Abstract:
An anti-islanding implementation that introduces a small, continuously varying phase shift pattern in the output current of an inverter. In grid-connected mode, this phase shift pattern has no impact on the frequency of the inverter's output voltage. However, when islanded, the phase shift will cause the voltage frequency to deviate from nominal. Changes in the output current phase thus correlate well with the voltage frequency, so a covariance index is used to detect an islanding configuration. When this index exceeds a threshold, a larger phase shift pattern is introduced in the output current, large enough to cause the voltage frequency to fall outside the inverter's trip protection window without compromising the inverter's power quality yet ensuring reliable tripping of the inverter.
Abstract:
A photovoltaic inverter for coupling a direct current photovoltaic source to an alternating current energy grid and performing a low voltage ride through. The inverter includes a power bridge to convert direct current voltage to alternating current voltage. A switching crowbar is coupled to the photovoltaic energy source and the power bridge. The crowbar has a switching device having a closed position causing the switching crowbar to dissipate energy from the photovoltaic energy source and an open position to allow direct output from the photovoltaic source to the power bridge. A voltage sensor detects a low voltage condition on the grid. A controller is coupled to the voltage sensor and controls the switching crowbar when a low voltage condition is detected. The switching device is placed in the closed position when the voltage from the photovoltaic energy source is higher than a predetermined threshold voltage and the switching device being placed in the open position when the voltage of the photovoltaic source reaches the voltage when the low voltage condition is detected.
Abstract:
A sensor-less technique is described for detecting the status of an AC contactor of a power inverter. In one embodiment, a method is provided of sensing an unexpected condition of an AC contactor used to couple to a power distribution system a power inverter having at least one power conductor. The method includes determining a voltage value for the conductor; determining a current value for the conductor; determining a phase difference using the voltage value and the current value; and monitoring successive values of the phase difference to produce a monitoring result. Depending on the monitoring result, a determination is made whether or not to issue an alert signal. Control routines embodying such technique may be stored on computer-readable media. A power inverter using such technique is described.
Abstract:
A sensor-less technique is described for detecting the status of an AC contactor of a power inverter. In one embodiment, a method is provided of sensing an unexpected condition of an AC contactor used to couple to a power distribution system a power inverter having at least one power conductor. The method includes determining a voltage value for the conductor; determining a current value for the conductor; determining a phase difference using the voltage value and the current value; and monitoring successive values of the phase difference to produce a monitoring result. Depending on the monitoring result, a determination is made whether or not to issue an alert signal. Control routines embodying such technique may be stored on computer-readable media. A power inverter using such technique is described.
Abstract:
A time division multiple access (TDMA) controller and method for operating the same includes a frame position module that generates a frame position signal. The controller also includes a signal module that generates a signal-on signal and a signal-off signal and a comparison module that generates a timing control signal based on the frame position signal, the signal-on signal and the signal-off signal.
Abstract:
A data entry and scanning apparatus that includes a commercially available mobile device wherein said commercially available mobile device with a touch screen display, a processor, and a wireless communications network access point, a scanning device, an interface, and a power source that external to the commercially available mobile device and connected to the interface, and a casing that does not cover the touch screen display.
Abstract:
Applications can be localized by localization experts to allow them to be used by a broader customer base. The localization can be done given interface context to produce more applicable results. A localization expert may determine that certain content within the interface context should be localized, however is not localizable by the expert. The localization expert may indicate that the content is localizable and the developer may receive the indication and provide the localization expert with updated interface context allowing localization of the previously un-localizable content.
Abstract:
Applications can be localized by localization experts to allow them to be used by a broader customer base. The localization can be done given interface context to produce more applicable results. A localization expert may determine that certain content within the interface context should be localized, however is not localizable by the expert. The localization expert may indicate that the content is localizable and the developer may receive the indication and provide the localization expert with updated interface context allowing localization of the previously un-localizable content.
Abstract:
Applications can be localized by localization experts to allow them to be used by a broader customer base. The localization can be done given resource files containing localization resources. A localization resource may contain a programming component and non-programming component. The non-programming component can be sent to a machine localizer. The machine localizer may provide a plurality of localizations corresponding to a plurality of languages based on the non-programming component of the localization resource. A plurality of localized applications can be complied based on the localized non-programming components and the original programming component.
Abstract:
Computer-storage media, methods, and systems for improving the ability of a user to accomplish a task that is pending during a search session are provided. This pending task can be distilled by identifying a current searching intent associated with a recently submitted query and by determining which candidate tasks are most comparable to the current searching intent of a user. The candidate tasks are mined from a search history of the user by categorizing those navigation events that appear to share a semantically common concept. Upon performing a comparison, the candidate task that captures the user's true current searching intent is designated as the pending task. When a user invokes the pending task, a collection of elements that are associated with the pending task are dynamically organized into a sharable content page, thereby providing a collaborative experience that involves exposing the collection to contacts and accepting feedback therefrom.