公开(公告)号：US20210273551A1

公开(公告)日：2021-09-02

申请号：US17260461

申请日：2019-06-18

Applicant: SHANDONG UNIVERSITY

Inventor： Chenghui ZHANG ,  Changwei QIN ,  Xiaoyan LI ,  Xiangyang XING ,  Shunquan HU ,  Ying JIANG ,  Alian CHEN

IPC: H02M1/12 ,  H02M7/5387 ,  H02M1/44 ,  H02M7/487

Abstract: A neutral-point voltage balance control method and system for a three-level converter in a full power factor range. The method includes: using a large, medium, and zero vector modulation method to synthesize a reference voltage vector, and duty cycles of a large vector, a medium vector, and a zero vector; obtaining a voltage difference between two dc-link capacitors of signal acquisition, and the voltage difference as a neutral-point potential of the three-level converter; according to a value relationship between the neutral-point potential of the three-level converter and a specified threshold, selecting a small vector and calculating a duty cycle of the small vector; and updating a duty cycle of each basic vector, and obtaining a switching sequence for controlling a power switch of a three-phase bridge arm. An amplitude of a common-mode voltage of an NPC three-level converter is equal to one sixth of a dc-link voltage.