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

Abstract

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.