Servo Drives
High-Performance Servo Drives for Industrial Automation
Reliable and customizable servo
drives designed to optimize your production and improve efficiency.
Quickly select the right solution for your machinery.
T3A / T3L Series
General-purpose AC servo drives supporting pulse input, analog, and RS485 communication. Perfect for a wide range of automation machines.
Send Inquiry
T3D Series
Single-board 17/23 bit absolute servo drives, ideal for high-precision positioning applications.
Send Inquiry
T3DF / C30G Series
Compact pulse-type servo drives, designed to save installation space while delivering reliable performance.
Send Inquiry
T5A Series
RS485 absolute servo drives for systems requiring high positioning accuracy and feedback control.
Send Inquiry
T5ML / T6M Series
Bus-type absolute servo drives, supporting MECHATROLINK-II/III protocols for high-speed communication.
Send Inquiry
T6E / T6DE Series
EtherCAT bus servo drives, ideal for high-speed EtherCAT networked industrial systems.
Send Inquiry
T3DC Series
CANopen bus servo drives, fully supporting CANOpen protocol for embedded control systems.
Send Inquiry
S3a Series
Spindle servo drives, specially designed for CNC spindle motors and high-load applications.
Send Inquiry
T3M / T3G Series
Machine tool specialized servo drives, optimized for maximum pulse input performance.
Send Inquiry
Servo drives, also known as "servo controllers" or "servo amplifiers," are controllers used to control servo motors. Their function is similar to that of a frequency converter on a conventional AC motor. They are part of a servo system and are primarily used in high-precision positioning systems. They typically control servo motors using position, speed, and torque to achieve high-precision positioning in transmission systems. They are a high-end product in transmission technology.
What is a Servo Drive?
Servo drives are a crucial component of modern motion control and are widely used in automated equipment such as industrial robots and CNC machining centers. In particular, servo drives used to control AC permanent magnet synchronous motors have become a hot topic of research both domestically and internationally. Current AC servo drive designs generally utilize a three-loop control algorithm based on vector control: current, speed, and position. The rationality of the speed closed-loop design within this algorithm plays a key role in the overall servo control system, particularly in speed control performance.
In a servo drive's closed-loop speed loop, the accuracy of real-time motor rotor speed measurement is crucial for improving the dynamic and static characteristics of the speed loop's speed control. To strike a balance between measurement accuracy and system cost, incremental photoelectric encoders are generally used as speed sensors, and the corresponding commonly used speed measurement method is the MT speed measurement method. While the MIT speed measurement method offers a certain degree of measurement accuracy and a wide measurement range, it has inherent drawbacks, primarily:
1) It requires at least one complete encoder pulse to be detected within the speed measurement cycle, limiting the
minimum measurable speed;
2) The two control system timer switches used for speed measurement are difficult to maintain strict
synchronization, making speed measurement accuracy unreliable in situations with large speed variations.
Therefore, conventional speed loop designs employing this speed measurement method struggle to improve the speed
tracking and control performance of servo drives.
How Servo Drives Work
Mainstream servo drives all use digital signal processors (DSPs) as their control core, which can implement relatively complex control algorithms and achieve digitalization, networking, and intelligence. Power devices generally use drive circuits designed with intelligent power modules (IPMs) as the core. The IPM integrates the drive circuit internally and also has fault detection and protection circuits such as overvoltage, overcurrent, overheating, and undervoltage. A soft start circuit is also added to the main circuit to reduce the impact of the startup process on the drive. The power drive unit first rectifies the input three-phase power or mains power through a three-phase full-bridge rectifier circuit to obtain the corresponding direct current. The rectified three-phase power or mains power is then converted to 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 rectifier unit (AC-DC) is a three-phase full-bridge uncontrolled rectifier circuit.
With the widespread adoption of servo systems, servo drive operation, commissioning, and maintenance are all crucial technical issues for servo drives today. An increasing number of servo drive manufacturers are conducting in-depth technical research on servo drives.
Servo drives are a crucial component of modern motion control and are widely used in automation equipment such as industrial robots and CNC machining centers. In particular, servo drives used to control AC permanent magnet synchronous motors have become a research hotspot both domestically and internationally. Current AC servo drive designs generally utilize a three-loop control algorithm based on vector control: current, speed, and position. The rationality of the speed closed-loop design within this algorithm plays a key role in the overall servo control system, particularly in speed control performance.
Application areas: Servo drives are widely used in injection molding machines, textile machinery, packaging machinery, CNC machine tools, etc.
