US 12,456,932 B2
Power conversion device
Takuya Kajiyama, Tokyo (JP); Toshiyuki Fujii, Tokyo (JP); Shuhei Fujiwara, Tokyo (JP); and Kazuyori Tahata, Tokyo (JP)
Assigned to Mitsubishi Electric Corporation, Tokyo (JP)
Appl. No. 18/254,584
Filed by Mitsubishi Electric Corporation, Tokyo (JP)
PCT Filed Dec. 9, 2020, PCT No. PCT/JP2020/045900
§ 371(c)(1), (2) Date May 25, 2023,
PCT Pub. No. WO2022/123697, PCT Pub. Date Jun. 16, 2022.
Prior Publication US 2024/0022183 A1, Jan. 18, 2024
Int. Cl. H02M 7/5395 (2006.01); H02M 1/00 (2007.01); H02M 7/483 (2007.01)
CPC H02M 7/5395 (2013.01) [H02M 1/0012 (2021.05); H02M 1/0054 (2021.05); H02M 7/4835 (2021.05)] 9 Claims
OG exemplary drawing
 
1. A power conversion device comprising:
a power converter including a plurality of arms each having a plurality of converter cells cascaded to each other; and
a control device to control the power converter, wherein
each of the arms is electrically connected to a corresponding phase of an AC circuit,
each of the converter cells includes:
a pair of input/output terminals;
a plurality of switching elements; and
a power storage element electrically connected to the input/output terminals through the switching elements,
the control device includes:
an AC current controller to control AC current flowing between the power converter and the AC circuit; and
a circulating current controller to control circulating current flowing between the arms of the power converter,
the circulating current controller controls the circulating current such that an imbalance in voltage of the power storage elements between different arms is eliminated, in a first operation mode,
the circulating current controller lowers a voltage of the power storage element of each of the converter cells constituting the power converter by increasing an effective value or amplitude value of the circulating current in a second operation mode, compared with in the first operation mode, and
the AC current controller reduces an effective value or amplitude value of the AC current in the second operation mode, compared with in the first operation mode.