【摘要】 在可再生能源发电系统中,并网逆变器是实现电能馈送电网的重要环节。文中研究了二极管钳位型三电平逆变器及其并网运行控制策略。建立了并网逆变器在两相同步旋转坐标系下的数学模型;分析了并网模式下电压、电流的矢量关系;采用基于d-q坐标系的矢量控制策略及并网电流跟踪控制,实现了以单位功率因数馈送电能;分析了逆变器直流侧电容不均压的原因,提出了一种基于模糊控制的中点均压策略。仿真和实验结果验证了其有效性。更多还原

【Abstract】 Inverter plays an important role for energy conversion and transmission in grid connected renewable power generation systems. The diode-clamped three-level inverter and its control under grid connected operation mode are studied. The math model of inverter is built in the two-phase synchronously rotating reference frame,and the vector relationship between voltage and current of the model under grid connected operation mode are analyzed. The vector control in d-q rotating reference frame and tracing control of grid current is adopted to achieve unit power factor for power transmission. The voltage unbalance of capacitor-leg in DC link of the inverter is analyzed in detail and a novel neutral point voltage balancing strategy based on fuzzy control is proposed. Simulation and experimental results verify the validity of the analysis and design.更多还原