Servo Drives Basic Requirements
1. Wide speed regulation range
2. High positioning accuracy
3. Sufficient transmission rigidity and high speed stability
4. Fast response with no overshoot
To ensure productivity and machining quality, in addition to high positioning accuracy, excellent fast response
characteristics are also required. This means that the response must track the command signal. This is because CNC
systems require sufficiently large accelerations and decelerations during startup and braking to shorten the feed
system's transition time and minimize wheel transition errors.
5. High torque at low speed and strong overload capacity
Generally speaking, servo drives have an overload capacity of more than 1.5 times the speed for several minutes or
even half an hour, and can withstand overloads of 4 to 6 times the speed for short periods without damage.
6. High reliability
The feed drive system of a CNC machine tool must have high reliability and excellent operating stability, strong
adaptability to environmental factors such as temperature, humidity, and vibration, and strong anti-interference
capabilities.
Motor Requirements
1) The motor must operate smoothly from the lowest to the highest speed, with minimal
torque fluctuation. Especially at low speeds, such as 0.1 rpm or lower, it must maintain a stable speed without
any creeping.
2) The motor must have a large, long-term overload capacity to meet the requirements of low speed and high torque.
Generally, DC servo motors are required to withstand an overload of 4 to 6 times their rated torque for several
minutes without damage.
3) To meet the requirements of fast response, the motor must have a small moment of inertia and high stall torque,
with the smallest possible time constant and starting voltage.
4) The motor must be able to withstand frequent starting, braking, and reversing.
Servo Drives Test Platform
There are mainly the following types of test platforms for servo drives: a test platform that uses mutual feedback between servo drives and motors, a test platform that uses adjustable simulated loads, a test platform that uses an actuator motor but no load, a test platform that uses an actuator motor to drag an inherent load, and a test platform that uses online testing methods.
Servo Drive-Motor Mutually Feedback Test Platform
This test system consists of four components: a three-phase PWM rectifier, a servo drive-motor system under test, a load servo drive-motor system, and a host computer. The two motors are connected via a coupling. The servo drive-motor system under test operates in a motoring mode, while the load motor operates in a generating mode. The servo drive-motor system under test operates in a closed-loop speed mode, controlling the speed of the entire test platform. The load servo drive-motor system operates in a closed-loop torque mode, varying the load motor's torque by controlling its current, simulating load variations on the servo drive under test. This mutually feedback test platform allows for flexible speed and torque adjustments, enabling various functional tests. The host computer monitors the entire system's operation, issuing control commands to the two servo drives according to test requirements. It also receives, stores, analyzes, and displays operational data.
This test system uses high-performance vector control to control the speed and torque of the motor under test and the load device, respectively. This simulates the dynamic and static performance of the servo drive under various load conditions, enabling comprehensive and accurate testing of the servo drive. However, due to the use of two servo drive and one motor system, this test system is bulky and cannot meet portability requirements. Furthermore, the system's measurement and control circuits are complex and costly.
Test Platform Using an Adjustable Simulated Load
This test system consists of three parts: the servo drive-motor system under test, an adjustable simulated load, and a host computer. The adjustable simulated load, such as a magnetic powder brake or electric dynamometer, is coaxially connected to the motor under test. The host computer and data acquisition card control the load torque by controlling the adjustable simulated load, while simultaneously collecting, storing, analyzing, and displaying servo system operating data. By controlling the adjustable simulated load, this test system can simulate the dynamic and static performance of the servo drive under various load conditions, enabling comprehensive and accurate testing of the servo drive. However, this test system is still relatively large, making it difficult to be portable. Furthermore, the system's measurement and control circuitry is complex and expensive.
Using a test platform with an actuator motor but no load
This test system consists of two parts: the servo drive under test (DUT) and the motor system, and a host computer. The host computer sends speed command signals to the servo drive, which then begins operating accordingly. During operation, the host computer and data acquisition circuitry collect servo system operating data, storing, analyzing, and displaying the data. Because the motor in this test system is unloaded, it is relatively smaller than the previous two test systems, and its measurement and control circuitry is simpler. However, this also makes it unable to simulate the actual operating conditions of the servo drive. Typically, this type of test system is only used to test the speed and angular displacement of the DUT under no-load conditions, and cannot provide comprehensive and accurate testing of the servo drive.
