Soft-start method and system for hybrid input series output parallel DC transformer

Abstract

The present disclosure provides a soft start method and system for a hybrid input series output parallel DC transformer, including the configuration of the capacitance value and withstand voltage value of the input side of the ISOP and the soft start of the three-stage variable modulation strategy of SR-DAB and PS-DAB. Start-up method; the present disclosure limits the start-up current, capacitance, and load voltage overshoot by using different modulation, current limiting, and conversion control strategies in different start-up stages, and enables the ISOP output to quickly and smoothly reach the specified output voltage; The method can solve the soft start problem of the hybrid ISOP DC transformer, avoid the problem of overcurrent and overvoltage, has simple implementation, high efficiency and low loss, and has high practical value.

Description

technical field [0001] The present disclosure relates to the technical field of start-up control of DC transformers, in particular to a soft-start method and system for hybrid input-series-output parallel-connected DC transformers. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may 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 sources 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 equipment for connecting DC buses 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-outpu...

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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