High-speed CNC gantry drilling machines require drive systems with a wide speed range, high speed accuracy, good acceleration and deceleration performance, precise positioning control, and strong protection and fault self-diagnosis functions. In developed countries, AC servo spindle drive systems have largely replaced DC spindle drive systems, forming a series of products that basically cover the majority of machine tool spindle drive capacity. In recent years, although China's CNC technology has made rapid progress, due to uneven development, high-performance digital AC spindle drive systems mainly rely on imports, which are expensive and difficult to maintain. Developing a series of domestically produced AC spindle drive systems with high technical performance and low price as soon as possible to improve the performance of high-speed CNC gantry drilling machines and reduce costs is an important issue that urgently needs to be addressed.
Basic Principles of Spindle Drive System : The spindle motor's operating characteristics require a wide speed range during actual machine tool processing. Below the base speed, it should meet constant torque requirements, and above the base speed, it should meet constant power requirements. Basic Principles of Control System: Spindle Drive Unit Control Strategy: To achieve high-precision speed regulation and positioning requirements during spindle tool changes, closed-loop flux vector control is adopted. Vector control technology, based on the dynamic mathematical model of the AC motor, uses coordinate transformation to decompose the AC motor stator current into two components: one is the excitation component M used to generate rotor flux, and the other is the torque component i used to generate electromagnetic torque, thus achieving decoupling control. At this time, the motor's electromagnetic torque is: This is similar to the torque equation of a DC motor. With decoupling control, high-performance speed regulation characteristics comparable to DC speed regulation can be obtained by controlling and implementing speed regulation control similar to a DC motor.