Test platform using an executive motor to drag the inherent load
This test system consists of three components: the servo drive-motor system under test, the system's inherent load, and a host computer. The host computer sends a speed command signal to the servo drive, and the servo system begins operating according to the command. During operation, the host computer and data acquisition circuit collect operating data from the servo system, which is then stored, analyzed, and displayed.
This test system uses the inherent load of the system under test, so the test process closely matches the actual operating conditions of the servo drive and provides relatively accurate test results. However, because the inherent load of some systems under test cannot be easily removed from the equipment, the test process can only be performed on the equipment, which is not very convenient.
Test Platforms Using Online Testing Methods
This test system consists solely of a data acquisition system and a data processing unit. The digital acquisition system collects and conditions the servo drive's real-time operating status signals within the equipment, then sends them to the data processing unit for processing and analysis. The data processing unit ultimately draws the test conclusions. Because it uses online testing methods, this test system is relatively simple in structure and eliminates the need to disconnect the servo drive from the equipment, making testing more convenient. This type of test system conducts tests entirely during actual servo drive operation, resulting in test results that are more accurate. However, due to the manufacturing and assembly characteristics of many servo drives, selecting the installation locations for the various sensors and signal measurement components within this test system can be challenging. Furthermore, failures in other parts of the equipment can adversely affect the servo drive's operation, ultimately affecting the test results.
Servo Drive Parameters
Position Proportional Gain
1. Sets the proportional gain of the position loop regulator.
2. A larger value results in higher gain, greater stiffness, and reduced position lag under the same command pulse frequency. However, excessive values may cause oscillation or overshoot.
3. The parameter value is determined by the specific servo system model and load conditions.
Position Feedforward Gain
1. Sets the feedforward gain of the position loop.
2. A larger value results in reduced position lag under any command pulse frequency.
3. A larger feedforward gain improves the control system's high-speed response, but can also cause system position instability and oscillation.
4. When high response is not required, this parameter is typically set to 0. The range is 0 to 100%.
Speed Proportional Gain
1. Sets the proportional gain of the speed regulator.
2. A larger setting results in higher gain and greater stiffness. The parameter value is determined based on the specific servo drive system model and load conditions. Generally, the larger the load inertia, the larger the setting value.
3. Set a maximum value as long as the system does not oscillate.
Speed Feedback Filter Factor
1. Sets the speed feedback low-pass filter characteristics.
2. A larger value lowers the cutoff frequency and reduces motor noise. If the load inertia is large, the setting can be reduced. A larger value can cause oscillation due to variable response.
3. A smaller value increases the cutoff frequency and increases the speed feedback response. If a higher speed response is required, the setting can be reduced.
Maximum Output Torque Setting
1. Sets the servo motor's internal torque limit;
2. The setting is a percentage of the rated torque;
3. This limit applies to the positioning completion range at all times;
4. Sets the positioning completion pulse range in position control mode;
5. This parameter provides the basis for the driver to determine whether positioning is complete in position control mode. When the number of remaining pulses in the position deviation counter is less than or equal to the setting value of this parameter, the driver considers positioning complete and the in-position switch signal turns on; otherwise, it turns off;
6. In position control mode, outputs the positioning completion signal and acceleration/deceleration time constant;
7. The setting value represents the motor's acceleration time from 0 to 2000 rpm or deceleration time from 2000 to 0 rpm;
8. The acceleration/deceleration characteristics are linear in the speed range;
9. Set the speed arrival;
10. In non-position control mode, if the motor speed exceeds this setting value, the speed arrival switch signal turns on; otherwise, it turns off;
11. This parameter is not used in position control mode;
12. This parameter is independent of the direction of rotation.
Controller Features
Speed ratio 1:5000
Rate ratio 0.3:1500
Position control
Zero-speed lock
Overload capacity 200%-300%
High starting torque
Speed unaffected by load
Three-loop closed-loop control
Related knowledge
1. Servo controllers can easily switch between operating modules and fieldbus modules through automation interfaces. They can also use different fieldbus modules to implement various control modes (RS232, RS485, fiber optic, InterBus, and ProfiBus). General-purpose inverters, on the other hand, offer a more limited control approach.
2. Servo controllers directly connect to resolvers or encoders to create closed-loop speed and displacement control. General-purpose inverters, on the other hand, can only operate in open-loop control systems.
3. Servo controllers offer superior control performance (such as steady-state accuracy and dynamic performance) compared to general-purpose inverters.
As one of the leading servo drives manufacturers and suppliers in China, we warmly welcome you to buy the best servo drives at competitive price from our factory. For more company information, contact us now.