High Speed Common-Mode Switching in the Context of Highly Integrated Drive Systems

In modern drives with wide-bandgap (WBG) inverters, the trend is towards faster switching speeds to achieve high efficiency and power density, and thus a more compact design. Modern, highly integrated drive systems (HIDSs) exhibit extreme compactness. These two aspects affect the common-mode (CM) network and, in turn, the CM current, shaft voltage, and bearing currents differently than conventional drive systems do. To predict and reduce bearing failures also in HIDSs, these mechanisms must be understood within the context of the new sets of parameters. Although bearing currents have already been well studied, and the impact of WBG inverters has been partially investigated, a systematic analysis of parasitic effects in HIDSs has yet to be proposed. To address this gap, a common understanding of HIDSs is developed in the first step. Subsequently, the recent literature regarding the parasitic mechanisms is reviewed, and the open research questions are identified. This is complemented by a first assessment of the influence of high switching speeds on overvoltage, CM current, and bearing currents, considering the specifics of HIDSs.