Abstract: A power conversion device is connected to a power transmission line which is connected to a generator. The power conversion device includes a frequency detector that detects a system frequency, the system frequency being a frequency of an AC voltage on the power transmission line, a controller that generates a reactive power command value to compensate for a variation in the detected system frequency, and a power converter that outputs reactive power in accordance with the reactive power command value to the power transmission line.

Abstract: A frequency detector detects a system frequency from an AC voltage on an AC power line to which a power conditioner performing system interconnection of a distributed power supply is connected. A power converter is configured to inject lead reactive power or delay reactive power into the AC power line. A controller controls reactive power output from the power converter to output the lead reactive power in response to an increase in the system frequency while outputting the delay reactive power in response to a decrease in the system frequency.

Abstract: A power conversion device includes: a plurality of 3-level converters (31 to 35) that are multiple-connected in series to an AC power supply; and a control device (10) controlling operations of the plurality of 3-level converters (31 to 35). The control device (10) includes: a calculation unit calculating an output voltage command for the plurality of 3-level converters (31 to 35); a carrier signal generation unit generating a carrier signal; a correction unit correcting a phase of the carrier signal based on a potential variation on a DC neutral point bus (7); and a pulse width modulation control. unit delaying the phase by a prescribed amount based on the carrier signal having the phase corrected by the correction unit as a reference phase, to generate a plurality of carrier signals, and comparing the output voltage command with each of the plurality of carrier signals to generate a control command for each of the plurality of 3-level converters (31 to 35).

Abstract: A power conversion device includes: a plurality of 3-level converters (31 to 35) that are multiple-connected in series to an AC power supply; and a control device (10) controlling operations of the plurality of 3-level converters (31 to 35). The control device (10) includes: a calculation unit calculating an output voltage command for the plurality of 3-level converters (31 to 35); a carrier signal generation unit generating a carrier signal; a correction unit correcting a phase of the carrier signal based on a potential variation on a DC neutral point bus (7); and a pulse width modulation control. unit delaying the phase by a prescribed amount based on the carrier signal having the phase corrected by the correction unit as a reference phase, to generate a plurality of carrier signals, and comparing the output voltage command with each of the plurality of carrier signals to generate a control command for each of the plurality of 3-level converters (31 to 35).

Abstract: An ultraviolet light emitting device having high quality and high reliability is provided by preventing deterioration of electrical characteristics which is associated with an ultraviolet light emission operation and caused by a sealing resin. The ultraviolet light emitting device is an ultraviolet light emitting device including: an ultraviolet light emitting element (2) formed of a nitride semiconductor; and an ultraviolet-transparent sealing resin (3) covering the ultraviolet light emitting element (2), wherein at least a specific portion (3a) of the sealing resin (3), which is in contact with pad electrodes (18) and (17) of the ultraviolet light emitting element (2), is a first type amorphous fluororesin, and a terminal functional group of a polymer or a copolymer that forms the first type amorphous fluororesin is a nonreactive terminal functional group which is not bondable to a metal that forms the pad electrodes (16) and (17).

Abstract: An ultraviolet light emitting device having high quality and high reliability is provided by preventing deterioration of electrical characteristics which is associated with an ultraviolet light emission operation and caused by a sealing resin. The ultraviolet light emitting device is an ultraviolet light emitting device including: an ultraviolet light emitting element (2) formed of a nitride semiconductor; and an ultraviolet-transparent sealing resin (3) covering the ultraviolet light emitting element (2), wherein at least a specific portion (3a) of the sealing resin (3), which is in contact with pad electrodes (18) and (17) of the ultraviolet light emitting element (2), is a first type amorphous fluororesin, and a terminal functional group of a polymer or a copolymer that forms the first type amorphous fluororesin is a nonreactive terminal functional group which is not bondable to a metal that forms the pad electrodes (16) and (17).

Abstract: A control device of a self-excited reactive power compensation apparatus controls a reactive current output from a self-excited converter to a power system. The control device includes a first reference generating unit, a second reference generating unit, and a selecting unit. The first reference generating unit generates a first voltage reference of an output voltage output from the self-excited converter, such that the reactive current detected by a reactive current detecting unit follows a current reference. The second reference generating unit generates a second voltage reference of the output voltage output from the self-excited converter, such that a value of the reactive current becomes a predetermined value. The selecting unit selects a maximum value from the first and second voltage references.

