Abstract：To solve the problem of communication abnormality due to electromagnetic interference during loading test of new energy prototype, the data transmission signal was measured, and the working principle of motor drive system was investigated. The Fourier expression was used to analyze the harmonic signals from inverters operating in three-phase load balancing and unbalanced states.The measurement and analysis results show that the second harmonic and the higher harmonic generated by high-speed switching action of inverter under load imbalance are coupled to the acquisition chip through the voltage sampling line, which causes the differential signal drive anomalies, destroys the communication link signal integrity and results in communication failure.Through optimization measures of optimizing the filter and perfecting the shielding layer, the influence of interference signal on transmission link is suppressed, and the communication is ensured normally.
2019, Vol. 40 
