US 12,255,545 B2
Inverter device for capable of performing overheating protection to switching elements when driving electric motor and control method thereof
Hirotaka Yoshioka, Kanagawa (JP); Jun Katsumata, Kanagawa (JP); and Toshiyuki Watanabe, Kanagawa (JP)
Assigned to NIDEC ELESYS CORPORATION, Kanagawa (JP)
Filed by NIDEC ELESYS CORPORATION, Kanagawa (JP)
Filed on May 25, 2022, as Appl. No. 17/752,875.
Claims priority of application No. 202110576589.X (CN), filed on May 26, 2021.
Prior Publication US 2022/0385207 A1, Dec. 1, 2022
Int. Cl. H02M 7/537 (2006.01); H02P 6/08 (2016.01); H02P 27/06 (2006.01); H02P 29/60 (2016.01); H02M 1/084 (2006.01)
CPC H02M 7/537 (2013.01) [H02P 6/08 (2013.01); H02P 27/06 (2013.01); H02P 29/60 (2016.02); H02M 1/084 (2013.01)] 2 Claims
OG exemplary drawing
 
1. An inverter device for driving an electric motor, comprising:
an inverter circuit comprising a plurality of switching elements; and
a control circuit controlling the inverter circuit,
wherein in response to a rotation speed of the electric motor being equal to or less than a preset rotation speed threshold and a torque of the electric motor being equal to or greater than a preset torque threshold, the control circuit changes a temperature estimation logic of the switching elements of the inverter circuit,
the temperature estimation logic comprises a normal estimation logic and a lock state estimation logic,
the lock state estimation logic is used to estimate a temperature in response to the rotation speed of the electric motor being equal to or less than the preset rotation speed threshold and the torque of the electric motor being equal to or greater than the preset torque threshold, and
a difference between a temperature estimated according to the lock state estimation logic and an actual temperature of the switching elements is less than a difference between a temperature estimated according to the normal estimation logic and the actual temperature of the switching elements under a same condition.