公开(公告)号：US11081967B2

公开(公告)日：2021-08-03

申请号：US16617508

申请日：2018-09-28

申请人： SOUTHEAST UNIVERSITY

发明人： Qinsong Qian ,  Shengyou Xu ,  Qi Liu ,  Weifeng Sun ,  Shengli Lu ,  Longxing Shi

IPC分类号： H02M3/335 ,  H02M1/08 ,  H02M1/00

摘要： The invention discloses a self-adaptive synchronous rectification control system and a self-adaptive synchronous rectification control method of an active clamp flyback converter. The control system comprises a sampling and signal processing circuit, a control circuit with a microcontroller as a core and a gate driver. According to the control method, a switching-on state, an early switching-off state, a late switching-off state and an exact switching-off state of a secondary synchronous rectifier of the active clamp flyback converter can be directly detected, and the synchronous rectifier and a switching-on time of the synchronous rectifier in next cycle can be controlled according to a detection result. After several cycles of self-adaptive control, the synchronous rectifier enters the exact switching-on state, thus avoiding oscillation of an output waveform of the active clamp flyback converter.

公开(公告)号：US12062985B1

公开(公告)日：2024-08-13

申请号：US18566102

申请日：2022-09-26

申请人： SOUTHEAST UNIVERSITY

发明人： Qi Liu ,  Weiwei Zhai ,  Leilei Shi ,  Qinsong Qian ,  Weifeng Sun ,  Longxing Shi

IPC分类号： H02M3/158 ,  H02M1/00 ,  H02M1/088

CPC分类号： H02M3/1582 ,  H02M1/0058 ,  H02M1/088

摘要： A control method for a four-switch buck-boost converter is provided. The control method adopts four-stage control, and divides the load range into two sections and adopts different control strategies according to a critical load value corresponding to optimal control. In Boost mode, before the critical load, T1 and T2 are kept constant, T3 is a minimum value for realizing soft-switching, and T4 decreases with the increase of the load; when the critical load is reached, T4 drops to 0; and after the critical load, T1, T2, T3 and T increase with the load. In Buck mode, before the critical load, T2 and T3 are kept constant, T1 is a minimum value for realizing soft-switching, and T4 decreases with the increase of the load; when the critical load is reached, T4 drops to 0; and after the critical load, T1, T2, T3 and T increase with the load.

公开(公告)号：US11201557B2

公开(公告)日：2021-12-14

申请号：US16959116

申请日：2018-12-29

申请人： CSMC TECHNOLOGIES FAB2 CO., LTD. ,  SOUTHEAST UNIVERSITY

发明人： Qinsong Qian ,  Shengyou Xu ,  Feng Lin ,  Hao Wang ,  Wei Su ,  Qi Liu ,  Longxing Shi

IPC分类号： H02M3/335 ,  H02M1/00 ,  H02M3/00

摘要： A control system for synchronous rectifying transistor of LLC converter, the system comprising a voltage sampling circuit, a high-pass filtering circuit, a PI compensation and effective value detection circuit, and a control system taking a microcontroller (MCU) as a core. When the LLC converter is operating at a high frequency, a drain-source voltage VDS(SR) of the synchronous rectifying transistor delivers, via the sampling circuit, a change signal of the drain-source voltage during turn-off into the high-pass filtering circuit and the PI compensation and effective value detection circuit to obtain an effective value amplification signal of a drain-source voltage oscillation signal caused by parasitic parameters, and the current value is compared with a previously collected value via a control circuit taking a microcontroller (MCU) as a core, so as to change a turning-on time of the synchronous rectifying transistor in the next period.