单相H桥级联型APF模型预测控制方法研究

Model Predictive Control of Single-Phase Cascaded H-Bridge Active Power Filter

针对单相H桥级联型有源电力滤波器(active power filter,APF),提出一种基于模型预测控制的单目标预测控制法。通过建立电流跟踪误差的指标函数,将输出电平作为控制变量,选取使指标函数值最小的输出电平,实现对参考电流的跟踪。结合改进的电压排序法,采用子模块电容电压的改进平衡控制策略,实现子模块电容电压平衡,并降低了器件的平均开关频率。对输出电流模型预测控制的稳态误差进行理论分析,探索了系统参数与系统补偿性能的关系。与传统控制方法相比,该方法无需考虑复杂的参数整定与权重系数设计,且具有计算量少与易于数字化实现等优点。搭建了H桥级联型APF仿真平台,仿真结果表明,APF系统可快速补偿中压大容量系统中的谐波电流,具有优越的动、静态性能。

A single-objective predictive control method based on model predictive control is proposed for single-phase H-bridge cascaded active power filter（APF）. Taking output level as control variable and tracking current difference as cost function, it searches optimal voltage level resulting in minimum cost function value, tracking reference current. Combined with improved voltage sorting method, submodular capacitor voltage balancing control strategy is adopted to realize capacitor voltage balance and average switching frequency is reduced. Theoretical analysis is carried out for steady-state error of output current based on model predictive control, searching relationship between system parameters and compensation performance. Compared with traditional control method, this method does not need to consider complicated parameter setting and weighting factor design, with advantages of less computation amount and easy digital realization. An H-bridge cascaded APF simulation platform is constructed. Simulation results show that the APF system can compensate harmonic current in medium voltage large capacity system effectively, and has excellent static and dynamic performance.