The mainstream servo drives all adopt digital signal processors (DSP) as the control core, which can implement relatively complex control algorithms and achieve digitalization, networking, and intelligence. The power components generally adopt drive circuits designed with intelligent power modules (IPM) as the core. The IPM integrates the drive circuit internally and also has fault detection and protection circuits for overvoltage, overcurrent, overheating, and undervoltage. A soft-start circuit is also added in the main circuit to reduce the impact on the drive during startup. The power drive unit first rectifies the input three-phase electricity or mains electricity through a three-phase full-bridge rectifier circuit to obtain the corresponding direct current. The rectified three-phase electricity or mains electricity is then transformed to frequency by a three-phase sinusoidal PWM voltage-type inverter to drive the three-phase permanent magnet synchronous AC servo motor. The entire process of the power drive unit can be simply described as an AC-DC-AC process. The main topology circuit of the rectification unit (AC-DC) is the three-phase full-bridge uncontrolled rectifier circuit.
With the large-scale application of servo systems, the use, debugging, and maintenance of servo drives are all important technical topics of servo drives in today’s era. More and more industrial control technology service providers have conducted in-depth technical research on servo drives.
Servo drives are an important component of modern motion control and are widely used in industrial robots and CNC machining centers and other automated equipment. Especially, servo drives used for controlling AC permanent magnet synchronous motors have become a research hotspot at home and abroad. Currently, in the design of AC servo drives, the 3-closed-loop control algorithm based on vector control, which includes current, speed, and position control, is commonly used. Whether the speed closed-loop design is reasonable plays a key role in the entire servo control system, especially in the performance of speed control.