单相级联H桥虚拟磁链模型预测功率控制

Virtual Flux Model Prediction Power Control Algorithm for Single-phase Cascaded H-bridge

由于借助交流电压传感器测量电网电压会带来硬件成本高、安装困难及可靠性低等问题,所以为实现无网压传感器,将虚拟磁链引入级联H桥整流器模型预测功率控制中。以单相七电平整流器为例,虚拟磁链空间矢量需通过电压矢量积分获得,这个积分环节通常用一阶低通滤波器,可消除纯积分环节带来的积分初值问题和直流偏置问题,但会存在由一阶低通滤波器带来的相位偏移问题,因此提出一种相位补偿方法并应用于一阶低通滤波器对电网虚拟磁链进行估计;针对H桥整流器模块间电压不均衡问题,采用基于电压反馈的直流电压平衡控制方法,调节占空比实现电压均衡。实验结果证明了所提出的虚拟磁链模型预测功率控制的正确性和有效性。

The AC voltage sensors are used to measure the grid voltage,which brings high hardware cost,difficult installation and low reliability.In order to realize that grid voltage sensors are not necessary,virtual flux was introducted to model prediction power control algorithm for cascaded H-bridge rectifier.The virtual flux space vector was obtained by integrating the voltage vector taking a single-phase seven-level rectifier as an example.The first-order low-pass filter was usually used in the integration to solve initial value problem and DC offset problem.Aiming at solving phase shift,the phase compensation method was proposed and applied to the first-order low-pass filter estimating the virtual flux of grid voltage.For balanced DC voltage between modules of H-bridge rectifier,the DC voltage balanced control method based on voltage feedback by adjusting duty ratio was used.The experimental results show that the proposed algorithm is correct and effective.