Soft start method and system of hybrid input-series output-parallel direct current transformer

Abstract

The invention provides a soft start method and system of a hybrid input-series output-parallel direct current transformer. The soft start method comprises configuration of an ISOP input side capacitor capacitance value and a withstand voltage value and SR-DAB and PS-DAB three-section variable modulation strategies. According to the invention, different modulation, current limiting and conversion control strategies are used in different starting stages, so that the overshoot of the starting current and the voltage of the capacitor and the load is limited, and the output of the ISOP can quickly and stably reach the specified output voltage; the soft start problem of the hybrid ISOP direct current transformer can be solved, the over-current and over-voltage problems are solved, the implementation is simple, the efficiency is high, the loss is low, and the practical value is very high.

Description

technical field [0001] The present disclosure relates to the technical field of DC transformer start-up control, in particular to a soft-start method and system for a hybrid input-series-output parallel-connected DC transformer. Background technique [0002] The statements in this section merely provide background related to the present disclosure and do not necessarily constitute prior art. [0003] With the rapid development of power electronics technology, there are more and more DC loads represented by distributed energy and electric vehicles. Compared with the traditional AC system, the DC distributed system can better adapt to the demand for distributed energy in modern life and the development of future loads. As a key device for connecting DC busbars and DC loads of different voltage levels in a DC distributed system, DC transformers need to be improved in terms of operational reliability, efficiency, and volume. [0004] Input-series-output-parallel (ISOP) topolog...

AI Technical Summary

Problems solved by technology

The ISOP transformer based on SR-DAB has the advantage of high transmission efficiency, but its voltage regulation capability is lower than that of PS-DAB, while the ISOP transformer based on PS-DAB has the advantage of wide voltage regulation range, but its efficiency is lower than that of SR-DAB. Therefore, the current ISOP type DC transformer is difficult to achieve a good trade-off between the voltage regulation range and efficiency, and the hybrid ISOP DC transformer that mixes the two topologies of SR-DAB and PS-DAB has become a hot spot in academic research and engineering practice.

[0006] The inventors found that because the hybrid ISOP DC transformer mixes two different topologies of SR-DAB and PS-DAB, the input and output of multiple converters inside it are coupled with each other and affect each other. The hybrid ISOP DC transformer is only based on SR -DAB or PS-DAB kind of ISOP, its start-up control is more complex. If it is started directly or improperly controlled, over-current and over-voltage will easily occur during the start-up process of the hybrid ISOP DC transformer, resulting in start-up failure. Research on Soft Start Method of Type ISOP DC Transformer

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