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The working principle of servo drive

1. Working principle of servo driver:

At present, the mainstream servo drivers all use 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.

With the large-scale application of servo system, the use of servo drive, servo drive debugging, servo drive maintenance are more important technical topics in today’s servo drive, more and more industrial control technology service providers on the servo drive technology in-depth research.

Servo driver is an important part of modern motion control, which is widely used in industrial robots and CNC machining centers and other automation equipment. Especially, the servo driver used to control AC permanent magnet synchronous motor has become a research hotspot at home and abroad. Current, speed, position 3 closed-loop control algorithm based on vector control is widely used in AC servo driver design. Whether the speed closed-loop design in this algorithm is reasonable or not plays a key role in the whole servo control system, especially in the performance of speed control.

2. Servo driver:

As an important part of modern motion control, it is widely used in industrial robots and CNC machining centers and other automation equipment. Especially, the servo driver used to control AC permanent magnet synchronous motor has become a research hotspot at home and abroad. Current, speed, position 3 closed-loop control algorithm based on vector control is widely used in AC servo driver design. Whether the speed closed-loop design in this algorithm is reasonable or not plays a key role in the whole servo control system, especially in the performance of speed control.

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.

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Further information:

I. Application field:

Servo drive is widely used in the field of injection molding machine, textile machinery, packaging machinery, CNC machine tools and so on.

Ii. Relevant Differences:

1. The servo controller can easily convert the operation module and fieldbus module through the automatic interface. At the same time, different fieldbus modules are used to achieve different control modes (RS232, RS485, optical fiber, InterBus, ProfiBus), and the control mode of the general frequency converter is relatively single.

2. The servo controller is directly connected to the rotary transformer or encoder to form a closed loop of speed and displacement control. But the universal frequency converter can only form an open loop control system.

3. Each control index (such as steady-state accuracy and dynamic performance, etc.) of servo controller is better than that of general frequency converter.


Post time: May-26-2023