A three-level DC conversion device and an electric energy conversion method using the device

Abstract

The invention discloses a three-level DC converter apparatus and an electric energy conversion method employing the same. The three-level DC converter apparatus comprises n three-level DC conversion modules M1, M2..., Mi,..., and Mn. The n three-level DC conversion modules are connected with each other in parallel. Each module has the same circuit structure and parameters. The electric energy conversion method provided by the invention can perform phase shift control on switch tubes in the modules and among the modules. The three-level DC converter apparatus has the following advantages: the structure is simple, the expansibility is high, the redundancy capability is high, and a low-voltage single switch tube is applied to a high-voltage large-power electric energy conversion occasion; and the control method provided by the method can improve the equivalent switch frequency of the three-level DC converter apparatus to 2n times of an original switch frequency, substantially reduces the pulsation of input current and output voltage, and accordingly greatly reduces the volume, weight and cost of an input and output filter, and at the same time, the efficiency and dynamic performance of a circuit are also enhanced.

Description

technical field [0001] The invention relates to a DC-DC power conversion device, in particular to a three-level DC conversion device suitable for high-voltage and high-power applications and a power conversion method using the device. Background technique [0002] In recent years, the application of power electronics technology in modern industrial society has become more and more extensive, and the requirements for power conversion devices have become higher and higher. High efficiency, high reliability, high power density, low cost, and modularization have become power electronics technologies major trends in development. In many occasions, such as communication power supplies, three-phase power factor correction converters, marine electrics, high-speed railway electrics, rail transit electrics, etc., their input or output voltages are relatively high, and traditional converters such as Buck, Boost, Buck, etc. are used. -Boost, Cuk, SEPIC, Zeta, half-bridge and full-bridg...

AI Technical Summary

Problems solved by technology

The high-voltage MOSFET switch tube has large on-state resistance and large conduction loss, which is not conducive to improving the efficiency of the converter; the high-voltage IGBT switch tube has serious current tailing phenomenon, which limits the increase of switching frequency, which is not conducive to reducing the transformer and filter. Volume, weight and cost; the switching tubes are connected in series, requiring more complex circuits and controls to ensure better synchronous control and voltage equalization between the series switching tubes

In addition, in the above occasions, the input or output current is also very large, and the switch tubes are connected in parallel to meet the high current demand. On the one hand, the device itself is required to have better consistency. This greatly increases the cost of device screening and the difficulty of circuit control, and the reliability of the entire system is also low; moreover, the manufacturing process of high-power transformers and filters is complicated, the cost is high, and it is not conducive to installation And maintenance

[0003] Therefore, at present, there are various problems in the application of traditional converters and technologies in high-voltage and high-power applications, and these problems have not been resolved

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