US 12,445,023 B2
Magnetic gap length estimating device, magnetic gap length estimating method, and driving device for rotating electric machine
Kodai Okazaki, Tokyo (JP); and Kan Akatsu, Yokohama (JP)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP); and NATIONAL UNIVERSITY CORPORATION YOKOHAMA NATIONAL UNIVERSITY, Yokohama (JP)
Appl. No. 18/282,240
Filed by Mitsubishi Electric Corporation, Tokyo (JP); and National University Corporation YOKOHAMA National University, Yokohama (JP)
PCT Filed Mar. 24, 2021, PCT No. PCT/JP2021/012144
§ 371(c)(1), (2) Date Sep. 15, 2023,
PCT Pub. No. WO2022/201344, PCT Pub. Date Sep. 29, 2022.
Prior Publication US 2024/0162790 A1, May 16, 2024
Int. Cl. H02K 11/33 (2016.01); H02K 3/28 (2006.01); H02K 11/26 (2016.01)
CPC H02K 11/33 (2016.01) [H02K 3/28 (2013.01); H02K 11/26 (2016.01); H02K 2201/03 (2013.01); H02K 2213/03 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A magnetic gap length estimating device for estimating a magnetic gap length in an M-group N-phase rotating electric machine to be driven by an inverter where M represents a natural number and N represents a natural number not smaller than 2, the rotating electric machine being formed by connection wires with a phase difference in electrical angle among phases being 360/N degrees, the magnetic gap length estimating device comprising:
a voltage acquiring circuitry which acquires a no-load-induced line-to-line voltage induced between the connection wires under no load; and
a magnetic gap estimating circuitry which estimates the magnetic gap length, wherein
the magnetic gap estimating circuitry includes
a spectrum analysis circuitry which converts the no-load-induced line-to-line voltage acquired by the voltage acquiring circuitry into amplitudes and phases for respective frequencies,
a frequency analysis circuitry which extracts amplitudes and phases of a fundamental wave component and an Nth-order harmonic component of the no-load-induced line-to-line voltage from among the amplitudes and the phases, for the respective frequencies, that have been obtained through the conversion by the spectrum analysis circuitry, and
an estimating-and-calculating circuitry which estimates the magnetic gap length from the amplitudes and the phases, of the fundamental wave component and the Nth-order harmonic component of the no-load-induced line-to-line voltage, that have been extracted by the frequency analysis circuitry.