三相T型逆变器有限控制集模型预测控制策略

Finite control set model prediction control strategy for three-phase T-type inverter

LCL滤波器的三相三电平并网逆变器预测控制研究较少,预测模型搭建复杂,计算量大。基于逆变器侧滤波电感三相电流搭建预测模型,可将逆变器数学模型由三阶降为一阶,并用逆变器状态函数计算得到的电流值替换电网侧电感电流传感器测试值,减少系统采样设备。在此模型基础上,首先利用有限控制集模型预测控制算法,其次对参考电压矢量空间角度做判断,使接近开关状态阈值的参考电压矢量优先参与计算,从而减少参与计算矢量(由27个减少到12个)。经Simulink仿真,结果表明此算法提高了控制系统动态响应与稳态性能。

The research on the prediction control of three-phase three-level grid connected inverter based on LCL filter is less,the construction of prediction model is complex and the calculation is large.Based on the three-phase current prediction model of the filter inductor on the inverter side,the mathematical model of the inverter could be reduced from third order to first order,and the measured value of the inductor current sensor on the grid side could be replaced by the current value calculated by the inverter state function to reduce the system sampling equipments.On the basis of this model,firstly,the finite control set model prediction control algorithm was used.Secondly,the reference voltage vector space angle was judged to make the reference voltage vector close to the switch state threshold participate in the calculation preferentially,so as to reduce the number of the calculation vectors(from 27 to 12).The simulation results show that the algorithm improves the dynamics response and steadystate performance of the control system.