Stability analysis of synchronous generators with constant power loads

The stability of synchronous generators with constant power loads was studied.The difference between AC constant power loads and DC constant power loads was reviewed and the small-signal model of AC constant power loads given.When the damper windings and the transformer potentials of armature windings are neglected,the small-signal transfer function of a synchronous generator with constant power loads can be deduced,and the stable operating conditions of the system obtained.The exact state-space equations of the system were derived.For different values of constant power loads and resistive loads,the stable and unstable regions of the system were plotted using Matlab.A conclusion can be drawn: constant power loads may cause the system to be unstable.Systems with higher output voltage have better stability than systems with low output voltage,and increasing the value of the output filter capacitance within specified limits can also improve stability of the system.