Abstract: Each phase arm of a power conversion device includes at least one converter cell connected in series. For each converter cell, an element driving unit is provided which turns on one switching element in the converter cell as a startup element. The element driving unit is supplied with power from a DC capacitor, and when voltage of the DC capacitor exceeds startup voltage Vsh, turns on the startup element. Thus, at the time of startup of the power conversion device, the DC capacitor in each converter cell is initially charged to desired voltage.

Abstract: When switching operations of converter cells are stopped due to temporary voltage reduction in an AC system, a voltage determination unit performs determination regarding a voltage of each DC capacitor after a predetermined period has passed, and a charge control unit transmits a charging gate signal, via a gate control unit, to select a converter cell at a voltage level at which a self-feeding circuit of the converter cell is operable. Thus, a DC capacitor of a converter cell whose voltage is lower than the voltage level at which a self-feeding circuit is operable is charged, thereby enabling switching operations of all the converter cells.

Abstract: Since a power converter including a modular multilevel converter uses a large number of cells each combining a plurality of switching elements and a DC capacitor, there is a problem of conduction loss due to the switching elements. The conduction loss is reduced by connecting a bypass circuit between terminals of each of the cells, controlling to open and close the switching element, and controlling to short-circuit the bypass circuit connected to the cell controlled to output zero voltage.

Abstract: In a control device of a power conversion device, an AC control portion generates a first voltage command value representing an AC voltage component to be output from a plurality of chopper cells of each leg circuit. A DC control portion generates a second voltage command value representing a DC voltage component to be output from the plurality of chopper cells of each leg circuit. A circulating current control portion generates a third voltage command value to be output from the plurality of chopper cells of each leg circuit in order to suppress a circulating current. The circulating current control portion performs a non-linear operation with the first, second, and third voltage command values. The plurality of chopper cells of each leg circuit operate in accordance with a result of the non-linear operation.

Abstract: An endoscope system includes: an endoscope having an insertion section adapted to be inserted into a subject; an optical member positioned at a distal end portion; a heating section configured to heat the optical member; a first temperature detector configured to detect first temperature information of the distal end portion; a second temperature detector connected in parallel with the heating section and configured to detect second temperature information of the distal end portion; a control unit configured to control the heating section based on the first temperature information; and an abnormality determination unit configured to determine presence or absence of abnormality in the first temperature detector and the second temperature detector based on the first temperature information and the second temperature information.

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: The present invention is provided with a power converter and a control device for controlling the power converter, wherein each of the positive arm and the negative arm is comprised one converter cell or a plurality of converter cells connected in series, each converter cell being comprised: a series unit in which a plurality of switching elements are connected in series to each other; and a DC capacitor connected in parallel to the series unit, and the control device includes a DC voltage command value calculation unit which calculates a voltage command value for outputting, during a DC short circuit fault, AC voltage similar to that in a steady state to the AC terminal of the power converter, and for outputting, to the DC terminal of the power converter, DC voltage that allows the protection relay in the DC line to operate.

Abstract: A power conversion device includes: a positive arm and a negative arm each of which is formed by connecting a plurality of converter cells in series, the converter cells each being composed of a plurality of semiconductor switching elements and a DC capacitor; and a control circuit. An arm balance control unit in the control circuit calculates a first voltage adjustment value for balancing voltage of the DC capacitors in the positive arm and voltage of the DC capacitors in the negative arm. The control circuit adjusts an AC control command using the first voltage adjustment value, thereby calculating an AC voltage command for AC voltage to be outputted to an AC line for each phase.

Abstract: A power conversion device includes: a positive arm and a negative arm each of which is formed by connecting a plurality of converter cells in series, the converter cells each being composed of a plurality of semiconductor switching elements and a DC capacitor; and a control circuit. An arm balance control unit in the control circuit calculates a first voltage adjustment value for balancing voltage of the DC capacitors in the positive arm and voltage of the DC capacitors in the negative arm. The control circuit adjusts an AC control command using the first voltage adjustment value, thereby calculating an AC voltage command for AC voltage to be outputted to an AC line for each phase.

Abstract: When switching operations of converter cells are stopped due to temporary voltage reduction in an AC system, a voltage determination unit performs determination regarding a voltage of each DC capacitor after a predetermined period has passed, and a charge control unit transmits a charging gate signal, via a gate control unit, to select a converter cell at a voltage level at which a self-feeding circuit of the converter cell is operable. Thus, a DC capacitor of a converter cell whose voltage is lower than the voltage level at which a self-feeding circuit is operable is charged, thereby enabling switching operations of all the converter cells.

