High-Frequency Evaluation of Two-Level Voltage-Source and Current-Source Inverters with Different Output Cables

Overvoltages and other transient phenomena caused by the fast switching characteristics of wide-bandgap (WBG) power switches in hard-switched voltage-source inverters (VSIs) has raised concerns about their use in motor drives. A comparative study of the transient phenomena in WBG-based two-level VSIs and current-source inverters (CSIs) has been carried out using different lengths of non-shielded and shielded cables to connect the inverter and machine. Experimental test results are presented that highlight the transient phenomena of the two inverters during machine excitation. Overvoltages and capacitive charging currents at multiple locations in the motor drive system are documented, including conducted common-mode (CM) EMI and dc bus leakage current. The results highlight advantages of CSIs over VSIs for reducing transient overvoltages, charging current spikes, and CM EMI, particularly for long cables.