Optimization strategy of switch state sequence transition in Vienna topology under discontinuous space-vector modulation

As front-end rectifier, Vienna topology is widely used in many applications. However, the available space vector of the Vienna topology is affected by the current, which leads to transition problem when the state sequence of the three-phase switch changes, especially under the discontinuous space vector modulation. To find out the mechanism of transition problems and reduce its impact, firstly, the possible situation of sequence transition when the current does not change is analyzed. And then the vector synthesis error caused by the lag or lead deviation between the ideal sector and the actual sector when the current change is deduced. On this basis, an optimization strategy for selecting a specific switching sequence before and after transition is given. In addition, the sequence transition problems of several common discontinuous vector modulation schemes are analyzed, and the optimization scheme is given in combination with the proposed optimization strategy. Finally, simulations and experiments verify that the optimized scheme can achieve smooth sequence transition, and the corresponding optimization strategy is simple to implement and has certain practicability.