Abstract: A power converter includes: a converter (1) which rectifies an AC power; capacitor series assemblies (2A, 2B) connected to the DC side of the converter; an inverter (3) which assumes that one end of the capacitor series assemblies is at a high potential, the other end is at a low potential, and a series connection point is at an intermediate potential and selects one of the high potential, the intermediate potential, and the low potential for output of a 3-phase AC; an inverter control unit (4) which controls the inverter (3); and a voltage measuring device (8) which measures a capacitor voltage Vdc as a voltage between the both ends of the capacitor series assemblies (2A, 2B). The inverter control unit (4) has a beatless control unit (21) which controls the modulation ratio ? in accordance with a capacitor voltage Vdc and a frequency fixation unit (22) which fixes the frequency of the AC voltage outputted by the inverter (3) to an instruction value.

Abstract: A power conversion system includes a first power converter converting AC to DC, a second power converter converting DC to AC, a current detector detecting output current of the second power converter, a pulsation detector detecting a pulsating component associated with the AC to DC conversion of the first power converter from a pulsating component contained in at least any one of effective power, power, and apparent power of the second power converter, a voltage corrector outputting a correction amount correcting at least one of phase, frequency, and amplitude of a voltage output from the second power converter based on the pulsating component from the pulsation detector, and a voltage controller outputting a voltage instruction to be output from the second power converter based on the correction amount from the voltage corrector, wherein the second power converter converts DC to AC based on the voltage instruction from the voltage controller.

Abstract: A control apparatus for an electric railcar includes an inverter that exchanges power with an AC rotating machine, a filter capacitor connected in parallel to a DC side of the inverter, a filter reactor provided between the filter capacitor and an overhead line, an overhead line voltage measuring instrument that measures a voltage value of the overhead line, a voltage increase detection unit that senses an amount of voltage increase occurring when, with an overhead line voltage being supplied, the overhead line voltage goes beyond a reference voltage value and rises at a rate equal to or higher than that by a predetermined time constant.

Abstract: A detected DC voltage value estimation mechanism samples detected DC voltage values at specific intervals of a period T, stores detected DC voltage values Vn to Vn?m detected at a present time tn up to a sampling time tn?m which is m sampling cycles (m?1) before the present time tn, and calculates a DC voltage estimation value Vn+1 at a next time tn+1 using the detected DC voltage values Vn to Vn,m, expressing a curve connecting the voltage values Vn to Vn?m by a specific function. An output voltage control into which the DC voltage estimation value Vn+1 is input corrects an output voltage command value and outputs the corrected output voltage command value to a power converter.

Abstract: A controller for an AC rotary machine is proposed, by which a stable rotation angular-frequency estimate value can be obtained even in an extremely low speed region of the AC rotary machine, and consequently stable control can be performed. A controller for an AC rotary machine has an angular-frequency estimate output means 20 that outputs an angular-frequency estimate value ?i based on an angular-frequency calculated value ?1 including a rotation angular-frequency estimate value ?e.

Abstract: A control controls starting of an AC rotary machine by calculating a resistance drop component, corresponding to a resistance drop of the AC rotary machine, based on a detection current, and adjusts angular frequency of an AC output voltage based on subtracting the resistance drop component from a voltage command, and, simultaneously, adjusting amplitude of the AC output voltage so that amplitude of an AC phase current may change in conformity with a predetermined function.

Abstract: A control apparatus for an AC rotary machine, comprising a VVVF inverter 1 which exchanges electric power between it and the AC rotary machine, a voltage detector 16 which detects voltage information of a DC side of the inverter 1, current detectors 3 which detect current information items of an AC side of the inverter 1, an inverter-electric-power command unit 20 which determines an inverter-electric-power command value in accordance with the detected voltage information, an actual-inverter-electric-power calculation unit 19 which calculates an actual inverter-electric-power value on the basis of the detected current information items, a secondary-magnetic-flux command calculation unit 18 which calculates a secondary-magnetic-flux command value for the AC rotary machine, on the basis of a difference between the inverter-electric-power command value and the actual inverter-electric-power value, a-predetermined-secondary-magnetic-flux command unit 23 which outputs a predetermined secondary-magnetic-flux comman

Abstract: A power converting device for an electric train includes a power converter, an alternating-current motor, a primary control unit, and a control unit. The power converter converts direct-current power into alternating-current power. The alternating-current motor is driven by the alternating-current power output from the power converter. The primary control unit outputs a power-running notch command that determines an acceleration speed for the electric train. The control unit controls an amount of the alternating-current power based on the power-running notch command. The control unit sets the amount of the alternating-current power to zero without a delay after receiving an OFF signal of the power-running notch command during power running.

