Energy regulating and controlling method of DC micro power grid

Abstract

The invention discloses an energy regulating and controlling method of a DC micro power grid. The DC micro power grid mainly comprises various load units, a storage battery energy storage unit, distributed generating units, a static switch, various converter interfaces, and a grid-connected current transformer. A mode A means that when a power grid operates normally, the DC micro power grid is in a grid-connected operation mode; the grid-connected current transformer controls DC bus voltage to be constant; the distributed generating units operate in respective maximum power tracing modes; and the storage battery energy storage unit operates in a droop control mode. The specific structure of the DC micro power grid and five modes for achieving system operation are disclosed in the invention. The energy management of the five modes uses specific mode transformation strategies. In order to guarantee smooth switching processes among the five modes and prevent frequent switching among the five modes, mode switching uses a hysteresis comparator. The energy regulating and controlling method of the DC micro power grid may effectively achieve power grid energy management and coordination control.

Description

technical field [0001] The invention relates to the technical field of micro-grid and distributed power generation, in particular to an energy regulation method of a DC micro-grid. Background technique [0002] Energy crisis, environmental protection, and energy sustainable development issues have led to the development and utilization of renewable energy. Distributed power generation units such as wind power and photovoltaics can be used as effective grid-connected power generation units to solve a series of contradictions such as energy shortages. However, the power output of these distributed generation units has the characteristics of randomness, fluctuation and intermittent, and at the same time, there are certainties such as high cost of single unit connection, low capacity and inflexible configuration. Merging into the main network in the form of a micro-grid is an effective way to improve the overall efficiency. [0003] Compared with AC microgrid, DC microgrid has ...

AI Technical Summary

Problems solved by technology

Most of the traditional control methods are based on the hierarchical control strategy of the DC bus voltage signal. This method can achieve better operation under normal grid conditions. However, in the actual control process, the DC side voltage will deviate from the ideal reference point. The DC microgrid contains A large number of constant power loads may cause voltage fluctuations on the DC side, causing system instability

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