AC/DC (alternating current/direct current) convertor implementation method based on asymmetrical multi-level synthesis technology

Abstract

The invention discloses an AC / DC (alternating current / direct current) convertor implementation method based on an asymmetrical multi-level synthesis technology, belongs to an AC / DC conversion and control technology related to the electrical technology, and aims to research develop an AC / DC convertor which has low harmonic wave and high quality and is suitable for application requirements for various capacities. The AC / DC convertor implementation method is characterized in that the traditional mode that current of a 12-pulse-wave AC / DC convertor is symmetrically distributed to two three-phase bridge inverters for conversion is replaced with the novel method that the current is asymmetrically distributed to two three-phase bridge inverters, direct current is distributed to the two three-phase bridge inverters according to a given conversion rule, so that three-phase alternating current of an incoming line of the convertor is sine-wave current, then an equal-increment step-shaped triangular wave current waveform is adopted for approximate substitution of ideal transformation, and the AC / DC convertor implementation method based on the asymmetrical multi-level synthesis technology has the characteristics of low harmonic wave, thyristor controllability, lead-lag continuous adjustment of a power factor, high combined efficiency of a system and suitability to application requirements for various capacities and can be applied to direct-current power sources with various capacities and active front-end converters with various applications.

Description

technical field [0001] The invention belongs to AC / DC conversion and control technology related to electrical technology. Background technique [0002] In the practical application of large-capacity AC / DC converters, load-commutated converters are mostly used at present. The disadvantages are that they only have the ability to control power in two directions, poor power factor, and high harmonic content. Therefore, corresponding power factor compensation and filtering devices are required, which makes the whole system complicated and expensive. [0003] Small and medium-capacity AC / DC converters usually use diode rectification and thyristor rectification. The disadvantage of this type of converter is that the incoming current of the power supply contains a large number of harmonics, and the waveform is distorted, which will pollute the power grid. At present, the method to improve this situation is to use multiple technology and fully controlled devices such as insulated ga...

AI Technical Summary

Problems solved by technology

[0009] To sum up, the current way to obtain AC / DC converters with low harmonics, high quality, and suitable for various capacity applications is to increase the number of pulses or adopt complex control means or supplemented by other devices. The result is to pay A lot of economic costs, in addition, because it contains some passive remedies, there may be hidden dangers that may have adverse effects on the entire system

Whether a simple, economical, positive and effective method can be found to realize AC / DC converters with low harmonics, high quality, and suitable for various capacity applications is an important issue in the field of AC / DC converters. Up to now No innovative research results have been seen so far

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