【摘要】 针对中点嵌位型NPC(Neutral Point Clamp)三电平逆变器的中点电压波动会引起输出电压失真的问题,设计了一种观测器对中点电压波动进行观测,并根据观测结果设计了模糊PI控制器对其进行控制。首先建立了NPC三电平逆变器的数学模型,通过对直流侧电容电压的数学模型进行分析,将逆变器的中点电位不平衡问题近似为系统存在扰动下的误差估计;其次,根据模糊逻辑规则定义了新的误差变量,设计了模糊PI控制器,对中点电位波动问题进行控制;最后通过仿真和实验结果表明:设计的观测器可有效完成对中点电位的准确观测,利用模糊PI控制器实现了对中点电压波动的有效控制。更多还原

【Abstract】 Aiming at the output voltage distortion of NPC three-level inverter caused by neutral point voltage fluctuation,an observer for monitoring neutral point voltage is designed,and the Fuzzy PI controller is designed according to the observation results. Firstly,the NPC three-level inverter model is setup,and the neutral point voltage imbalance problem of the inverter is approximated as an error estimate under the disturbance of the system by analyzing the mathematical model of DC side capacitor voltage. Secondly,a new error variable is defined according to the fuzzy logic rules,and the fuzzy PI controller is designed to control the neutral point voltage fluctuation. The simulation and experiment results show that the designed observer can effectively observe the neutral point voltage,and the neutral point voltage fluctuation is effectively controlled using Fuzzy PI controller.更多还原