Johri, Rajit (Ford Motor Company), liang, wei (Ford Motor Company), McGee, Ryan (Ford Motor Company)

Hybrid Electric Vehicle Energy Management with Battery Thermal Considerations Using Multi-Rate Dynamic Programming

Scheduled for presentation during the Contributed session "Battery Systems" (TuBT4), Tuesday, October 22, 2013, 14:30−14:50, Paul Brest West

6th Annual Dynamic Systems and Control Conference, October 21-23, 2020, Stanford University, Munger Center, Palo Alto, CA

This information is tentative and subject to change. Compiled on April 25, 2024

Abstract

Battery capacity and battery thermal management control have a significant impact on the Hybrid Electric Vehicle (HEV) fuel economy. Additionally, battery temperature has a key influ- ence on the battery health in an HEV. In the past, battery tem- perature and cooling capacity has not been included while per- forming optimization studies for power management or optimal battery sizing. This paper presents an application of Dynamic Programming (DP) to HEV optimization with battery thermal constraints. The optimization problem is formulated with 3 state variables, namely, the battery State Of Charge (SOC), the en- gine speed and the battery bulk temperature. This optimization is critical for determining appropriate battery size and battery thermal management design. The proposed problem has a major challenge in computation time due to the large state space. The paper describes a novel multi-rate DP algorithm to reduce the computational challenges associated with the particular class of large-scale problem where states evolve at very different rates. In HEV applications, the battery thermal dynamics is orders of magnitude slower than powertrain dynamics. The proposed DP algorithm provides a novel way of tackling this problem with multiple time rates for DP with each time rate associated with the fast and slow states separately. Additionally, the paper gives possible numerical techniques to reduce the DP computational time and the time reduction for each technique is shown.