This paper proposes a novel maximum-power-point tracking (MPPT) method with a simple algorithm for photovoltaic (PV) power generation systems. The method is based on use of a short-current pulse of the PV to determine an optimum operating current where the maximum output power can be obtained and completely differs from conventional hill-climbing-based methods. In the proposed system, the optimum operating current is instantaneously determined simply by taking a product of the short-current pulse amplitude and a parameter because the optimum operating current is exactly proportional to the short current under various conditions of illuminance and temperature. Also, the system offers an identification capability of by means of fast power-versus-current curve scanning, which makes the short-current pulse-based MPPT method adaptive to disturbances such as shades partially covering the PV panels and surface contamination. The above adaptive MPPT algorithm has been introduced into a current-controlled boost chopper and a multiple power converter system composed of PV-and-chopper modules. Various operating characteristics have experimentally been examined on this multiple PV-and-chopper module system from a practical viewpoint and excellent MPPT performance has been confirmed through the tests.Index Terms-Current-controlled chopper, maximum-powerpoint tracking, multiple module system, photovoltaic, short-current pulse.

The calcium hydroxyapatite Ca(10)(PO(4))(6)(OH)(2) (Hap) nanoparticles were prepared by using microreactor and employed these Hap nanoparticles to clarify the adsorption behavior of proteins. The size of Hap particles produced by the microreactor reduced in the order of a hardness of the reaction conditions for mixing Ca(OH)(2) and H(3)PO(4) aqueous solutions, such as flow rates of both solutions and temperature. Finally, the size of the smallest Hap nanoparticle became 2 × 15 nm(2), similar to that of BSA molecule (4 × 14 nm(2)). It is noteworthy that the smallest Hap nanoparticles still possesses rodlike shape, suggesting that particles are grown along c-axis even though the reactants mixed very rapidly in narrow channels of the microreactors. The X-ray diffraction patterns of the Hap nanoparticles revealed that the crystallinity of the materials produced by the microreactor is low. The FTIR measurement indicated that the Hap nanoparticles produced by microreactor were carbonate-substituted type B Hap, where the carbonate ions replace the phosphate ions in the crystal lattice. All the adsorption isotherms of acidic bovine serum albumin (BSA), neutral myoglobin (MGB), and basic lysozyme (LSZ) onto Hap nanoparticles from 1 × 10(-4) mol/dm(3) KCl solution were the Langmuirian type. The saturated amounts of adsorbed BSA (n(S)(BSA)) for the Hap nanoparticles produced by microreactor were decreased with decrease in the mean particle length, and finally it reduced to zero for the smallest Hap nanoparticles. Similar results were observed for the adsorption of LSZ; the saturated amounts of adsorbed LSZ (n(S)(LSZ)) also reduced to zero for the smallest Hap nanoparticles. However, in the case of MGB, the saturated mounts of adsorbed MGB (n(S)(MGB)) are also depressed with decreased in their particle size, but about half of MGB molecules still adsorbed onto the smallest Hap nanoparticles. This difference in the protein adsorption behavior was explained by the difference in the size and flexibility of three kinds of proteins. The reduction of n(S)(BSA) is due to the decrease in the fraction of C sites on the side face of each Hap nanoparticle; i.e., there is not enough area left on the nanoparticle surface to adsorb large BSA molecules even though the BSA molecules are soft and their conformations are alterable. The reduction of n(S)(LSZ) was explained by the reduction of P sites. Further, rigidity of the LSZ molecules was given another possibility of the depression of n(S)(LSZ) for the Hap nanoparticles. However, MGB molecules with small and soft structure were adsorbed on the Hap nanoparticle surface by changing their conformation. We could control the amounts of adsorbed proteins by changing the particle size of Hap in the nanometer range and kinds of proteins. These obtained results may be useful for developing biomimetic materials for bone grafts and successful surgical devices in the biochemical field.

This paper focuses on a maximum power point tracking method of photovoltaics by means of use of the short-current pulse. It has been reported that the optimum operating current is proportional to the short current and the maximum power point tracking can be performed by detecting the short current. The pro posed method utilizes the intermittent short-current pulse to estimate the optimum operating current and its operating characteristics have experimentally been verified. Also, an adaptive mechanism to identify the parameter between the optimum current and the short current is discussed. A prototype of the controller has been set up and the experimental results have demonstrated excellent performance, which proves feasibility of the system. 78T.