DSOGI-FLL-based three-phase converter non-dead-zone half-period modulation method

Abstract

The invention discloses a DSOGI-FLL-based three-phase converter non-dead-zone half-period modulation method. The DSOGI-FLL-based three-phase converter non-dead-zone half-period modulation method comprises the steps of: subjecting current signals of a three-phase converter to Clark transform; performing filtering and frequency-locking treatment on two phases of current signals by means of a DSOGI-FLL module, so as to obtain a fundamental wave current signal and an orthogonal signal thereof, and performing Clark transform on the fundamental wave current signal and the orthogonal signal; comparing a voltage modulation signal with a carrier signal in a half-period modulation module to obtain an initial driving signal; and allocating the initial driving signal according to current polarities ofthe fundamental wave current signal after inverse transformation, so as to obtain a non-dead-zone half-period driving signal which can be enabled along with alternation of the current polarities of the fundamental wave current signal after inverse transformation, and controlling the three-phase converter to realize non-dead-zone half-period modulation. The non-dead-zone half-period modulation method can obtain the current polarities precisely under the conditions of three-phase current balance, unbalance and presence of harmonics, realize the non-dead-zone half-period modulation of the three-phase converter, and reduces current zero-crossing distortion.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a DSOGI-FLL-based half-cycle modulation method for a three-phase converter without a dead zone. Background technique [0002] If the traditional modulation method with dead zone is used, the converter will have a dead zone effect, resulting in loss of output voltage, distortion of output current, and reduction of DC voltage utilization. The half-cycle modulation without dead zone is adopted, and the driving signals of the upper and lower tubes are alternately enabled according to the current polarity, which can avoid the dead zone effect of the converter. Among them, accurate current polarity detection is crucial to the realization of half-cycle modulation, which directly affects the quality of the output current. [0003] For a three-phase balanced system, the amplitudes of the three-phase currents are the same and the phases differ from each other by 120°, and the po...

AI Technical Summary

Problems solved by technology

But in the three-phase unbalanced system, there are positive and negative sequence components in the three-phase current, the amplitude of the three-phase current is different and the phase is no longer 120° from each other, the detection of the current polarity is more complex

If the current polarity of one of the phases is inaccurate, it will cause severe distortion of the zero-crossing point of the phase current, which will also cause distortion of the other two phase currents

Moreover, the output current of the converter often contains harmonics and noise, which can easily interfere with the current polarity detection

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