Sumitomo Electric Industries, Limited

Koichi Takeshita

Naoki Ayai

Tetsuo Akita

Fumio Urakawa

Toshiaki Okumura

Tomohiro Yamaguchi

Shinjirou Shinada

Tadatsugu Udono

This abnormality detection method for a single-phase AC input voltage is executed by a control unit having a function of a phase locked loop, and includes: sequentially generating a simulated voltage waveform with a phase synchronized with the input voltage, by using the phase locked loop; and within a period until a next update of the generated simulated voltage waveform, comparing the instantaneous value of the input voltage with the simulated voltage waveform, and when the instantaneous value of the input voltage changes from a state of being along the simulated voltage waveform to a state of not being along the simulated voltage waveform, determining that the input voltage is abnormal.

Input-voltage-abnormality detection method and power source device

A power conversion device provided between a DC power supply and an AC electric path, including: a breaking device provided to at least one line of an output electric path in the power conversion device; a first voltage sensor provided on a primary side of the breaking device; a second voltage sensor provided on a secondary side of the breaking device; and a determination unit which calculates a primary-side voltage and a secondary-side voltage, and a primary-side phase and a secondary-side phase and determines that the breaking device is opened, by occurrence of an event in which an absolute value of a voltage difference between the primary-side voltage and the secondary-side voltage is greater than a voltage difference threshold value and an absolute value of a phase difference between the primary-side phase and the secondary-side phase is greater than a phase difference threshold value.

Power conversion device and method for determining operational state of breaking device

This power supply unit includes: an AC path from an input end to an output end; a first voltage sensor configured to detect an input voltage at the input end; a second voltage sensor configured to detect an output voltage at the output end; a bidirectional inverter connected to the AC path; a storage battery connected to the AC path via the bidirectional inverter; an AC switch provided between the input end and a point at which the bidirectional inverter is connected to the AC path; and a control unit configured such that, in a state in which the AC switch is controlled to be opened, if current conduction via the AC switch is detected on the basis of an operation state of the bidirectional inverter, the input voltage, and the output voltage, the control unit determines that the AC switch has failed, and stops the bidirectional inverter.

Power supply unit and method for backfeed protection thereof

Provided is a power conversion device that converts power between DC units and three-phase AC. A first-phase conversion device, a second-phase conversion device, and a third-phase conversion device each include a DC/DC conversion circuit and a single-phase power conversion circuit. For each of the first-phase conversion device, the second-phase conversion device, and the third-phase conversion device, when an absolute value of a voltage target value for the AC exceeds DC voltage of each DC unit, a control unit causes the DC/DC conversion circuit to operate to achieve the absolute value of the voltage target value and causes the single-phase power conversion circuit to only perform necessary polarity inversion, and when the absolute value of the voltage target value is smaller than the DC voltage, the control unit stops operation of the DC/DC conversion circuit and causes the single-phase power conversion circuit to operate to achieve the voltage target value.

Growing community of inventors

Osaka, Japan

Koichi Takeshita