A Balanced Current-Source Inverter and its dc-Link Shunted Variant for Common-Mode Voltage Cancellation

Abstract

The use of wide bandgap (WBG) devices in the dominant voltage-source inverters (VSIs) creates more challenging conducted common-mode (CM) electromagnetic interference (EMI) issues. Traditional way of suppressing CM EMI is by adding external filters. However, the added filter can add significant mass and volume to the inverter. The use of existing current-source inverter (CSI) can help relieve the CM EMI issue, but WBG-CSI’s EMI profile still exceeds EMI standards. In this paper, two new balanced current-source inverter (CSI) topologies are proposed that provide several advantages over the standard VSIs or existing CSI topology when using WBG power switches. For both balanced CSI topologies, the use of additional three switches generate a second common-mode voltage (V_cm) component that forces the total V_cm of both inverters to be close to zero. This significantly reduces the inverters’ conducted CM EMI. Moreover, the proposed H10-Balanced-CSI topology combined with its modulation scheme make its CMV cancellation insensitive to propagational delay distortions among its switches.