An Overlap-Time Optimization SVM Method based on Vector Sequential Reconstruction for Current Source Converters

In order to effectively reduce the current distortion caused by introducing overlap time, an overlap-time optimization space vector modulation (SVM) method based on vector sequential reconstruction (VSR-SVM) for current source converters (CSCs) is proposed. First, the rules that are not affected by the overlap-time effect (OTE) are identified, and the sequence of the current vectors is adjusted on this basis to eliminate the OTE within the carrier. Next, a modulation increment is added to the adjusted modulation signal to obtain a new modulation signal to remove the OTE between carriers. Then, the driving signals are obtained by comparing the new modulation signals with the carrier. Finally, the overlap time is added after the turn-off signals to correct the dwell time. This method intentionally modifies the modulation signals so that the effective dwell time of the current vector is the same as the ideal dwell time. Simulation and experimental results show that this method can effectively improve the current quality under different power factors, loads, overlap time, and modulation indices.