With the widespread application and popularization of inverters, interference issues have become increasingly prominent.What are the main causes of electromagnetic interference from inverters, and how can it be reduced?

Main Causes

1. Harmonic Interference

During operation, inverters generate harmonic currents that distort voltage waveforms, causing interference to electronic equipment. 

2.RF Conducted Emission Interference  

Since the load voltage is pulsed and the inverter draws current from the power grid in pulses as well, these contain substantial high-frequency components that form radio-frequency interference, affecting other equipment connected to the same power grid.

3.RF Radiated Interference

Radio-frequency interference currents exist on both the input and output cables of the inverter, generating electromagnetic radiation and causing interference. Such interference becomes severe when electronic equipment is placed close to the inverter. a. Grounding: 

Solutions

1. Hardware Anti-Interference Measures

a. Grounding: 

Connect the inverter to the control cabinet and the motor housing, with a grounding resistance of less than 100Ω to absorb surge interference.

b. Filtering:

Install filters at the input or output terminals of the inverter to effectively reduce high-order harmonics.

c. Shielding: 

Use shielding materials to enclose cables and equipment, reducing electromagnetic radiation and conduction.

d. Isolation:

 Install signal isolation modules between PLCs and inverters to prevent the transmission of interference signals.

2. Software Anti-Interference Measures

Electromagnetic interference can be reduced by adjusting the carrier frequency of the inverter and setting it within an appropriate range.