DC transformer for access of new energy to DC power grid, and implementation method for DC transformer

Abstract

The invention relates to a DC transformer for the access of new energy to a DC power grid, and an implementation method for the DC transformer. The DC transformer employs an isolation-type DC / DC converter mode, and is characterized in that the DC transformer comprises a low-voltage side full-bridge converter and a high-voltage side modular multi-level converter; the low-voltage side single-phase full-bridge converter and the high-voltage side single-phase modular multi-level converter are connected through a high-frequency transformer. The DC transformer provided by the invention can achieve the interconnection of a new energy DC power generation station with the low voltage level and a DC power grid with the high voltage level. The low-voltage side single-phase full-bridge converter is used for connecting the new energy DC power generation station with the low voltage level. The high-voltage side single-phase modular multi-level converter is used for connecting the DC power grid with the high voltage level.

Description

technical field [0001] The invention relates to a DC transformer and its implementation method, in particular to a DC transformer for connecting new energy sources to a DC grid and its implementation method. Background technique [0002] With the escalation of many problems such as global environmental pollution, energy shortage, and manufacturing technology upgrades, the scale and capacity of new energy power generation represented by wind power and solar power generation continue to increase. The issue of energy and power delivery is particularly important. Compared with AC transmission, HVDC transmission technology has the advantages of large transmission capacity, long transmission distance and low loss, so it has been widely used in my country's power grid. From the perspective of power transmission, the traditional power system is difficult to meet the requirements of improving the quality of power supply for users and transmitting power over long distances. From the...

AI Technical Summary

Problems solved by technology

[0008] At present, universities and research institutions at home and abroad have done some research on DC transformers. Among them, AlonsoAR et al. proposed a double-sided active DC / DC converter, which requires IGBT bridge arms to withstand all voltages in high-voltage direct current transmission. The problem of device voltage equalization, which needs to be connected in series or in parallel when applied to high voltage and high power; Jovcic D et al. proposed a resonant DC / DC converter, which needs IGBT bridge arms to bear all Voltage and lack of electrical isolation function, Kish G J et al. proposed a DC / DC converter based on MMC technology topology, which has problems such as power device loss, low converter efficiency, and high economic cost

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