US 11,757,387 B2
Resistance determination in an electric motor assembly
Jinku Hu, Delft (NL); Bastiaan Huijzers, Dordrecht (NL); and Hendrik Jan Meijdam, Utrecht (NL)
Assigned to MCi (Mirror Controls International) Netherlands B.V., Woerden (NL)
Appl. No. 17/430,826
Filed by MCi (Mirror Controls International) Netherlands B.V., Woerden (NL)
PCT Filed Feb. 14, 2020, PCT No. PCT/NL2020/050082
§ 371(c)(1), (2) Date Aug. 13, 2021,
PCT Pub. No. WO2020/167124, PCT Pub. Date Aug. 20, 2020.
Claims priority of application No. 2022591 (NL), filed on Feb. 15, 2019.
Prior Publication US 2022/0166354 A1, May 26, 2022
Int. Cl. H02P 1/00 (2006.01); H02P 7/00 (2016.01); G01P 3/48 (2006.01); G01R 31/34 (2020.01)
CPC H02P 7/0094 (2013.01) [G01P 3/48 (2013.01); G01R 31/346 (2013.01)] 11 Claims
OG exemplary drawing
 
1. An electric motor assembly, comprising:
an electric motor, comprising brushes and sections of a commutator ring, wherein positions of the sections and the brushes change relative to each other during rotation of the motor;
a current sensor, coupled to the electric motor to measure an electric current to the electric motor;
a temperature sensor, thermally coupled to the electric motor; and
a processing circuit with inputs coupled to outputs of the current sensor and the temperature sensor, the processing circuit being configured to determine a motor resistance value by:
determining predicted values of the motor resistance for a first and second position of the sections relative to the brushes, at least one of the brushes contacting different numbers of the sections in the first position and the second position respectively, the predicted values being based on a temperature value measured by the temperature sensor and a predetermined dependence of variation of the motor resistance dependent on the temperature value;
determining an electric current value measured by the current sensor, when the electric motor is at least substantially at standstill;
selecting between different ways for determining the motor resistance value using the electric current value, dependent on which of the predicted values of the motor resistance most closely corresponds to the electric current value; and
determining the motor resistance using said electric current value that was selected using the electric current value based on which of the predicted values of the motor resistance most closely corresponds to the electric current value, and
wherein the selecting between different ways for determining the motor resistance value comprises selection between different factors to be applied to the electric current value measured by the current sensor substantially at standstill, dependent on which of the predicted values of the motor resistance most closely corresponds to the electric current value.