This paper investigates the asymptotical stabilization of port-controlled Hamiltonian （PCH） systems via the improved potential energy-shaping （IPES） method. First, a desired potential energy introduced by a transitive Hamiltonian function is added to the original kinetic energy to yield a desired Hamiltonian function. Second, an asymptotically stabilized controller is designed based on a new matching equation with the obtained Hamiltonian function. Finally, a numerical example is given to show the effectiveness of the proposed method.
In order to analyze power system stability in environment of WAMS(wide area measurement system),a new steady state stability model with time-varying delay was proposed for power system.The factors of exciter and power system stabilizer with delay were introduced into analytical model.To decrease conservativeness of stability analysis,an improved Lyapunov-Krasovskii functional was constructed,and then a new delay-dependent steady state stability criterion for power system,which overcomes the disadvantages of eigenvalue computation method,was derived.The proposed model and criterion were tested on synchronous-machine infinite-bus power system.The test results demonstrate that Lyapunov-Krasovskii functional based power system stability analysis method is applicable and effective in the analysis of time delay power system stability.
