US 12,274,038 B2
Electric power converter, such as an electric motor drive for driving an electric motor and method for operating the electric motor drive
Ari Ristimäki, Laihia (FI); Juha Norrena, Mustasaari (FI); Tuomas Yli-Rahnasto, Vaasa (FI); Pekka Hemminki, Laihia (FI); and Jani Matti Perkiö, Tampere (FI)
Assigned to VACON OY, Vaasa (FI)
Filed by Vacon Oy, Vaasa (FI)
Filed on Nov. 14, 2022, as Appl. No. 18/055,003.
Claims priority of application No. 102021129727.3 (DE), filed on Nov. 15, 2021.
Prior Publication US 2023/0156981 A1, May 18, 2023
Int. Cl. H02P 29/60 (2016.01); H02M 7/00 (2006.01); H05K 7/20 (2006.01)
CPC H05K 7/20945 (2013.01) [H02M 7/003 (2013.01); H02P 29/60 (2016.02); H05K 7/209 (2013.01); H05K 7/20927 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An electric power converter comprising:
a cooling system with a heat sink for dissipating thermal energy generated by the converter and with coolant flow means for cooling the heat sink;
first measuring means for measuring the coolant inlet temperature;
second measuring means for measuring the heat sink temperature; and
estimating means for estimating the thermal energy transferred to the heat sink, wherein the converter is provided for estimating the thermal resistance (Rth) of the heat sink based on the measured temperatures and the estimated thermal energy transferred to the heat sink, for comparing the estimated thermal resistance (Rth) to reference values and for outputting a signal when a difference between the estimated thermal resistance (Rth) and the reference values exceeds a threshold value.