Abstract: A controlling apparatus includes a storage unit for storing, for each sampling period, a combination of a primary frequency of connected induction motors and the amplitude of a voltage command value, and a gradient detection unit for calculating a value corresponding to an increase in the amplitude of the voltage command value divided by an increase in the primary frequency, and for outputting a failure signal upon determining, when a result of the division is less than a predetermined reference value, that the plurality of induction motors include at least one induction motor having a phase sequence that includes incorrect wiring with respect to the power converter.

Abstract: In a power supply device, the bridge circuit is configured by connecting, in parallel, a plurality of series circuits of an inverse-parallel connection circuit of a semiconductor switch and a diode. A control unit controls switching of a semiconductor switch so that a voltage v between AC terminals becomes zero voltage in equal periods ? before and after a center point shifted from one zero crossing point in one cycle of the input current by a compensation period (angle) ? calculated from a voltage applied to a resonance circuit constituted by the power receiving coil and a resonance capacitor Cr and an induced voltage of the power receiving coil, and becomes a positive-negative voltage whose peak value is the voltage Vo between DC terminals in other periods.

Abstract: In a power supply device the bridge circuit is configured such that a plurality of series circuits of two inverse parallel connection circuits of a semiconductor switch and a diode are connected in parallel. The power supply device includes a control unit configured to control the semiconductor switch such that a voltage between AC terminals of the bridge circuit becomes a zero voltage only during a prescribed time period before and after two zero crossing points in one cycle of the input current and such that the voltage becomes a positive-negative voltage in which the output voltage is a peak current value during other time periods. Consequently, a power factor of the power receiving circuit is improved and a loss of an entire device is inhibited, and a size and a cost of the entire device may be reduced.

Abstract: A controlling apparatus includes a storage unit for storing, for each sampling period, a combination of a primary frequency of connected induction motors and the amplitude of a voltage command value, and a gradient detection unit for calculating a value corresponding to an increase in the amplitude of the voltage command value divided by an increase in the primary frequency, and for outputting a failure signal upon determining, when a result of the division is less than a predetermined reference value, that the plurality of induction motors include at least one induction motor having a phase sequence that includes incorrect wiring with respect to the power converter.

Abstract: In a power supply device, the bridge circuit including a plurality of switching arms which is an inverse-parallel circuit of a semiconductor switch and a diode. The power supply device includes a control unit. The control unit switches the semiconductor switch such that a voltage v between AC terminals becomes a positive-negative voltage whose peak value is the voltage Vo between the DC terminals only during prescribed time periods before and after a point that has deviated from each zero crossing point ZCP of a current i by a prescribed compensation period ? and such that the voltage v between the AC terminals becomes a zero voltage during the other time periods, and sets the compensation period ? such that a time period during which the voltage v between the AC terminals becomes a zero voltage is the shortest.

Abstract: In a power supply device, the bridge circuit including a plurality of switching arms which is an inverse-parallel circuit of a semiconductor switch and a diode. The power supply device includes a control unit. The control unit switches the semiconductor switch such that a voltage v between AC terminals becomes a positive-negative voltage whose peak value is the voltage Vo between the DC terminals only during prescribed time periods before and after a point that has deviated from each zero crossing point ZCP of a current i by a prescribed compensation period ? and such that the voltage v between the AC terminals becomes a zero voltage during the other time periods, and sets the compensation period ? such that a time period during which the voltage v between the AC terminals becomes a zero voltage is the shortest.

Abstract: In a power supply device, the bridge circuit is configured by connecting, in parallel, a plurality of series circuits of an inverse-parallel connection circuit of a semiconductor switch and a diode. A control unit controls switching of a semiconductor switch so that a voltage v between AC terminals becomes zero voltage in equal periods ? before and after a center point shifted from one zero crossing point in one cycle of the input current by a compensation period (angle) ? calculated from a voltage applied to a resonance circuit constituted by the power receiving coil and a resonance capacitor Cr and an induced voltage of the power receiving coil, and becomes a positive-negative voltage whose peak value is the voltage Vo between DC terminals in other periods.

Abstract: In a power supply device the bridge circuit is configured such that a plurality of series circuits of two inverse parallel connection circuits of a semiconductor switch and a diode are connected in parallel. The power supply device includes a control unit configured to control the semiconductor switch such that a voltage between AC terminals of the bridge circuit becomes a zero voltage only during a prescribed time period before and after two zero crossing points in one cycle of the input current and such that the voltage becomes a positive-negative voltage in which the output voltage is a peak current value during other time periods. Consequently, a power factor of the power receiving circuit is improved and a loss of an entire device is inhibited, and a size and a cost of the entire device may be reduced.