US 12,489,360 B2
Multi-level AC/DC conversion circuit, multi-level DC/DC conversion circuit and control methods thereof
Kai Dong, Shanghai (CN); Yichao Wang, Shanghai (CN); Yuhua Hu, Shanghai (CN); and Jinfa Zhang, Shanghai (CN)
Assigned to Delta Electronics (Shanghai) Co., Ltd., Shanghai (CN)
Filed by Delta Electronics (Shanghai) Co., Ltd., Shanghai (CN)
Filed on Sep. 25, 2023, as Appl. No. 18/372,582.
Claims priority of application No. 202211401076.6 (CN), filed on Nov. 9, 2022.
Prior Publication US 2024/0162805 A1, May 16, 2024
Int. Cl. H02M 7/219 (2006.01); H02M 1/00 (2006.01); H02M 3/07 (2006.01); H02M 3/158 (2006.01); H02M 7/483 (2007.01)
CPC H02M 1/0095 (2021.05) [H02M 1/0032 (2021.05); H02M 3/158 (2013.01); H02M 7/219 (2013.01); H02M 7/4837 (2021.05); H02M 3/07 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A multi-level AC/DC conversion circuit, comprising:
a first input terminal and a second input terminal, configured to receive an input voltage;
a positive output terminal and a negative output terminal, configured to provide an output voltage to a load;
a switch bridge arm, connected between the positive output terminal and the negative output terminal, and comprising a first switch and a second switch electrically connected in series to form a connection node connected to the first input terminal;
an inductor, having a first terminal and a second terminal, wherein the first terminal of the inductor is electrically connected to the second input terminal;
an N-level conversion circuit, wherein N is a natural number greater than 2, and the N-level conversion circuit comprises:
N−1 upper switches, wherein a first upper switch to an (N−1)th upper switch among the N−1 upper switches are electrically connected in series between the second terminal of the inductor and the positive output terminal sequentially and form a first upper connection node to an (N−2)th upper connection node sequentially;
N−1 lower switches, wherein a first lower switch to an (N−1)th lower switch among the N−1 lower switches are electrically connected in series between the second terminal of the inductor and the negative output terminal sequentially and form a first lower connection node to an (N−2)th lower connection node sequentially, the first to (N−1)th lower switches are corresponding to the first to (N−1)th upper switches respectively, the first to (N−2)th upper connection nodes are corresponding to the first to (N−2)th lower connection nodes respectively, and the first to (N−2)th upper connection nodes and the first to (N−2)th lower connection nodes collectively form a first pair of connection nodes to an (N−2)th pair of connection nodes; and
N−2 flying capacitors, respectively connected to the first pair of connection nodes to the (N−2)th pair of connection nodes sequentially; and
a control module, wherein when the multi-level AC/DC conversion circuit operates in a discontinuous conduction mode, the control module is configured to:
regard the N−1 lower switches and the N−1 upper switches as N−1 main switches and N−1 synchronous rectification switches respectively when a potential at the first input terminal is lower than a potential at the second input terminal, and regard the N−1 upper switches and the N−1 lower switches as the N−1 main switches and the N−1 synchronous rectification switches respectively when the potential at the first input terminal is higher than the potential at the second input terminal;
control the N−1 main switches to operate with a switching cycle and to turn on alternately with an interval time; and
calculate a duty ratio of the N−1 synchronous rectification switches according to at least the input voltage, the output voltage, the interval time, the switching cycle and a duty ratio of the N−1 main switches.