Enhancing Diesel Generator Fuel Efficiency by Operating in Optimum Variable-Speed Combined with Vienna Converter

– Diesel engine generators are commonly used in refinery systems to provide electrical power. The engines are generally Constant Speed Diesel Wound Rotor Synchronous Generator (CSD-WRSG) type and are operated in parallel with ones. In this study, a Variable Speed Diesel Wound Rotor Synchronous Generator (VSD-WRSG) system is proposed, combined with additional AC-to-DC and DC-to-AC converters, in order to meet the low load condition and save the fuel. The Diesel Generator's current rotation, which is set at a constant speed, is then changed to the optimum speed. It varies depending on the load demand. The electrical frequency is controlled through the converters. This research focuses on a single diesel generator with a capacity of 880 kW for supplying 343 kW average load demand. The AC-to-DC converter employs a Vienna Rectifier with hysteresis control. In order to enable smooth power transmission during load changes, a DC-to-AC converter is used with a Virtual Synchronous Generator control method. All the simulations are completed using MatLab/Simulink. The simulation results indicate that the proposed model is effective. When daily load data is employed, the VSD-WRSG system can save up to 5.3% or 121 liters of fuel per day if compared to the CSD-WRSG system.