Abstract: A distributed-power-supply power conversion system includes a plurality of power inverters configured to invert DC power to AC power; and a control device configured to select at least one power inverter from the plurality of power inverters as a power inverter used for testing, and configured to perform an energization test of the power inverter used for testing in a state where an AC side of the power inverter used for testing is disconnected from a system, and is connected to an AC power supply device and to a load bank, and a voltage on the AC side of the power inverter used for testing is established. The distributed-power-supply power conversion system can perform an energization test of a power inverter before a system receives power.

Abstract: A distributed-power-supply power conversion system includes a plurality of power inverters configured to invert DC power to AC power; and a control device configured to select at least one power inverter from the plurality of power inverters as a power inverter used for testing, and configured to perform an energization test of the power inverter used for testing in a state where an AC side of the power inverter used for testing is disconnected from a system, and is connected to an AC power supply device and to a load bank, and a voltage on the AC side of the power inverter used for testing is established. The distributed-power-supply power conversion system can perform an energization test of a power inverter before a system receives power.

Abstract: A control device for an electric power conversion apparatus, the control device detecting occurrence of an earth fault in a direct-current path in a system in which the direct-current path between a solar cell module and an electric power conversion apparatus is grounded, is provided. The control device for the electric power conversion apparatus includes: a grounding control unit configured to, in a system in which a direct-current path between a solar cell module and an electric power conversion apparatus is grounded via a switch, control a switch; and an earth fault determination unit configured to, when the switch is open under the controlled of the grounding control unit, detect whether or not an earth fault has occurred in the direct-current path.

Abstract: A control device for an electric power conversion apparatus, the control device detecting occurrence of an earth fault in a direct-current path in a system in which the direct-current path between a solar cell module and an electric power conversion apparatus is grounded, is provided. The control device for the electric power conversion apparatus includes: a grounding control unit configured to, in a system in which a direct-current path between a solar cell module and an electric power conversion apparatus is grounded via a switch, control a switch; and an earth fault determination unit configured to, when the switch is open under the controlled of the grounding control unit, detect whether or not an earth fault has occurred in the direct-current path.

Abstract: There is provided an inverter control apparatus, a capacitor being provided on an AC side of the inverter. The apparatus includes a system voltage detector detects a system voltage, a differentiation unit calculates a differential value of the system voltage, a correction current instruction value calculator calculates a correction current instruction value for correcting a current instruction value set for an output current of the inverter, based on the differential value of the system voltage, a current instruction value correction unit corrects the current instruction value, based on the correction current instruction value, and a controller controls the inverter based on the current instruction value.

Abstract: There is provided a control apparatus for a photovoltaic inverter. The control apparatus includes a system voltage detector, a DC voltage detector that detects a DC voltage applied to the inverter, an output voltage deficiency detector that detects an output voltage deficiency of the inverter based on the system voltage and the DC voltage, an output-current detector, an output-current distortion detector that detects distortion of the output current based on a harmonic included in the output current, a MPPT controller, and an output-current distortion controller that performs control to set the DC voltage applied to the inverter to a voltage at a power point less than a maximum power point when the output voltage deficiency is detected and the distortion of the output current is detected.

Abstract: There is provided an inverter control apparatus, a capacitor being provided on an AC side of the inverter. The apparatus includes a system voltage detector detects a system voltage, a differentiation unit calculates a differential value of the system voltage, a correction current instruction value calculator calculates a correction current instruction value for correcting a current instruction value set for an output current of the inverter, based on the differential value of the system voltage, a current instruction value correction unit corrects the current instruction value, based on the correction current instruction value, and a controller controls the inverter based on the current instruction value.

Abstract: There is provided an inverter test apparatus for testing an inverter interconnected with an alternating-current power system, the apparatus including an alternating-current power output unit configured to output alternating-current power, and an alternating-current power controller configured to control the alternating-current power output from the alternating-current power output unit to simulate an alternating-current load of the inverter.

Abstract: There is provided a control apparatus for a photovoltaic inverter. The control apparatus includes a system voltage detector, a DC voltage detector that detects a DC voltage applied to the inverter, an output voltage deficiency detector that detects an output voltage deficiency of the inverter based on the system voltage and the DC voltage, an output-current detector, an output-current distortion detector that detects distortion of the output current based on a harmonic included in the output current, a MPPT controller, and an output-current distortion controller that performs control to set the DC voltage applied to the inverter to a voltage at a power point less than a maximum power point when the output voltage deficiency is detected and the distortion of the output current is detected.

