Bridge arm through protecting system for 6KV three-level integrated gate phase-changing thyristor inverter

Abstract

The present invention belongs to the field of three-level voltage source inverter. The bridge arm through protecting system includes a bridge arm through protecting IGCT switching device connected between the quadruple input filtering and rectifying circuit and inverter, a short-circuit signal generator and a pulse state protecting control circuit as well as a fault detecting and pulse blocking circuit comprising gate signal feedback circuit and IGCT fault diagnosing circuit. In some fault occurs, the electric connection to the rectifying bridge and the inverter is cut out immediately while the short-circuit current is borne by the IGCTs of the invverter until the fault judging signal opens the pulse blocking system and blocks the IGCTs.

Description

technical field [0001] A 6KV three-level integrated gate commutation thyristor inverter bridge arm through protection system belongs to the field of three-level voltage inverter manufacturing. Background technique [0002] Integrated gate-commutated thyristor (IGCT) is the latest generation of high-voltage, high-power, and fast-acting power electronic devices. The three-level IGCT inverter composed of it as the main switching device has become the preferred choice of medium and high voltage AC frequency conversion speed control devices. The main direction of development. [0003] When the bridge arm of the three-level IGCT inverter is short-circuited, the DC capacitor will discharge through the short-circuited bridge arm, and the current rises very fast. Reliable protection must be used to prevent the IGCT device from being damaged. Such as figure 1 As shown, it is one of the bridge arms of a three-level IGCT inverter. Among them, SA1 and SA3 are a pair of tubes, and SA2 ...

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Problems solved by technology

At present, there are mainly three protection methods: one is to use fast fuses connected in series on the bridge arms for protection. Suitable high-voltage fast fuses are available; the second is to trigger and open all the switching devices of the inverter bridge, and trigger the crowbar protection at the same time to share the short-circuit current, but it may also damage the switching devices when a large current is turned on; the third is Circulating current protection method, but its implementation is very complicated and has limited reliability by means of current-limiting reactors, isolated DC power supplies, and circulating current diodes.

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