Abstract: A gate drive circuit includes first and second transistors for turning on and off semiconductor switching devices. The circuit includes a DC power supply for driving the first and second transistors. The gate drive circuit further includes a third transistor, a fourth transistor, and a DC power supply being a power supply for the third and fourth transistors with a voltage value lower than the voltage value of the DC power supply, thereby making lower the impedance of the path of a current flowing from the DC power supply to the gates of the switching devices through the third transistor than the impedance of the path of a current flowing from the DC power supply to the gates of the switching devices through the first transistor.

Abstract: A gate drive circuit includes first and second transistors for turning on and off semiconductor switching devices. The circuit includes a DC power supply for driving the first and second transistors. The gate drive circuit further includes a third transistor, a fourth transistor, and a DC power supply being a power supply for the third and fourth transistors with a voltage value lower than the voltage value of the DC power supply, thereby making lower the impedance of the path of a current flowing from the DC power supply to the gates of the switching devices through the third transistor than the impedance of the path of a current flowing from the DC power supply to the gates of the switching devices through the first transistor.

Abstract: A power supply circuit for a gate driving circuit for driving semiconductor switching devices of a power converter that is configured to perform a DC to AC conversion. The power supply circuit includes a DC power supply including a plurality of serially-connected single DC power supplies, a flying capacitor type power conversion circuit including a plurality of flying capacitors connected in parallel to a plurality of the semiconductor switching devices, and a plurality of serially-connected circuits each having an insulating device, a middle part of the series-connected circuits being connected to a middle potential point of the flying capacitors, and to a fixed potential point of the DC power supply.

Abstract: A multilevel power converter circuit driven by two direct current power supplies in series includes a first semiconductor switch series circuit that combines a series circuit of 2n IGBTs connected between positive and negative electrodes with a capacitor, a second semiconductor switch series circuit that combines a series circuit of 2n?2 IGBTs connected between the emitter of a first IGBT of the first semiconductor switch series circuit and the collector of a 2nth IGBT with a capacitor, and a bidirectional switch connected between an intermediate point of the second semiconductor switch series circuit and an intermediate point of the direct current power supply, to reduce a voltage change in the alternating current output when semiconductor switches are switching.

Abstract: Aspects of the invention are directed to a gate driving circuit for a power conversion circuit having an upper and lower arm circuit composed of series-connected upper arm and a lower arm, each arm including two or more semiconductor switching devices connected in series. In some aspects, a gate driving circuit of the invention includes a circuit of series connection including a diode and a resistor between a positive potential side of a positive side power supply and a positive electrode side. The gate driving circuit can determine a short-circuit fault of the semiconductor switching device that is connected to the gate driving circuit by detecting the current that flows through the circuit of series connection including the diode and the resistor when an OFF command of ON/OFF command signals is given to the semiconductor switching device.

Abstract: In a process of changing an AC voltage from zero to +Ed (or negative to positive) or from zero to ?Ed (or positive to negative), a control method in accordance with some aspects of the invention detects voltage across the capacitors and when the detected voltage is lower than a predetermined voltage value, switching operation pattern capable of charging the capacitor is given to the switching elements during a short period of time; when the detected voltage is higher than the predetermined voltage value, a switching operation pattern capable of discharging the capacitor is given to the switching elements during a short period of time. Thus, the width of voltage variation of the capacitors is limited within a specified variation range.

Abstract: Aspects of the invention are directed to a protection control system of the invention is a protection control system for a multilevel power conversion circuit of a flying capacitor type, the power conversion circuit including six semiconductor switches of first through sixth semiconductor switches sequentially connected in series from a positive terminal to a negative terminal of a DC power supply, a first capacitor connected between the connection point of the second and third semiconductor switches and the connection point of the fourth and fifth semiconductor switches and a second capacitor connected between the connection point of the first and second semiconductor switches and the connection point of the fifth and sixth semiconductor switches, wherein the protection control system of the invention turns ON the second semiconductor switch or maintains the second semiconductor switch in an ON state, in the case of short-circuit fault of the third semiconductor switch.

