Abstract: Described herein are methods, systems, and apparatus for a controller for a power circuit that interfaces distributed power generation with a power distribution grid, comprising: a first portion, including a maximum power point tracker, that receives signals corresponding to the distributed power generation voltage and current, and outputs to the power circuit a signal for controlling the voltage of the distributed power generation; a second portion, including a current reference generator, a current controller, and a dc voltage controller, that receives signals corresponding to a dc voltage of the power circuit, the power distribution grid voltage and current, and the inverter current, and outputs signals for controlling the power circuit output voltage; wherein the current reference generator includes nonlinear circuit elements and generates a current reference signal from the dc voltage of the power circuit and the grid voltage and current; such that substantially harmonic-free power is injected into the p

Abstract: Provided is a maximum power point (MPP) tracker for a PV cell inverter, and a PV cell inverter. The MPP tracker decouples output power oscillations from the input power generation and extracts maximum available power from the PV cell. The PV cell inverter uses the MPP tracker and generates a sinusoidal output current from the MPP tracker output. The sinusoidal output current may be fed to a power distribution grid. The PV cell inverter may use a pulse width modulation technique to cancel harmonics in the sinusoidal output current. The circuits use a minimum number of components and avoid use of large electrolytic capacitors.

Abstract: A processing device displays a physical network topology associated with a storage area network on a display screen. The physical network topology generated by the processing device includes identification of at least one switch resource that supports connectivity among resources in a corresponding storage area network. The processing device typically receives input from a user to display at least one virtual network associated with the storage area network. In response to receiving the input, the processing device displays a virtual network topology associated with the selected at least one virtual network in relation to the physical network topology on the display screen. Displaying the virtual network topology in relation to the physically network topology provides a unique view for the network manager to identify network resources in physical fabric associated with a selected virtual storage area network.

Abstract: Apparatus and method for detecting the formation and dissociation of gas hydrates in a fluid. The apparatus used comprises a piezoelectric crystal sensor and a signal analyzer. The crystal sensor has a deposition surface in contact with the fluid. Under a range of pressures and or temperatures the resonant frequency or an electrical parameter dependent on the resonant frequency of the piezoelectric sensor is measured. There is a step change in the resonant frequency which occurs upon the formation or dissociation of a clathrate hydrate on the deposition surface, so that the formation or dissociation of said clathrate hydrate may be detected.

Abstract: Apparatus and method for detecting the dew point or bubble point phase transition in fluid. The apparatus used comprises a piezoelectric crystal sensor and a signal analyser. The phase transition of the fluid is measured by monitoring, directly or indirectly, change in the resonant frequency of the piezoelectric crystal sensor while said one of the temperature and pressure is varied, so as to detect a substantial change in said resonant frequency and/or in the rate of change in resonant frequency with change in the varying one of the temperature and pressure.