基于T型三电平整流器的改进模型预测功率控制

Improved Model Predictive Power Control Based on T-type Three-level Rectifier

为解决传统模型预测功率控制(MPPC)的谐波含量高、计算量大、权重因子设计困难等问题,提出了一种改进MPPC。首先使用一种低运算量的最优扇区判断方法,再通过代价函数最小化原则来确定其作用时间。为平衡中点电位(NP-V),将矢量序列分为P型序列和N型序列,它们对NP-V的影响相反,使用一个代价函数选择下一时刻选用的矢量序列类型,从而达到动态平衡NP-V的目的,同时消除了权重因子带来的影响。为提高输出电压的动态响应速度,使用改进滑模控制(SMC)来代替传统MPPC中的PI控制对直流侧电压进行控制。最后,仿真与实验验证了所提控制策略在电网侧电流、直流输出电压、输出功率及算法运算时间方面具有有效性。

In order to solve the problems of the conventional model predictive power control(MPPC),such as high har-monic,large computational complexity and difficulty in weighting factor design,an improved MPPC is proposed.First of all,an optimal sector judgment method with low computational burden is used to determine the optimal sector.Sec-ondly,the action time is calculated by the cost function minimization principle.To balance the neutral-point voltage(NP-V),the vector sequences are divided into P-type sequence and N-type sequence which have opposite effects on the NP-V,the type of the vector sequence is selected through a cost function at the next time instant,thus achieving the goal of dynamically balancing the NP-V and eliminating the influence of weighting factors.In order to improve the dynamic response of the output voltage,an improved sliding-mode control(SMC)is utilized to regulate the output voltage on DC side instead of the PI control in the conventional MPPC.Finally,the simulation and experiment verify the effectiveness of the proposed control method in terms of grid-side current,DC output voltage,output power and the operation time of the algorithm.