Abstract: The present invention provides a power converter system in which forward conversion capacities and reverse conversion capacities of semiconductor power converter apparatuses connected to a D.C. capacitor can be different from one another. The more suitable semiconductor power converter apparatuses can be selected in accordance with various loads. A power converter system includes semiconductor power converter apparatuses including a D.C. capacitor and power devices cooled by a cooling elements having an output terminal connected to a load. The semiconductor power converter apparatuses are connected in parallel with one another through the D.C. capacitor. Each of the power devices includes self-arc-suppressing semiconductor devices and diodes connected in anti-parallel with the self-arc-suppressing semiconductor devices. All of the semiconductor power converter apparatuses have the same circuit configuration.

Abstract: The present invention provides a power converter system with which the forward conversion capacities and the reverse conversion capacities of a plurality of semiconductor power converter apparatuses connected to a D.C. capacitor can be made different from one another, and the more suitable semiconductor power converter apparatuses can be selected in accordance with various loads. In a power converter system which includes at least a plurality of semiconductor power converter apparatuses constituted by a D.C. capacitor and a plurality of power devices cooled by a cooling piece(s) having an output terminal connected to a load, and which the plurality of semiconductor power converter apparatuses are connected in parallel with one another through the D.C.

Abstract: An inverter having a large-capacity self-arc-extinguishing semiconductor element. Recovery capacitors recover energy stored in groups of elements for suppressing the rate of change in current, and are provided within a two-level or three-level inverter bridge. The thus-recovered energy is fed back to a d.c. voltage circuit by an energy regenerative circuit. The energy regenerative circuit controls the charging voltage of the recovery capacitors in proportion to the magnitude of a load current. In a case where the inverter includes inverter bridges connected to a single d.c. voltage circuit, the inverter bridges are divided into groups. A different energy regenerative circuit is connected to the inverter bridge on a per-group basis, and each of the energy regenerative circuits feeds power back to the d.c. voltage circuit.

Abstract: The invention relates to a compensator device connected in series to power transmission lines and including at least one compensator unit with a transformerless reactive series compensator. The compensator unit includes an AC switch coupled to output terminals of the series compensator. Furthermore, the invention also relates to such a compensation device including multiple compensator units connected in series at the output terminals and a continuous operation control for selectively controlling the series-connected compensators. With such a compensation device, the transformerless reactive series compensator can be prevented, by the AC switch, from conducting an overcurrent and the main components of the compensation device can be compact.

Abstract: A compensation device connected in series with power transmission lines having at least one circuit breaker and including at least one compensator unit with a transformerless reactive series compensator having a DC capacitor and a single-phase inverter. A pre-charger pre-charges the DC capacitor of at least one compensator unit. The pre-charger may decouple the DC capacitor from the power transmission lines during pre-charging. The pre-charger may include an AC switch and an AC switch controller opening the AC switch for a time interval (alfa) after a zero-crossing of the line current.

Abstract: A multi-level inverter apparatus comprises: first and second GTOs connected in series between a positive electrode of a D.C. power supply having a mid-potential point and an output terminal, and third and fourth GTOs connected in series between a negative electrode of the D.C. power supply and the output terminal. First and second reactors cooperate with the first and second GTOs and the third and fourth GTOs so as to form a positive and negative arms, respectively. A first diode is connected between one end of the first reactor and the mid-potential point of the D.C. power supply in forward direction with respect to the output terminal, while a second diode is connected between one end of the second reactor and the mid-potential point of the D.C. power supply in backward direction with respect to the output terminal. First to fourth series connections, each including a diode and a capacitor connected in series to each other, are connected in parallel with the first to fourth GTOs, respectively.