The Application Research Of Vector Inverter In High Speed Milling Machine

Inverter is an important equipment which can regulate motor speed by controlling voltage frequency on electrical towage in modern times, and vector inverter depending on a lot of complicated compution can control not only motor speed but also motor torque. It provides stable torque even if the motor load changes. As the development of science and technology, the quality of mechanical parts must live up to the high standard of modern machinofacture, high-speed milling machine could finish several kinds of processing technic, so its high performance would stimulate the development of machinofacture. Using vector inverter control high speed spindle would improve productivity. This paper studies in the control algorithm and the harmonic distribution of vector inverter, then design external control circuit of MFC710 inverter which drives high speed spindle.First, this paper presents the development of vector inverter, illustrates superiority of high speed milling. Then establish a mathematical model of high speed spindle. After studying in bipolar sinusoidal pulse width modulation (SPWM) technology and space voltage pulse width modulation (SVPWM) technology, complete simulation of the control system using constant V/F algorithm and direct torque control algorithm based on SVPWM (DTC-SVPWM).The output voltage of inverter contain lots of harmonic, these harmonic will case synchronous parasitic torque and asynchronous parasitic torque to high speed spindle, and work efficiency will be reduced, so this paper presents the harmonic distribution via analyzing output voltage using FFT transform, and optimizes switching frequency in oder to reduce the fluence of harmonic. To some specific harmonic, using adapt notch filter can reduce its influence.Finally, this article presents a multi-section speed running method of driving high speed spindle using MFC710 inverter after studying the hardware of MFC710 inverter, this running mode can provide more precise speed for high speed spindle, then design the local and remote control circuit of MFC710 inverter, the circuit makes use of optocopler and relay to protect inverter, and the speed of spindle can meet the requirement of production.