Three-phase solid-state transformer topology capable of reducing duty cycle loss and separated modulation method

Abstract

The invention discloses a three-phase solid-state transformer topology capable of reducing duty cycle loss and a separated modulation method, and relates to a novel three-phase current type AC-AC high-frequency chain matrix power electronic transformer topology capable of reducing duty cycle loss and an auxiliary resonance circuit separated control strategy. The topology is mainly formed by connecting a three-phase alternating current power supply, an input filter, a pre-stage matrix converter, an auxiliary resonance circuit, a high-frequency transformer, a post-stage matrix converter, an output filter and a load. The auxiliary resonance circuit is composed of a switching tube S2, a switching tube S1 and a parallel capacitor Cr, wherein the switching tube S2 and the switching tube S1 are connected through a common collector. A zero vector bridge arm direct connection thought in a current type space vector is combined with a resonance period current zero crossing thought, and a separated control strategy is adopted for an auxiliary resonance circuit, so that the duty ratio loss can be effectively reduced, the power loss can be reduced, and the transmission efficiency can be improved.

Description

technical field [0001] The invention relates to a three-phase solid-state transformer topology and a separate modulation method for reducing the loss of duty-to-width ratio, and belongs to the field of power electronic power converter topology and modulation thereof. Background technique [0002] Compared with traditional transformers, power electronic transformers have the advantages of small size, light weight, controllable voltage and frequency, etc., and can be widely used in distribution networks, microgrids, photovoltaic power generation and energy routers. [0003] Power electronic transformers, also known as solid-state transformers, can be divided into single-stage and multi-stage solid-state transformers according to the number of transformation stages. Multistage solid state transformers have a DC link to interface with renewable energy or storage systems. However, the multi-level solid state transformer has the disadvantages of low efficiency, low power density ...

AI Technical Summary

Problems solved by technology

Aiming at the problem of duty cycle loss of current-type three-phase matrix power electronic transformers, the publication number is: CN112436733A, and the invention patent titled: "Three-phase resonant topology and auxiliary switch modulation method for reducing duty cycle loss" discloses a A three-phase power electronic transformer topology and an integrated control method for an auxiliary resonant circuit that can reduce the loss of duty cycle; r , resistance R r Composition, the bidirectional switch adopts integral control; in this patented technology, the auxiliary bidirectional switch used in the integral modulation scheme exists so that the parallel capacitor C r At the moment of short circuit, the current peak of the capacitor will be caused. In order to solve this problem, an improved auxiliary resonant circuit is proposed in the patent, that is, for C r A small resistor R in series r , Figure 5 , Image 6 and Figure 7 Both are explained

Although this patented technology can achieve the purpose of reducing the loss of duty cycle, due to the resistance R during the resonance process of the converter r Absorbing active power will cause power loss

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