Optimization of Electric Vehicle Radiator Fan Duty Cycle using KULI 1D Transient Simulation

As the whole world moves toward the electric drive in the automotive sector, it is important for us to focus on the performance of electric vehicles in the bus segment. For the better efficiency and performance of the vehicle, the temperature balance of the traction motor & auxiliary power electronic components is of utmost importance. One of the main contributors to the power electronic components and traction motor thermal system is the Radiator fan. Two electric fans of smaller diameter are used, unlike a single fan in the engine cooling system. Both these fans are driven by individual BLDC motors, RPM and power consumption of the 2 electric fans purely depends on the radiator coolant outlet temperature. At full engaged condition, these 2 electric fans alone consume nearly 26% of the total LV load available for a 250 KW traction motor. In this paper a methodology is defined to calculate the power consumption of the 2 electric fans in actual vehicle running conditions using KULI 1D software. Fan revolution is controlled on the basis of the coolant temperature and this is optimized to obtain an optimum control logic.