A simplified model of a variable speed synchronous generator loaded with diode rectifier

This paper presents a new, time-continuous, nonlinear model of a synchronous generator loaded with diode rectifier. The developed model is used for study of a system consisting of two synchronous generators (exciter and main generator) connected in cascade, each loaded with a diode rectifier. Speed of the system is not constant, but varies as the load changes. Some particularities of this system are described and reasons for nonsinusoidal generator voltage and current waveforms are discussed. Simplified equations of the system are developed based on first harmonic assumption, generator space vector diagram and losslessness of a diode bridge. Model validity for large signal (transient) analysis is confirmed through comparison with the switching model simulation results and with measurements. Linearization of the model and application to control purposes through small signal analysis is considered