EMI system model for a gearbox electronic control unit

A system simulation approach to model conducted emissions of a gearbox electronic control unit (ECU) is presented. The system is partitioned in ECU, cable harness, and load. The ECU itself is modeled using 3D electromagnetic simulation. For the cable harness and loads analytic models are employed, so that the incorporation of these parts into the model can be done without any increase in simulation time. The model is used to investigate resonances between PCB and housing, and common and differential mode currents on the cable harness. Also, optimal positions of critical subassemblies on the printed circuit board inside the ECU have been investigated.