some nonlinear controllers info

Hi

i need following papers to study nonlinear controllers

A sliding mode approach to robust generation on DC-to-DC nonlinear converters
Fossas, E. Biel, D.
Univ. Politecnica de Catalunya, Barcelona


Nonlinear co-ordinated control of excitation and governor for hydraulic power plants
Jin, M.J. Hu, W. Liu, F. Mei, S.W. Lu, Q.
Dept. of Electr. Eng., Tsinghua Univ., Beijing, China


Nonlinear governor control for hydroturbine generator sets
Qiang Lu Chunxiao Sun Yuangzhang Sun
Dept. of Electr. Eng., Tsinghua Univ., Beijing


Small signal stability improvement by nonlinear controller design for shunt-connected synchronous voltage sources
Ming Wu; Rastgoufard, P.;
Dept. of Electr. Eng. & Comput. Sci., Tulane Univ., New Orleans, LA



i will b really thankful

hehe, my IEEE account still works