Three level power converting device

Abstract

Aspects of the invention are directed to a three-level power converter that has, as one phase, a bidirectional switching element connected to the series connection point of a series circuit of a first insulated gate bi-polar transistor ("IGBT") and second IGBT and an intermediate electrode of a direct current power supply. Also included is a fuse connected between the bidirectional switching element and the intermediate electrode of the direct current power supply, and an overcurrent shutdown unit provided in each gate drive circuit of the first and second IGBTs, are provided as protection from a power supply short circuit phenomenon occurring in the event of a short circuit failure of any of the IGBTs or diodes.

Description

technical field [0001] The invention relates to an arm short-circuit protection method of a three-level inverter or converter. Background technique [0002] JP-A-2004-248479( Figure 1~3 ) shows a protection circuit using fuses in a three-level converter. The three-level converter circuit shown here is a structure having a circuit as one phase in which a capacitor as a DC power supply is connected in series, a positive electrode, an intermediate electrode, and a negative electrode are used as DC terminals, and a diode is connected between the positive electrode and the negative electrode. A series connection circuit of four IGBTs (two on the upper arm and two on the lower arm) connected in antiparallel, between the series connection point of the two upper arm IGBTs and the middle electrode of the DC power supply, and in the series connection of the two lower arm IGBTs A diode for clamping the middle electrode is connected between the connection point and the middle electrod...

AI Technical Summary

Problems solved by technology

[0023] In general, by making the main circuit conductors of the DC part into a parallel plate structure (laminated structure), any generated magnetic field is eliminated and a reduction in wiring inductance is achieved, but in such Image 6 When the fuse is connected like in the system, the parallel plate structure cannot be used in this part, so that the reduction of the wiring inductance cannot be realized.

[0024] Moreover, due to Figure 15 Fuses are also used in two places in the structure shown, so the wiring inductance increases in the same way

[0025] When connecting a fuse as described above, a high surge voltage is generated at the time of switching due to an increase in inductance, so it is necessary to use a module with a high withstand voltage, connect a snubber circuit, etc., resulting in a problem of size increase and device price increase

Especially in the case of a three-level inverter, since fuses need to be connected at two locations, the problem is significant

[0026] Moreover, in Figure 16 In the circuit structure shown, no protection can be performed for two-level operation

Images