Commonly used asynchronous motor frequency control of motor speed control mode

Common induction motor variable frequency speed regulation control method usually has two kinds,namely the constant torque frequency control of motor speed and constant power variable frequency speed regulation.(1) the constant torque frequency control of motor speed.Simply adjust the frequency of the ac power,although can achieve the purpose of adjusting the motor speed,but will worsen motor operation performance.Balance equations,this is because the motor U1 material E1 K1N1f1 phi wholesalemotor.blogspot.com m = 4.44,if the supply voltage U1 is changeless,is reduced when the frequency of f1,main flux phi m would increase,this will lead to motor magnetic circuit saturation overly,increase the excitation current,core loss increase,the power factor decreased;On the other hand,if increase frequency f1,phi m reduced,decreased the output torque of the motor,the motor capacity is not full play.In motor learning,we know that the asynchronous motor output torque,T2 is proportional to the U21 / F21 so asynchronous motor in the process of frequency control of acmotortrading.blogspot.com motor speed,if keep U1 / f1 is constant,the power supply voltage and frequency proportional adjustment,namely before and after the output torque of the motor can maintain speed control is constant,constant torque control is currently the most widely used a way of frequency control of motor speed control.(2) constant power variable frequency speed regulation.The output small electric motors power of motor lamination the asynchronous motor P2 is proportional to the U21 / F21.Therefore in the process of speed regulation,if can keep the U21 / f1 is constant,the speed before and after asynchronous motor output power remains the same,namely the constant power speed regulation.Some transportation machinery,such as electric drive locomotives,urban rail transportation,trolley buses,etc.,hoping to realize constant power control of motor speed,namely when the motor speed is low,the output torque is big,can produce large enough traction locomotive,vehicle speed,motor speed,high output torque can be smaller (only need to overcome the running resistance).