Abstract: A controller of each power conversion device in a power conversion system controls a switching element unit, based on a detected value of reactor current flowing through a filter reactor, a detected value of output voltage output between the terminals of a filter capacitor, and a detected value of output current flowing through an output reactor. The controller generates a voltage command based on the output current and the output voltage and generates a correction amount of the voltage command based on the output current in which a reference frequency component is removed. The controller generates a current command based on the addition value of the voltage command and the correction amount and controls the switching element unit such that the reactor current matches the current command.

Abstract: A power system and a power conversion device are interconnected via an interconnection switch. A user load is provided between the power conversion device and the interconnection switch. In parallel with the interconnection switch, a series circuit composed of a load disconnection switch and a voltage maintenance load for maintaining voltage of the user load at the time of system momentary power interruption is connected. Control is performed such that, when momentary power interruption occurs, the interconnection switch is turned off and the power system and the power conversion device are connected via the voltage maintenance load, and at the time of recovery from the momentary power interruption, the interconnection switch is turned on, further the power system and the power conversion device are connected.

Abstract: A power conversion device includes: a power conversion unit composed of a power conversion circuit having switching elements, an output current measurement unit, an output voltage measurement unit, and reactor; a voltage command generating unit for generating a voltage command; a dead time correction unit for calculating a dead time correction amount for correcting voltage error, between the voltage command and output voltage, caused due to dead time; and a PWM signal generating unit for generating switching signals according to the voltage command and the dead time correction amount, wherein the dead time correction unit calculates the dead time correction amount from the voltage command, the measured output voltage, and the measured output current.

Abstract: In a control unit for drive-controlling a switching element unit of each power conversion device, a voltage correction amount calculation unit calculates a correction amount corresponding to voltage drop due to impedance between the switching element unit and filter reactor. A voltage command correcting unit corrects a voltage command generated by the voltage command generation unit, using the correction amount. Thus, for a power conversion device 21 that has a small output impedance, correction is performed so as to increase the output impedance, and a PLL unit changes the frequency in accordance with active power calculated from output voltage and output current of the power conversion device, so as to uniform power allocations.

Abstract: A power conversion device which converts power between a power grid and a DC power supply, includes: AC/DC converters for performing conversion from AC power to DC power or from DC power to AC power between the power grid and the DC power supply; a capacitor provided on the DC power supply side of the AC/DC converters and storing DC power; and a step-up unit for charging the capacitor.

Abstract: In a control unit for drive-controlling a switching element unit of each power conversion device, a voltage correction amount calculation unit calculates a correction amount corresponding to voltage drop due to impedance between the switching element unit and filter reactor. A voltage command correcting unit corrects a voltage command generated by the voltage command generation unit, using the correction amount. Thus, for a power conversion device 21 that has a small output impedance, correction is performed so as to increase the output impedance, and a PLL unit changes the frequency in accordance with active power calculated from output voltage and output current of the power conversion device, so as to uniform power allocations.

Abstract: A power conversion circuit for converting DC power supplied from a DC power supply to AC power; and a power conversion control section for controlling operation of the power conversion circuit so as to generate autonomous operation power as an AC voltage source in a parallel-off state from a power grid. The power conversion control section includes: an AC voltage control section for controlling AC voltage; an AC current suppression section for limiting AC current to a predetermined current limit value or smaller; and a DC voltage shortage suppression section for, when DC voltage of the power conversion circuit reduces, in response thereto, reducing the current limit value to be given to the AC current suppression section.

Abstract: A power conversion device which converts power between a power grid and a DC power supply, includes: AC/DC converters for performing conversion from AC power to DC power or from DC power to AC power between the power grid and the DC power supply; a capacitor provided on the DC power supply side of the AC/DC converters and storing DC power; and a step-up unit for charging the capacitor.

Abstract: In a power control system which connects power from the power storage device to a power grid and supplies power to a load, the power from the power storage device is connected to the load and the power grid via a DC/DC converter, a smoothing capacitor, and a DC/AC converter. By a first power control unit for controlling flow power of the power grid to be a power command value, and by a second power control unit for suppressing reverse flow power, an output power command for the DC/AC converter is generated, an output power command for the DC/DC converter is generated so that voltage of the smoothing capacitor becomes target voltage, and the output power command is corrected so as to suppress voltage variation in the smoothing capacitor.

Abstract: A power conversion device includes: a power conversion unit composed of a power conversion circuit having switching elements, an output current measurement unit, an output voltage measurement unit, and reactor; a voltage command generating unit for generating a voltage command; a dead time correction unit for calculating a dead time correction amount for correcting voltage error, between the voltage command and output voltage, caused due to dead time; and a PWM signal generating unit for generating switching signals according to the voltage command and the dead time correction amount, wherein the dead time correction unit calculates the dead time correction amount from the voltage command, the measured output voltage, and the measured output current.

Abstract: A power conversion circuit for converting DC power supplied from a DC power supply to AC power; and a power conversion control section for controlling operation of the power conversion circuit so as to generate autonomous operation power as an AC voltage source in a parallel-off state from a power grid. The power conversion control section includes: an AC voltage control section for controlling AC voltage; an AC current suppression section for limiting AC current to a predetermined current limit value or smaller; and a DC voltage shortage suppression section for, when DC voltage of the power conversion circuit reduces, in response thereto, reducing the current limit value to be given to the AC current suppression section.

