Solid-state switch switching control method with fault circulation inhibiting effect

Abstract

The invention relates to a solid-state switch switching control method with a fault circulation inhibiting effect. When a first power supply is switched to a second power supply, firstly a triggering signal of an electronic switch K1 of a power supply branch circuit is cut off, and the current direction of current of the branch circuit is read. A sequence that thyristors of the second power supply are turned on is determined according to the direction of current. The principle for selecting moments when the thyristors of the second power supply are turned on is as follows: a thyristor xP2 / xN2 is triggered in an xP2 triggering safety zone if the current of an M1 branch circuit flows to a load from the first power supply for an x phase when the triggering signal of the K1 is cut off, otherwise a thyristor xP2 / xN2 is triggered in an xN2 triggering safety zone. The triggering safety zone is determined by a voltage at the two ends of the thyristor xP2 / xN2. In the method provided by the invention, the voltage at the two ends of the thyristor is observed, and an appropriate switching point is selected, thus the maximum of the fault circuit is limited even if the fault that power supplies are connected in a solid switch switching process and the fault circulation is produced, and no permanent damage is produced to a system.

Description

technical field [0001] The invention relates to a switching control method of a solid-state switch with fault circulating current suppression function, and belongs to the technical field of application of power electronics in power systems. Background technique [0002] In recent years, with the economic development and the wide application of high-tech equipment, users have continuously improved the quality of power supply, and the problem of power quality has become increasingly prominent. Power quality problems directly affect the power supply security of the power system and the normal operation of user equipment. Common power quality problems include voltage sag and short-term interruption of power supply, which have a large impact and cause huge economic losses, and are problems that need to be solved urgently in the power system. [0003] Solid-state switches utilize high-power power electronics technology and are one of the most economical means of solving sensitive...

AI Technical Summary

Problems solved by technology

However, this switching method requires accurate determination of the zero-crossing state of the current and the direction of the current

In the actual system, due to factors such as sensor accuracy and conditioning circuit filtering performance, there is often a certain sampling error near the current zero point, resulting in the inability to accurately determine the direction of the current and the current zero-crossing state.

However, when the system misjudges the current state, the switching process will cause the power supply 1 and the power supply 2 to be directly connected, resulting in a huge fault current

For example, as attached figure 1 As shown, if the system current direction is misjudged, the actual current direction is the same as I in the figure A1 The direction is opposite, but the thyristor AP2 on the second power supply side is turned on. The first power supply and the second power supply are almost directly connected, and the system will experience a large fault current, which will cause permanent damage to devices and equipment.

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