A detection circuit for voltage change rate at both ends of a thyristor

Abstract

The invention discloses a detection circuit for the voltage change rate at both ends of a thyristor, which comprises a capacitor Ct connected in series across the two ends of the thyristor T and a sampling resistor Rt, and also includes a protection module, a signal conditioning module and a dv / dt detection and signal transmission module; the dv / dt detection and signal transmission module realizes the detection of dv / dt at both ends of the thyristor T and the output of the over-standard alarm signal; the protection module realizes the process of the signal conditioning module and the dv / dt detection and signal transmission module Voltage protection and high current bypass, the signal conditioning module realizes the conditioning of dv / dt detection and alarm signal output by the signal transmission module, so that the pulse width of the alarm signal is greater than the minimum identifiable pulse width of the peripheral control equipment. The detection circuit of the invention has simple principle, rapid and reliable action, and can be used to protect the thyristor from damage caused by excessive dv / dt.

Description

technical field [0001] The invention relates to the field of control and protection of electronic power devices, in particular to a detection circuit for the rate of change of voltage at both ends of a thyristor. Background technique [0002] When the thyristor is in the off state, when the rate of change of the voltage across the thyristor (dv / dt) is greater than a certain value, due to the existence of the gate junction capacitance, a large enough gate current may be generated, causing the thyristor to turn on by mistake, which in turn causes the device Work abnormally. During the turn-off period of the thyristor, due to the existence of the reverse recovery charge, the thyristor current will continue to flow in the reverse direction after being reduced to zero. This process is called the reverse recovery period of the thyristor device. If the thyristor on the thyristor during the reverse recovery period If the forward voltage rise rate is too high, the thyristor will be ...

AI Technical Summary

Problems solved by technology

[0003] In the application process of thyristor devices at home and abroad, it is usually adopted to reduce the dv / dt at both ends of the thyristor by connecting a resistance-capacity absorption circuit in parallel at both ends of the thyristor, but this will increase the capacity of the resistance-capacity absorption circuit, increase the overall loss of the thyristor device, and suppress dv / dt limited ability

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