US 12,438,476 B2
Power conversion device
Akito Nakayama, Tokyo (JP); and Takuya Kajiyama, Tokyo (JP)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
Appl. No. 18/276,447
Filed by Mitsubishi Electric Corporation, Tokyo (JP)
PCT Filed Mar. 31, 2021, PCT No. PCT/JP2021/013862
§ 371(c)(1), (2) Date Aug. 9, 2023,
PCT Pub. No. WO2022/208735, PCT Pub. Date Oct. 6, 2022.
Prior Publication US 2024/0128889 A1, Apr. 18, 2024
Int. Cl. H02M 7/49 (2007.01); H02M 7/483 (2007.01); H02M 1/32 (2007.01)
CPC H02M 7/49 (2013.01) [H02M 7/4835 (2021.05); H02M 1/325 (2021.05); H02M 7/4833 (2021.05)] 20 Claims
OG exemplary drawing
 
1. A power conversion device comprising:
a power converter which performs power conversion between plural-phase AC and DC and includes, for the respective phases of the AC, leg circuits each having a pair of arms connected in series to each other, each arm including a plurality of converter cells which are connected in series and each of which includes an energy storage element and a plurality of semiconductor elements, the leg circuits being connected in parallel between positive and negative DC terminals; and
a controlling circuitry which controls the power converter, wherein
the controlling circuitry has a first control mode for controlling circulation current circulating among the leg circuits for the respective phases in the power converter so that an AC component having a frequency that is an even multiple other than a multiple of 3 with respect to a frequency of a fundamental component of the AC is contained in the circulation current, and
the controlling circuitry determines whether to make the first control mode active or inactive, on the basis of a voltage value of at least one of the energy storage elements.