As this blog has noted before, PEEM (Power Electronics and Electrical Machine) technology is essential with electric-drive vehicles. PEEM technology comprises three main elements: power electronics (e.g., boost converters and inverters); electric motors; and thermal control and system integration. And, thermal control is a critical element to enable power density, cost, and reliability of the other components. It also is an important part of battery modules.
According to a pair of researchers from NREL (the US Department of Energy’s National Renewable Energy Laboratory), system thermal and fluid models and heat exchanger sizing models show the potential of integrating the power electronics and electric machine cooling with the air conditioning system. Kevin Bennion and Matthew Thornton believe that a low temperature liquid coolant not only could benefit the air conditioning in the vehicle, but also work to cool the electric drive.
In previous research there seem a benefit to replacing conventional evaporators in standard refrigeration systems with a “micro-channel heat sink”. The NREL researchers’ model indicates a benefit to a sealed HVAC system. A sealed system cuts refrigerant leaks and the need to refill the AC refrigerant.
Locating the AC condenser close to the HVAC system would also reduce the length of the refrigerant lines, leading to a lower pressure drop through the system. The reduced pressure drop improves the AC operating efficiency. The electric drive system benefits by sharing the cost of the low temperature coolant loop. The system also enables forms of power electronics and electric machine temperature protection without reducing the electric drive performance.