| Hybrid power generation technology is an effective way to relieve intermittent and instability of renewable energy(RE) generation, and overcome power shortage by using a single power supply. It is well known that developing and utilizing marine renewable energy(MRE) is one of the best ways to solve the problem of energy supply of the island which is not covered by the power grid. Due to getting starting late, the technology of hybrid multiple MRE on island in China needs to be improved. Small-scale hybrid multiple MRE generation system on island, which installs simply and operates stably, is suitable for users’ scattered and limited electricity consumption. Energy storage device(ESD) is an important part for the balance of power supply and demand. The smooth operation of ESD is crucial to the performance of the whole power system. As one kind of ESD, Lead-acid battery is most widely applied in the MRE generation system. For the research on operation and control of lead-acid battery, it is lack of achievements including both feasibility and accuracy. Due to highly nonlinear of working process, battery’s operating condition influenced by power system has the characteristics of strong volatility. Therefore it is very difficult to accurately estimate the operation state of ESD and effectively control it. In order to solve the above problems, also for the operation and control of ESD in hybrid multiple MRE power system on island, the following research works have been carried out:1. A kind of intelligent integrated battery charging and discharging control method is proposed according to the MRE hybrid power system on island. The energy storage state of the battery is determined to control the charging and discharging process of battery and manage the load dynamically and hierarchically. Furthermore, the paper analyzes and discusses the method’s principle, performance and implementation.2. Considering the influence of the capacity change and state of charge and discharge, the paper establishes an enhanced internal-resistance equivalent circuit model. The software MATLAB/Simulink is used to estimate battery state under different operation status. And the error between simulation results and actual-operation results is obtained. An OCV-SOC correction method is put forward to overcome the model’s estimation error in the static status. The research results indicate that the corrected model has significantly higher estimation precision in battery’s constant-current charge and discharge experiment.3. An online Kalman filter energy storage state estimation method, which has the function of parameter update based on dual equivalent circuit model, is proposed. According to the operation data of the battery in hybrid power system, software simulation and comparative analysis of the error are promoted. Compared with the estimation results of the equivalent circuit model estimation method and the traditional Kalman filter estimation method, the results show that the proposed method could more accurately estimate the terminal voltage and SOC on the condition of state changing severely.4. A small-scale wind/solar hybrid power experimental prototype is designed to verify the operation of the energy storage control method proposed in this paper. By analyzing of the operation results, the control system can adjust the load according to energy storage state in the condition of output changing of power system. Meanwhile the operation status maintains at a safe range. The simulation experiment of ESD operation in small-scale hybrid power system on island is designed by using simulation circuit model under MATLAB/Simulink environment. The simulation and experimental results show that the control system not only can scientifically manage the load according to the battery state but also can guarantee battery’s stable and safe operation. |
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