单相PWM整流器两矢量有限集模型预测电流控制

Two-vector-based Finite-control-set Model Predictive Current Control of Single-phase PWM Converter

为解决传统有限集模型预测电流控制FCS-MPCC(finite-control-set model predictive current control)方法下开关频率不固定和网侧电流谐波大等问题,以单相PWM整流器为研究对象,研究了一种两矢量有限集模型预测电流控制TV-FCS-MPCC(two-vector-based finite-control-set model predictive current control)方法。该方法根据整流器的3种电压矢量进行扇区划分,并在每个开关周期内同时作用一个扇区内的2个边界矢量;结合电流误差评价函数,求解出各扇区边界电压矢量的最优作用时间;最后采用电流误差评价函数值最小的扇区边界矢量,并通过调制模块产生相应开关信号。为验证所提方法的正确性和有效性,在小功率实验平台上对该TV-FCS-MPCC与传统FCS-MPCC方法进行了实验对比研究,研究结果表明:TV-FCS-MPCC方法可以有效实现单相PWM整流器的控制目标,与传统FCS-MPCC方法相比,所提方法可以实现开关频率的固定,并降低网侧电流THD。

A two-vector-based finite-control-set model predictive current control(TV-FCS-MPCC)method is studied to deal with the drawbacks of inconstant switching frequency and large harmonic in grid current when the traditional finite-control-set model predictive current control(FCS-MPCC)method is applied to single-phase pulse width modulation(PWM)rectifiers.In this method,several sectors are divided according to the three kinds of voltage vector of the rectifier,and two boundary vectors within one sector are taken during each switching period.Then,the current error evaluation function is combined to calculate the optimal boundary voltage vector duration for each sector.Finally,the boundary voltage vectors which can minimize the current error evaluation function are adopted,and the corresponding switching signals are generated via a modulator.To verify the correctness and effectiveness of the proposed method,TV-FCS-MPCC and the traditional FCS-MPCC method were experimentally compared on a scale-down experimental platform,and results show that TV-FCS-MPCC can realize the control objectives of single-phase PWM rectifiers effectively.Compared with the traditional FCS-MPCC method,it can fix the switching frequency and lower the THD of grid current.