Stability Study Of Distributed Generation Unit Based On Energy Storage Control

With the growing of grid-connected electricity generation based on the renewableenergy, distributed generation was widely used. Intermittent energy can be in one sampleand reliable DC distributed network, but there are also many problems to be solved. Theconstant power loads due to their negative impedance characteristics have a negativeimpact on the stability of the system voltage, and it will lead to reduced stability with theirincreasing power. Based on the research of the relationship between the constant powerload and the voltage stability, the idea that introduction of the super capacitor power bufferlink was proposed.Based on the impedance mode indicator, the negative damping effect of the constantpower load on the voltage stability of DC distributed power generation unit was studied.The unit parts were modular and impedance defined with a simplified circuit model ofdistributed unit, and constant power load’s power constraint was obtained based on thesystem voltage stability criterion. According to the relationship between the load powerlevel and the intensity of the negative damping effect, introduction of the super capacitorpower buffer link to improve voltage stability was proposed. Matlab simulation resultsverified the correctness of the power constraint and the feasibility of the proposed scheme.Finally, the experimental platform based on digital control DSP TMSF2812 was built on,use the dual interleaved bi-directional Buck-Boost Converter as the super-capacitor’sinterface circuit, DC distributed power generation unit experiments were completed.Through the theoretical analysis and experimental results, the correctness of theconstant power load power constraint was verified, and the purpose of improving thevoltage stability of DC distributed unit by using super capacitor power buffer link wasrealized, while the working status of the super capacitor was optimized.