D19.9 - Battery Preheating Strategy for Electric Vehicles Utilizing Motor Drive System with Maximum Power Loss Point Tracking

Lithium-ion batteries in electric vehicles (EVs) face significant performance degradation and safety risks at low temperatures. To ensure reliable operation, preheating the battery before charging or use is necessary. This paper presents a battery preheating method that utilizes motor drive system by injecting sinusoidal current along the d-axis while maintaining zero torque. Safety limits and electrical constraints are considered to define feasible operating conditions. Based on the motor drive system’s loss characteristics, the relationships among the injected current parameters are determined to achieve maximum power-loss within the operational limits. A real-time control method is proposed to track and maintain the maximum power-loss operating point, enabling time-efficient battery heating. Experimental results verify that the proposed method successfully tracks the maximum power-loss point, generating heating power of up to 2.486 kW, thereby demonstrating its feasibility and potential for practical EV battery thermal management in cold climates.