H8 inverter for common-mode voltage reduction in electric drives

This paper presents a modified two-level three-phase inverter for the reduction of the leakage current. With respect to a traditional two-level inverter, the proposed solution reduces the common-mode voltage (CMV), both in amplitude and frequency. Between the dc source and the traditional three-phase bridge, two active dc-decoupling devices and a voltage-clamping network have been added. A dedicated control strategy was developed adopting a modified space vector pulse-width modulation, oriented to the reduction of the CMV. Simulations showing the good performance of the solution are presented. A preliminary prototype was developed and experimental results are presented.