A Flux Map-Based Approach for Experimental Characterization of an Ipm 2-In-1 Drive Unit for Electric Vehicles

This paper proposes a methodology for the experimental characterization of an interior permanent magnet (IPM) synchronous machine integrated into a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2-\text{in}-1$</tex> drive unit. The procedure creates flux maps, which describe the machine's flux linkages as a function of the current in synchronous dq coordinates. These maps form the basis for control strategy development and the evaluation of loss and efficiency maps with inverter constraints. The primary objective is to ensure a straightforward methodology for characterizing production traction IPM electric drive units. An off the shelf automotivegrade inverter controls the unit under test, while a power analyzer measures the electrical quantities. The flux map identification does not rely directly on position sensor data but solely utilizes the dq current control provided by the inverter and the measured three-phase voltages. Furthermore, the methodology extends beyond electric machines and can be applied to the entire system. The characterized 87 kW drive unit includes an electric machine and a dual-stage, single-speed gearbox. The measured maximum efficiency of the drive unit is 94 %, while 95.8 % peak electric machine efficiency is estimated using a gearbox loss model. Maximum loss of 8 kW is recorded at the maximum torque point at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$11,000 \text{rpm}$</tex>. All experimental data is publicly available.