Low voltage ride through module and control method thereof

Abstract

The invention discloses a low-voltage ride-through module and a control method thereof. The low-voltage ride-through module comprises an embedded microprocessor and a power part topological unit; the embedded microprocessor is used for receiving the drop trend of the power grid voltage of the system and obtaining an instruction of entering a low voltage ride through mode or an instruction of exiting the low voltage ride through mode; a Hall sampling result of the power part topological unit is processed by using a PI algorithm, and pulse width modulation is carried out by using a bipolar PWM principle to obtain a low-voltage ride-through pulse control signal; and the power part topological unit is used for receiving and responding to the low-voltage ride-through pulse control signal, and the static error between the output voltage of the output end of the power part topological unit and the set voltage value of the frequency converter is kept by using an energy-taking boost type direct current chopping method. The residual voltage of a system power grid can be rectified and boosted and be connected in parallel to a direct-current bus of the frequency converter to serve as voltage support, and the state switching time is short; and meanwhile, the invention has the advantages of being small in occupied space, low in transformation cost and free of maintenance.

Description

technical field [0001] The invention belongs to the technical field of electrical engineering, and in particular relates to a low-voltage ride-through module and a control method thereof. Background technique [0002] During the operation of the power plant, due to lightning strikes, short-circuit faults, reclosing, internal or external power grid failures, and large-scale equipment startups, etc., the voltage will fluctuate greatly instantaneously or the power will be restored after a short-term power failure, causing the electrical equipment to malfunction. This phenomenon is commonly known as the "low voltage ride through" phenomenon. [0003] The phenomenon of "low voltage ride through" is more or less encountered in many industrial enterprises, and it is inevitable; for power plants with high continuity requirements, many low-voltage motors do not allow control loops and frequency converters in the process. Among them, the frequency converter of the coal feeder is the ...

AI Technical Summary

Problems solved by technology

[0009] Aiming at the technical problems existing in the prior art, the present invention provides a low-voltage ride-through module and its control method to solve the existing failure rate of the low-voltage ride-through device installed on the frequency converter of the coal feeder or powder feeder High, takes up a lot of space, high cost of transformation, technical problems that require regular maintenance

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