Kabushiki Kaisha Toshiba

Junichi Tsuda

Hiroshi Mochikawa

Yushi Koyama

Atsuhiko Kuzumaki

Tateo Koyama

According to one embodiment, a switch includes a first element with a first withstand voltage, a second element whose withstand voltage is lower than the first withstand voltage, a diode which is connected between a positive electrode of the first element and a positive electrode of the second element in such a manner that a direction from the positive electrode of the second element toward the positive electrode of the first element is a forward direction and whose withstand voltage is equal to the first withstand voltage, a negative electrode of the first element and a negative electrode of the second element being connected, and a circuit configured to apply a positive voltage to the positive terminal output a pulse lower than the first withstand voltage when the first element goes off.

Semiconductor switch and power conversion apparatus

The present invention includes: an inverterconfigured to perform pulse wide modulation on an output from a DC power source; a first capacitor pairprovided at an input side of the inverter and including two capacitors serially connected to form a neutral point; a second capacitor pairprovided at an output side of the inverter and including two capacitors serially connected to form a neutral point; a bypass path g for a leakage current formed by connecting the neutral point of the first capacitor pair and the neutral point of the second capacitor pair to each other; at least one common mode choke coilprovided between the first capacitor pair and the second capacitor pair and configured to suppress a common mode current generated in the inverter; and an output filterconfigured to convert a voltage, which is outputted from the inverter and subjected to the pulse wide modulation, into a voltage in a sine wave form.

System interconnection inverter with bypass path

According to one embodiment, a grid-tie inverter includes: a inverter performing pulse width modulation for a DC voltage; a first capacitor circuit connected to an input side of the inverter so as to form a neutral point; a second capacitor circuit connected to an output side of the inverter so as to form a neutral point; a common mode current bypass channel formed by connecting the neutral points of the first capacitor circuit and the second capacitor circuit; a grounded capacitor provided between the bypass channel and a ground; a first common mode choke coil unit including a common mode choke coil at least one of between the first capacitor circuit and the inverter and between the inverter and the second capacitor circuit; and an output filter converting a pulse width-modulated voltage outputted from the inverter into a sine AC voltage.

Grid-tie inverter for interconnecting AC voltage to electric power grid

A semiconductor switch is provided with a main element having reverse conductivity and serving as a voltage-driven switching element having a high withstand voltage, an auxiliary element serving as a voltage-driven switching element having a withstand voltage lower than that of the main element, and a high-speed freewheel diode having a withstand voltage equal to that of the main element, wherein a negative pole of the main element is connected to a negative pole of the auxiliary element to define the positive pole of the main element as a positive pole terminal and the positive pole of the auxiliary element as a negative pole terminal, and the high-speed freewheel diode is parallel-connected between the positive pole terminal and the negative pole terminal so that a direction from the negative pole terminal toward the positive pole terminal constitutes a forward direction.

Semiconductor switch and power conversion system provided with semiconductor switch

There are provided: a main three-phase full-wave rectifier ( ) that converts three-phase AC (R phase, S phase, T phase) into DC; a transformer ( ) that outputs AC of a total of six phases corresponding to the points that equally divide by three the arcs drawn in a transformer vector diagram in which an equilateral triangle is formed whereof the R phase, S phase and T phase are vertices, centered on each vertex and linking the remaining two points; and two auxiliary three-phase full-wave rectifiers ( ) and ( ) in that convert into DC the six-phase AC that is output from the transformer ( ), the output lines of the main three-phase full-wave rectifier ( ) and two auxiliary three-phase full-wave rectifiers ( ) and ( ) being connected in parallel. The current flowing in the DC line through the transformer can therefore be reduced to &frac13; of the whole in the case of an 18-pulse rectifier, so enabling the capacity of the transformer to be reduced.

Growing community of inventors

Inagi, Japan

Junichi Tsuda