Abstract：In order to study performance influence of active power filter by the DC side voltage fluctuation,a mathematical model which shows the relationship between the fluctuation of DC voltage and the capacitance and the active power of harmonics is established based on the instantaneous power balance theory,and analyzes the main influence factors of the fluctuation of DC voltage. In order to control DC side voltage,the transfer function is deduced so as to show the relationship of the DC voltage input with output quantities according to the active power balance theory. The PI controller of DC voltage control is designed according to the transfer function. The control simulation is carried out to verify the correction of the PI controller using DC side voltage control in the Matlab / Simulink. The results show that the control method of the active filter has a good harmonic compensation effect.

Keyword：active power filter(APF);instantaneous energy balance;DC side voltage control;PI controller;