Modeling, Analysis, and Reduction of Radiated EMI Due to the Voltage Across Input and Output Cables in an Automotive Non-Isolated Power Converter

This article investigates the radiated electromagnetic interference (EMI) due to the voltage between input and output cables in a non-isolated power converter. The radiated EMI model of a non-isolated power converter is first developed and quantified based on the circuit topologies, printed circuit board (PCB) parasitics, switching waveforms, and transfer functions. Second, an antenna model is developed for converter cables based on the antenna impedance and the antenna transfer function. Third, a complete radiated EMI model is developed based on the converter's EMI model and the cable's antenna model. Fourth, the radiated EMI is analyzed based on the developed model. Finally, two radiated EMI noise reduction techniques, optimizing PCB layout and adding a cross capacitor, are proposed. The developed radiated EMI model and the proposed radiated EMI reduction techniques are verified with both simulations and experiments. The techniques are also extended to other two non-isolated power converter topologies when the radiated EMI is caused by the voltage between the input and output cables.