Abstract: Aspects of the invention are related to a power semiconductor module applied to a multi-level converter circuit with three or more levels of voltage waveform. Aspects of the invention can include a first IGBT to which a diode is reverse parallel connected and a second IGBT having reverse blocking voltage whose emitter is connected to the emitter of the first IGBT are housed in one package, and each of the collector of the first IGBT, the collector of the second IGBT, and the connection points of the emitter of the first IGBT and the emitter of the second IGBT, is an external terminal.

Abstract: Aspects of the invention address a circumstance in multilevel power converter devices having a bidirectional switch connected to a middle point of a DC power supply assembly, whereby interruption of the device may cause break down of semiconductor switches due to overvoltage if the semiconductor switches are totally interrupted simultaneously. In some aspects, a shut down procedure of a multilevel power converter device having a bidirectional switch connected to the middle point of a DC power supply assembly, gates of semiconductor switches are interrupted one by one according to a predetermined sequence or a sequence corresponding to the conditions of voltage and current at that moment with a time interval, and finally the bidirectional switch connected to the middle point of a DC power supply assembly is interrupted. As a result, a transition from an operating state to a shut down state can be made with minimum voltage variation.

Abstract: A three-level power conversion circuit includes a plurality of one-phase switch circuits which receive power from direct current power supplies that are connected in series. Each of the one-phase switch circuits includes a semiconductor switch series circuit that is connected in parallel to the direct current power supplies, and also a bidirectional switch and a circuit-opening device that are connected in series between a series connection point of the semiconductor switch series circuit and a series connection point of the direct current power supplies. If a semiconductor element in a bidirectional switch fails, the circuit opening device opens a path along which the main current of the semiconductor element flows, and operation of the inverter is continued as a two-level inverter with the remaining bidirectional switches in a constant off-state.

Abstract: A multilevel power conversion circuit using a flying capacitor(s) can include two bidirectional switches connected in series between a middle potential terminal of DC power supplies and a conversion circuit using semiconductor switches. Gate driving circuits for the bidirectional switches are provided with a short-circuit fault detecting circuit for detecting short-circuit of the semiconductor switching device composing the bidirectional switch circuit in an OFF signal period. Upon detection of a short-circuit fault, all semiconductor switching devices are interrupted to stop the whole system.

Abstract: In some aspects of the invention, a power semiconductor module is applied to a multi-level converter circuit with three or more levels of voltage waveform. A first IGBT, a diode whose cathode is connected to the emitter of the first IGBT, and a second IGBT having reverse blocking voltage whose emitter is connected to the emitter of the first IGBT, are housed in one package, and each of the collector of the first IGBT, the collector of the second IGBT, the connection point of the emitter of the first IGBT and the emitter of the second IGBT, and the anode of the diode, is an external terminal.

Abstract: A power supply circuit for a gate driving circuit for driving semiconductor switching devices of a power converter that is configured to perform a DC to AC conversion. The power supply circuit includes a DC power supply including a plurality of serially-connected single DC power supplies, a flying capacitor type power conversion circuit including a plurality of flying capacitors connected in parallel to a plurality of the semiconductor switching devices, and a plurality of serially-connected circuits each having an insulating device, a middle part of the series-connected circuits being connected to a middle potential point of the flying capacitors, and to a fixed potential point of the DC power supply.

Abstract: A multilevel power converter circuit driven by two direct current power supplies in series includes a first semiconductor switch series circuit that combines a series circuit of 2n IGBTs connected between positive and negative electrodes with a capacitor, a second semiconductor switch series circuit that combines a series circuit of 2n-2 IGBTs connected between the emitter of a first IGBT of the first semiconductor switch series circuit and the collector of a 2nth IGBT with a capacitor, and a bidirectional switch connected between an intermediate point of the second semiconductor switch series circuit and an intermediate point of the direct current power supply, to reduce a voltage change in the alternating current output when semiconductor switches are switching.

