Fuji Electric Co., Ltd.

Kunio Matsubara

Tsuyoshi Nagano

Hirotoshi Kaneda

Ryoga Kiguchi

Yukihiro Nishikawa

Hiromu Takubo

Natsuko Takeuchi

There is provided a short circuit determination apparatus including: a sensor configured to detect, in a switching device that has a control terminal, a first main terminal, and a second main terminal, a temporal change of a main current flowing between the first main terminal and the second main terminal; and a short circuit determination unit configured to determine that the switching device is short-circuited, in a case where the temporal change of the main current is larger than or equal to a first threshold value, after a first timing after a control signal for driving the control terminal is turned on.

Short circuit determination apparatus, switch apparatus, and short circuit determination method

A short-circuit detector includes: a first Rogowski coil configured to generate a first detection signal in accordance with a current that flows through a first arm due to a short circuit in a load; a second Rogowski coil configured to generate a second detection signal in accordance with a current that flows through the first arm due to a short circuit in the first arm or a second arm; a load short-circuit detection circuit configured to detect the short circuit in the load, based on the first detection signal; an arm short-circuit detection circuit configured to detect the short circuit in the first arm or the second arm, based on the second detection signal; and a short-circuit detection circuit configured to detect a short-circuit, based on: an output signal output from the load short-circuit detection circuit; and an output signal output from the arm short-circuit detection circuit.

Short-circuit detector and power converter

Provided is a gate driving apparatus, including: a gate driving unit for driving a gate of a switching device; a switching unit for switching a gate current of the switching device during, within a turn-on period of the switching device, at least a part of the period, which is after timing when a current starts to flow in the switching device, to a smaller current when compared to the gate current before at least a part of the period.

Gate driving apparatus, switching apparatus and gate driving method

A short circuit detector is included in a power converter, the power converter being configured to supply power to a load via a first arm including a first semiconductor switch and a second arm including a second semiconductor switch. The short circuit detector includes a Rogowski coil; and a detection circuit configured to detect a short circuit in one of the first arm, the second arm and the load, based on a detection signal obtained from the Rogowski coil. The Rogowski coil is inserted into both: (i) first current path through which a first current flows in common with the first arm and the load, and (ii) a second current path through which a second current flows in common with the second arm and the load.

Short circuit detector and power converter

Provided is a short-circuit determining apparatus comprising: a sensor configured to detect a time change of a main current flowing between a first main terminal and a second main terminal of a switching device having a control terminal, the first main terminal and the second main terminal; an integration unit configured to integrate an output of the sensor; a polarity determining unit configured to determine a polarity of the output of the sensor; and a short-circuit determining unit configured to determine a short-circuit of the switching device, based on a comparison result of an output of the integration unit and a short-circuit determination reference value according to a determination result of the polarity.

Short-circuit determining apparatus, switch apparatus and short-circuit determining method

A driving apparatus including: gate driving circuit to drive gates of a first semiconductor element and a second semiconductor element connected in series between a positive side power supply line and a negative side power supply line; a first timing generating circuit to generate a first timing signal when voltage applied to the second semiconductor element becomes reference voltage during a turn-off period of the first semiconductor element; and a first driving condition change circuit, wherein the gate driving circuit relaxes change in a charge amount of the gate of the first semiconductor element, according to the first timing signal.

Driving apparatus and switching apparatus

A gate drive apparatus is provided. The gate drive apparatus includes a gate drive unit configured to drive a gate of a switching device; a parameter measuring unit configured to measure a parameter corresponding to current flowing through the switching device; a discrepancy detection unit configured to detect discrepancy between current flowing through the switching device during an on-state of the switching device and a reference value, based on the parameter; and a control unit that, if the discrepancy is not detected, switches a change speed of a gate voltage of the switching device at a timing when a reference time has elapsed since a turn-off start of the switching device during a next turn-off time period of the switching device, and if the discrepancy is detected, keeps the change speed of the gate voltage during the next turn-off time period of the switching device.

Gate drive apparatus, switching apparatus, and gate drive method

Provided is a gate drive device, including: a gate drive unit for driving a gate of a switching element; a measurement unit for measuring a parameter that changes according to a current flowing through the switching element; and a switching unit for switching a changing speed of a gate voltage of the switching element by the gate driving unit after a first reference period from a start of turning off the switching element based on the parameter.

Gate drive device and switching device

A gate driver includes: a timing determination unit configured to measure an on-time of a switching element and configured to determine, based on the on-time, a certain timing during a turn-off period of the switching element as an intermediate timing; and a driving condition changing unit configured to change a gate driving condition of the switching element at the intermediate timing determined by the timing determination unit.

Gate driver and power converter

A gate drive apparatus including a gate drive unit configured to drive a gate of a switching device, a peak detection unit configured to detect that a voltage across main terminals applied between the main terminals of the switching device during a turn-off period of the switching device is at a peak, and a driving condition changing unit configured to increase a change speed of a gate voltage of the switching device caused by the gate drive unit, in response to a detection that the voltage across main terminals is at a peak.

Gate drive apparatus and switching apparatus

A gate driver includes: a drive circuit configured to drive, in accordance with an input signal that commands to turn on/off a switching element connected between high and low power supply potential parts, a gate of the switching element; a time storage circuit configured to store a time length from when the input signal is switched to an on command to when a recovery surge voltage generated by a diode that is opposite to the switching element is detected; a switching determination circuit configured to determine, in accordance with a detected value of a power supply voltage, whether to switch a gate driving condition; and a driving condition change circuit configured to change, in accordance with a determination result of the switching determination circuit, the gate driving condition at a time of current turn-on by the time length stored at a time of previous turn-on.

Provided is a driving apparatus that includes a gate driving circuit that turns off a first semiconductor element upon receiving a turn-off signal, a measuring circuit that measures a parameter according to a voltage applied to the second semiconductor element, a timing generating circuit that generates a timing signal if the parameter satisfies a first condition during a time period in which the first semiconductor element is tuned off; and a driving condition change circuit that, in response to the timing signal, further decreases a changing speed of a gate voltage of the first semiconductor element than a reference speed during the time period in which the first semiconductor element is tuned off, wherein the gate driving circuit turns off the first semiconductor element in response to that the parameter satisfies a second condition during a time period in which the first semiconductor element is tuned on.

A gate driver for driving a gate of a switching element in accordance with an input signal is provided. The gate driver is configured to change a gate driving condition in accordance with a detected value of power supply voltage. Each time when the switching element is turned off, the gate driver stores a time width from a time when the input signal is switched to an off command to a time when switch-off surge occurs in the switching device. If it is determined that the gate driving condition should be changed during turn-off operation of the switching element, the gate driver switches the gate driving condition when a time corresponding to the time width stored at a previous turn-off is elapsed after a current turn-off of the switching element is started.

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Hino, Japan

Kunio Matsubara