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Research On Hybrid Energy Storage For DC Micro Grid Based On Batteries And Super Capacitors

Posted on:2017-05-08Degree:MasterType:Thesis
Country:ChinaCandidate:M J TianFull Text:PDF
GTID:2272330482487088Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
ABSTRACT:In recent years, the solar energy Distributed Generation (DG) technology has received more and more attention, and by the DG and other components of the DC micro grid has become the current research hotspot. Because of the randomness of the output power and the load power consumption of DG, the isolated DC micro grid has a natural weak inertia. Hybrid energy storage as a kind of scheduling resource applied to DC micro grid system, which can make full use of the characteristics of high power density and high energy density of battery, and with the corresponding control strategy, the system can effectively extend the life cycle of the system.This paper is supported by the Beijing Science and Technology Commission "Research and demonstration application of large-scale photovoltaic power plants based on the unified power control equipment and DC microgrid technology (D131104002013003)", and the Fundamental Research Funds for the Central Universities "Research on bidirectional multi port converter based on hybrid energy storage and SiC devices (E15JB00140)".Theoretical research, simulation analysis and physical experiment verification of the Hybrid Energy Storage System (HESS)which based on storage batteries and super capacitors are carried out. The main work includes the following aspects:First, the structure of the DC micro grid system is introduced, which is composed of DG, super capacitor module, battery module, Multi Port DC/DC Converter (MPC) and load. In this paper, the overall structure and working principle are analyzed in detail, and the control method of each part is studied.Second, as the problem of generating great transient disturbance in the hybrid energy storage system which is caused by the starting investment of a single DC/DC port, the soft start control strategy of the system is proposed. In this paper, the optimal selection of soft starting resistance and the setting of the initial duty cycle of the power port are analyzed in detail by the equivalent circuit equivalent and formula.Then, the Adaptive Energy Control Strategy (AECS) based on the moving average filtering algorithm is proposed for the problem of severe impact on the normal operation of the DC bus voltage and battery set. The pulse load power is filtered through this algorithm, and then the battery pack is assumed to change the power, and the power of the super capacitor is used to compensate the instantaneous power, so as to optimize the battery charge and discharge process, and extend its service life. An adaptive control is introduced to stabilize the terminal voltage of the super capacitor so as the voltage stability is near the reference value. And the energy flow balance is used to control the battery pack, which makes the State of Charge (SOC) of the battery pack in the same way.Finally, the hybrid energy storage system and DC micro grid experimental platform with the rated power 3.8kW which can be connected with 3 groups of battery and 1 group of super capacitor are developed. And then the hardware parameters and software programming of the experimental system are designed, and through experiments, the soft start control strategy and adaptive energy control strategy are verified.
Keywords/Search Tags:DC Micro Grid, Hybrid Energy Storage System, Super Capacitor, Battery, Soft Start, Adaptive Control Strategy
PDF Full Text Request
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