Abstract
High voltage battery, inverters and electric motors form the critical components of the hybrid electric propulsion system. Optimal sizing of the high voltage components is essential to ensure efficiency, durability, lower cost and mass of the propulsion system while meeting the vehicle technical specifications. For sizing a durable system, the propulsion system needs to be simulated for various drive / duty cycles that subject the vehicle to extreme operating conditions. These operating conditions represent maneuvering capability of the vehicle through various levels of accelerations, braking and gradeability. This would translate into the design requirements for the transmission and power electronics components such as HV battery power and current requirements, DC and AC cable sizing, inverter sizing, motor torques, transmission endurance limit, cooling system etc. This paper discusses an analytical method to post process the time series data of duty cycle simulation using moving average techniques to rank duty cycle severity and estimate equivalent current, power and torque values at various durations. Three different methods are analyzed – exponential moving average, RMS moving average and simple moving average. The details of each of the method and the use case regarding the hybrid vehicle component sizing will be discussed.