Abstract: [Problem] When load power is assisted, the number of component parts becomes greater because an AC power detector is provided in the AC power supply of an inverter. [Means for Solution] An instantaneous output power calculating section comprises a power calculating section to calculate power by using detected values of voltage and current on the output side of an inverter, and a correction calculating section to correct the calculated power. Moreover, limiter sections are provided, respectively, in charge control section and discharge control section for a chopper, and limiter values of the limiter sections are varied by the power calculated by the instantaneous output power calculating section.

Abstract: A power conversion device in which an inverter for controlling a load is connected to an alternating current power system, and arranged to perform an electric power assist by connecting a direct-current power assist device having a chopper and a charge device to a direct-current circuit of the inverter. The device including a setting section to set charge and discharge target values in accordance with a sensed value of the direct-current voltage of the inverter; a charge control section to perform a charge control based on the charge target value; a discharge control section to perform a discharge control based on the discharge target value; and an instantaneous-low high-speed-compensation section to estimate an electric power corresponding to a direct-current sensed voltage of the inverter, and to output a value to the discharge control section which is obtained by dividing the estimated value by the direct-current sensed voltage.

Abstract: [Problem] When load power is assisted, the number of component parts becomes greater because an AC power detector is provided in the AC power supply of an inverter. [Means for Solution] An instantaneous output power calculating section comprises a power calculating section to calculate power by using detected values of voltage and current on the output side of an inverter, and a correction calculating section to correct the calculated power. Moreover, limiter sections are provided, respectively, in charge control section and discharge control section for a chopper, and limiter values of the limiter sections are varied by the power calculated by the instantaneous output power calculating section.

Abstract: While the amount of stored electricity is maintained at about 50 percent of a charging capacity using a direct-current power assist device connected to a direct-current circuit of an inverter, a certain period of time is monitored. When electricity is charged or discharged, the amount of peak cut, as a power assist, cannot be controlled. Moreover, it is impossible to carry out charge-and-discharge discrete control unique to a load corresponding to the intended use. In a setting section of a chopper control section of the direct-current power assist device, a charge start voltage, a charge stop voltage, a non-control voltage range, a discharge stop voltage, and a discharge start voltage are set as setting values. Each setting value is selected in accordance with a detection value of a direct-current detection voltage of the inverter, and output to a charge control section and a discharge control section as a charge target value and a discharge target value, respectively.

Abstract: A sheet feeding apparatus includes a sending element of an ultrasonic sensor for outputting ultrasonic waves, a drive circuit for supplying the sending element of the ultrasonic sensor with a drive signal for driving the sending element, a receiving element of the ultrasonic sensor disposed opposite the sending element of the ultrasonic sensor across a sheet transfer path in the sheet feeding apparatus, and for receiving the ultrasonic waves, a setting unit for setting a threshold for the detection of transfer of the plurality of paper sheets by using the output of the receiving element of the ultrasonic sensor at the time of stopping of the output of the sending element of the ultrasonic sensor as a basic value, and a detection unit for detecting transfer of the plurality of paper sheets by comparing the output of the receiving element of the ultrasonic sensor with the threshold.