一种新型的基于变压器谐波磁势平衡的有源电力滤波方法

A novel active power filtering method based on harmonic magnetic potential balance of transformer

为降低有源电力滤波器(APF)开关器件耐压水平,充分发挥低压大电流开关器件和装置容量潜能,节省APF与网侧线路相连接的升压变压器成本,并有效降低直流稳压电容的额定电压,提出一种新型的基于变压器谐波磁势平衡的有源电力滤波方法。该方法将有源电力滤波装置接于变压器二次侧绕组抽头中间,使该装置产生的谐波电流磁势在变压器二次侧与负载谐波电流磁势相互抵消,从而使得网侧电流谐波含量显著降低。详细分析了运用该谐波磁势平衡在变压器二次侧绕组进行滤波的数学原理,并对配电网侧常用的10 k V/380 V Y/△及△/Y变压器进行了负载谐波电流滤波仿真,并通过实验验证了该滤波方法的可行性。

To reduce the voltage withstand capability of APF( Active Power Filter) switch,exploit the capacity potential of both low-voltage large-current switches and devices,save the cost of boosting transformer which connected with APF and grid-side lines,and reduce the nominal voltage of DC stabilized voltage capacitor effectively,a novel active power filtering approach based on the harmonic magnetic potential balance of transformer is proposed. The active power filtering device is connected to the middle of the secondary side winding tap of transformer in this approach,the harmonic current magnetic potential produced by the device and load cancels out each other at the secondary side of transformer consequently,hence the grid-side harmonic current is significantly decreased. The detailed filtering mathematical principle associated with the harmonic magnetic potential balance in the secondary side winding of transformer is analyzed. Filtering simulation on widely used 10 k V/380 V Y/△ and △/Y transformers at the distribution network side is performed. Finally,the effectiveness of the proposed filtering approach is verified by experiments.