Abstract

The global transition toward electrified mobility has created new opportunities for converting existing internal combustion engine (ICE) vehicles into sustainable electric vehicles (EVs) through cost-effective retrofitting. This paper presents the design, implementation, and performance analysis of a 3 kW BLDC motor-driven internal transport vehicle converted to an electric configuration using an STM32-based controller platform. The primary objective of this work is to develop an adaptive control algorithm that enhances energy efficiency and drive smoothness without major hardware modifications. The proposed system integrates a 48 V, 75 Ah lithium-ion battery pack with a 3 kW BLDC motor drive, designed to meet short-distance, high-torque internal transport operations such as factory logistics and campus utility movement.

A novel adaptive soft-start and torque-ramp control strategy has been implemented to regulate the motor’s current surge and improve energy utilization. Unlike conventional fixed-ramp controllers, the proposed system dynamically adjusts PWM duty cycle and ramp profile based on load and battery state, thereby minimizing thermal stress and current peaks during acceleration. The control logic was developed using STM32 microcontroller firmware and validated through MATLAB/Simulink and Proteus co-simulation environments before hardware testing. Simulation and experimental results confirm that the system effectively reduces inrush current by 20%, lowers energy consumption per duty cycle by approximately 8%, and improves thermal stability of the inverter circuit.

The retrofit approach demonstrates that efficiency enhancement in low-power EVs can be achieved through intelligent controller-level modifications rather than costly hardware upgrades. This study provides a scalable and economical pathway for transitioning existing internal transport fleets toward sustainable electric operation with improved performance, reliability, and lifespan.