High-voltage transformation ratio bidirectional DC converter and control method thereof

Abstract

The invention discloses a high-voltage transmission ratio bidirectional DC converter and a control method thereof. The high-voltage transmission ratio bidirectional DC converter mainly comprises a high-voltage side three-phase full-bridge consisting of six switch tubes, a Y-delta shaped three-phase transformer and a low-voltage side three-phase bridge arm consisting of three filtering inductors and three switch tubes. The invention also provides a control method of the high-voltage transmission ratio bidirectional DC converter. The internal characteristics and the control mode of the Y-delta shaped three-phase transformer are utilized to improve the voltage transformation ratio by one time in comparison with a traditional bidirectional DC converter, so that the turn ratio of the transformer is reduced by one time, and the leakage inductance is greatly reduced, the electromagnetism compatibility of the transformer is improved. The low-voltage side three-phase inductors are parallelly connected in a staggered manner, and the output current ripple is greatly reduced after the three-phase current ripples are stacked, so that the service life of a storage battery can be favorably prolonged, and the size of a filter is favorably reduced. The high voltage side and the low voltage side both adopt the three-phase staggered shunt-wound structure, so that the current stress of the switch tubes is reduced and suitable switch tubes can be conveniently selected for high-power application occasions.

Description

technical field [0001] The invention relates to a high voltage ratio bidirectional DC converter and a control method thereof, in particular to a high voltage ratio bidirectional DC converter using a three-phase transformer and a control method thereof, belonging to the fields of new energy power generation and power electronic conversion. Background technique [0002] With the increasingly serious energy crisis and environmental pollution, the development and utilization of new energy sources such as solar energy, wind energy, and hydrogen energy have attracted more and more attention. Due to the limitation of weather and climate conditions, new energy has the disadvantages of unstable and discontinuous power supply. In order to make up for the uncertainty of new energy sources such as solar energy, batteries are introduced into the new energy combined power supply system as a backup energy source. When the electric energy generated by new energy sources is not enough to pro...

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Problems solved by technology

[0003] In recent years, the voltage transformation ratio of the isolated bidirectional DC converter proposed by scholars is VL / VH = D / N. In the case of a large difference in the power supply voltage levels at both ends, the voltage transformation ratio of the converter can only be increased by increasing the transformer turn ratio. Ratio, but the increase of the transformer turns ratio increases the leakage inductance, and the resonance between the leakage inductance and the junction capacitance of the switch tube causes a voltage spike, which not only increases the voltage stress of the switch tube, but also deteriorates the electromagnetic compatibility performance of the converter

In addition, most of the existing bidirectional DC converters have two bridge arms. In high-power applications, the switching tubes are subjected to large current stress, making it difficult to select the switching tubes.

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