US 12,276,707 B2
Self-diagnostic method of open-circuit faults, computerized survey system, and modular inverter
Andreja Rojko, Rennes (FR)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
Appl. No. 17/924,043
Filed by MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
PCT Filed Apr. 16, 2021, PCT No. PCT/JP2021/017314
§ 371(c)(1), (2) Date Nov. 8, 2022,
PCT Pub. No. WO2021/251030, PCT Pub. Date Dec. 16, 2021.
Claims priority of application No. 20305639 (EP), filed on Jun. 11, 2020.
Prior Publication US 2023/0176142 A1, Jun. 8, 2023
Int. Cl. G01R 31/26 (2020.01); G01B 7/14 (2006.01); G01B 7/30 (2006.01); G01R 31/42 (2006.01); G01R 31/54 (2020.01); H02M 1/32 (2007.01)
CPC G01R 31/54 (2020.01) [G01R 31/42 (2013.01); H02M 1/327 (2021.05)] 15 Claims
OG exemplary drawing
 
1. Self-diagnostic method of open-circuit faults, said method comprising a first loop comprising:
sampling, by a modular inverter configured to drive a three phase motor, power switching blocks of the modular inverter comprising a plurality (k=1 . . . n) of blocks paralleled in a phase leg, and each of the plurality of blocks including a temperature sensor among a plurality of temperature sensors, temperatures data Tkp of said n blocks (k=1 . . . n) in a phase leg measured by said plurality of temperature sensors at relevant sampling times tSD with a relevant sampling interval ΔtSD, and storing the sampled temperatures data Tkp;
at least one step of comparing current temperature data Tkp of a block k with current average temperature data

OG Complex Work Unit Math
of all other blocks of said phase leg at sampling time tSDP, considering said block k as an open circuit block block kf and raising an open-circuit fault flag OF on said open circuit block kf if the following condition is not fulfilled:

OG Complex Work Unit Math
where ThAV is a predefined average temperature deviation threshold.