Short-circuit protection circuit and method of solid state electronic switch of direct current micro-grid

Abstract

The invention discloses a short-circuit protection circuit and method of a solid state electronic switch of a direct current micro-grid. The short-circuit protection circuit comprises an RC buffer branch circuit and an RD follow current branch circuit. The RC buffer branch circuit is connected to the solid state electronic switch in parallel, one end of a buffer capacitor Cs of the RC buffer branch circuit is connected with one end of a resistor Rs in series, the other end of the buffer capacitor Cs is connected to a collector of V1, and the other end of the resistor Rs is connected to an emitter of the V1. The RD follow current branch circuit is sequentially connected with a diode D1, a resistor R1, a diode D2 and a resistor R2 in series, the cathode of the diode D1 is connected to a positive busbar, the other end of the resistor R2 is connected to a negative busbar, and the cathode of the diode D2 is connected to the signal ground. By means of the short-circuit protection circuit and method of the solid state electronic switch of the direct current micro-grid, larger peak voltage at the two ends of the solid-circuit electronic switch occurring when the solid-circuit electronic switch is on or off can be prevented, impact of the short-circuit current on the solid state electronic switch is reduced, the faults of the monopole-to-ground short-circuit and the interelectrode short-circuit on the circuit can be cut off effectively, other power electronic devices on the circuit can be protected from being damaged, and the safety and reliability of the direct current micro-grid are improved.

Description

[0001] technical field [0002] The invention belongs to the technical field of direct current micro-grid, relates to a short-circuit protection circuit and a protection method of a solid-state electronic switch, in particular to a short-circuit protection circuit and a protection method of a solid-state electronic switch of a direct current micro-grid transmission line. [0003] Background technique [0004] Solid-state electronic switch is a new type of power automation equipment used to quickly cut off faults. It has a very high application prospect because of its advantages such as short breaking time, no arc, no light, no sound, long life and high working reliability. [0005] However, the application of solid-state electronic switches in the DC field has its own characteristics and difficulties compared with AC systems: the DC current is constant, unlike the natural zero-crossing point in the AC system. In the case of high voltage and high current, the current rise ra...

AI Technical Summary

Problems solved by technology

In addition, even if the solid-state electronic switch completes the turn-off action, the energy stored in the inductance on the line will generate an excessive voltage at both ends of the device. If no effective measures are taken, the DC solid-state electronic switch will operate at high current and high voltage. under hard shutdown, which will make it suffer a huge shock or even damage the

[0006] At present, this problem has not been well solved, and the application of solid-state electronic switches in the DC field is limited.

In the field of DC, there are also studies on thyristor-based DC solid-state electronic switches, such as a resonant DC solid-state electronic switch provided by the Chinese invention patent (patent number: 200910026473.8), whose core is to use resonant soft switching to create zero-crossing points in the DC field , realize the soft turn-on (turn-off) of power devices, and avoid damage to power devices caused by hard turn-on (turn-off). The solid-state electronic switches composed of thyristors have poor quickness, and it is difficult to meet the requirements of fast and reliable fault removal in DC microgrids, so there are certain limitations.

The invention patent with the patent number 201110154838.2 provides a DC solid-state circuit breaker, including a main switch unit and an auxiliary switch unit. Through the cooperative control of these two units, the energy storage pulse capacitor voltage caused by the inherent leakage current of the device is avoided. It is unreliable to shut down due to lowering and the power supply has the problem of a large resonant current flowing when the fault is turned off. However, the DC solid-state circuit breaker is a solid-state electronic switch based on a thyristor, and the quick action is also poor, and if it is applied to DC In the microgrid, the bidirectional flow of energy cannot be realized, so it is not suitable for DC microgrids

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