Research On The Analysis And Control Strategy Of Ultracapacitor DC Storage Energy System Application

Electric energy is the most convenient and clean energy sources, and it is used far and wide. While there are many problems of power quality which imperil greatly electronic loads. Modern times, high quality power supply is required by modern manufacturers, and a quick and efficient energy storage technology is now starved for in order to improve and solve the transitory power quality. As a new kind of energy storage component, ultracapacitors have fast response, high charge-discharge efficiency, and there are types of commodities on sale which speedup assemble and facilitate to enlarge energy storage capacity, therefore the ultracapacitor is considered the most promising energy storage technology to improve power quality.In order to research the validity of ultracapacitor dc energy storage unit applied to improve power quality. This paper set up the math model, and different control strategies are provided and analysed. A experimental prototype test rig is constructed, and the theoretical analysis results are verified with it.With the analysis of ultracapacitor charge and discharge characteristics, a conclusion is described that when the ultracapacitors number is fixed on, the in series or parallel connection mode will not affect the output efficiency of each ultracapacitor.Ultracapacitor DC energy storage system is composed of ultracapacitors bank and a dc-dc convertor. Based on large signal model for operational stability, a restriction is added to d (duty ratio).Based on small-signal low-frequency linear circuit model, transfer functions are obtained, and linear control theory can be adopted to design simple PI controller. To stabilize the dc bus between Dynamic voltage restorer and ultracapacitors dc energy storage unit, positive and negative power flows should both be regulated. A new method is proposed to design energy storage system to easy implement unified controlbi-directional power flows, effectively avoid the possible vibration which caused by controllers changed. Experiment results show that the proposed strategy is effective and feasible.Because PWM dc-dc power converters are nonlinear and time-varying system, and ultracapacitors bank has a wide voltage change scope, nonlinear synergetic control is provided. This way is not limited to an operating point, and easy to understand the physical meaning. In this paper, particular parameters of the synergetic controller are presented, which can simple the debug process. Both simulation results and experimental results are presented to show the feasibility and strong robustness.In conclusion, based on some important aspects of ultracapacitor dc energy storage unit application, set up a model of energy storage system, analysis and design some ways to regulate the system operation which have theory and practical meanings to provide optional scheme to the project applications...