交交自控同步电动机的低速工作特性及其改进

 本文在分析交交型自控同步电动机低速借电源电压实现电机换相的基础上,提出了进一步提高电机过载能力和扩大低速工作转速范围的原理和方案。经计算机仿真和实验验证,证明了原理的正确性,为进一步开发此型电机低速工作领域打下了良好的基础。

THE PERFORMANCE AND STS LMPROVEMENT OF AC-AC SELF-CONTROLLED SYNCHRONOUS MOTOR OPERATING AT LOW ROTOR SPEED

Good starting performance of AC-AC self-controlled synchronous machine is due to that at low rotor speed the machine commutation is completed by source voltage. In this case there is a commutation delay and the maximum operation time of the source voltage in the machine commutation is about half period of source voltage.The ability of machine commutation may be estimated by the commutation voltage-time area. At low rotor speed the. area is produced by the source voltage and machine electro motive force, and it is larger than the area at high rotor speed. So that the maximum machine torque at low rotor speed is larger than the maximum torque at high rotor speed also.In order to increase the ability of machine commutation at low rotor speed too new control methods for increasing the machine commutation vol-tagetime area. Are proposed in this paper. The principle of these methods is to decrease the firing angle a in the period of machine commutation. Using these new control methods the critical current of motor is more larger than the one controlled by ordinary method,so the overload ability of the machine using these new methods is increased also.As a result of the commutation delay reduction the rotor speed range of the machine operating at low speed can be expanded.The maximum machine torque is effected by the commutation angle Y of the machine. It should be regulated automatically when the rotor speed and load change. So that the maximum machine torque will be larger.