A hybrid power source and its control strategy optimization for low-speed electric vehicle

This study addresses the urgent need for advanced energy storage solutions in low-speed electric vehicles (LSEVs) by introducing a reconfigurable ultra-capacitor (UC)/battery hybrid power source (HPS). The key contributions lie in: (i) A dual-UC-bank topology enabling real-time series/parallel switching, which generates adjustable voltage outputs to optimize power delivery across wide operating ranges; (ii) Dynamic voltage switching between high-efficiency modes with fault-tolerant operation capability, ensuring reliable power transition during high-power demand or low-speed torque requirements; (iii) A bi-directional DC-DC power converter (BDPC) with an optimized voltage conversion ratio (about 2–3), enhancing motor control precision and regenerative braking efficiency through improved voltage-speed matching; (iv) A Harris Hawks Optimization (HHO)-based power distribution strategy targeting energy consumption rate (ECR) reduction. Simulations under scaled New European Driving Cycle (NEDC) and Federal Test Procedure-75 (FTP-75) achieve average efficiency of 88.61%–89.93% and ECR 0.070–0.071 kW h/km, validating the superior energy utilization of the system compared to conventional fixed-voltage HPS. Experimental results confirm the proposed solution’s effectiveness in balancing cost, volume, and performance constraints specific to LSEVs. These advancements provide scalable solutions for various new energy vehicles (NEVs), particularly cost-sensitive LSEV applications where traditional HPS configurations fail to balance efficiency and practicality.