The invention relates to the technical field of low-
voltage direct-current power supply, and discloses a direct-current active filtering method and
system based on a three-level topological connection low-
voltage direct-current power supply
system. Firstly, a three-level topological
active filter is connected with the low-
voltage direct-current power supply
system in parallel, so that the voltage stress of a switching tube is reduced; reference voltages under different working conditions are dynamically generated through a preset working condition proportionality coefficient, the compensation
capacitor voltage can be more accurately adjusted, the compensation precision is improved, a
processing mode of firstly adopting a proportional
resonance controller and then adopting a proportional controller is adopted, so that the
active filter more effectively suppresses various
ripple components, and finally, the
active filter can be effectively controlled. The three-level topological active filter can drive the switching tube to be switched on and switched off according to different modulation results, the filter
inductor is flexibly controlled to generate the compensation current, finally, the compensation current injected into the low-voltage direct-current power supply system can be more effectively subjected to
ripple filtering, and the
ripple suppression capacity in the system is remarkably improved.