87-008145-03 SERVO DRIVE 95-132VAC 50/60HZ PARKER

87-008145-03

In the speed closed-loop of servo driver, the real-time speed measurement accuracy of motor rotor is very important to improve the dynamic and static characteristics of the speed control of the speed loop. In order to find the balance between measurement accuracy and system cost, incremental photoelectric encoder is generally used as the speed measurement sensor, and the corresponding speed measurement method is M/T. Although M/T tachometer has certain measuring accuracy and wide measuring range, it has its inherent defects, including: 1) at least one complete code disk pulse must be detected in the measuring period, which limits the minimum measurable speed; 2) It is difficult for the timer switches of the two control systems used for speed measurement to maintain strict synchronization, and the accuracy of speed measurement cannot be guaranteed in the measurement occasions with large speed changes. Therefore, it is difficult to improve the performance of servo driver speed following and control by using the traditional speed loop design method.

Principle of servo driver: At present, the mainstream servo driver adopts digital signal processor (DSP) as the control core, which can realize more complex control algorithm, and realize digitalization, networking and intellectualization. Power devices generally use intelligent power module (IPM) as the core design of the drive circuit, IPM internal integrated drive circuit, and has overvoltage, overcurrent, overheating, undervoltage and other fault detection protection circuit, in the main circuit also added soft start circuit, in order to reduce the impact of the start process on the driver.

The power driving unit first rectifies the input three-phase or mains power through the three-phase full-bridge rectifier circuit to obtain the corresponding direct current. The three-phase permanent magnet synchronous AC servo motor is driven by the three-phase sinusoidal PWM voltage inverter. The whole process of power drive unit can be simply described as AC-DC-AC process. The main topological circuit of AC-DC is the three – phase full – bridge uncontrolled rectifier circuit.