A Fault Tolerant Modulation Scheme to Eliminate DC Offset and Harmonic Fault Currents in the Balanced Inverter Under Switch Short-Circuits Faults

The objective of this research is to investigate a new modulation scheme for balanced voltage-source inverters to suppress the DC offset in phase currents when switch short-circuit faults occur. Because of its superior common-mode voltage cancellation capability, the balanced VSI is an excellent topology for mitigating electromagnetic interference (EMI), especially in power converters using wide-bandgap (WBG) power semiconductors. In addition, the balanced inverter topology offers valuable opportunities for fault-tolerant operation. When a switch fails as a short circuit, significant amounts of DC offset currents are induced in the phase currents if the baseline switching algorithm is not changed, risking damage to other healthy switches and inverter loads such as electric machines. A new modulation scheme is proposed for eliminating the DC offset currents while maintaining the balanced inverter’s power conversion capability. This new algorithm enhances the balanced inverter’s appeal by expanding its operating range to include fault-mode conditions with switch short-circuit faults.