Abstract: A control device of a self-excited reactive power compensation apparatus controls a reactive current output from a self-excited converter to a power system. The control device includes a first reference generating unit, a second reference generating unit, and a selecting unit. The first reference generating unit generates a first voltage reference of an output voltage output from the self-excited converter, such that the reactive current detected by a reactive current detecting unit follows a current reference. The second reference generating unit generates a second voltage reference of the output voltage output from the self-excited converter, such that a value of the reactive current becomes a predetermined value. The selecting unit selects a maximum value from the first and second voltage references.

Abstract: This invention provides a power conversion circuit control apparatus which rapidly detects the voltage amplitude and phase of each phase, corrects the output of a current controller by the mean voltage amplitude and mean phase, and corrects, on the basis of the voltage amplitude and phase of each phase, a voltage amplitude command and voltage phase command to be applied to pulse width modulation. The apparatus can suppress an overcurrent even when the AC voltage is unbalanced, and restart the operation without generating any overcurrent when the circuit is to be reactivated.

Abstract: This invention provides a power conversion circuit control apparatus which rapidly detects the voltage amplitude and phase of each phase, corrects the output of a current controller by the mean voltage amplitude and mean phase, and corrects, on the basis of the voltage amplitude and phase of each phase, a voltage amplitude command and voltage phase command to be applied to pulse width modulation. The apparatus can suppress an overcurrent even when the AC voltage is unbalanced, and restart the operation without generating any overcurrent when the circuit is to be reactivated.

Abstract: A reactive power compensator continues operation even when a higher harmonic wave component of an alternating-current power system increases. For an alternating current electric amount indicating one of an alternating voltage and an alternating electric current in an alternating-current power system, the reactive power compensator outputs a changing amount showing a change of the alternating current electric amount. An electric current command limits an electric current command signal based on the changing amount. For example, the changing amount is changed in accordance with the higher harmonic wave component included in the alternating current electric amount.

Abstract: A reactive power compensator continues operation even when a higher harmonic wave component of an alternating-current power system increases. For an alternating current electric amount indicating one of an alternating voltage and an alternating electric current in an alternating-current power system, the reactive power compensator outputs a changing amount showing a change of the alternating current electric amount. An electric current command limits an electric current command signal based on the changing amount. For example, the changing amount is changed in accordance with the higher harmonic wave component included in the alternating current electric amount.

Abstract: A power conversion apparatus connected to an AC voltage system, including current control circuits provides individual feedback control of an active current and a reactive current. The active current control circuit changes control gain of the active current according to a detected active current value or a deviation of the detected active current value from an active current command value.

Abstract: Power conversion units using pulse width modulation for elimination of harmonics of specific orders are connected in parallel with an ac power system so that the power conversion units supply voltages of mutually different waveforms to the ac power system.

Abstract: There is a power conversion apparatus connected to an AC voltage system 5, comprising current control circuits 11, 12 capable of individually performing feedback control of an active current and a reactive current, and the active current control circuit 11 is constructed so as to change a control gain of the active current according to a detected active current value or a deviation of a detected active current value from an active current command value.

Abstract: Power conversion units using pulse width modulation for elimination of harmonics of specific orders are connected in parallel with an ac power system so that the power conversion units supply voltages of mutually different waveforms to the ac power system.

Abstract: The present invention relates to Saintopin derivatives represented by the following formula (I): ##STR1## wherein R.sup.1 is hydrogen and R.sup.2 is SO.sub.2 OH (UCE 1022), or R.sup.1 is acetyl and R.sup.2 is H (Saintopin E), which are useful as antibacterial and anti-tumor agents.

Abstract: A control apparatus for thyristor motor comprises a voltage detector (27), a speed detecting circuit (600) and a correction circuit (800). The voltage detector (27) detects DC voltage (E.sub.d) supplied to an inverter circuit (200). The speed detecting circuit (600) detects the rotational speed of a synchronous motor (3) and provides speed voltage (E.omega.) proportional thereto. The correction circuit (800) detects a difference between the detected DC voltage (E.sub.d) and the speed voltage (E.omega.) and provides a correction signal to an excitation circuit (700) when a difference is detected. The excitation circuit (700) corrects field current in response to the correction signal so that the DC voltage (E.sub.d) and the speed voltage may be equal. Thus, a proportional relation can be maintained between the instructed torque and the generated torque.