Development Of High Performance AC Servo Drive For CNC Machines

The CNC machine is the foundation for the entire manufacturing industry and its performance does not only mirror China’s industrial modernization situation but also directly impact China’s comprehensive national power. The kernel of a CNC machine lies in the servo drive system, which determines CNC machines’ processing performance. Hence, it is of great significance to develop a set of high-performance servo drive system.Taking application requirements into consideration, this research attempts to design an AC servo motor by studying and improving previous laboratory achievements. Herein, adopting the DSP chip TMS320F2812 of TI as the kernel and supplementing it with AVR chip and CPLD chip this research succeeds in alternating current permanent magnet synchronous servo motor speed control. Based on the researches and reviews on current servo system field background, this research has conducted an analysis of the current condition and the future development of the alternating current servo drive system technology and put forward the essentiality of developing application of high-performance servo drive system in CNC machines. The space vector width modulation(SVPWM) technology is adopted after the comparison of three frequently-used control methods. This research has analyzed and understood the mechanics of the SVPWM, deducted and calculated the mathematic model of the permanent magnet synchronous motor. The sample machine electricity supplying system adopts TOP244 as control core and the PIM of the main circuit is 7MBR50UA-120. The pilot circuit adopts TMS320F2812 as the kernel to build the control system. The menu interface adopts ATmega16 A as kernel, setting up communication with DSP via RS-232 and adopting CPLD to collect and examine the location information of the absolute encoder and send data in parallel with DSP. As far as the software design is concerned, the setting of the PI parameter also has direct influence on the motor performance. This research constantly improves the procedure design according to the laboratory servo drive modulation experience.When having completed the hardware design and software development, this research further system working examining platform. Repeatedly, modulate and run the system. Finally, examine the system performance in the laboratory. The steady-state static of the permanent synchronous motor is zero, step response examining establishing time 0.05s~0.15 s, torque changes response time within 0.1s. The examination indicates that this set of servomotor’s practical performance meets the standard of the design and development requirement. Hence, this research has laid foundation for the productization of alternating current servo drive in the future.