Abstract: The open winding electric machine (OWEM) is a special cascaded power supply mode, which opens the neutral point and connects each end with an inverter. In the case that only a single DC power supply can be provided, two inverters share one common DC power supply, which is called as the common DC bus topology in this paper. Due to its advantages of single DC power supply, high output power, multiple effective voltage vectors, strong redundancy, and fault tolerance, it has broad applications in high voltage, high power, and high safety requirements. At the same time, due to the existence of the zero-sequence path, the zero-sequence current will occur, which can cause additional losses and torque ripples. Therefore, the effective suppression of the zero-sequence current is necessary for the common DC bus topology. In this paper, the common DC bus topology was presented firstly. And then the causes of the zero-sequence current were analyzed. Thirdly, the zero-sequence current suppression strategies were overviewed. Finally, these strategies were summarized, and their future development trends were discussed.