Low-voltage ship DC power grid structure based on energy weak storage, and control method

Abstract

The invention relates to a low-voltage ship DC power grid structure based on energy weak storage, and a control method. A DC power grid structure of a DC circuit breaker with the rapid turn-off capability is replaced by a common circuit breaker. The structure is mainly characterized in that a high-capacity capacitor with a voltage supporting effect is cancelled from a DC link, and a DC power gridis in an energy weak storage state, and can achieve the power loss protection rapidly when a fault occurs. The power grid structure is that the controllable rectification is carried out through a front-end converter with the DC short-circuit fault ride-through capacity, and the voltage fluctuation of a DC power grid is restrained through an interface converter with the high switching frequency ofa supercapacitor. By the adoption of the power grid structure, the structure can achieve the automatic current limiting when a DC side short-circuit fault occurs, does not need a special DC circuit breaker, thereby simplifying a circuit, and facilitating the popularization of the ship DC power grid.

Description

technical field [0001] The invention belongs to the technical field of ship power grids, and specifically relates to a low-voltage ship DC power grid structure and control method based on weak energy storage. control to achieve voltage stability. Background technique [0002] Traditionally, the ship power system adopts AC system, which has the advantages of easy voltage transformation, protection and fault handling, but its limitations are also obvious. Since the output voltage of the diesel generator is directly connected to the grid, in order to stabilize the voltage and frequency of the grid, the diesel generator is required to work at a fixed speed, so that the diesel generator often cannot work at the best energy efficiency point. At the same time, there are many power quality problems in the AC power grid, such as harmonics, reactive power, synchronization, etc., especially in high-penetration micro-grids such as ship power grids. In addition, the AC system uses a po...

AI Technical Summary

Problems solved by technology

Since there is no voltage zero-crossing point in the DC circuit, it is difficult to extinguish the arc, so it is difficult to turn off the circuit breaker. Compared with the AC circuit breaker, there is a big difference in the structure of the circuit breaker

At present, the DC circuit breakers on the market are all mechanical DC circuit breakers, which have the ability to shut off the current, but the shutdown speed is slow, which is difficult to meet the protection requirements of the DC power grid.

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