Study Grid-side Converter Device Of Wind Power

Wind power will become one of important pillar in the future world energy. The core technology of wind power is converter. In this paper, through theoretical analysis, simulation and the grid-side converter experimental platform study the three aspects grid-side converter about construct, control theory and characteristics.At first, When studied converter System structure, analysis the different between the IGBT bridge and the L and LCL filters, and find control structure based on the L and LCL converter filte is same, and derive LCL filter simplified mathematical control model. Another time, the model based on the voltage feed-forward decoupling control strategy was tested to utilize the feedback of the energy converter experimental platform based on DSP. A typical voltage source PWM converter configuration consists of three parts: line filter, bridge and DC voltage link. Also the LCL-topology has higher attenuation above the resonance frequency and better line voltage disturbance rejection capability compared to the L-filter.The second aspect, the Voltage Source Converter Low frequency mathematical models and high frequency mathematical models are set up in ABC coordinate,αβcoordinate, and dq coordinate. On the basis of three-phase voltage source PWM converter control carried out a detailed theoretical analysis, and both the SVPWM and SPWM modulation method are compared and analyzed to get a specific implementation based on SVPWM modulation and synchronous coordinates PI decoupling control the.When SVPWM and SPWM modulation method are studied, it was found that algorithm nature of SPWM and SVPWM is same. In order to avoid harmonic problems, during the prototype test, select the line voltage as a detected Signal, thereby reducing the system's low harmonic output.In order to make DC energy change into AC energy and improve power quality issues, more research had performed to investigate the power quality issues through to study different control system program and different detect way. Another aspect for more work is that the LCL-filter and L-filter are studied and find performance of LCL-filter is the best.The third aspect, in order to study structural characteristics based on synchronous PI decoupling control. Through simulation and test unit equipment, research converter characteristics when the grid is normal and abnormal situations. Especially, when the power grid come into no power or low-voltage power state, study the grid-side converter how to work and how to be protected. When grid is not power, the converter will enter the island state. In order to overcome these problems, use a positive feedback anti-islanding control way. The anti-islanding program is based on two parts: positive feedback and the dq control structure in coordinate system.In addition, when grid voltage is low, the power system requirements of wind turbine with low voltage ride through ability. The fast and accurate detection of the power voltage drop is able to ensure the safe operation of wind power systems and it is an important precondition condition of LVRT (Low Voltage Ride Through) features. It can also meet need of three-phase power voltage drop to be detected.Finally, there is a note, in order to observe the amplitude and phase of voltage and current waveform relation and phase angle relation. Bifferent current orient is selected for simulation and test. When grid power is as a orient, phase angle between current and voltage is 180°when converter work as converter. Converter is as orient in order that it is easy observing phase angle difference between voltage and current. Angle is same between the voltage and current when converter is inverter in unity power factor.