以三相Vienna整流器为研究对象,针对有限集模型预测控制FCS-MPC(finite control set model predictive control)实现中点电位平衡控制时权重因子选取困难,采样周期内作用单一矢量引起网侧电流纹波较大的问题,提出一种基于双矢量的无权重型模型预测控制UF-MPC(unweighted factor model predictive control)策略.首先,构建基于功率预测的单目标价值函数.然后,通过扇区划分同时采用无权重因子的方式来提高单次寻优效率,根据直流侧中点电位的波动优选冗余小矢量,实现无权重因子的中点电位平衡控制.在获取最优矢量的基础上,结合零矢量实现了双矢量固定开关频率控制.最后,基于RT-LAB半实物平台从稳态、暂态、中点电位波动方面进行验证,有效证明了所提控制策略的正确性和有效性.
Abstract
A three-phase Vienna rectifier is taken as the research object in this paper.In view of the difficulty in selecting the weight factor when the finite control set model predictive control realizes the neutral-point potential balance control,as well as the problem of large current ripple on grid-side caused by the action of one single vector during the sampling period,an unweighted factor model predictive control strategy based on double vectors is proposed.First,a single-objective cost function based on power prediction is constructed,and the efficiency of single optimization is im-proved by sector division and unweighted factor.According to the fluctuation of neutral-point potential on DC side,the redundant small vector is selected to realize the unweighted factor neutral-point potential balance control.Then,based on the obtained optimal vector,the double-vector fixed switching frequency control is realized by combining with the ze-ro vector.Finally,the proposed control strategy is verified on a hardware-in-the-loop platform based on RT-LAB from the as-pects of steady state,transient state and neutral-point potential fluctuation,and results effectively prove its correctness and ef-fectiveness.
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