. At low speeds, operating noise and torque ripple problems are more prominent. This needs to be further improved.

AC synchronous motor has become a new star in AC adjustable transmission, especially permanent magnetic synchronous motor, the motor obtains brushless structure, high power factor, high efficiency, rotor speed strictly in sync with the power frequency. The synchronous motor variable frequency speed control system has his control frequency and self-control frequency conversion two categories. Self-controlled variable frequency synchronous motor in principle and DC motor is very similar, with the electric electronic converter instead of the DC motor mechanical changer, such as the use of cross-straight-cross-voltage inverter called "DC non-converter motor" or "brushless DC motor (BLDC)." The traditional self-controlled variable frequency synchronous speed control system has a rotor position sensor, and a system without rotor position sensor is being developed. The synchronous motor's other frequency control mode can also be vector control, which is easier to direct vector control by rotor magnetic field than asynchronous motor. Switch magneto-resisting motor (SR) is a special type of synchronous motor, fixed rotor for the double convex structure, strong brushless, the output torque is large, because the winding of the SR motor only needs a single direction current, so it is powered by only a unipolar power converter, the circuit is simple. Traditional SR motor speed control systems also require position detectors, and SR speed control systems without position sensors are being developed. SR motor advantages outstanding, the application field is expanding day by day, slightly inferior is: SR motor power converter output is irregular current pulse, low speed leads to operating noise and torque pulsation problem is more prominent, which needs to be further improved control method.

AC synchronous motor has become a new star in AC adjustable drive, especially permanent magnet synchronous motor. The motor has a brush free structure, high power factor, high efficiency, and the rotor speed is strictly synchronized with the power frequency. There are two kinds of synchronous motor frequency control system, i.e. other control frequency conversion and automatic control frequency conversion. The principle of the self-control variable frequency synchronous motor is very similar to that of the DC motor. The mechanical commutator of the DC motor is replaced by the power electronic converter. For example, when the AC-DC-AC variable voltage converter is used, it is called "DC commutator less motor" or "BLDC motor". The traditional speed control system of automatic frequency conversion synchronous machine has rotor position sensor. Now the system without rotor position sensor is being developed. Vector control can also be used in other control frequency conversion mode of synchronous motor. The vector control based on rotor field orientation is simpler than that of asynchronous motor. Switched reluctance motor (SR) is a special type of synchronous motor. Its stator and rotor are of doubly salient pole structure. It is strong and without brush, and its output torque is large. Because the winding of SR motor only needs single direction current, it only needs a single polarity power converter to supply it, and the circuit is simple. The traditional SR motor speed control system also needs position detector. At present, the SR speed control system without position sensor is also being developed. The advantages of SR motor are outstanding, and its application field is expanding day by day. What's worse is that the output of power converter of SR motor is irregular current pulse, which causes operation noise and torque ripple at low speed, which needs to be further improved.<br>