Abstract: Provided is a control device for suppressing performance reduction of a power storage device. The control device includes: a detector to detect a power storage device parameter relevant to a power storage device; an impedance calculator to calculate an impedance of the power storage device from output of the detector; and a ripple current calculator to calculate an amplitude of ripple current applied to the power storage device, from output of the detector. A converter is controlled on the basis of output of the impedance calculator and output of the ripple current calculator.

Abstract: The power conversion device includes common DC buses, AC buses, DC connection terminals, AC connection terminals, N pairs of distributed power supply connection terminals, N DC/DC converters for transferring power between the common DC buses and the distributed power supply connection terminals, M DC/AC converters for transferring power between the AC buses and the common DC buses, and a control unit for controlling each converter on the basis of a high-order control command. The DC connection terminals are connected to the common DC buses and connected to an external DC power distribution grid, the AC connection terminals are connected to the AC buses and connected to an external AC power distribution grid, and the distributed power supply connection terminals are connected to the DC/DC converters and connected to external DC distributed power supplies.

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: The power conversion device includes common DC buses, AC buses, DC connection terminals, AC connection terminals, N pairs of distributed power supply connection terminals, N DC/DC converters for transferring power between the common DC buses and the distributed power supply connection terminals, M DC/AC converters for transferring power between the AC buses and the common DC buses, and a control unit for controlling each converter on the basis of a high-order control command. The DC connection terminals are connected to the common DC buses and connected to an external DC power distribution grid, the AC connection terminals are connected to the AC buses and connected to an external AC power distribution grid, and the distributed power supply connection terminals are connected to the DC/DC converters and connected to external DC distributed power supplies.

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 generation system is provided in which, when a static frequency converter (SFC) is connected to synchronous generator's armature windings, an AC exciter performs AC excitation by allowing a d-axis winding and a q-axis winding of the AC exciter to configure d-q orthogonal axes; and, at the time of steady-state operation of the synchronous generator, an alternating current(s) supplied from an electric power source is rectified by a thyristor excitation device, and also the AC exciter thereby performs DC excitation by connecting the d-axis winding and the q-axis winding in series with each other.

Abstract: An AC motor drive motor system includes a charge and discharge controller controlling a charging and discharging circuit based on a DC voltage value on the output side of a converter and a charging and discharging current value of a power storage device. The charge and discharge controller, when regenerative power via an inverter from an AC motor exceeds a power threshold, charges the power storage device such that the DC voltage value becomes a voltage threshold corresponding to the power threshold. When regenerative power is the power threshold or less, the converter performs regeneration when the DC voltage value reaches a regeneration start voltage threshold or higher, and ends regeneration when the DC voltage value reaches a regeneration end voltage threshold or lower. The DC-voltage-value time averaged value during regeneration is set lower than that at no-load time when the converter does not perform power supply and regeneration.

Abstract: A power generation system is provided in which, when a static frequency converter (SFC) is connected to synchronous generator's armature windings, an AC exciter performs AC excitation by allowing a d-axis winding and a q-axis winding of the AC exciter to configure d-q orthogonal axes; and, at the time of steady-state operation of the synchronous generator, an alternating current(s) supplied from an electric power source is rectified by a thyristor excitation device, and also the AC exciter thereby performs DC excitation by connecting the d-axis winding and the q-axis winding in series with each other.

Abstract: An AC motor drive motor system includes a charge and discharge controller controlling a charging and discharging circuit based on a DC voltage value on the output side of a converter and a charging and discharging current value of a power storage device. The charge and discharge controller, when regenerative power via an inverter from an AC motor exceeds a power threshold, charges the power storage device such that the DC voltage value becomes a voltage threshold corresponding to the power threshold. When regenerative power is the power threshold or less, the converter performs regeneration when the DC voltage value reaches a regeneration start voltage threshold or higher, and ends regeneration when the DC voltage value reaches a regeneration end voltage threshold or lower. The DC-voltage-value time averaged value during regeneration is set lower than that at no-load time when the converter does not perform power supply and regeneration.

Abstract: When regenerative power from an AC motor via an inverter exceeds a predetermined power threshold, a charging/discharging control unit, which outputs a control signal for controlling the inverter on the basis of a DC bus voltage value and a charging/discharging current value, causes a power storage device to be charged such that the DC bus voltage value becomes a voltage threshold corresponding to the power threshold and causes a charging current at a start time of charging to the power storage device to start from a charging current value that is based on a DC bus voltage value.

Abstract: When regenerative power from an AC motor via an inverter exceeds a predetermined power threshold, a charging/discharging control unit, which outputs a control signal for controlling the inverter on the basis of a DC bus voltage value and a charging/discharging current value, causes a power storage device to be charged such that the DC bus voltage value becomes a voltage threshold corresponding to the power threshold and causes a charging current at a start time of charging to the power storage device to start from a charging current value that is based on a DC bus voltage value.

