Eliminating Common-Mode Voltage Spikes Caused by Dead-Time Effect in Three-Phase Inverters Through Symmetrical Rotation Reverse Carriers

In the three-phase inverters, high common-mode voltage (CMV) will produce some serious negative effects. Compared with the conventional pulse width modulation, the use of reverse carrier scheme (RCS) is a simple way to reduce the CMV peaks to one third of the original peaks in theory. However, in practice, some CMV spikes will appear in the inverter when using the RCS. The CMV spikes are caused by the switching dead-time effect. This article presents an improved RCS, which is called the scheme of symmetrical rotation reverse carriers (SRRCs). In this scheme, three-phase carriers are reversed periodically in turn. This ensures that only one phase carrier is reversed at any time, which eliminates the generation mechanism of the CMV spikes. The SRRC scheme is not only suitable for the three-phase inverters with a fixed-frequency carrier but also suitable for the inverters with the carrier frequency modulation. The feasibility and effectiveness of the proposed SRRC scheme are verified by the simulations and experimental results in a three-phase inverter.