Magnetic Near-Field Strength Prediction of a Power Module by Measurement-Independent Modeling of Its Structure

Abstract

This paper presents a simulation scheme based on the S-parameters for simultaneously predicting the circuit operation of a power module (PM) and its consequent magnetic near-field (NF) strength. The PM comprises silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs). The circuit simulation is carried out using the S-parameterized PM aided by the SiC MOSFET die model, which allows for a precise replication of the switching waveforms. Note that the S-parameterized process needs no measurement data of the PM. The only experimental data are the characteristics of the specific SiC MOSFET dies used in the PM to adjust the die model. A buck converter is configured with the PM, and the magnetic NF radiated from the PM is measured in order to verify the validity of the proposed scheme. The magnetic field detection probe does not measure the magnetic field itself; instead, it measures the electromotive force (EMF) induced by the magnetic field. Accordingly, the simulated magnetic NF should be converted to the corresponding EMF, which enables a comparison of the measured and simulated results. This simulation scheme works successfully to predict the magnetic NF, but modeling the whole converter system is indispensable.

Keywords

• Power electronics
• power module
• S-parameter
• circuit simulation
• electromagnetic noise