Abstract: An alternating current (AC) motor drive system is provided in which electric power can be supplied between a direct current (DC) bus and an electric power storage device, using a voltage value across a DC bus, without providing means that measures an amount of current flowing through the DC bus. In the AC motor drive system of the invention, according to a voltage value measured by DC voltage value detection means and a charge/discharge current amount measured by charge/discharge current amount detection means, a charge/discharge circuit causes an electric power storage device to discharge an amount of electric power, from among amounts of electric power supplied from an inverter to an AC motor, that exceeds a first electric power threshold value, or the circuit causes the electric storage device to store an amount of electric power, from among amounts of AC motor regenerative electric power regenerated via the inverter, that exceeds a second electric power threshold value.

Abstract: A state-of-charge estimation apparatus connected to a power storage device having cell batteries, and estimating a state of charge of the power storage device, the apparatus including a first SOC computation unit computing a current integration value based on a total current from a current detector detecting the total current flowing to the storage device from a power conversion device using a previous SOC value as an initial value, and outputting the integration value as a first state-of-charge estimated value, and a second SOC computation unit estimating, after discharge suspension in the storage device, an open-circuit voltage based on a total voltage on a connection point between the conversion device and the storage device, a previous value of the total voltage, and a gain with time passage after discharge suspension in the storage device, and outputting the open-circuit voltage as a second state-of-charge estimated value.

Abstract: A state-of-charge estimating apparatus includes at least a first arithmetic unit configured to calculate, as a first estimation value, the present estimation value calculated based on a battery capacity, the last estimation value, and an electric current flowing in and out between a current control apparatus, which controls charge and discharge amounts of a power storage apparatus, and the power storage apparatus, and a second arithmetic unit configured to calculate, during constant current control, as the present value of a second estimation value, an estimation value calculated based on an equivalent circuit model of a battery and a voltage of the battery and, on the other hand, calculate, during constant voltage control, as the second estimation value, the present estimation value calculated taking into account a resistance change of the battery based on the equivalent circuit model of the battery and the voltage of the battery.

Abstract: In the case where DC power from a DC power supply is converted to AC power by an inverter and supplied to an AC motor, a power compensator is connected in parallel with a DC power input portion of the inverter, and a control device of the power compensator charges/discharges a power storage device to perform a power compensation process A when power demand for the AC motor exceeds a predetermined value, and takes into account power allowance which can be inputted and outputted from the DC power supply to the power storage device and performs a power storage adjustment process B of performing auxiliary charge of the power storage device within the range of the power allowance when the power compensation process A is unnecessary.

Abstract: In the case where DC power from a DC power supply is converted to AC power by an inverter and supplied to an AC motor, a power compensator is connected in parallel with a DC power input portion of the inverter, and a control device of the power compensator charges/discharges a power storage device to perform a power compensation process A when power demand for the AC motor exceeds a predetermined value, and takes into account power allowance which can be inputted and outputted from the DC power supply to the power storage device and performs a power storage adjustment process B of performing auxiliary charge of the power storage device within the range of the power allowance when the power compensation process A is unnecessary.

Abstract: A state-of-charge estimating apparatus includes at least a first arithmetic unit configured to calculate, as a first estimation value, the present estimation value calculated based on a battery capacity, the last estimation value, and an electric current flowing in and out between a current control apparatus, which controls charge and discharge amounts of a power storage apparatus, and the power storage apparatus, and a second arithmetic unit configured to calculate, during constant current control, as the present value of a second estimation value, an estimation value calculated based on an equivalent circuit model of a battery and a voltage of the battery and, on the other hand, calculate, during constant voltage control, as the second estimation value, the present estimation value calculated taking into account a resistance change of the battery based on the equivalent circuit model of the battery and the voltage of the battery.

Abstract: A state-of-charge estimation apparatus connected to a power storage device having cell batteries, and estimating a state of charge of the power storage device, the apparatus including a first SOC computation unit computing a current integration value based on a total current from a current detector detecting the total current flowing to the storage device from a power conversion device using a previous SOC value as an initial value, and outputting the integration value as a first state-of-charge estimated value, and a second SOC computation unit estimating, after discharge suspension in the storage device, an open-circuit voltage based on a total voltage on a connection point between the conversion device and the storage device, a previous value of the total voltage, and a gain with time passage after discharge suspension in the storage device, and outputting the open-circuit voltage as a second state-of-charge estimated value.

Abstract: A reclining bed for childbirth includes a seat board and a backrest. The seat board is provided with a curved cut-out which opens to the center front of it and with thigh crutches provided at the right and left sides of the buttock supporting seat portion of the seat board. The thigh crutches securely support the thighs of woman in labor. The further improved version of this reclining bed for childbirth includes grip handles and armrests. The grip handles are provided at the right and left sides of a seat board installing base. The armrests are provided at the right and left sides of the backrest in an adjustable manner with regard to their tilting angle. This reclining bed for childbirth is effective in enabling a delivery to be performed easily with sitting position, thereby facilitating the works for both the woman in labor and the obstetrical assistants. It is also readily converted whenever it is necessary to be used either as bed or as chair.