STABILITY ANALYSIS OF A MODULATED AC/DC SYSTEM USING THE EIGENVALUE SENSITIVITY APPROACH.

An optimal control strategy for improved dynamic performance of integrated ac/dc systems, based on power modulation techniques, is discussed. The basic feature of the method is the minimization of the adverse reactive power interactions between the controls and voltage sensitivity loads, which tend to reduce the effectiveness of the modulation process. A method for stability analysis, based on linearization techniques and eigenvalue sensitivities, is developed and applied to a typical ac/dc system with nonlinearly-voltage-dependent load. The dynamic performance of the system, both with dc power modulation and power system stabilizer, is evaluated for various operating conditions, different load characteristics and different excitation systems. Finally, a dynamic simulation program is used to obtain the exact transient response of the ac/dc system in the time domain. The simulation results verify the response predicted by the linear eigenvalue sensitivity analysis.