Synchronous phase detection method of stationary frequency converter with direct voltage compensation

Abstract

The invention discloses a synchronous phase detection method for a static frequency converter with direct voltage compensation. The method comprise: (1) measuring the AC-side three-phase line voltage of the converter in real time, and eliminating the waveform distortion of the AC-side three-phase line voltage in a commutation area by directly pre-estimating and compensating the waveform of actual frequency conversion line voltage so as to obtain a sine estimated amount; (2) using a software phase-locked loop to perform real-time phase locking on the estimated amount to achieve robust synchronous phase detection of the static frequency converter. The method uses only a single PT to realize the accurate tracking of the synchronous phase of the static frequency converter under the variable frequency conditions, so as to ensure that the a converter bridge does not generate commutation failure, to ensure the safe equipment operation, and to improve the power factor on the output side of the static frequency converter. The algorithm does not depend on a complex hardware filter circuit, and is small in software calculation amount, and is low in cost.

Description

technical field [0001] The invention relates to a phase detection method of a frequency conversion synchronous signal of a static frequency converter, in particular to a phase detection method of a static frequency converter with direct voltage compensation. Background technique [0002] Such as figure 1 As shown, in order to ensure that the commutation failure of the machine-side converter bridge does not occur and improve the power factor of the output side of the static frequency converter, it is necessary to accurately track the phase of the synchronization signal of the machine-side converter. However, due to the commutation of the thyristors, the measured synchronous signal of the stationary frequency converter is severely distorted, as figure 2 shown. Secondly, when the rotation speed of the generator is different, the fundamental frequency of the synchronous signal of the generator-side converter also varies in a large range. Therefore, there are many difficultie...

AI Technical Summary

Problems solved by technology

Therefore, there are many difficulties in accurately detecting the phase of the synchronous signal of the static frequency converter

[0003] The patent "CN 201220367024.7" proposes a circuit that triggers the thyristor module after zero detection, but there is a complex hardware loop

[0004] The patent "CN 201310046799.3" proposes a new software phase-locked loop implementation method for SVC control system, but it does not involve the compensation of distorted synchronous signals, and the large-range frequency change conditions of static frequency converters

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