Abstract: A stereo image pickup unit includes a first image pickup device configured to receive a first optical image formed by a first objective optical system, a second image pickup device configured to receive a second optical image formed by a second objective optical system, a single centering glass that is disposed on optical paths of the respective first and second optical images and to which light receiving surfaces of the respective first and second image pickup devices are positioned and fixed through bonding, and a holding frame that holds the first and second image pickup devices through the centering glass.

Abstract: An endoscope includes: a first lens located at a distal-most position, a part of the first lens being exposed outside; a movable lens barrel configured to be able to move, and configured to hold a movable lens disposed on a proximal end side with respect to the first lens; an actuator unit including a coil that drives the movable lens barrel and generates heat by receiving a supply of electric power; and a control section that outputs first electric power to the coil when holding the movable lens barrel at a predetermined position, and outputs second electric power larger than the first electric power to the coil when conducting heat generated from the coil to the first lens at the predetermined position.

Abstract: In a power conversion system in which one or more converter cells are connected in series to form an arm for each phase, a control device includes a voltage command generating unit for generating a positive arm voltage command and a negative arm voltage command for each phase. The voltage command generating unit includes an AC current control unit, a circulating current control unit, and a command distributing unit. On the basis of inputted voltage commands, the command distributing unit subtracts voltage drop portions due to inductance values in the arms from respective voltages assigned as outputs of the positive arm and the negative arm, to distribute voltage components, thereby determining the positive arm voltage command and the negative arm voltage command.

Abstract: A power conversion device performs power conversion between three-phase AC, and DC, and includes a positive arm and a negative arm for each phase, each of which includes one or more converter cells connected in series. A voltage command generating unit in a control device includes an AC current control unit, a circulating current control unit, and a command distributing unit, and generates a positive arm voltage command and a negative arm voltage command for each phase. In the circulating current control unit, a compensator calculates a first control command so that circulating current for each phase approaches a circulating current command value, a suppression unit generates a second control command so as to suppress a 2f component and a 4f component contained in the first control command, and then the first control command and the second control command are combined to generate a circulation control command.

Abstract: In a power converter which performs power conversion between plural-phase AC and DC, variation in voltage of the DC capacitor in each converter cell is detected, and when the variation exceeds a predetermined value, a DC voltage command value as a control target value in a DC voltage control unit which controls DC voltage between DC buses is corrected by being increased or decreased. Thus, when AC grid failure occurs, the capacitor voltage of each converter cell is maintained and the operation continuity is improved.

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: A power conversion device performs power conversion between three-phase AC, and DC, and includes a positive arm and a negative arm for each phase, each of which includes one or more converter cells connected in series. A voltage command generating unit in a control device includes an AC current control unit, a circulating current control unit, and a command distributing unit, and generates a positive arm voltage command and a negative arm voltage command for each phase. In the circulating current control unit, a compensator calculates a first control command so that circulating current for each phase approaches a circulating current command value, a suppression unit generates a second control command so as to suppress a 2f component and a 4f component contained in the first control command, and then the first control command and the second control command are combined to generate a circulation control command.

Abstract: An electric power conversion device includes a power conversion unit and a converter control unit. The power conversion unit includes three arms connected to an AC circuit. The converter control unit includes a phase DC voltage control unit, a negative sequence current command value calculation unit, an output current control unit, a circulating current control unit, a voltage command value calculation unit, and a gate signal generation unit, and imbalance of cell DC capacitor voltages among phases due to grid imbalance is controlled by circulating current and negative sequence current.

Abstract: An imaging module includes: a chip size package having an image sensor that has a light receiving unit on a front side of the image sensor, the chip size package having connection lands on a back side of the image sensor; a circuit board having connection electrodes being electrically and mechanically connected to the connection lands of the chip size package through bumps; and an underfill material filled into a gap between the chip size package and the circuit board. The circuit board and the underfill material are provided within a projection plane on which the chip size package is projected in an optical axis direction of the image sensor. The circuit board has a cutout portion on a side surface thereof orthogonal to a connection surface of the circuit board with the chip size package such that the cutout portion is open to at least the connection surface.

Abstract: In a power converter which performs power conversion between plural-phase AC and DC, variation in voltage of the DC capacitor in each converter cell is detected, and when the variation exceeds a predetermined value, a DC voltage command value as a control target value in a DC voltage control unit which controls DC voltage between DC buses is corrected by being increased or decreased. Thus, when AC grid failure occurs, the capacitor voltage of each converter cell is maintained and the operation continuity is improved.