System level heat pump model for investigations into thermal management of electric vehicles at low temperatures.

Abstract

One of the challenges concerning electric vehicles is their performance in cold climates. As the temperature drops below 10 • C battery capacity begins to reduce and heating demand starts to claim a larger proportion of total vehicle energy expenditure. Although efficient, electric vehicles waste heat through a few components, resulting in opportunity to harvest waste heat through a heat pump. With multiple options for harvesting heat and the option to heat the battery, a model and architecture has been developed to give flexibility in a wide range of thermal management scenarios. This paper explores the details of the model and presents two example cases of interest to demonstrate the model's applicability.

Optimisation of Control Input Allocation Maps for Electric Vehicle Heat Pump-based Cabin Heating Systems

“…Some safety features, such as limiting the compressor outlet pressure p 3 and the evaporator outlet pressure p 1 (see Figure 2), as well as the compressor pressure ratio p 3 /p 2 , cannot rely solely on the model accuracy, i.e., they need to be satisfied explicitly. For this purpose, the overall control strategy should be extended with secondary feedback controllers of measurable variables that need to be limited (see e.g., [31]). There may be additional practical extensions of the proposed, overall control strategy, such as switching the compressor off when the cabin air temperature tends to overshoot the target temperature, which may typically occur for the conditions of relatively high ambient temperature, i.e., low thermal loads.…”