Research on vibration suppression method of alternating current motor based on fractional order control strategy

Abstract

At present, the changing structure, material and increasing device are used to suppress the vibration of motor in general. These methods increase system complexity in the different degree. So a novel vibration suppression method based on fractional order Proportional-Integral-Derivative (PID) controller is proposed in this article. First, the digital realization process of fractional order PID controller is illustrated in detail. Then the integer order PID controller and fractional order PID controller are, respectively, used to adjust the input current of inverter to control the 1.5 kW alternating current motor. The vibration frequency spectrums and stator current frequency spectrums in low-frequency and carrier frequency band are, respectively, studied by using the comparison and analysis methods. At the same time, the vibration frequency spectrum and stator current frequency spectrum of 15 kW alternating current motor are compared and analyzed. And the frequency spectrums near the rotating frequency of stator current of 1.5 kW and 15 kW alternating current motors are amplified to deeply analyze spectrum characteristics. The experimental results show that the fractional order PID controller has the characteristics of multi-point control by comparing with the integer order PID controller. It changes the frequency components of stator current, and then the electromagnetic torque is more stable. So, the fractional order PID controller can better suppress the vibration of alternating current motor. The proposed method can provide a new idea for vibration suppression of rotating machinery.