Patent ID: 9735702
Date: 2017-08-15
CPC Classifications: H02J,H02M,Y02E

Claim:
1. An operating method of a full-bridge sub-module (FBSM)-based modular multilevel converter with AC-side voltage boosting, comprising: (1) obtaining a rated DC-link voltage U (2) calculating the number of FBSMs in each arm N satisfying AC-side voltage boosting requirements without considering the redundancy of FBSMs using a converter modulation index m after AC-side voltage boosting, the rated DC-link voltage U (3) calculating a reference value of converter's output active power P according to different control objectives, and calculating AC-side output voltages u (4) calculating a reference value of output voltage of each arm according to the AC-side output voltages u (5) calculating the number of the inserted FBSMs in each arm according to the reference value of output voltage of each arm and the rated capacitor voltage of FBSMs U (6) determining the inserted FBSMs of each arm in the principle of balancing capacitor voltages of FBSMs in each arm according to the detected capacitor voltages of FBSMs in each arm and polarity of the arm currents; and (7) making FBSMs of each arm required to output positive voltage output positive voltage and those required to output negative voltage output negative voltage, and bypassing other FBSMs, thereby boosting AC-side voltages of the full-bridge modular multilevel converter.