How to solve the electromagnetic interference problem of servo drive system?

1. Classification of harmonic interference problems in servo drive systems

The harmonic interference problems faced by the servo drive system can be divided into three categories according to the interference source and the disturbed source, namely, external harmonic interference to the servo drive system, servo drive system harmonic interference to the internal components of the servo drive system, and servo drive system interference to the outside world:

⑴ External harmonics interfere with the servo drive system

External harmonics mainly include: harmonics in the power supply, harmonics in nature (harmonics caused by lightning, etc.). These harmonics can cause a series of problems such as false alarms, false operations, and refusal to operate of the servo drive in the servo drive system. In more serious cases, the rectifier module and electrolytic capacitor in the servo drive may overheat, burst, explode, and other problems. Therefore, this part of the harmonics must be taken seriously.

⑵ The servo drive system interferes with the internal components of the servo drive system

This is a common situation. For example, the harmonics generated by the servo drive in the servo drive system can enter the servo motor, causing the servo motor to overheat, make noise (screaming, abnormal sound, etc.), vibrate (or oscillate), have pits, pits and cracks on the bearings, frequently break down the servo motor insulation, and severely shorten the life of the servo motor. Of course, the harmonics in the servo drive system will not only affect the servo motor, but may also affect a series of problems such as communication and analog signals.

⑶ Servo drive system harmonic interference to the outside world

There are two situations in which the servo drive system interferes with the outside world. One is that the harmonic interference of the servo drive system interferes with the electrical equipment that uses the same power supply, such as low voltage, instruments, meters, sensors, etc.; the other is that the harmonics of the servo drive system will radiate outward, causing the surrounding equipment to not work properly, such as communications, monitoring, instruments, meters, sensors, etc.

2. Solutions for reference to harmonic interference in servo drive systems

When it comes to the harmonic interference problem of the servo drive system, first of all, don't blindly rush to install any servo harmonic suppression devices. This will not only increase costs and space occupancy, but also increase failure points. Therefore, this is not the preferred solution .

⑴ Grounding

Do a good job of grounding the servo drive system. The grounding of the servo drive system must be independent and distinguished from the grounding of other equipment; the grounding wire must be short and thick, and the wire diameter of the grounding wire must be at least half of the main wire diameter or more. We recommend that the grounding wire and the main wire of the servo drive system use the same wire diameter;

⑵ Shielding

It is recommended to use shielded wires for the connection wires between the servo drive system and the servo motor, and cut the shielding layer in a circular manner to expose the metal mesh, and then use a U-shaped clip or the like to ground it.

For weak-wires such as communication lines and signal lines of the servo drive system, shielded wires should be used as much as possible, and the shielding layer should be reliably grounded;

⑶ Filtering

The filter components available for servo drive systems include: servo input filter, servo input inductor, MLAD-GFC servo-specific passive harmonic filter, servo-specific active harmonic filter, Du/Dt inductor, sine wave inductor, etc.