Research On Power Conditioning System In Isolated Wind Power Grid

Wind power is a sort of inexhaustible and renewable resource. Among the development of all kinds of renewable and new resources, the wind power generation has great potential of scale production and commercial development prospect. However, there are some uncertainties in wind energy. So there are some restrictions to combine wind energy with the grid. In order to break through the bottleneck, wind power and energy storage batteries constitute the power supply to load in the isolated region is regarded as a way. This is isolated wind power grid which is the premise of this research. Isolated wind power research focus is how to control the voltage and frequency stability. Energy should be stored into batteries when wind speed is high, and energy in batteries should be released the when wind speed is low. Therefore, isolated wind power grid need a unit to achieve the various functions described above. This unit is power conditioning system which is the core of this study.Firstly the paper introduces the situation and the development of wind power generation technology at home and abroad, and briefly describes the functions of each module in isolated wind power grid. Then the paper propsed the concept of power conditioning system and the functions which power conditioning system need to implement. On the basis of foregoing study, the paper focus on the basic power regulator control theory, and introduces a control algorithm in line with the principle of operation of isolated wind power grid. This algorithm can help isolated wind power grid to stabilize the voltage and frequency and also balance the power flow.Both steady-state simulation and dynamic simulation are maked to verify the control algorithm of power conditioning system is reasonable. Steady state refers the state which system load and wind speed is stable. Verified by simulation, power conditioning system can stabilize the voltage and frequency of isolated wind power grid and balance the power flow. Dynamic state refers the state which there is a sudden change in load or wind speed in isolated wind power grid. Verified by simulation, power conditioning system have sufficient dynamical adjust ability and meets various conditions which wind speed and load change in isolated wind power grid. On the basis of simulation, power conditioning system is designed in detail. Power conditioning system design includes hardware design and software design. In hardware design, main circuit of isolatd wind power grid and circuit of power conditioning system are designed. Besides, parameters of each component of power conditioning system are given. In software design, core control algorithm and other features and protection software flow chart is given by modular design. 2*75kVA power conditioning system prototype is developed.Finally the paper gives experiment results and experimental waveforms. Experiments mainly include steady-state experiment and dynamic experiment. The former case verifys the power conditioning system can stabilize frequency and voltage in isolated wind power grid and balance power flow through experiments with different load conditon. The latter case verifys the power conditioning system meets the dynamic regulation requriements of isolated wind power grid through experiment with sudden change in load condition.