Voltage flexible control method of direct current distribution network system

Abstract

The invention discloses a voltage flexible control method of a direct current distribution network system. The method comprises the following steps of collecting operation electric quantity information of each bus node, determining an operation mode of an interface converter, and building an initial equilibrium condition of the direct current distribution network system; judging a net power state and an operation mode of a direct current microgrid or an alternating current microgrid, and forming a voltage control target of the bus node according to an actual operation requirement; establishing an equation for virtual inertia of an alternating current and direct current interface for analysis, and according to different power operation states, designing parameters of the interface converter and an electricity using unit; and analyzing drooping characteristics of a bidirectional direct current interface of a first DC / DC converter, and according to cascading drooping characteristics of the bidirectional direct current interface, designing an output compensation object and a control parameter of an inner energy-storing unit of the direct current microgrid. By a voltage flexible control way, the stability, convenience and reliability of control on a direct current distribution network are improved, energy-storing adjustment is fully used, and power fluctuation is reduced.

Description

technical field [0001] The invention belongs to the field of power electronics, and in particular relates to a voltage flexible control method of a DC distribution network system. Background technique [0002] The relationship between DC grid voltage and power balance will determine the stable operation of DC distribution network, so voltage stability is an important indicator reflecting the stability of DC distribution network. At present, there is no mature scheme for the voltage control strategy of the DC distribution network. It mainly refers to the voltage control strategy of flexible DC transmission and DC microgrid, including: [0003] The master-slave control strategy based on high-bandwidth communication, that is, select a certain converter station as a balanced bus node, and the rest of the converter stations are controlled by constant power. This strategy is simple to implement, but there are problems of too much dependence on inter-station communication and low r...

AI Technical Summary

Problems solved by technology

The above operation methods have the problem that the idle rate of energy storage in a single mode is too high or the control accuracy of relying on historical data is low

[0009] With the expansion of the scale of the DC distribution network, the number of busbar nodes increases, and the voltage control of the busbar nodes far away from the converter station becomes more and more complicated and difficult; secondly, the random and frequent fluctuation of the high penetration rate of renewable energy power also poses a threat to the stable operation of the system. great challenge

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