A three-level full-bridge DC conversion device

Abstract

The invention discloses a three-level full-bridge DC conversion device. The three-level full-bridge DC conversion device of the present invention can directly use low-voltage diodes on the rectifier side of the secondary side of the transformer to achieve high-voltage output, and at the same time eliminate the problem of uneven voltage caused by inconsistent reverse recovery of directly connected diodes; during most of the switching cycle, The secondary rectifier diode is clamped by the secondary flying capacitor, which eliminates voltage oscillation and spikes on the diode without additional auxiliary circuits, which is beneficial to reduce volume and improve conversion efficiency; the output voltage of the secondary rectifier bridge has a certain DC bias Compared with the conventional rectifier circuit, it can output higher voltage, and the current ripple on the output filter inductor is also smaller, so it is beneficial to improve the DC voltage utilization rate and power density of the device, thereby reducing the volume and weight of the device.

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

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