Abstract: A power conversion apparatus includes an inverter circuit including a switching element, a system voltage measurement unit measuring a system voltage of a power system, a voltage drop detector detecting a voltage drop of the power system, a carrier wave generator generating a carrier wave, a carrier wave frequency modulator increasing a frequency of the carrier wave, when the voltage drop is detected, a signal wave generator generating a signal wave to control the inverter circuit, a gate signal generator comparing the carrier wave with the signal wave, and generating a gate signal, and a power conversion controller controlling the inverter circuit, based on the gate signal.

Abstract: There is provided a solar power generation system including a solar cell, an inverter converting a direct current power generated by the solar cell into an alternating current power, a system voltage measurement unit measuring a system voltage, a voltage drop detector detecting a voltage drop of a power system, based on the system voltage, a first direct current voltage controller controlling a direct current voltage of the inverter to enhance a power generation efficiency of the solar cell, when the voltage drop is not detected, and a second direct current voltage controller controlling the direct current voltage of the inverter to suppress a current output from the inverter, when the voltage drop is detected.

Abstract: A power converter apparatus is provided with a lead-in board in which alternating-current power received from power converting units is connected in parallel, and a connection base including frames for installing the power converting units therein. The frames are provided with connection sections for connecting the main circuits of the power converting units. The lead-in board is provided with breakers for cut off alternating-current power from the power converting units.

Abstract: A power conversion apparatus includes an inverter circuit, a system voltage measurement unit measuring a system voltage, a voltage drop detector detecting a voltage drop of a power system, based on the system voltage, a direct current power measurement unit measuring a direct current power to be input into the inverter circuit, an alternating current command value calculator calculating an alternating current command value to control an alternating current output from the inverter circuit, based on the direct current power and the system voltage, and a current limiter that decrease a current limit value to limit the alternating current command value, when the voltage drop is detected.

Abstract: There is provided a solar power generation system including a solar cell, an inverter converting a direct current power generated by the solar cell into an alternating current power, a system voltage measurement unit measuring a system voltage, a voltage drop detector detecting a voltage drop of a power system, based on the system voltage, a first direct current voltage controller controlling a direct current voltage of the inverter to enhance a power generation efficiency of the solar cell, when the voltage drop is not detected, and a second direct current voltage controller controlling the direct current voltage of the inverter to suppress a current output from the inverter, when the voltage drop is detected.

Abstract: A power conversion apparatus includes an inverter circuit, a system voltage measurement unit measuring a system voltage, a voltage drop detector detecting a voltage drop of a power system, based on the system voltage, a direct current power measurement unit measuring a direct current power to be input into the inverter circuit, an alternating current command value calculator calculating an alternating current command value to control an alternating current output from the inverter circuit, based on the direct current power and the system voltage, and a current limiter that decrease a current limit value to limit the alternating current command value, when the voltage drop is detected.

Abstract: A power conversion apparatus includes an inverter circuit including a switching element, a system voltage measurement unit measuring a system voltage of a power system, a voltage drop detector detecting a voltage drop of the power system, a carrier wave generator generating a carrier wave, a carrier wave frequency modulator increasing a frequency of the carrier wave, when the voltage drop is detected, a signal wave generator generating a signal wave to control the inverter circuit, a gate signal generator comparing the carrier wave with the signal wave, and generating a gate signal, and a power conversion controller controlling the inverter circuit, based on the gate signal.

Abstract: There is provided a protection circuit that protects a power converter connected to a secondary winding of a double-fed induction generator, the protection circuit including a rectifying unit connected to the secondary winding and configured to rectify an electric power coming through the secondary winding, a power consumption unit configured to consume the electric power rectified by the rectifying unit, and a switching unit connected to the power consumption unit in series and configured to switch to adjust the electric power flowing into the power consumption unit.

Abstract: There is provided a protection circuit that protects a power converter connected to a secondary winding of a double-fed induction generator, the protection circuit including a rectifying unit connected to the secondary winding and configured to rectify an electric power coming through the secondary winding, a power consumption unit configured to consume the electric power rectified by the rectifying unit, and a switching unit connected to the power consumption unit in series and configured to switch to adjust the electric power flowing into the power consumption unit.