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Control Strategy Design Of The Energy Storage Power System Based On Vanadium Battery

Posted on:2015-12-21Degree:MasterType:Thesis
Country:ChinaCandidate:Y ZhouFull Text:PDF
GTID:2272330473951791Subject:Control theory and control engineering
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Electricity plays an important role in the development of the society. Sudden power lost will bring serious consequences to both production and life. Especially for important facilities, such as hospitals, steel mills and so on, if there is a power failure, it will cause significant political influence and economic losses. This paper studied a new energy storage power supply system. In the aspect of energy storage, the power supply system adopts the structure in which vanadium battery is priori and lead-acid battery is complementary. In the aspect of converter, bi-directional converters are used to realise dual-purpose, including charging and discharging. Controled by improving energy control algorithm, the power supply system optimizes energy-scheduling and improves the service life and reliability of the system. Improving energy control algorithm also makes the system easier to be modularization and expansion.Vanadium redox battery is introduced in the beginning. And the main parameters of the battery are simulated through an equivalent loss simulation model. After a preliminary understanding of the battery characteristic, bidirectional interface converter needed for battery charge and discharge is studied. Because of simple structure and low electrical stressing, half bridge buck/boost is selected as converter topology.Then, based on vanadium battery, paper presents whole structure of the power supply system. In the system, lead-acid battery and its interface converter work as auxiliary module, cooperating with vanadium battery module. When the power grid is in severce, bi-directinal DC-AC inverter works as power supply module to charge batteries. Otherwise, it works as load. In view of a variety of energy supply and demand states among grid, vanadium battery, lead-acid battery, and load, system needs to control power distribution. Considering the common dc bus structure, paper references and improves dc bus voltage level signaling control alorithm. Using the improved algorithm, paper classifys the system work modes and analyzes the conversion between work modes.Paper designs control block diagram for each module. DC-DC converter adopts a control structure in which voltage outer loops’ outputs sum and current inner loop is shared. This control structure can make mode switching smoothly, but brings a problem which makes PI controller exiting satuarion slowly. Paper improves PI controller and solve the problem. As to bi-directinal DC-AC inverter, because of big difference between grid mode and off-grid mode, conrollers are designed indepengdently. Based on mathematical model, controllers’ parameters are designed in discrete domain.Finally, Matlab/simulink simulation model is established. The previous theoretical analysis results and control strategy are proved to be correct and effective.
Keywords/Search Tags:vanadium battery, lead-acid battery, bi-directional converter, power control, PI controller
PDF Full Text Request
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