A novel analysis of parallel operated self-excited induction generators

This paper presents a novel approach based on eigenvalue and eigenvalue sensitivity analyses to predict both minimum and maximum values of the capacitance required for the self-excitation of parallel operated three-phase induction generators. Numerous numerical methods based on steady-state equivalent circuit models have been proposed to find the minimum capacitance of a self-excited induction generator by solving simultaneous nonlinear equations. Steady-state and sensitivity analyses of different capacitance values concerning various system limits are performed. Transient analyses of the studied induction generators under different loading conditions are also carried out. The results show those induction generators with different speeds can be operated in parallel properly, but the requirement before they may be connected in parallel is the phase sequence of the running and incoming induction generators must be the same. Experimental results obtained on 1.1 kW induction machines confirm the feasibility and effectiveness of the proposed approach.