Comparative Analysis of CM Interference of a Buck-Converter for Different Transistor Technologies in Frequency and Time Domain

In recent years, power semiconductor technologies have made considerable progress with the result that a large number of different transistor technologies are available. Wide band gap semiconductors such as silicon-carbide (SiC) MOSFETs are preferred in power electronic applications due to lower switching losses compared to Si-MOSFETs and IGBTs. At lower voltages the gallium-nitrite (GaN) technology can reduce losses further. This makes modern power electronics application a potential source of electromagnetic interference (EMI). The half-bridge is a central circuit topology in most applications. In this paper, a half-bridge Buck-Converter is investigated and the switching signals are analyzed together with their resulting common mode (CM) EMI. Si, SiC and GaN transistor technologies are compared with each other under different operating points and the influence on the CM EMI is discussed.