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: In a DC/DC converter, a first operation section calculates a first operation value, based on a difference voltage between an instruction value for a high-voltage-side voltage and a detected value of a high-voltage-side voltage, a second operation section calculates a second operation value, based on a difference voltage between a voltage instruction value for a charge-discharge capacitor and a voltage detected value of the charge-discharge capacitor, and a switching control section obtains a conduction ratio, based on the first operation value and the second operation value, and controls, based on the conduction ratio, switching operations of first to fourth semiconductor circuits, thereby controlling the high-voltage-side voltage, and the voltage of the charge-discharge capacitor.

Abstract: A method and apparatus for controlling the output voltage of a boost converter including a number n of bridge devices connected in series, each bridge device including plural switches and a capacitor. The method and apparatus provide control of the switches according to a selected periodical matrix pattern including a number N of time intervals, N being a positive integer greater than 2, and in that in each time interval, the voltage between the input and the output of each ith bridge device with i from one to n, is equal to one of a null value, a number ki times a positive value, and minus the number ki times the positive value, the positive value being the result of the division of the output voltage of the boost converter including the n bridge devices by the number of time intervals N of the periodical matrix pattern.

Abstract: An object of the present invention is to provide a DC/DC power conversion apparatus that can reduce the average power consumption over a wide range of DC voltage ratios. A control circuit (120) changes a switching frequency f at which IGBTs S1 to S4 perform ON/OFF operation, in accordance with a voltage ratio k (k=V2/V1) for DC voltage conversion, based on the following expressions, such that a magnitude ?I of a current ripple flowing in a reactor Lc is a predetermined constant value irrespective of the voltage ratio k.

Abstract: In a power conversion device which performs DC/DC conversion, an inverter circuit (20), which is formed of one or more single-phase inverters (20a) and (20b) connected in series to each other, is connected in series to a DC power supply (1) in its subsequent stage. In further subsequent stage, a smoothing capacitor (6) connected to the inverter circuit (20) via a rectifier diode (5), and a shorting switch (4) which bypasses the smoothing capacitor (6) are provided. The shorting switch (4) is switched ON to charge capacitors (25) and (35) included in the single-phase inverter (20a) and (20b), respectively, whereas the shorting switch (4) is switched OFF to discharge the capacitors (25) and (35), whereby the voltage of the smoothing capacitor (6) is controlled.

Abstract: Power generated by a solar battery of thin-film type is stepped up to a predetermined DC voltage by a step-up chopper circuit, and the predetermined DC voltage is converted into three-phase AC power by an inverter circuit, and the three-phase AC power is supplied to an AC power supply system via an output DC voltage circuit. The solar battery is not grounded, and a negative electrode thereof has a floating capacitance between the negative electrode and the ground. The AC power supply system is configured by three-phase star-connection, and the neutral point is grounded. The output DC voltage circuit includes three batteries, and the batteries are provided, for the respective phases, between the AC power supply system and a sine wave filter connected to the AC output side of the inverter circuit. Therefore, it is possible to prevent acceleration of the deterioration of the solar battery.

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 DC/DC power conversion apparatus includes a reactor connected to a DC power supply and a DC voltage conversion section connected to the reactor. The DC voltage conversion section includes a plurality of switching devices, a charge-discharge capacitor which is charged or discharged by ON/OFF operations of the switching devices, a plurality of diodes which provide a charging route and a discharging route for the charge-discharge capacitor. The DC/DC power conversion apparatus also includes a smoothing capacitor on an output side, which is connected to the DC voltage conversion section and including a plurality of voltage division capacitors connected in series to each other, and a switching device for voltage equalization provided on a connection line provided between the negative terminal of the charge-discharge capacitor and a connection point between the voltage division capacitors.

Abstract: A power supply apparatus includes: an AC generator including an AC generating section, and a rectifier for rectifying an AC voltage generated in the AC generating section, and outputting a DC voltage; and a DC/DC converter for converting the output voltage of the rectifier into a DC voltage having a different voltage value, wherein the output voltage of the rectifier is set to be larger than the output voltage of the DC/DC converter in accordance with the rotation speed of the AC generating section and the amount of power supply to an electrical load connected to the DC/DC converter, and is stepped down and outputted by using the DC/DC converter. The power supply apparatus is capable of increasing an output power efficiently.

Abstract: In a DC/DC converter, a first operation section calculates a first operation value, based on a difference voltage between an instruction value for a high-voltage-side voltage and a detected value of a high-voltage-side voltage, a second operation section calculates a second operation value, based on a difference voltage between a voltage instruction value for a charge-discharge capacitor and a voltage detected value of the charge-discharge capacitor, and a switching control section obtains a conduction ratio, based on the first operation value and the second operation value, and controls, based on the conduction ratio, switching operations of first to fourth semiconductor circuits, thereby controlling the high-voltage-side voltage, and the voltage of the charge-discharge capacitor.

