High-frequency isolation type tri-level inverter based on forward converter

Abstract

The invention discloses a high-frequency isolation type tri-level inverter based on a forward converter. The high-frequency isolation type tri-level inverter based on the forward converter is composed of an input direct-current power supply (Ui), a dividing capacitor, a high-frequency isolation type forward tri-level conversion unit, a frequency converter, an output filter and an output alternating-current load, wherein the input direct-current power supply (Ui), the dividing capacitor, the high-frequency isolation type forward tri-level conversion unit, the frequency converter, the output filter and the output alternating-current load are connected in sequence. The high-frequency isolation type tri-level inverter based on the forward converter has two stages of power conversion (direct current DC--high frequency alternating current HFAC--low frequency alternating current LFAC), and has bidirectional power flow, the front end of the output filter is good in voltage spectral characteristic, and the high-frequency isolation type tri-level inverter based on the forward converter has high power density, can reduce the voltage stress of a switching element, and can achieve high-frequency electrical isolation of alternating current load and direct-current power supply.

Description

technical field [0001] The invention belongs to the technical field of power electronic conversion, in particular to a high-frequency isolated three-level inverter based on a forward converter. Background technique [0002] Direct-to-AC (DC-AC) conversion technology is a conversion technology that uses power semiconductor devices to convert DC power into AC power. It is widely used in national defense, industrial and mining enterprises, scientific research institutes, university laboratories and daily life. . [0003] So far, research on DC-AC converters by power electronics researchers at home and abroad has mainly focused on non-electrically isolated, low-frequency and high-frequency electrically isolated two-level DC-AC converters; for multi-level converters The research mainly focuses on multi-level DC-DC, DC-AC and AC-DC converters, while the research on multi-level DC-AC converters is very little, and is only limited to non-isolated, low-frequency or intermediate-freq...

AI Technical Summary

Problems solved by technology

However, the diode-clamped and capacitor-clamped multi-level multi-point flat inverter technologies have defects such as single topology and no electrical isolation: the cascaded multi-level inverter technology with independent DC power supply has complicated circuit topology on the input side Low power factor, low conversion efficiency, low power density and other defects;

It only reduces the voltage stress of the switching tube in the DC / DC converter with high-frequency electrical isolation, but does not really realize multi-level at the front end of the output filter inductor, and does not reduce the voltage stress of the switching tube of the Buck inverter bridge. , the output filter inductor and capacitor values ​​have not been reduced

Moreover, this multi-level topology is proposed on the basis of the unidirectional Buck-type high-frequency link inverter. Due to the inherent defects of the unidirectional Buck-type high-frequency link inverter, this series of high-frequency isolation types are mostly Level topology applications are limited

Images