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In this paper investigations are made with different maximum power point tracking (MPPT) techniques for a photovoltaic generator (PVG). The PVG is used to supply an induction motor driving a centrifugal pump. Boost converter and inverter are connected in between PVG and motor for power conditioning. Three MPPT techniques are designed and compared. These techniques are incremental conductance (IC), constant voltage controlled (CVC) and fuzzy based perturbation and observation (FPO). Rule Base of FPO is designed with nine rules only, so that it can be implemented on limited memory and speed processors. System performance is analyzed with the help of developed simulation models. A comparative study of these techniques is also summarized. The obtained simulation results indicate that FPO scheme yields better performance. [ABSTRACT FROM AUTHOR]

This paper presents the analysis and design of tapered coplanar waveguide based RF phase shifter using MEMS switches for microwave and millimeter-wave applications. The equivalent circuit of the phase shifter has been analyzed with the capacitances of MEMS switches in both up and down states. A control voltage applied between the center conductor and the switch's membrane actuates it and pulls down the membrane, creating a slow-wave transmission line. The loading capacitance gets added up with the line capacitance, thus varying the characteristic impedance of the line. This change in impedance varies the phase velocity, thereby producing a phase shift. The use of tapered coplanar waveguide as an alternative to the conventional waveguide produces an increase in phase shift per unit length with a small increase in insertion loss. By accurate design of the taper sections, the losses can be reduced further. [ABSTRACT FROM AUTHOR]