Abstract: A first DC/DC converter is connected to a higher-voltage output terminal of a rectifier by alternator wiring, a battery that supplies electric power to an on-board load is connected to the first DC/DC converter, a second DC/DC converter is connected to the higher-voltage output terminal of the rectifier by alternator wiring, and an electrical double-layer capacitor is connected to the second DC/DC converter.

Abstract: To obtain a gate driving circuit in which rising of a constant current of a constant current circuit is fast and power saving is achieved, the gate driving circuit includes: a constant current driving circuit (28) for supplying a constant current; a gate terminal of a power semiconductor element (1), which is connected to an output terminal of the constant current driving circuit; a comparator (22) for comparing a voltage at the gate terminal with a predetermined voltage value and outputting a signal indicating that the voltage is higher than the predetermined voltage value; and a driving control section (20) for increasing a current from the constant current driving circuit in response to a signal for turning on the power semiconductor element, and reducing the current from the constant current driving circuit in response to the signal from the comparator.

Abstract: A DC/DC power conversion apparatus includes a reactor connected to a DC power supply and a DC voltage conversion section connected to the reactor. The DC voltage conversion section includes a plurality of switching devices, a charge-discharge capacitor which is charged or discharged by ON/OFF operations of the switching devices, a plurality of diodes which provide a charging route and a discharging route for the charge-discharge capacitor. The DC/DC power conversion apparatus also includes a smoothing capacitor on an output side, which is connected to the DC voltage conversion section and including a plurality of voltage division capacitors connected in series to each other, and a switching device for voltage equalization provided on a connection line provided between the negative terminal of the charge-discharge capacitor and a connection point between the voltage division capacitors.

Abstract: A first DC/DC converter is connected to a higher-voltage output terminal of a rectifier by alternator wiring, a battery that supplies electric power to an on-board load is connected to the first DC/DC converter, a second DC/DC converter is connected to the higher-voltage output terminal of the rectifier by alternator wiring, and an electrical double-layer capacitor is connected to the second DC/DC converter.

Abstract: An object of the present invention is to provide a DC/DC power conversion apparatus that can reduce the average power consumption over a wide range of DC voltage ratios. A control circuit (120) changes a switching frequency f at which IGBTs S1 to S4 perform ON/OFF operation, in accordance with a voltage ratio k (k=V2/V1) for DC voltage conversion, based on the following expressions, such that a magnitude ?I of a current ripple flowing in a reactor Lc is a predetermined constant value irrespective of the voltage ratio k.

Abstract: Power generated by a solar battery of thin-film type is stepped up to a predetermined DC voltage by a step-up chopper circuit, and the predetermined DC voltage is converted into three-phase AC power by an inverter circuit, and the three-phase AC power is supplied to an AC power supply system via an output DC voltage circuit. The solar battery is not grounded, and a negative electrode thereof has a floating capacitance between the negative electrode and the ground. The AC power supply system is configured by three-phase star-connection, and the neutral point is grounded. The output DC voltage circuit includes three batteries, and the batteries are provided, for the respective phases, between the AC power supply system and a sine wave filter connected to the AC output side of the inverter circuit. Therefore, it is possible to prevent acceleration of the deterioration of the solar battery.

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 gate drive apparatus including a constant-current-pulse gate drive circuit which creates a gate signal for a switching device as a constant-current output, a constant-voltage-pulse gate drive circuit which creates the gate signal as a constant-voltage output, and a decision/switch circuit which switches the operation of the constant-current-pulse gate drive circuit and the operation of the constant-voltage-pulse gate drive circuit. The variance of switching speeds attributed to the variances of threshold voltages and mirror voltages in a plurality of switching devices which are driven by the gate drive apparatus can be suppressed, and the variance of losses can be minimized.

Abstract: A method and device for detecting insulation degradation of a power module, which detects, in advance, degradation of an insulating sheet based on a current change immediately before breakdown of an insulation characteristic from a current value of a current flowing through the insulating sheet, thereby detecting a failure of a power module caused by the degradation of insulation.

Abstract: The present invention concerns an apparatus for controlling the output voltage of a boost converter composed of a number n of bridge devices (B, B2, B3) connected in series, each bridge device being composed of plural switches (S11, S12, S21, S22, S31, S32) and a capacitor (C1, C2, C3). The apparatus comprises means for controlling the switches according to one periodical pattern being decomposed in a number N of time intervals and in that in each time interval, the voltage between the input and the output (B, B2, B3) of each ith bridge device with i from one to n, is equal to a null value, or a number ki times a positive value, or minus the number ki times the positive value, the positive value being the result of the division of the output voltage of the boost converter composed of n bridge (B1, B2, B3) devices by the number of time intervals of the periodical pattern.