Towards EMI prediction of a PM motor drive for automotive applications

Technology innovations in automobiles increasingly involve high power electric motor drives, leading to an increasing level of electromagnetic interference (EMI) and the requirements to meet electromagnetic compatibility (EMC). A numerical prediction of EMI/EMC has the potential to evaluate EMI performances at the design stage and before prototyping. It can also help reduce the post-prototype EMC cost by minimizing late re-design and modifications of a drive implementation. This paper describes a systematic approach towards early EMI prediction of motor drives. It is able to calculate the conducted EMI through modeling of parasitic coupling and circuit simulation. Methodologies for extracting parasitic parameters of major EMI components of a PM motor drive are developed using FEM analysis, experimental measurement and analytical approximation. Major EMI characteristics of the PM motor drive is then predicted by using a circuit simulator to solve the motor drive circuitry with high frequency parasitic parameters. Simulation results are compared with experimental data and the effectiveness of the EMI simulation approach is demonstrated.