Abstract: Begiiiiiiiig witli fuiidainental properties such as passivity- or iiicrriiieiit,al passivit,y of tlie network eleiiieiits comprising a swi thlietl power converter, the iioiiiiiial opeii-loop opemtion of a Ixoatl class of such converters is showii to be sta.ble in tlic large via. a Lyapuiiov arguiiieiit. The obta.ined Lyapunov fuiictioii is t,lieii shown to be useful for designing globally st,al)iliziiig coiitrols that include adaptive scheiiies for liaiitlliiig uncertain iioiiliiial parameters. Numerical simulations illiistrate the application of this control approach in DC-DC coiivcrt,ers.

Abstract: Mossaheb et al (1987) have presented a method for the design of a robust sampled regulator for uncertain systems which ensures the passivity of the controlled system and thereby also ensures its stability The use of the passivity argument also enables stability to be guaranteed in the face of perturbations to the parameters of the system and/or the controller The strength of the method lies in the fact that a step response model of the process to be controlled is used, so that design can be carried out based on straightforward experimental procedures The present work offers several significant enhancements to the results described by Mossaheb et al (1987) which extend the class of systems to which the method can be applied, increase the flexibility of the design process and provide an alternative means of implementing the control law which will usually be more efficient than the original method

Abstract: An examination is made of the activity and stability of circuits built from device models formed by a linear active or passive multiport resistor in parallel with a positive definite, but nonreciprocal, multiport capacitor. Numerical range methods are used to determine the maximum frequency of oscillation and maximum exponential growth rate of the solutions for both conservation of real power and conservation of complex power. Also examined are the stability and activity of these devices when a positive-definite multiport resistor is added in series. It is shown that with the inclusion of the resistor, the circuit becomes passive at high frequencies even if the capacitor is nonreciprocal. The implications of these results for MOSFET device modeling are discussed. >

Abstract: Extension of passivity to a class of nonlinear systems linear in control and its application to robust adaptive control of robots are considered. Passivity, also called positive realness in linear time-invariant systems, is needed for realizability of networks, optimality of control systems, and stability of nonlinear or adaptive controllers. It is shown that stabilizability and parallel feedforward can be used to satisfy passivity conditions in manipulators. This result guarantees robust stability of nonstationary, nonlinear, or adaptive controllers if they are applied to almost strictly passive (ASP) configurations. >

Abstract: The passivity and passivity breakdown of polycrystalline iron is investigated through electrochemical methods complemented with ellipsometry, by employing plain 0.04 M NaOH and saturated Ca(OH)2 solutions with the addition of chloride salt of concentrations up to 1 M. The comparative results indicate that the initial reactions of Fe(OH)2 formation at the inner part of the passive layer level (Fe3O4) are only slightly influenced by either the cation or the presence of Cl− ion in solution, in contrast to their large influence at the outer part of the passive layer (hydrous FeOOH species) where Fe2+/Fe3+ redox reactions take place. At high positive potential the breakdown of passivity is also influenced by both Cl− ion and cation present in solution.