Abstract: A controller that controls ON/OFF of switching elements and opening/closing of an opening/closing unit based on currents detected by current detectors. The controller includes a fault detector that detects whether any of the switching elements has a short-circuit fault and outputs a signal indicating a detection result, an ON/OFF controller that sets one of the switching elements that constitutes a phase other than a first phase that involves the short-circuit fault to an ON operation state and outputs a signal for opening the opening/closing unit, and an opening/closing controller that opens an opening/closing unit connected to a third phase other than the first phase and the second phase in which one of the switching elements is set to the ON operation state by the ON/OFF controller.

Abstract: Based on rotation information of a synchronous machine detected by a rotation information detector, a controller causes a converter to boost a charge voltage of a capacitor so as to be higher than an induced voltage generated by the synchronous machine at a time of shifting to a coasting operation, maintains the charge voltage during the coasting operation, and performs weak field control so that the induced voltage generated by the synchronous machine becomes lower than a DC voltage at the time of shifting from the coasting operation to a power running operation or to a regenerative operation.

Abstract: A power conversion apparatus of an electric vehicle includes: a power converter for driving an induction machine based on arbitrary d- and q-axis voltage commands Vd* and Vq*, and a control unit for controlling the power converter based on a power running command P and a brake command B from outside.

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: An electrical conversion apparatus including a converter and an inverter comprises a capacitor that stores a DC electrical power; a ripple detection unit that detects a ripple of an active power that is output from the inverter; a voltage measuring instrument that measures a voltage across the capacitor; a DC voltage command generation unit that calculates a command value of the voltage across the capacitor according to a frequency of the AC voltage output from the inverter; and a DC voltage control unit that receives the voltage measured by the voltage measuring instrument and the command value calculated by the DC voltage command generation unit, to control the converter so that the voltage across the capacitor becomes the command value, wherein the DC voltage command generation unit makes the command value of the voltage across the capacitor higher than usual, within a predetermined range including a frequency of a ripple component of the voltage across the capacitor.

Abstract: In a conventional electrical power conversion apparatus, a control microprocessor performs a control for eliminating or curbing a beat phenomenon, so that a control delay occurs because computing time is required in the control microprocessor. Because of the control delay, it is not possible to obtain an effect of sufficiently reducing a current ripple and torque pulsation. In addition, in an electric train in which a frequency of an AC power source is changed over while the train is running, it is required for a method of detecting a ripple component by a band-pass filter that a plurality of band-pass filters are provided and then the changeover is performed depending on the power source frequency, resulting in difficulties to take countermeasures.

Abstract: A control apparatus for an AC rotary machine includes a control circuit, a power converter, a current detector, and a voltage detector. The control circuit includes: an activation current instruction unit which generates a current instruction for activation; and a start phase setting unit which sets an initial rotation phase for activation control, based on the rotation direction of the AC rotary machine just after activation and on the polarity of current detected by the current detector just after activation. Thus, the current amplitude and torque shock just after activation control is started can be reduced, and assured and stable reactivation is allowed without causing the protection operation.

Abstract: An object is to provide a magnetic-pole position detection apparatus for synchronous machines that allows a desired accuracy of magnetic-pole position detection regardless of variation in DC voltage of a DC voltage source. Calculation means (2a) changes a pulse width (tp) and a pulse-quiescent width (tn) in accordance with a DC voltage detection value (Vdc), using a pulse width determination section (22a), such that a desired accuracy of magnetic-pole position detection can be obtained regardless of variation in DC voltage of a DC voltage source (5). The calculation means (2a) also performs control such that a sampling timing is fixed at the end point of the pulse width (tp) of voltage vectors regardless of the DC voltage detection value (Vdc).

Abstract: A power conversion device includes a first capacitor connected in parallel to a direct-current power supply, plural power converters that drive plural synchronous machines, a second capacitor connected in parallel to a direct-current side of power converters, a switching circuit inserted between the first and second capacitors, a switch-start instruction unit that controls starting of an operation of the power converters, and a control unit that controls the power converters based on a motor velocity and a voltage of the first capacitor. The switch-start instruction unit turns off the switching circuit while the power converters stop, turns off the switching circuit until a terminal voltage of each of the synchronous machines becomes equal to a predetermined value when each of the power converters starts operating, and turns on the switching circuit when the terminal voltage of each synchronous machine becomes equal to or smaller than the predetermined value.

