Model of the Field Winding Current of an Automobile Generator

Abstract

The field winding of an automobile generator converts DC energy (from the generator or battery) into magnetic energy. The field winding current strength is determined by not only the generator and battery voltage but also its technical condition. The field winding performance affects the current generated by the generator, therefore, control over its technical condition is an urgent problem. The entire range of the generator speed is divided into three regions differing in the devices involved: a battery only; a battery and a generator; a battery, a generator, and a voltage regulator. A mathematical model of the field winding voltage and current in no load operation and under load has been developed for each region chosen. During the experiments, the change in the power supply system parameters over time has been determined with a smooth increase in the rotor speed on a special bench. An increase and decrease in the field winding resistance (field loss and turn-to-turn short circuit, respectively) have been simulated. The nature of the impact of the generator load mode and the field winding technical condition on the vehicle's power supply system parameters has been determined. The data and mathematical model obtained can be used to predict and identify possible failures of the vehicle's power supply system.