Study on High Frequency Coupling Model of Multiconductor Cable

Multi-conductor cable is the key factor that causes voltage reflection and electromagnetic interference (EMI) in motor drive system. In order to accurately predict the EMI noise of motor drive system, it is necessary to establish an accurate multi-conductor cable model. However, the measuring port of impedance analyzer is too narrow to accurately measure the impedance parameters of long straight cable. In this paper, it is proved by theory and simulation that the impedance of the unit length circular cable can be equivalent to that of the unit length long straight cable when the radius of circular cable is greater than 0.25 m. The long straight cable is bent into the circular cable to measure the impedance parameters, and the multiconductor cable coupling model with shielding is established. Compared with the Q3D model, the simulation results of the multi-conductor cable coupling model are closer to the experimental results.