Measurement Uncertainty and Its Influence on E-Drive Optimization Applications 2024-26-0097

This paper gives insights in the theoretical measurement uncertainty of E-Drive rotor position dependent results, like I_d and I_q calculations, done by a modern propulsion power analyzer (PA). The calculation of I_d and I_qis fundamental to perform control optimization and application tasks for an E-Drive system. To optimize the E-Drive system application towards e.g., best efficiency, best performance, or improved NVH the importance of the testing toolchain is described: a power analyzer delivering the required results, an automation system, and a Design of Experiment tool to set improved target values.

Consequently, inverters applications featuring field-oriented control (FOC) with permanent magnet synchronous machines (PMSM) are updated with a chosen control strategy. For achieving a certain behavior of an E-Drive, different degrees of freedom in the Inverter Control Unit are available; Lookup tables I_d and I_q represent two fundamental application labels to be considered. Since the inverter must rely on the built-in current sensors and the measurement of resolver signals at low bit rate, its controlling signals underly the propagation of the underlying measurement uncertainty. Such as with the calibration of measurement devices, it is recommended to use calibrators of lower measurement uncertainty to define the offset values or adjust calibration values. Therefore, it is recommended to use a highly adaptable power analyzer to perform the measurement task. It is shown what the assumed measurement uncertainty of an inverter reveals compared to a high precision device with automatic and independent resolver offset detection and highly accurate current measurement. It is described how an inaccurate resolver offset value propagates into results like I_d and I_q. Also, the PA gives a qualitative evaluation of the inverter settings for rotor position detection. The knowledge about the right measurement technology lays out the base for a successful E-Drive optimization application.