EDM (ELECTRIC DRIVE MODULE) EFFICIENCY TEST METHODOLOGY: ACCURACY IMPROVEMENT

Efficiency plays a central role in evaluating the capability of the Electric Drive Module (EDM) to convert electric energy into mechanical energy. This master’s thesis focuses on optimising the testing methodology used to measure the EDM efficiency, defining the accuracy and repeatability levels of the tests. The accuracy of the EDM efficiency measurements is strongly dependent on the testing methodology, as factors such as measurement instruments precision, calibration, data acquisition rate and environmental conditions can all introduce uncertainty. Measurement quality is characterised by accuracy and repeatability, which can be assessed through uncertainty evaluation. Accuracy refers to the closeness of a measurement to the true value, whereas repeatability describes the consistency of a measurement under identical testing conditions. Uncertainty evaluation provides a quantitative measure of confidence in the measurement results by defining the interval within which the true value is expected to lie. According to Guide to Expression of Uncertainty in Measurement (GUM), total uncertainty consists of several components, which can be grouped in two categories: those evaluated by statistical methods and those evaluated by other means. The methodology adopted for this thesis is consistent with the framework presented in GUM and it is applied to uncertainty evaluation of EDM efficiency testing. An analytical model of the measurement chain was computed, with the identified uncertainty sources quantified and propagated to the resulting efficiency value using a MATLAB script. Efficiency tests were carried out at Centro Ricerche Fiat (CRF) using an integrated test bench that couples motor and inverter, equipped with an HBM power analyser. The MATLAB tool provides quantitative information on measurement accuracy and repeatability. The outcome of this thesis contributes to defining a more robust EDM testing methodology, supporting the evaluation of electric drivetrain performance in research and development environments.