公开(公告)号：EP4439947A1

公开(公告)日：2024-10-02

申请号：EP24166032.3

申请日：2024-03-25

申请人： Guangzhou Metro Design and Research Institute Co., Ltd. ,  Qingdao University

发明人： Lin, Shan ,  Nong, Xingzhong ,  Zhao, Tao ,  Liao, Jing ,  Lu, Yun ,  Wang, Chunfang

IPC分类号： H02M1/00 ,  H02M1/32 ,  H02M3/00 ,  H02M3/335 ,  H02M7/483 ,  H02M7/487 ,  H02M7/49 ,  H02J3/01 ,  H02J3/12 ,  H02J3/38

CPC分类号： Y02E10/56 ,  H02M1/325 ,  H02M7/49 ,  H02M1/007 ,  H02M1/0077 ,  H02M3/01 ,  H02M3/33573 ,  H02M7/4837 ,  H02M7/487 ,  H02J3/381 ,  H02J2300/2420200101 ,  H02J3/01 ,  H02J3/12

摘要： The present invention discloses a control method for a cascaded H-bridge medium-voltage direct-mounted photovoltaic inverter, including the steps of: S1, determining two phases of a power grid where a short circuit occurs; S2, calculating an adaptive zero-sequence voltage of a phase A by means of an adaptive zero-sequence voltage compensation strategy, wherein the phase A refers to a phase of three-phase the power grid where no short circuit occurs; S3, compensating for the adaptive zero-sequence voltage, then calculating an amplitude of a modulation voltage of the phase A, and calculating the modulation voltage of the phase A based on the amplitude of the modulation voltage of the phase A; S4, expanding the modulation voltage of the phase A to symmetrical three-phase voltages based on the modulation voltage of the phase A; S5, calculating a harmonic zero-sequence voltage by means of a maximum-minimum harmonic zero-sequence voltage compensation strategy; and S6, acquiring three-phase modulation voltages based on the adaptive zero-sequence voltage and the harmonic zero-sequence voltage, to suppress active power backflow. The present invention can significantly reduce a region with the active power backflow, and is more applicable to conditions with higher voltage sag depth and lower system output power.