Abstract: In a power control system which connects power from the power storage device to a power grid and supplies power to a load, the power from the power storage device is connected to the load and the power grid via a DC/DC converter, a smoothing capacitor, and a DC/AC converter. By a first power control unit for controlling flow power of the power grid to be a power command value, and by a second power control unit for suppressing reverse flow power, an output power command for the DC/AC converter is generated, an output power command for the DC/DC converter is generated so that voltage of the smoothing capacitor becomes target voltage, and the output power command is corrected so as to suppress voltage variation in the smoothing capacitor.

Abstract: A power conversion apparatus including: a three-level inverter including bridge circuits each including a first semiconductor switching device and a second semiconductor switching device connected in series, the bridge circuits being connected to a positive terminal and a negative terminal of a DC power supply, and switch circuits having bidirectional characteristics and connected to respective AC output terminals of the bridge circuits which are the connection points between the first semiconductor switching devices and the second semiconductor switching devices, and to an intermediate potential point of the DC power supply; and single-phase inverters each including a plurality of semiconductor switching devices and respectively connected in series to the AC output terminals of the bridge circuits. The sum of an output voltage of the three-level inverter and output voltages of the single-phase inverters is supplied to a load.

Abstract: A power conversion apparatus including: a three-level inverter including bridge circuits each including a first semiconductor switching device and a second semiconductor switching device connected in series, the bridge circuits being connected to a positive terminal and a negative terminal of a DC power supply, and switch circuits having bidirectional characteristics and connected to respective AC output terminals of the bridge circuits which are the connection points between the first semiconductor switching devices and the second semiconductor switching devices, and to an intermediate potential point of the DC power supply; and single-phase inverters each including a plurality of semiconductor switching devices and respectively connected in series to the AC output terminals of the bridge circuits. The sum of an output voltage of the three-level inverter and output voltages of the single-phase inverters is supplied to a load.

Abstract: A discharge lamp lighting apparatus includes: a DC power supply to supply power to a HID lamp; a transformer to transmit a voltage of DC power supply to the HID lamp; a switch connected between the DC power supply and a primary winding of the transformer; switches connected to a primary side of the transformer; an inductance connected in series to a secondary winding of the transformer; a series resonance circuit connected to a secondary side of the transformer and including an inductance and a capacitor; and a parallel resonance circuit connected to the secondary side of the transformer and including an inductance and a capacitor. The switches are opened or closed to intermittently supply power from the DC power source to the transformer to always supply a current to the transformer.

Abstract: A discharge lamp ballast circuit is provided which can prolong the life of a discharge lamp, and reduce the size and cost of the ballast circuit. It generates from an AC voltage boosted by a DC-AC inverter circuit a DC voltage higher than the breakdown voltage of an HID lamp, or a superimposed voltage in which a pulsating component is superimposed on the DC voltage, and starts the discharge by applying the DC voltage or the superimposed voltage to the HID lamp. It can make the life of the HID lamp longer than that of the case where a high voltage short pulse is applied to the HID lamp.

Abstract: A ballast for a vehicle metal halide lamp is simplified using a DC-AC one-step-boost high frequency ballast system. To satisfy requirements specific to a metal halide lamp, a discharge developing capacitor is installed on a primary side of a transformer in parallel with a DC power supply, ensuring discharge development after a breakdown. To reduce the size and increase the operating voltage of the transformer, a booster circuit and voltage-doubler circuit are installed on the primary side and secondary side of the transformer, respectively. To reduce the size of the transformer and achieve a stable discharge, the ballast frequency is swept within a range between the specified minimum frequency and maximum frequency so that the center frequency is from 80 kHz to 120 kHz, and the same frequency is unsustained for more than 10 msec.

Abstract: A compact, low cost high intensity discharge lamp ballast apparatus which can carry out normal ballasting without extinction at discharge start includes a DC-AC inverting booster circuit, a first resonance circuit, and a second resonance circuit. The DC-AC inverting booster circuit includes a DC-AC converter transformer for converting a DC voltage fed from a DC power supply to an AC voltage in response to switching on and off of FETs, boosting the voltage. The first resonance circuit includes a leakage inductance connected in series with the secondary winding of the DC-AC converter transformer, and a first resonant capacitor connected in parallel with the secondary winding. The second resonance circuit includes a metal halide lamp, an ignitor transformer for producing a voltage to start lighting of the metal halide lamp, and a second resonant capacitor.

Abstract: A discharge lamp ballast circuit is provided which can prolong the life of a discharge lamp, and reduce the size and cost of the ballast circuit. It generates from an AC voltage boosted by a DC-AC inverter circuit a DC voltage higher than the breakdown voltage of an HID lamp, or a superimposed voltage in which a pulsating component is superimposed on the DC voltage, and starts the discharge by applying the DC voltage or the superimposed voltage to the HID lamp. It can make the life of the HID lamp longer than that of the case where a high voltage short pulse is applied to the HID lamp.

Abstract: A compact, low cost high intensity discharge lamp ballast apparatus which can carry out normal ballasting without extinction at discharge start includes a DC-AC inverting booster circuit, a first resonance circuit, and a second resonance circuit. The DC-AC inverting booster circuit includes a DC-AC converter transformer for converting a DC voltage fed from a DC power supply to an AC voltage in response to switching on and off of FETs, boosting the voltage. The first resonance circuit includes a leakage inductance connected in series with the secondary winding of the DC-AC converter transformer, and a first resonant capacitor connected in parallel with the secondary winding. The second resonance circuit includes a metal halide lamp, an ignitor transformer for producing a voltage to start lighting of the metal halide lamp, and a second resonant capacitor.