一种基于模型预测控制的T型三电平逆变器中点电位平衡控制方法  

A Neutral-Point Voltage Balancing Control Method Based on Model Predictive Control for T-Type Three-Level Inverter

作　　者：王美龄[1] 王丽梅[1] 孙永亮[1] 

机构地区：[1]沈阳工业大学电气工程学院,沈阳110870

出　　处：《电气工程学报》2015年第9期66-72,共7页Journal of Electrical Engineering

基　　金：辽宁省高等学校创新团队项目(201334068);辽宁省高等学校优秀人才支持计划资助项目(LR2013006)

摘　　要：中点电位的平衡控制是T型三电平光伏并网逆变器系统首要解决的问题。本文建立了T型三电平逆变器的主电路数学模型及负载模型,并分析了中点电位不平衡的主要原因,在传统预测电流控制方法的基础上,研究了一种基于模型预测控制的中点电位平衡控制方法:首先对负载电流进行采样,用采样值计算出预测值,同时检测直流母线中点电流,得到中点电位的偏差值;然后优化由预测电流与参考电流之间的平方误差及中点电位的偏差值构成的性能指标函数,选择使性能指标函数最小的开关状态,在下一个采样周期作用于逆变器,从而实现中点电位的平衡控制。最后采用Matlab/Simulink进行仿真验证,仿真结果表明,该方法具有快速的动态响应,实现了中点电位的平衡控制,且输出了高质量的电压波形。The neutral-point voltage balancing control of the T-type three-level inverter system is the primary problem. The main circuit mathematical model and the load model of the T-type three-level inverter are set up, and the main reasons of neutral-point voltage unbalancing are analyzed, then based on the traditional predictive current control method, a neutral-point voltage balancing control method based on model predictive control（MPC） is proposed. Firstly, the load current is sampled used to calculate predictive value, meanwhile the DC bus neutral-point current is sampled to get the neutral-point voltage deviation; then minimize the quality function composed of the squared error between the predictive and reference current values and the neutral-point voltage deviation by choosing the appropriate state＇s switching signals and then applied to the inverter, the neutral-point voltage balancing control is achieved. Finally the results obtained through the Matlab/Simulink simulation verify that the proposed method ensures fast dynamic response and keeps the neutral-point voltage balancing, and the quality of its output voltage is high.

关 键 词：中点电位平衡 T型三电平 模型预测控制 光伏并网 

分 类 号：TM464[电气工程—电器]