Uncertainty analysis and propagation for an Auxiliary Power Module

Abstract

In modern hybrid electric vehicles (HEVs), the Auxiliary Power Module (APM) acts as the DC/DC converter which regulates the power flow between the high voltage (HV) battery and the low voltage (LV) DC bus. Optimizing the control and operation of the APM is an important component of minimizing vehicle energy consumption. Characterizing the performance of the APM requires extensive testing of APM under different operating conditions. However, in the state-of-the-art experimental validation testing using industry standard modeling practices, addressing uncertainties in the test results is not very common. A consequence of this shortcoming is the propagation of uncertainty from test to simulation, which can cause simulated results to diverge significantly from real world performance. In this paper we present test procedures and results for a Delphi Auxiliary Power Module (APM) that was installed in a 2011MY Chevrolet Volt. Experimental uncertainty in the measurand of efficiency is modeled using Scheffe confidence intervals as a function of APM output current. Uncertainty is then propagated through a vehicle fuel economy simulation to understand the role of APM experimental uncertainty in vehicle fuel economy prediction.