Abstract: A charge and discharge control device includes: a coordination unit which generates coordination information for calculating an output value which each storage battery is caused to output, based on a bus voltage value and a target voltage value; a string output calculating unit which calculates, based on the coordination information, an output target value indicating the output value which the storage battery is caused to output to maintain the bus voltage value at the target voltage value; and a control unit which causes, among the storage batteries, a storage battery corresponding to the calculated output target value to output an output having a magnitude indicated by the calculated output target value, wherein the coordination unit generates the coordination information to avoid simultaneous presence of a storage battery that outputs an output in a charge direction and a storage battery that outputs an output in a discharge direction.

Abstract: A storage battery system includes: electric storage units; and DC-DC converters each provided between one of the electric storage units and a DC bus. Each of the DC-DC converters includes: a voltage sensor for detecting a voltage value at a connection point between the DC bus and the DC-DC converter; a second obtainment unit which obtains voltage values detected by the voltage sensors of the other DC-DC converters; and a control unit which, when a difference value between a statistic of the voltage values obtained by the second obtainment unit and the voltage value detected by the voltage sensor is not less than a predetermined threshold value, changes the voltage value detected by the voltage sensor, and controls an amount of charge in and an amount of discharge from a corresponding one of the electric storage units to approximate the changed voltage value to a predetermined target value.

Abstract: A storage battery system includes: electric storage units; and DC-DC converters each provided between one of the electric storage units and a DC bus. Each of the DC-DC converters includes: a voltage sensor for detecting a voltage value at a connection point between the DC bus and the DC-DC converter; a second obtainment unit which obtains voltage values detected by the voltage sensors of the other DC-DC converters; and a control unit which, when a difference value between a statistic of the voltage values obtained by the second obtainment unit and the voltage value detected by the voltage sensor is not less than a predetermined threshold value, changes the voltage value detected by the voltage sensor, and controls an amount of charge in and an amount of discharge from a corresponding one of the electric storage units to approximate the changed voltage value to a predetermined target value.

Abstract: A charge and discharge control device includes: a coordination unit which generates coordination information for calculating an output value which each storage battery is caused to output, based on a bus voltage value and a target voltage value; a string output calculating unit which calculates, based on the coordination information, an output target value indicating the output value which the storage battery is caused to output to maintain the bus voltage value at the target voltage value; and a control unit which causes, among the storage batteries, a storage battery corresponding to the calculated output target value to output an output having magnitude indicated by the calculated output target value, wherein the coordination unit generates the coordination information to avoid simultaneous presence of a storage battery that outputs an output in a charge direction and a storage battery that outputs an output in a discharge direction.

Abstract: A communication system provided with a battery assembly obtained by connecting in series a plurality of battery packs having at least one rechargeable battery cell; a battery management unit for managing the battery packs; and an optical line used for transmitting from the battery packs to the battery management unit, along with battery data, an emergency stop signal for cutting off the connection between the battery assembly and a power conversion system when unsafe conditions are detected by the battery packs.

Abstract: A reception device includes: a variable-directivity antenna; an antenna amplifier which amplifies a signal inputted from the variable-directivity antenna; a regulator which supplies DC power to the antenna amplifier; a full wave rectification unit which supplies the DC power to the regulator; a signal line; a DC power source; and a switching unit which switches connection with the DC power source. DC voltage is applied to the DC power source by the signal line so as to control the directivity of the variable-directivity antenna. Moreover, the DC power is supplied to the regulator via the full wave rectification unit. When the connection of the switching unit is switched, the DC voltage supplied to the variable-directivity antenna is reversed between positive and negative voltage but the DC voltage supplied to the regulator is not reversed.

Abstract: A first image pickup unit mainly captures the image of whole face. A second image pickup unit mainly captures an image of iris in an eye. A display unit simultaneously displays both an image picked up by the first image pickup unit and an image picked up by the second image pickup unit on divided display regions, and naturally prompts a user to operate in such manner as to include himself/herself within an image pickup range. When the user moves his/her face or an authentication apparatus upon seeing this display, a relative position or direction of the iris and the image pickup device can be set to a desired state.

Abstract: An undoped Al.sub.0.22 Ga.sub.0.78 As spacer layer having a large forbidden bandgap and an N-Al.sub.0.22 Ga.sub.0.78 As electron-supplying layer having a large forbidden bandgap are formed in order on an undoped GaAs buffer layer having a small forbidden bandgap, and InAs quantum boxes are provided in the Al.sub.0.22 Ga.sub.0.78 As spacer layer. The size of the InAs quantum box is about 150 .ANG. and the height is about 40 .ANG.. When a predetermined drain voltage is applied, electrons are accumulated in the InAs quantum boxes from a channel formed in the vicinity of the interface with the Al.sub.0.22 Ga.sub.0.78 As spacer layer in the GaAs buffer layer. Accordingly, a drain current will not flow almost at all even if a drain voltage is applied.

Abstract: An undoped Al.sub.0.22 Ga.sub.0.78 As layer, an undoped In.sub.0.2 Ga.sub.0.8 As electron-drifting layer, and an undoped GaAs electron-supplying layer are formed in order on a GaAs substrate. An impurity-doped layer .delta.-doped with Si donor is formed in the GaAs electron-supplying layer. An n-Al.sub.0.22 Ga.sub.0.78 As layer and n.sup.+ -GaAs cap layers are formed in order on the GaAs electron-supplying layer. A source electrode and a drain electrode are formed on the n.sup.+ -GaAs cap layers and a gate electrode is formed on the n-Al.sub.0.22 Ga.sub.0.78 As layer.

Abstract: An electron supply layer, a quantum well layer, a first barrier layer, a quantum well layer and a second barrier layer are formed in that order on a GaAs substrate to obtain a device, and source, drain and gate electrodes are provided on the surface of this device. In the above described quantum well layers, the lowest sub-band energies of respective carriers largely differ from each other. Accordingly, one of the above quantum well layers serves as a high-speed channel, and the other serves as a low-speed channel. The change in current value with the application of a gate bias depends only on the speed at which electrons move from the high-speed channel to the low-speed channel. Consequently, a velocity-modulation transistor can be constructed which operates at substantially high speed.