Five-level parallel current source converter for high power drives with DC current balance control and superior harmonic performance

In this thesis, space vector modulation is developed for a 5-level parallel current source converter for high power drives. The modulation scheme is designed to bring superior harmonic performance to the currents on the AC sides. This method synthesizes the rotating reference current vector in the converter's space vector's plane with three adjacent switching vectors. Unbalanced currents of DC links become a practical challenge when two converters are connected in parallel. To balance the DC currents, the proper switching state for every Small and Medium switching vector is chosen from redundant switching states corresponding to the vector based on circuit circumstances and the designed switching sequence. Simulated results verify the effectiveness of the method. In addition, the switching sequence is designed to lower the switching frequency and minimize the switching loss. Finally, the proposed converter and switching scheme are simulated and steady state and dynamic performance are investigated in detail.