Voltage source frequency converter bridge arm direct pass protector for three level integrated gate pole conversion transistor

Abstract

The invention discloses a three level integration gate commutation SCR potential source converter bridge arm through protector, the bridge arm through protector is parallel-connected in the direct-current circuit of a three level integration gate commutation SCR potential source converter which is formed by the parallel connection of a rectifier, a direct-current filter electric capacity and a inverter in turn, and consists of a protection unit, a bridge arm through protection control unit which is connected with the protection unit, and a plurality of bridge arm through signal detection unit which is connected with the bridge arm through protection control unit. The invention can rapidly bypasses and reduces the short-circuit current of a through bridge arm; bypasses a reverse surge current produced by a direct-current circuit inductance; consumes the direct current bus energy and speeds up the decay process of surge current; after examining the bridge arm goes nonstop, can trigger the bypass thyristor to drain direct current energy through the bypass, and sends out the alarm to the system, causes the system interconnection protection. When occurring the breakdown that the bridge arm goes nonstop, the invention can protect the three-level IGCT potential source medium voltage frequency converter effectively.

Description

technical field [0001] The invention belongs to a bridge arm straight-through protector in a high-power medium-voltage variable-frequency AC speed regulating device, in particular to a medium-voltage frequency conversion that can effectively protect a three-level integrated gate commutation thyristor voltage source when a bridge arm straight-through fault occurs Three-level integrated gate-commutated thyristor voltage source inverter bridge arm through protector. Background technique [0002] Integrated gate commutated thyristor (IGCT) is an advanced high-power semiconductor switching device currently used for power conversion. The main power switching device of the three-level medium voltage inverter. [0003] Figure 1 shows an active front-end type three-level IGCT voltage source type three-phase medium voltage inverter. Due to the failure of the IGCT device, or the reverse breakdown of the anti-parallel fast recovery freewheeling diode, or the hardware failure of the ex...

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Problems solved by technology

[0004] The fatal shortcoming of IGCT is that once the current flowing through it exceeds its shutdown current, it will not be able to shut down

However, this method has limitations. It is suitable for the case where the IGCT component used in the inverter has a small current (lower output power). If the IGCT used in the inverter has already reached the maximum current specification, this method is not suitable.

In addition, due to the high price of IGCT itself, the cost of using this method is relatively high

[0008] Another disadvantage of open circuit protection is that the protection components are connected in series in the DC circuit, and DC current flows during normal operation, which increases the conduction loss. If IGCT is used, a radiator needs to be added

[0009] The bypass shunt method overcomes the shortcomings of the above-mentioned open circuit protection, and is a more suitable and effective direct short-circuit protection method for high-power three-level IGCT voltage source medium-voltage inverters

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