Abstract: A test signal is applied from a continuity test source to a photovoltaic (PV) panel string, to test electrical continuity in the PV panel string and between the PV panel string and an inverter that is coupled to the PV panel string. If the test signal is detected at a PV panel disconnect switch that is separate from the continuity test source and switchably couples one or more Direct Current (DC) PV panels in the PV panel string, then the PV panel disconnect switch is controlled to connect the one or more DC PV panels in the PV panel string. Otherwise, the PV panel disconnect switch is controlled to disconnect the one or more DC PV panels from the PV panel string. The test signal could be, for example, an Alternating Current (AC) signal tuned to a PV installation that includes the PV panel string and the inverter.

Abstract: A test signal is applied from a continuity test source to a photovoltaic (PV) panel string, to test electrical continuity in the PV panel string and between the PV panel string and an inverter that is coupled to the PV panel string. If the test signal is detected at a PV panel disconnect switch that is separate from the continuity test source and switchably couples one or more Direct Current (DC) PV panels in the PV panel string, then the PV panel disconnect switch is controlled to connect the one or more DC PV panels in the PV panel string. Otherwise, the PV panel disconnect switch is controlled to disconnect the one or more DC PV panels from the PV panel string. The test signal could be, for example, an Alternating Current (AC) signal tuned to a PV installation that includes the PV panel string and the inverter.

Abstract: An electrical power source includes a power converter and either an electrical generator or an electrical energy storage device. Power flow is controlled through controlling power converter based on a voltage source and resistance model of the electrical power source. A power converter for an electrical generator is controlled to synthesize or produce a constant voltage of the voltage source and a variable value of the resistance. The resistance value is controlled to deliver a maximum available output power to the electrical microgrid over a range of microgrid voltages up to a voltage below a maximum allowable voltage of the electrical microgrid. For an electrical energy storage device, the power converter is controlled to synthesize or produce a resistance value of the resistance that is dependent upon a phase angle between the voltage at the microgrid side of the electrical power source and current of the electrical energy storage device.

Abstract: An electrical power source includes a power converter and either an electrical generator or an electrical energy storage device. Power flow is controlled through control of the power converter based on a voltage source and resistance model of the electrical power source. A power converter for an electrical generator is controlled to synthesize a constant voltage of the voltage source and a variable value of the resistance. The resistance value is controlled to deliver a maximum available output power to the electrical microgrid over a range of microgrid voltages up to a voltage below a maximum allowable voltage of the electrical microgrid. For an electrical energy storage device, the power converter is controlled to synthesize a resistance value of the resistance that is dependent upon a phase angle between the voltage at the microgrid side of the electrical power source and current of the electrical energy storage device.

Abstract: A gateway controller allows a plurality of individual power generation units coupled to an electrical distribution grid to be controlled in a coordinated fashion. The gateway controller allows control of the plurality of individual power generation units as a single power generation unit. The gateway controller may determine required control parameters of the power generation units that will provide a desired combined behavior, such as combined alternating current injected into the grid, and issues commands to the power generation units based on the determined control parameters.

Abstract: An electrical power source includes a power converter and either an electrical generator or an electrical energy storage device. Power flow is controlled through control of the power converter based on a voltage source and resistance model of the electrical power source. A power converter for an electrical generator is controlled to synthesize a constant voltage of the voltage source and a variable value of the resistance. The resistance value is controlled to deliver a maximum available output power to the electrical microgrid over a range of microgrid voltages up to a voltage below a maximum allowable voltage of the electrical microgrid. For an electrical energy storage device, the power converter is controlled to synthesize a resistance value of the resistance that is dependent upon a phase angle between the voltage at the microgrid side of the electrical power source and current of the electrical energy storage device.

Abstract: A method of testing a memory associated with a microprocessor, particularly for use in smart cards. The method involves comparing the output from the memory (2) passed along a read path (10) with predetermined data signals generated externally and passed via a port (7) along a read path (9). Comparison is carried out in a comparison device (3) which may, for example, be the microprocessor, suitably programmed. The output form the comparison device (3) is a simple pass/fail verification signal applied to a port (5). The stored data held in memory (2) may be permanently held data such as in a ROM, or (where the memory is alterable) may be specially written to the memory for the purpose of the text.