An apparatus according to an embodiment includes a control circuit to control operations of an inverter and a switch. The control circuit judges whether or not a power system has a power failure, based on values of the system voltage and a frequency of the power system; and calculates a phase difference between a phase of the output voltage of the inverter and a phase of the system voltage and generate, by means of the phase difference, an output frequency pattern for changing a frequency of the output voltage of the inverter. The control circuit, when it is judged that the power system has recovered from the power failure, controls the inverter to change the frequency of the output voltage of the inverter in line with the output frequency pattern, and closes the switch after the phase difference becomes smaller than or equal to a threshold.

A method and apparatus is described for conveying the amount of loading of a power source to a load control device by controlling the frequency of the AC power output from that power source in a manner that controlled frequency represents the loading. At a different location in the power system, the frequency is measured and the corresponding loading of the power source is used to prevent or alleviate a power source overload.

Methods, systems, and apparatus, including computer programs stored on a computer-readable storage medium, for obtaining a reference phase signal that is synchronized with an alternating current (AC) phase of a multi-phase electrical power distribution system. The apparatus obtains output signals from sensors, each output signal representative of an electromagnetic emission detected by a respective sensor. The apparatus identifies, based on comparing respective phases of the output signals to the reference phase signal, a particular AC phase of the multi-phase electrical power distribution system associated with a source of the emissions. The apparatus provides an indication of the particular AC phase to a user.

A method can be used to synchronize time between nodes of a converter device for high voltage power conversion. The method is performed in a first node of the converter device and includes receiving a time reference from a second node of the converter device, obtaining a delay value for receiving time references from the second node, determining a compensated time by adding the delay value to the time reference, and setting a clock in the first node to be the compensated time.

A method can be used to synchronize time between nodes of a converter device for high voltage power conversion. The method is performed in a first node of the converter device and includes receiving a time reference from a second node of the converter device, obtaining a delay value for receiving time references from the second node, determining a compensated time by adding the delay value to the time reference, and setting a clock in the first node to be the compensated time.

A power system comprising one or more power generators and a combiner. The system may be electrically connected to or include one or more loads. The combiner may have input terminals that are coupled to outputs of the power generators. The combiner may also have output terminals that are coupled to input(s) of the one or more loads. The power generators may be configured to transfer harvested power to the combiner, and the combiner may be configured to transfer the harvested power to the one or more loads.

A power system comprising one or more power generators and a combiner. The system may be electrically connected to or include one or more loads. The combiner may have input terminals that are coupled to outputs of the power generators. The combiner may also have output terminals that are coupled to input(s) of the one or more loads. The power generators may be configured to transfer harvested power to the combiner, and the combiner may be configured to transfer the harvested power to the one or more loads.

Embodiments of the present invention relate to a method and a device for providing a clock signal to an application, comprising (a) determining a time difference between a clock device and the clock signal; if the time difference is above a predetermined threshold x, (b) calibrating a first time unit and, during calibrating the first time unit, (c) using a second time unit for providing the clock signal to the application.

The present disclosure relates to a recloser control that provides autosynchronization of a microgrid to an area electric power system (EPS). For example, a recloser control may include an output connector that is communicatively coupled to a recloser at a point of common coupling (PCC) between the area EPS and the microgrid. The recloser control may include a processor that acquires a first set of measurements indicating electrical characteristics of the area EPS and acquires a second set of measurements indicating electrical characteristics of the microgrid. The recloser control may send synchronization signals to one or more distributed energy resource (DER) controllers to synchronize one or more DERs to the area EPS based on the first set of measurements and the second set of measurements.

The present disclosure relates to a recloser control that provides autosynchronization of a microgrid to an area electric power system (EPS). For example, a recloser control may include an output connector that is communicatively coupled to a recloser at a point of common coupling (PCC) between the area EPS and the microgrid. The recloser control may include a processor that acquires a first set of measurements indicating electrical characteristics of the area EPS and acquires a second set of measurements indicating electrical characteristics of the microgrid. The recloser control may send synchronization signals to one or more distributed energy resource (DER) controllers to synchronize one or more DERs to the area EPS based on the first set of measurements and the second set of measurements.