METHOD FOR ASCERTAINING A CABLE TEMPERATURE AND/OR CONNECTOR TEMPERATURE ON AN ELECTRIC DRIVE

• Main Authors: FEUERSTACK, Peter, RIES-MUELLER, Klaus
• Format: Patent
• Language: English; French; German
• Published: 09.10.2024
• Subjects: MEASURING; MEASURING QUANTITY OF HEAT; MEASURING TEMPERATURE; PHYSICS; TESTING; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR

The invention relates to a method for ascertaining a cable temperature and/or connector temperature on an electric drive having an e-axle module (32) with an electric machine (30), a power electronics system (18), and a DC voltage source (16), in particular a high-voltage battery (10), which are connected together via a connection cable (36), at least the following method steps being carried out:A voltage U_Batt voltage is measured at a DC voltage source (16) and a voltage U_INV is measured at an input of the power electronics system (18). Measurement accuracy is subsequently compared by referencing U_INV to U_Batt. This is followed by determining a reference sum resistance R_sum_ref of the connection cable (36) at a known temperature Tref. Then, with current flowing between the DC voltage source (16) and the power electronics system (18), a difference U_delta between the voltage U_Batt of the DC voltage source (16) and the voltage U_INV at an input of the power electronics system (18) is measured and the sum resistance R_sum is determined. Then, the temperature is determined from repeated determination of the sum resistance R_Sum during operation and the temperature of the connection cable (36), the connections and connecting elements, such as plugs, is calculated. This is followed by a differentiation between the resistances R1 of a connection (12, 14) of the DC voltage source (16), and/or a resistance R2 of a connection cable (36), and/or a resistance R3 of an input of the power electronics system (18). Subsequently, a drive power of the electric drive is reduced, while the temperature of the connections (12, 14), the connection cable (36) and the at least one input of the power electronics system (18) exceeds a temperature threshold.The invention further relates to the use of the method to ascertain the temperature of a connection cable (36) for connection terminals (12, 14) of a DC voltage source (16) and the temperature at least one input of a power electronics system (18) of an e-axle module (32) of an electrically powered vehicle.