EFFECT OF PARAMETER VARIATIONS ON THE STABILITY LIMITS OF PERMANENT-MAGNET SYNCHRONOUS MACHINES

This paper presents a comprehensive study of the effect of parameter variations on the stability behavior of permanent magnet (PM) machines. The state-variable equations are derived in terms of a set of non-dimensional parameters, so that their effects on the stability limits can be simply demonstrated. The stability is analyzed by means of state- space technique as it has the advantages of simplicity, accuracy and flexibility. The results of the analysis allow a choice of necessary and sufficient conditions for stable operation of the machine. The results also look interesting from a practical point of view, since a more realistic and efficient margin for stability limits can be defined. Simulation results are obtained using parameters of a 25-hp PM synchronous motor provided with a Neomax-35 magnets for excitation. Finally, useful conclusions have been provided, which are considered to be a good aid for designing these machines. © 1990 by Hemisphere Publishing Corporation.