Abstract: The voltage detection circuit (33) is a voltage divider circuit including a plurality of resistances (34a to 34c and 35a to 35c) and detects voltages (Vac1, Vac2) correlating with a power source voltage (Vin) of the AC power source (91). The calculation unit (40) obtains the across voltage (VL) of the reactor (29) using detection results (Vac1, Vac2) of the voltage detection circuit (33), and estimates a power source current (Iin) based on the across voltage (VL). The calculation unit (40) corrects gains of the detection results (Vac1, Vac2) so that a value correlating with an average value per predetermined time period of the estimated power source current (Iin) matches a value correlating with an average value per the predetermined time period of a current (Iinv) downstream of the capacitor (26), and obtains the across voltage (VL) using the detection results (Vac1, Vac2).

Abstract: The voltage detection circuit (33) is a voltage divider circuit including a plurality of resistances (34a to 34c and 35a to 35c) and detects voltages (Vac1, Vac2) correlating with a power source voltage (Vin) of the AC power source (91). The calculation unit (40) obtains the across voltage (VL) of the reactor (29) using detection results (Vac1, Vac2) of the voltage detection circuit (33), and estimates a power source current (Iin) based on the across voltage (VL). The calculation unit (40) corrects gains of the detection results (Vac1, Vac2) so that a value correlating with an average value per predetermined time period of the estimated power source current (Iin) matches a value correlating with an average value per the predetermined time period of a current (Iinv) downstream of the capacitor (26), and obtains the across voltage (VL) using the detection results (Vac1, Vac2).

Abstract: Disclosed herein is a power conversion device including a storage and a power conversion controller. The storage stores multiple values, each correlated to a disturbance that causes distortion in a current to a power converter, in association with a phase angle of a voltage of an AC power supply. The power conversion controller controls ON/OFF operations by using the values stored in the storage to compensate for a manipulated variable of control performed by the power converter in association with the phase angle of the voltage of the AC power supply.

Abstract: Disclosed herein is a power conversion device including a storage and a power conversion controller. The storage stores multiple values, each correlated to a disturbance that causes distortion in a current to a power converter, in association with a phase angle of a voltage of an AC power supply. The power conversion controller controls ON/OFF operations by using the values stored in the storage to compensate for a manipulated variable of control performed by the power converter in association with the phase angle of the voltage of the AC power supply.

Abstract: A power conversion apparatus is equipped with switching devices to perform power conversion of input AC power supplied from an AC power supply to output AC power having a predetermined voltage and a predetermined frequency, and to supply the power to a motor connected thereto. The apparatus includes a controller controlling switching of the switching devices, a capacitor smoothing a ripple generated by the switching of the switching devices, a current controller controlling a current flowing to the motor, and a voltage distortion corrector detecting a harmonic component caused by distortion in motor input power, and superimposing compensation values on an output of the current controller in accordance with a value of the harmonic component.

Abstract: A power conversion apparatus is equipped with switching devices to perform power conversion of input AC power supplied from an AC power supply to output AC power having a predetermined voltage and a predetermined frequency, and to supply the power to a motor connected thereto. The apparatus includes a controller controlling switching of the switching devices, a capacitor smoothing a ripple generated by the switching of the switching devices, a current controller controlling a current flowing to the motor, and a voltage distortion corrector detecting a harmonic component caused by distortion in motor input power, and superimposing compensation values on an output of the current controller in accordance with a value of the harmonic component.

Abstract: Sub-loop controllers arranged around a microprocessor are assigned to operation terminals to be controlled, and connected to a master controller and a host computer through a system bus to be supplied with a control command therefrom. Analog memories for manual control of the operation terminals are connected to the host computer through a special, common wiring. If one of the sub-loop controllers breaks down, the host computer directly controls the operation terminal by use of this analog memory thereby to back up the sub-loop controller.

Abstract: A control system for use with a data transmission system having a plurality of subscriber stations connected exchangeably to a pair of transmission paths comprises a transmission control station provided for each of the transmission paths which produce an access signal to enable data transmission to be performed among the subscriber stations. One of the control stations is constantly operated, while the other control station serves as a stand-by station. When the access signal is not supplied to the subscriber station properly within a predetermined time, the subscriber station is disconnected from the operative transmission path and self-checking is executed. If abnormality is found to be present in the subscriber station through the self-checking, the latter is held in the disconnected state. When abnormality is detected in the operative transmission path, the subscriber stations are changed over to the stand-by transmission path.