Compensation of Radial Mode 0 Vibration of an Electrically Excited Synchronous Machine using Harmonic Field Current Injection

This paper investigates a new method for compensating the radial mode 0 vibrations in the stator by injecting additional harmonic currents into the field winding of an electrically excited synchronous machine. In the presented method, an additional spatial fundamental field is injected using the field winding. The relationship between harmonic current and resulting magnetic force density in the stator bore is derived analytically and described in the form of an influence factor. The identified factor then allows the calculation of the required harmonic currents in a standardized, repeatable and exact way early in any development process. In this paper, the method is validated using extensive FEM simulations, demonstrating a 98% reduction in radial mode 0 force density at the investigated operating point and the frequency of interest.