Three-level full-bridge DC conversion device

Abstract

The invention discloses a three-level full-bridge DC conversion device. A low-voltage diode can be directly adopted by a secondary rectifier side of a transformer of the three-level full-bridge DC conversion device to achieve high voltage output, and meanwhile, the problem of non-uniform voltage, caused by the reverse recovery inconsistency, of the diode which is directly connected in series is solved. In most of the switching period, a secondary rectifier diode is clamped by a secondary flying capacitor, so that voltage oscillation and spikes on the diode can be eliminated without adding an auxiliary circuit and reduction of the volume and improvement of the conversion efficiency are facilitated. Output voltage of a secondary rectifier bridge has certain DC bias, the secondary rectifier bridge can output higher voltage than a conventional rectifier circuit, and current ripples on an output filter inductor are smaller, so that improvement of the DC voltage utilization ratio and the power density of the device is facilitated and the volume and the weight of the device are reduced.

Description

technical field [0001] The invention relates to a DC-DC power conversion device, in particular to a three-level full-bridge DC conversion device suitable for high-voltage and high-power applications. 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. Efficiency, high reliability, high power density and low cost have become the main factors for the development of power electronics technology trend. In many occasions, such as three-phase power factor correction converters, ship electrical, high-speed railway electrical, rail transit electrical, etc., their input or output voltages are high, and generally require electrical isolation. If traditional isolated converters are used , such as forward, flyback, push-pull, half-bridge and full-bridge, etc., you need to choose a switch tube with hi...

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

Images