Experimental Study of an Integrated Variable-Speed Diesel Power System with Adaptive Voltage Stabilisation and Battery Support

This study presents the development and experimental validation of an autonomous power-generation system integrating a variable-speed diesel generator, an adaptive voltage converter, and an energy-storage unit. The configuration was designed to improve fuel efficiency, reduce emissions, and enhance voltage stability under dynamic loads. Experiments were conducted using a Perkins 1104D-E44T diesel engine and a Leroy-Somer TAL046B synchronous generator, with operational speeds ranging from 800 to 1700 rpm. Results showed an average specific fuel consumption of 274 g/kWh and ±5% output-voltage deviations during load transients. Dynamic time-domain simulations (MATLAB/Simulink R2023b with Simscape Electrical) were developed to reproduce interactions among the engine, generator, converter, and battery under load steps and speed sweeps. Model predictions for RMS voltage, frequency recovery time, specific fuel consumption, and NOx/CO concentrations agreed with measurements within ≤5% across the tested operating envelope, supporting the generality of the proposed control concept. The integration of a lithium-iron phosphate battery effectively compensated for peak loads and smoothed voltage fluctuations, reducing diesel fuel consumption by up to 12%. Emission measurements confirmed average nitrogen oxide concentrations of approximately 410 ppm and carbon monoxide levels of roughly 190 ppm. A comparative analysis showed that the proposed solution outperformed conventional fixed-speed systems in response time, harmonic distortion, and energy efficiency. The findings highlight the benefits of combining variable-speed operation with adaptive voltage regulation and battery support for decentralised power applications.