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.

公开(公告)号：US20210391719A1

公开(公告)日：2021-12-16

申请号：US17159884

申请日：2019-12-28

Applicant: SHANDONG UNIVERSITY

Inventor： Chenghui ZHANG ,  Xi LIU ,  Hua GENG ,  Xiangyang XING

IPC: H02J3/01 ,  H02J3/16

Abstract: A hybrid cascaded APF topology and control method therefor for improving the ability of a system to compensate for higher harmonics, raise the quality of electric energy of output currents, and reduce costs. The topology includes: a three-phase cascaded H-bridge including bridge arms of three phases, each bridge arm including a plurality of H-bridge cells connected in series, and the bridge arms of the three phases connected to a power system needing active filtering via inductors; and a three-phase H-bridge circuit connected at star connection points of the three-phase cascaded H-bridge, the three-phase H-bridge circuit including branches of the three phases and two capacitors connected in parallel across the branches of the three phases, and the branch of each phase including two switching transistors connected in series, where switching transistors of the H-bridge cells use Si devices, and the switching transistors of the three-phase H-bridge circuit use SiC devices.