DC distribution system energy storage device adaptive virtual impedance droop control method

Abstract

The invention relates to a DC distribution system energy storage device adaptive virtual impedance droop control method, which is applied to multi-converter parallel control in a DC distribution system. The method comprises the steps of 1) acquiring electric power parameters of the DC distribution system, establishing a double closed-loop controller which consists a voltage outer loop and a capacitive current inner loop, and establishing a DC distribution system droop control model; 2) introducing virtual impedance ZD(s) into a part between converter output current and converter reference voltage signals of the double closed-loop controller in the DC distribution system droop control model so as to act as negative feedback, and acquiring equivalent output impedance Zov(s); and 3) enabling the equivalent output impedances Zov(s) corresponding to a plurality of lines to be equal through setting values of different virtual impedances ZD(s), and thus averaging output power and power distribution of the plurality of lines in the DC distribution system. Compared with the prior art, the method provided by the invention has the advantages of shock suppression, simple algorithm, low cost and the like.

Description

technical field [0001] The invention relates to the fields of power electronics, DC power distribution, energy storage control systems and power quality, in particular to an adaptive virtual impedance droop control method for an energy storage device of a DC power distribution system. Background technique [0002] The DC power distribution system integrates various new energy power generation systems, and then connects to the DC power distribution system with a unified interface. Such a networking form can weaken the adverse effects caused by the randomness and intermittent nature of distributed power, and better accept renewable energy. However, in order to stabilize the volatility of distributed energy such as wind power and photovoltaics, it is necessary to increase the energy storage system to maintain the stable operation of the DC power distribution system. [0003] Energy storage converters mostly adopt droop control strategies, and the converters of each energy stor...

AI Technical Summary

Problems solved by technology

[0004] In view of the resistive characteristics of the low-voltage micro-grid line, the traditional droop control strategy adopts the P-E and Q-f methods, but due to the difference in the length of each energy storage device and the PCC point line and the difference in the parameters of the converter itself, the energy storage converter will The output power is not evenly divided, causing current circulation, resulting in a decrease in efficiency

However, the P-E and Q-f control methods in traditional droop control do not consider the coupling effect of resistance and reactance, and non-decoupling control will cause power oscillation problems

Images