Real-Time Implementation of Droop Control in Low Voltage Direct Current Microgrid Using STM32F446 CORTEX-M4 ARM Controller with LCD-Based Field Adaptability and Safety Integration

This paper presents the real-time implementation of droop control in a low voltage direct current (LVDC) microgrid using the STM32F446 CORTEX-M4 ARM controller. The objective is to establish a decentralized control mechanism that stabilizes voltage regulation and ensures equal load sharing between converters. In practical LVDC systems, cable resistance causes voltage drops along distribution lines, leading to unequal load sharing and circulating current. To address this issue, droop control is implemented in real-time through embedded programming on the STM32F platform, with results compared against a system without droop control. The setup integrates voltage and current sensing with control logic and a feedback circuit. Furthermore, safety mechanisms provide immediate shutdown under excessive load current, thereby protecting the hardware. The novelty lies in the unique hardware integration on the STM32F446 controller, an LCD-based interface for real-time adaptability, embedded safety features, and quantified parameter analysis. To confirm the efficacy of the proposed research work, MATrix LABoratory (MATLAB) simulations were validated against hardware experiments. At full load, droop control reduces load sharing error from 19.7% to 4.9% and circulating current from 0.77 A to 0.18 A, demonstrating improved load sharing, though voltage regulation is adversely affected. Hardware results closely match simulations, confirming reliable and stable performance under varying load conditions. These findings demonstrate the practical viability of STM32F446-based droop control and represent a step toward scalable, robust DC microgrid deployment.