Single-stage type high-conversion-ratio Buck-Boost inverter

Abstract

The invention relates to a single-stage type high-conversion-ratio Buck-Boost inverter. The single-stage type high-conversion-ratio Buck-Boost inverter comprises a full bridge circuit consisting of four switching tubes (M1-M4), a coupling inductor Lcp having four windings, an output filtering capacitor Co and an equivalent load Rl. The coupling inductor is designed as two pairs of symmetric windings. The primary-end winding of the coupling inductor has same windings N1=N2 and the auxiliary side of the coupling inductor has same windings N3=N4. The transformation ratio of the coupling inductor is n=N3 / N1=N4 / N2. Targeting a problem that most of topologies of the Buck-Boost type single-stage type inverter are limited by limited voltage transformation ratios and although few topologies can realize high transformation ratios, the quantity of devices is greatly increased, the invention provides a single-stage high-transformation ratio Buck-Boost inverter topology, which can realize a high transformation ratio under a condition that semiconductor devices are few.

Description

technical field [0001] The invention belongs to the field of power electronics and relates to a single-stage Buck-Boost inverter with high conversion ratio. Background technique [0002] In the field of renewable energy such as photovoltaics and fuel cells, inverters with high conversion ratios are essential. Due to the ease of control and implementation, usually, a two-stage inverter is used. However, due to lower cost and higher efficiency, single-stage inverters have attracted widespread interest from scholars. Looking at the literature published so far, it mainly involves the types of flyback, Boost, and Buck-Boost. [0003] In the solution adopted by the single-stage high conversion ratio inverter, the flyback topology can have a high conversion ratio due to the use of a transformer. However, due to its single-stage structure, a decoupling circuit has to be added to reduce the solution. Coupling capacitors, which will weaken the simple characteristics of the flyback ...

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Problems solved by technology

[0003] In the solution adopted by the single-stage high conversion ratio inverter, the flyback topology can have a high conversion ratio due to the use of a transformer. However, due to its single-stage structure, a decoupling circuit has to be added to reduce the solution. Coupling capacitors, which will weaken the simple characteristics of the flyback topology, increase the number of devices, and reduce efficiency; Boost topology has a high-voltage bus that makes power decoupling easier, but the topologies that have been found in the literature are all restricted Due to the disadvantage of limited conversion ratio; most of the Buck-Boost topology is still limited by the limited voltage conversion ratio, and some topologies can achieve high conversion ratio, but the number of devices is greatly increased

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