Internal Capacitive Compensation of a Fan Drive in a Water-Hydrocarbon Mixture Combustion System

The efficiency of electric fan drives is crucial for experimental facilities designed to combust water-hydrocarbon mixtures, as aerosol injection ensures a stable combustion process and overall equipment safety. Conventional three-phase motors typically suffer from a low power factor and high starting currents. Furthermore, existing approaches such as geometric optimization or external compensation fail to eliminate the spatial harmonics of the magnetomotive force, which ultimately cause core heating and torque pulsations. Previous studies on a screw electromechanical converter demonstrated the effectiveness of a split-winding configuration. However, this approach resulted in a 34.7% increase in core losses, albeit technologically justified for that specific application. This study aims to analyze the impact of internal capacitive compensation on the operational characteristics of a fan drive and to compare these findings with the performance of solid-rotor machines. To achieve this, finite element modeling was applied to both a baseline three-phase model and a modified configuration featuring a split winding with a 30° spatial shift and an internal capacitor. An analysis of the magnetic flux density and current distributions revealed that the modified model reduced the peak electromagnetic loss density by 15% (from 4.8×10⁶ to 4.1×10⁶ W/m³). Additionally, the starting torque increased from 15.2 N·m to 16.0 N·m alongside a significant reduction in torque ripples. The active zone of the magnetomotive force expanded, and the power factor improved to 0.71. The results show that, unlike in solid-rotor converters, internal capacitive compensation in fan drives acts as a spatial harmonic filter, effectively reducing core losses. The proposed approach improves insulation lifespan and the overall energy efficiency of aerosol injection systems used in fuel combustion facilities.