Single-phase four-quadrant rectifier network voltage interruption detection method

Abstract

The invention discloses a single-phase four-quadrant rectifier network voltage interruption detection method, and belongs to the field of alternating current power supply interruption detection methods. The method comprises the following steps: after a single-phase four-quadrant rectifier starts to work normally, a sampling unit collecting the input current of the four-quadrant rectifier; transmitting the input current acquired by the sampling unit to the signal processing unit; the signal processing unit judging whether the single-phase four-quadrant rectifier generates network voltage interruption or not through a sampling current zero value proximity method. According to the method, whether the network voltage is interrupted or not can be rapidly detected, protection measures can be rapidly taken when the network voltage is interrupted, damage to electrical equipment such as a locomotive converter is prevented, only four-quadrant input current needs to be sampled, and a hardware circuit is simple in structure; and the principle is simple, and the reliability is high.

Description

technical field [0001] The invention relates to a method for detecting interruption of an AC power supply, in particular to a method for detecting interruption of network voltage of a single-phase four-quadrant rectifier. Background technique [0002] With the development of power electronics technology, grid-connected converter products are more and more widely used. The power supply of grid-connected products is either alternating current with constant frequency and amplitude, or direct current with constant amplitude. For grid-connected converter products, the stability of the power supply always affects the reliability of the grid-connected converter. [0003] The single-phase four-quadrant rectifier on railway locomotives and bullet trains is a pulse width modulation converter. Its power supply is an alternating current with a frequency of 50 Hz and a constant amplitude of 25 kV, and its output is often a DC voltage with adjustable amplitude. Its working principle is ...

AI Technical Summary

Problems solved by technology

[0008] The slope detection method judges whether the grid voltage is interrupted by detecting the rate of change of the grid voltage. This method has two main disadvantages. First, the grid voltage is a sine wave, and its value itself is constantly changing according to the sinusoidal law, that is, the voltage slope k itself is always changing. , under normal circumstances, the absolute value of the slope k is already very large when it is close to zero point; secondly, the grid voltage load in the same power supply section is large, and the waveform of the grid voltage is not an ideal sine wave, and there will be harmonics superimposed in it, and the grid voltage is normal Sometimes there will be ripples, and the two consecutive samplings are likely to sample ripples, and the absolute value of the ripple voltage change slope is relatively large.

The superposition of these two points makes this method easy to cause misjudgment in the actual application process

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