Capacitor clamping type three-level direct-current converter adopting asymmetric bidirectional switch

Abstract

The invention discloses a capacitor clamping type three-level direct-current converter adopting an asymmetric bidirectional switch. The capacitor clamping type three-level direct-current converter comprises a voltage source Vin, a voltage dividing capacitor Cin1, a voltage dividing capacitor Cin2, a primary side inversion unit and a transformer T. Input high-voltage direct current obtains alternating-current square waves on the primary side of the transformer by controlling on and off of a switch tube, passes through the transformer T, then is connected with a rectifier bridge on the secondaryside of the transformer, and then outputs direct-current voltage through the filter circuit. The problem of unbalanced current existing in an existing three-level circuit is solved. The turn-off current of a switching device in the circuit is reduced. The current stress of the switch tube is reduced. Zero-voltage zero-current turn-on and turn-off of the switch tube are achieved. The loss of the whole circuit is reduced. The reliability of the circuit is enhanced.

Description

technical field [0001] The invention belongs to the technical field of high-voltage DC converters, in particular to a capacitor-clamped three-level DC converter using an asymmetric bidirectional switch. Background technique [0002] Since high-performance high-input power DC converters have great potential in market applications, three-level DC-DC converters have become the subject of extensive research. Compared with the traditional two-level DC-DC converter, the three-level DC-DC converter has the advantages of large output capacity, high output voltage, and small current harmonic content. [0003] However, the traditional three-level DC-DC converter has the problem of unbalanced current and the unbalanced midpoint potential of the input capacitor, because when the charging and discharging times of the upper and lower switching tubes are not equal, there will be two If the charging and discharging times of two input capacitors are not equal, the inherent disadvantage of m...

AI Technical Summary

Problems solved by technology

[0003] However, the traditional three-level DC-DC converter has the problem of unbalanced current and the unbalanced midpoint potential of the input capacitor, because when the charging and discharging times of the upper and lower switching tubes are not equal, the upper and lower switching tubes will appear. If the charging and discharging times of two input capacitors are not equal, the inherent disadvantage of midpoint potential imbalance will appear.

Especially when the duty cycle is reduced, the current of the input capacitor and the switch tube will be extremely unbalanced, which will reduce the reliability of the entire circuit and increase the stress of the switch tube

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