Abstract: A three-level power conversion circuit includes a plurality of one-phase switch circuits which receive power from direct current power supplies that are connected in series. Each of the one-phase switch circuits includes a semiconductor switch series circuit that is connected in parallel to the direct current power supplies, and also a bidirectional switch and a circuit-opening device that are connected in series between a series connection point of the semiconductor switch series circuit and a series connection point of the direct current power supplies. If a semiconductor element in a bidirectional switch fails, the circuit opening device opens a path along which the main current of the semiconductor element flows, and operation of the inverter is continued as a two-level inverter with the remaining bidirectional switches in a constant off-state.

Abstract: A stacked structure of a power converter is disclosed. The stacked structure has a power conversion circuit that provides an output or input of alternating current in three phases and is composed of odd-numbered parallel-connected power semiconductor element modules for each phase, and a heat sink for cooling the power semiconductor element modules. An odd number of the parallel-connected power semiconductor element modules are arranged in a first phase and a third phase, and an even number of the parallel-connected power semiconductor element modules are arranged in a second phase respectively in two rows on the heat sink relative to a ventilation direction of air for cooling the heat sink.

Abstract: Aspects of the invention are directed to a gate driving circuit for a power conversion circuit having an upper and lower arm circuit composed of series-connected upper arm and a lower arm, each arm including two or more semiconductor switching devices connected in series. In some aspects, a gate driving circuit of the invention includes a circuit of series connection including a diode and a resistor between a positive potential side of a positive side power supply and a positive electrode side. The gate driving circuit can determine a short-circuit fault of the semiconductor switching device that is connected to the gate driving circuit by detecting the current that flows through the circuit of series connection including the diode and the resistor when an OFF command of ON/OFF command signals is given to the semiconductor switching device.

Abstract: In a process of changing an AC voltage from zero to +Ed (or negative to positive) or from zero to ?Ed (or positive to negative), a control method in accordance with some aspects of the invention detects voltage across the capacitors and when the detected voltage is lower than a predetermined voltage value, switching operation pattern capable of charging the capacitor is given to the switching elements during a short period of time; when the detected voltage is higher than the predetermined voltage value, a switching operation pattern capable of discharging the capacitor is given to the switching elements during a short period of time. Thus, the width of voltage variation of the capacitors is limited within a specified variation range.

Abstract: Aspects of the invention are directed to a protection control system of the invention is a protection control system for a multilevel power conversion circuit of a flying capacitor type, the power conversion circuit including six semiconductor switches of first through sixth semiconductor switches sequentially connected in series from a positive terminal to a negative terminal of a DC power supply, a first capacitor connected between the connection point of the second and third semiconductor switches and the connection point of the fourth and fifth semiconductor switches and a second capacitor connected between the connection point of the first and second semiconductor switches and the connection point of the fifth and sixth semiconductor switches, wherein the protection control system of the invention turns ON the second semiconductor switch or maintains the second semiconductor switch in an ON state, in the case of short-circuit fault of the third semiconductor switch.

Abstract: Aspects of the invention address a circumstance in multilevel power converter devices having a bidirectional switch connected to a middle point of a DC power supply assembly, whereby interruption of the device may cause break down of semiconductor switches due to overvoltage if the semiconductor switches are totally interrupted simultaneously. In some aspects, a shut down procedure of a multilevel power converter device having a bidirectional switch connected to the middle point of a DC power supply assembly, gates of semiconductor switches are interrupted one by one according to a predetermined sequence or a sequence corresponding to the conditions of voltage and current at that moment with a time interval, and finally the bidirectional switch connected to the middle point of a DC power supply assembly is interrupted. As a result, a transition from an operating state to a shut down state can be made with minimum voltage variation.