Climate comfort strategy for Electric Vehicle 2020-28-0023
In current days electric vehicles (EVs) are being promoted on significant scale through various government initiative as zero-emission means of transport. However the major hurdle for wider customer acceptance of EVs are higher cost, lack of charging station infrastructure and technologies, limited driving range.
It is known that Heating Ventilation and Air Conditioning (HVAC) system is major contributor in overall power consumption of electric vehicles. The HVAC system architecture and working logics in EVs are different from the one in fuel based vehicle. EVs are equipped with electric compressor for refrigeration cycle, PTC heater for heating purpose and also has additional cooling system for high voltage battery to maintain its temperature within a given limit. It is understood that HVAC system should work in manner which provides passengers thermal comfort as well as battery energy management.
Our work discusses the operation and working logics of various HVAC components which ensures cabin comfort at various ambient conditions with minimum stress on power consumption and thus optimizing the range at various ambient conditions. The control strategies on electric compressor was on the basis of optimum cooling capacity and power consumption over the range of operating speeds. Compressor operation is integrated with the Fully Automatic Temperature Control (FATC) system and battery cooling request to main control unit which ensures sufficient cooling and durable life.
PTC heater activation is also controlled through various strategies to ensure it activates only when there is significant heating requirement. There is control strategy for condenser fans for operating it at different speeds based on the heat rejection requirements across the condenser.
The activation and deactivation of solenoid valves are based on the defined cooling demand from either cabin side or battery cooling side. Thus instead of derating the whole HVAC system to reduce the power consumption, a complex matrix of various strategies on each component level would ensure optimizing the range of vehicle, providing sufficient cooling performance and durability of all components.
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