Comprehensive Analysis of Converter Output Voltage for Conducted Noise Simulation

The problem of EMI in power electronics takes a lot of attention because of the increased switching frequency and decreased commutation times in the modern power converters. The frequency domain models are often used to simulate the conducted noise generated by the power converters due to their simplicity and reduced computational effort. The replacement circuit of a power converter in the frequency domain consists of impedance and voltage source with the respective spectrum. In most cases, the applied spectrum is oversimplified decreasing the accuracy of the simulation. This paper presents an in-depth analysis of the inverter output voltage and its impact on the generated conducted noise. The output voltage is analysed by means of the time-frequency methods. A new methodology for spectrum generation is proposed, which takes the switching behaviour of SiC MOSFET into account as well properties of the applied EMI receiver.