有源电力滤波器两种补偿目标的分析和比较

在有源电力滤波器(APF)中，被广泛应用的有2种类型的补偿目标：一种是将非线性负载的馈线电流补偿为基波(正序)有功电流，另一种是将非线性负载补偿为一个等效线性电阻。采用不同的补偿目标，其APF补偿效果以及对电网的影响也不相同。该文从谐波传递的角度，分析比较了在2种补偿目标下的补偿特性对电网中谐波传递的影响。结果表明：无论在抑制电网谐波电压对负载的影响方面，还是在抑制谐波电流对电网的污染方面，采用后一种补偿目标的效果都要优于前一种补偿目标。仿真和实验验证了结论的正确性。上述结论对三相不平衡系统负序分量传递的影响也同样适合。

Comparison between two types of Compensation Objectives in Active Power Filters

Two main types of compensation objectives are widely used in active power filters(APF):the"classic"compensation objective which provides compensated line current being a fundamental frequency(and positive sequence) active current and the compensation objective which makes the nonlinear loads where the APF is connected become an equivalent linear resistance.The choice of APF compensation objective is considered to influence on the compensation effectiveness.In terms of harmonic propagation through power grids,this paper analyzes and compares the compensation effectiveness of APF and the different effects of the harmonic currents and voltages on power grids and loads with the two compensation objectives,and concludes that using the latter objective is more appropriate than the former for APF in diminishing the loads' voltage distortion caused by the power line harmonic voltage and the harmonic currents pollution to the power grids caused by the nonlinear loads.The conclusions are well supported by the simulation and experimental results. Similarly,this paper also concludes that using the latter objective is more effective than the former for APF in reducing the loads' negative sequence voltage caused by the asymmetrical power feed voltage and the negative sequence currents into the power grids caused by the unbalancing loads.