A, U / f constant control U / f control is performed while changing the frequency of the motor supply motor supply voltage changes, so that the motor flux constant, over a wide speed range, the motor efficiency, power factor does not drop. Because it is the control voltage (Voltage) and frequency (Frequency) ratio, called the U / f control. Constant U / f control the presence of the main problems is the poor performance of low-speed, low speed when the electromagnetic torque can not overcome the large static friction, can not properly adjust the motor torque compensation and adapt to changes in load torque; followed by can not accurately control the actual speed of the motor. Due to constant U / f open-loop speed drive is controlled by the mechanical characteristics of asynchronous motor Figure shows that the set value of the stator frequency is ideal no-load speed and the actual speed of the motor is determined by the slip, the U / f constant control mode error can not exist in a stable control, it can not accurately control the actual speed of the motor.
Four motor drive control
- Jun 29, 2016-