Kabushiki Kaisha Toshiba

Takeo Kanai

Hiroshi Uchino

Kiyoshi Kusunoki

Takashi Fujita

Takeshi Kitahata

Akira Kawaguchi

Ryuichi Morikawa

Hiroyuki Nishikawa

Tadashi Nishikawa

Takahisa Kageyama

Kimihiro Hoshi

Tadahiro Sakamoto

A control apparatus for a power converter having a plurality of semiconductor switching devices that converts DC power into AC power and outputs three levels of voltages, including a command voltage generator configured to output a command voltage vector that represents a voltage to be output from the power converter, an integrator configured to calculate a difference integral vector by integrating a difference between the command voltage vector and an output voltage vector that represents a voltage command for the power converter, a difference vector calculator configured to calculate difference vectors by subtracting the command voltage vector from each of the possible output voltage vectors, a vector selector configured to select one of the possible output voltage vectors which corresponds to one of the difference vectors making the largest angle with the difference integral vector as the output voltage vector only if the difference integral vector exceeds a predetermined value, and a gate signal generator configured to determine one of switching states that includes a plurality of ON-OFF pattern signals for turning on and off the semiconductor switching devices on the basis of the output voltage vector.

Control apparatus for power converter

In a gate circuit having a turn-off gate circuit composed of: OFF gate power source E,of which one terminal is connected to the emitter of semiconductor switching element 81, and switch SW,that connects the other terminal of OFF gate power source E,and the gate of semiconductor switching element S,via resistor R,, the gate circuit is provided with second switch SW,that connects the other terminal of OFF gate power source E,and the gate of semiconductor switching element S,By closing second switch SW,at the timing at which the turn-off operation is completed, it will connect to OFF gate power source E,without passing through a resistor.

Gate circuit

A switching circuit protection technique includes detecting the self-firing of at least one switching element due to an over-voltage in a switching circuit having multiple parallel circuits, applying a firing pulse to all switching elements and the switching circuit in response to the detected self-firing and firing all of the switching elements at the same time in response to a firing pulse.

Switching circuit protection apparatus and method

A power converting system has power converters for converting a direct current into an alternating current, a DC power source arranged on the DC side of the power converters, and voltage dividing transformers having windings whose first ends are connected to the power converters phase by phase and whose second ends are joined together and connected to a load phase by phase. Also provided is a controller for controlling the power converting system.

Power converting system multiplexed with voltage dividing transformers, the voltage transformers, and controller for the system

An overvoltage protection circuit including a plurality of series connected thyristors having an overvoltage protection function and a plurality of impedance circuits. Each of the impedance circuits is connected in parallel with one of the thyristors, respectively. The impedance circuits include at least a first impedance circuit having a first impedance value and a second impedance circuit having a second impedance value which is different from the first impedance value.

Growing community of inventors

Saitama-ken, Japan

Takeo Kanai