Abstract: An electric power conversion apparatus includes a converter 1 for rectifying ac electric power, a series-connected set, of capacitors 2A and 2B, connected to the dc side of the converter, an inverter 3 for, by setting one end of the series-connected capacitor set to a high-potential level, the other end of the set to a low-potential level, and a connection point between the capacitors to a medium-potential level, selecting any one of the levels and outputting three-phase ac, an inverter control unit 4 for controlling the inverter 3, and a voltage measurement device 8 for measuring a capacitor voltage Vdc as a voltage between both ends of the series-connected set, of the capacitors 2A and 2B; and the inverter control unit 4 further includes a beatless control unit 21 for controlling a modulation factor ? in response to the capacitor voltage Vdc, and a frequency fixing unit 22 for fixing to a command value the frequency of an ac voltage outputted from the inverter 3.

Abstract: A power conversion apparatus of an electric vehicle includes: a power converter for driving an induction machine based on arbitrary d- and q-axis voltage commands Vd* and Vq*, and a control unit for controlling the power converter based on a power running command P and a brake command B from outside.

Abstract: To include a power converter that drives an induction machine and a control unit that controls the, power converter. The control unit includes a drive stopping unit. The drive stopping unit includes a secondary-resistance-temperature detecting unit that detects temperature rise of a secondary resistance of the induction machine based on a current (a d-axis-current detection value and a q-axis-current detection value, or a d-axis current command and a q-axis current command) detected by the induction machine, an inverter angular frequency calculated based on the current, and speed information of an electric vehicle detected by an external-speed-information detecting unit, and the drive stopping unit also includes a drive-stopping-signal output unit that outputs a drive stopping signal for stopping a driving operation of the power converter based on the speed information ?train of an electric vehicle and an output (deviation) from the secondary-resistance-temperature detecting unit.

Abstract: Included are a power converter for driving an induction machine, a control unit for controlling the power converter, and a brake force command computing unit for computing a brake force command. The control unit includes a regenerative brake force computing unit. The regenerative brake force computing unit computes a first regenerative brake force that can be determined based on a d-axis current detected value, a q-axis current detected value, a d-axis voltage command, a q-axis voltage command, and speed information and also computes a second regenerative brake force that can be determined based on phase current information signals, the d-axis voltage command, the q-axis voltage command, and the speed information, and then selects any one of the first regenerative brake force and the second regenerative brake force according to the speed information and outputs the selected one to the brake force command computing unit.

Abstract: A controller that controls ON/OFF of switching elements and opening/closing of an opening/closing unit based on currents detected by current detectors. The controller includes a fault detector that detects whether any of the switching elements has a short-circuit fault and outputs a signal indicating a detection result, an ON/OFF controller that sets one of the switching elements that constitutes a phase other than a first phase that involves the short-circuit fault to an ON operation state and outputs a signal for opening the opening/closing unit, and an opening/closing controller that opens an opening/closing unit connected to a third phase other than the first phase and the second phase in which one of the switching elements is set to the ON operation state by the ON/OFF 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 power conversion apparatus includes: a line breaker that is connected in series to a direct-current power supply; a first capacitor that is connected in parallel to the direct-current power supply through the line breaker; a discharge circuit that includes a resistor and a first switching circuit connected in series and is connected in parallel to the first capacitor; a power converter for driving a synchronous machine; a second capacitor that is connected in parallel to a direct-current side of the power converter; a second switching circuit that is connected in series between the first capacitor and the second capacitor; and a control circuit for controlling the discharge circuit. The control circuit controls the discharge circuit on the basis of the voltage of the first capacitor and the voltage of the second capacitor.

Abstract: A power converting apparatus including a power converter that converts a DC voltage into an AC voltage and applies the AC voltage to an AC rotating machine and a control unit that controls the power converter based on an operation command from the outside is provided. The power converting apparatus includes: a first calculating unit that calculates and outputs, from a d-axis current detection value and a q-axis current detection value detected by the AC rotating machine and current command values based on the operation command, first voltage command values to the power converter, magnetic fluxes of the AC rotating machine, and an angular frequency; and a second calculating unit that sets, as an initial value, at least one of the magnetic fluxes and the angular frequency input from the first calculating unit and calculates and outputs second voltage command value to the power converter and an angular frequency.

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 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 a rotary machine, comprising a variable-voltage variable frequency (VVVF) inverter for driving the rotary machine, a voltage detector for detecting a DC voltage at the inverter's input, current detectors for detecting phase currents of the rotary machine, an inverter-electric-power command unit for determining an inverter-electric-power command value, an actual-inverter-electric-power calculation unit for calculating an actual inverter-electric-power value, a secondary-magnetic-flux command calculation unit for calculating a secondary-magnetic-flux command value, a predetermined-secondary-magnetic-flux command unit for outputting a predetermined secondary-magnetic-flux command value, and a secondary-magnetic-flux command changeover unit for selecting either one of the secondary-magnetic-flux command value and the predetermined secondary-magnetic-flux command value as a secondary-magnetic-flux command value which is used to control the rotary machine.