Study On The Power Fluctuation Smoothing Control Strategy Of Intermittent Power Based On Energy Storage

Energy crisis and environmental pollution have attracted wide attention from all over the world, and vigorously develop renewable energy power generation system is the key technology to solve the above problems. Wind and solar power is an important direction of development of renewable energy,with the rapid development of wind power and photovoltaic power generation, its installed capacity increased rapidly, however Wind-PV generation system is very sensitive due to the change of weather, and have random and intermittent characteristics, large-scale intermittent energy sources connected to the traditional power system will caused adverse effects for the power and frequency of PCC. In order to solve this problem, the energy storage system usually is installed in Wind-PV generation system to improve the power quality by smoothing output power fluctuation of intermittent energy sources. The Wind-PV-ES generation system is as the object of study, focus on the application of energy storage technology in the Wind-PV-ES generation system, and propose improving the power fluctuation smoothing control strategy of energy storage system.The mathematical models of the photovoltaic power generation system, direct drive permanent magnet synchronous wind power generation system and the storage battery are established, the output characteristics of photovoltaic cells and wind turbine are given, the impact of electrical characteristics of the photovoltaic changes of light and temperature is analyzed, at the same time, it also analyzes the influence of wind speed and pitch angle variation of torque and output power. The battery equivalent circuits are also given, and battery charging and discharging process are analyzed.The control strategy of the power electronic devices are formulated in photovoltaic systems and wind power generation system under the function of the renewable energy power generation system in different converter, the system control structure is given, and has carried on the detailed analysis. The PI parameters of the PWM converter of the outer and inner loop are designed by the typical type I and type II system. The simulation model of wind power generation system and photovoltaic power generation system is built by the simulation software. The wind generation system is researched by simulation model under wind speed change conditions, and the effectiveness of MPPT control strategy is verified; the photovoltaic generation system is researched by simulation model under light illumination intensity and temperature changes conditions, the simulation results show that the photovoltaic power generation system according to the change of external weather conditions always keep the system running at the maximum power point, and verify the effectiveness of model.In order to overcome the shortcomings of linear PI control strategy, and a control strategy based on fuzzy control theory is proposed, and the fuzzy control the basic principle, basic structure and implementation process are given, the simulation research is carried out for without and with power fluctuation smoothing control strategy respectively. The simulation results show that the improved control strategy can obtain better dynamic response performance and anti-disturbance ability.