Abstract: This invention provides a base station radio apparatus, a mobile unit communication system, and a control method for a base station radio apparatus that suppress a deterioration in communication quality. Success rates can be monitored by monitoring outgoing/incoming calls and call connections, and control can be executed to detect a potential card for which a success rate declines and force the card to enter an ALM state. Thus, a deterioration in communication quality can be suppressed.

Abstract: Provided is a vector control apparatus for an induction motor which is capable of obtaining stable rotation in a short period of time for adjustment even at the time of low-speed operation by increasing the SN ratio of an output voltage to suppress the arithmetic error in the primary angular frequency arithmetic value based on a magnetic flux command value calculated from a circuit constant and an actual measurement of the induction motor even in the case where the rotation velocity of the induction motor is lower.

Abstract: In a base station providing a large-distance service area (large area) such as a mobile communication system WLL of the CDMA method, the time required for performing call search (path search) is reduced so as to reduce the call connection time. When performing a path search in the base station (8), a predetermined offset value from a reference time is set so that path search is performed only in a doughnut-shaped service area (30). Thus, there is no need of performing path search in the vicinity of the base station (8) and search is performed only in the doughnut-shaped service area (30). Thus, it is possible to reduce the path search time and reduce the call connection time.

Abstract: A control apparatus for an electric car, including a power converter which feeds AC power of variable voltage and variable frequency to a primary side member of a linear electromagnetic actuator, voltage command means for giving a command of a voltage which is fed to the linear electromagnetic actuator, current detection means for detecting current information which flows between the power converter and the linear electromagnetic actuator, and motor constant calculation means for calculating a motor constant of the linear electromagnetic actuator on the basis of the voltage information Vu given by the voltage command means and the current information Iu detected by the current detection means.

Abstract: Provided is a vector control apparatus for an induction motor which is capable of obtaining stable rotation in a short period of time for adjustment even at the time of low-speed operation by increasing the SN ratio of an output voltage to suppress the arithmetic error in the primary angular frequency arithmetic value based on a magnetic flux command value calculated from a circuit constant and an actual measurement of the induction motor even in the case where the rotation velocity of the induction motor is lower.

Abstract: A satisfactory reception environment is secured efficiently regardless of a degree of the traffic intensity. A pilot power control unit is provided to a base station radio unit. The pilot power control unit controls a desired wave power-to-interference wave power ratio of a pilot signal to stay at a preset value. More specifically, upon receipt of a multiplex wave from a multiplexing unit, the pilot power control unit computes a desired wave power-to-interference wave power ratio of a pilot signal. Then, the pilot power control unit transmits a command signal to a coder to change a transmission power value of the pilot signal in an amount corresponding to a difference between the computed desired wave power-to-interference wave power ratio and a set desired wave power-to-interference wave power ratio.

Abstract: In a CDMA type mobile communication system, when both a radio channel in an up-link direction and a radio channel in a down-link direction are interrupted, a base station successively increases down-link transmission power by 1 dB in a constant interval until a response is sent from a mobile station, while releasing the normal down-link transmission power control operation. Also, the base station controls a power control bit produced by the base station so as to successively increase up-link transmission power of the mobile station.

Abstract: In a base station providing a large-distance service area (large area) such as a mobile communication system WLL of the CDMA method, the time required for performing call search (path search) is reduced so as to reduce the call connection time. When performing a path search in the base station (8), a predetermined offset value from a reference time is set so that path search is performed only in a doughnut-shaped service area (30). Thus, there is no need of performing path search in the vicinity of the base station (8) and search is performed only in the doughnut-shaped service area (30). Thus, it is possible to reduce the path search time and reduce the call connection time.

Abstract: The present invention has an object to secure a satisfactory reception environment efficiently regardless of a degree of the traffic intensity. The object is achieved by the following. A pilot power control unit is provided to a base station radio unit. The pilot power control unit controls a desired wave power-to-interference wave power ratio of a pilot signal to stay at a preset value. More specifically, upon receipt of a multiplex wave from a multiplexing unit, the pilot power control unit computes a desired wave power-to-interference wave power ratio of a pilot signal. Then, the pilot power control unit transmits a command signal to a coder to change a transmission power value of the pilot signal in an amount corresponding to a difference between the computed desired wave power-to-interference wave power ratio and a set desired wave power-to-interference wave power ratio.

Abstract: In a CDMA type mobile communication system, when both a radio channel in an up-link direction and a radio channel in a down-link direction are interrupted, a base station successively increases down-link transmission power by 1 dB in a constant interval until a response is sent from a mobile station, while releasing the normal down-link transmission power control operation. Also, the base station controls a power control bit produced by the base station so as to successively increase up-link transmission power of the mobile station.

Abstract: A locking device for electronic parts each having two or more lead wires, including clinch pawls which can move a little when they abut on the lead wires. The small movement of these clinch pawls is detected by a detection mechanism and utilized to confirm if a given electronic part has been mounted on a print-circuit board.