  The active power filter (APF) is attracting more and more attention for its
outstanding performance in current and voltage ripple compensation. As modern
high-energy accelerators are demanding much more stringent current ripple
guideline, the APF is introduced to the magnet power supply (MPS) in
accelerator system. However, the conventional APF has a lot of shortages and
drawbacks due to its traditional topology, such as complex structure,
nonadjustable working voltage, requirement of power supply, and so on. This
paper proposes a new topology of APF, which is working as two types of chopper
circuits. This APF need not extra electricity, but to use the power of the MPS
current ripple to realize ripple depressing. At the end of this paper, the
experiment result proves its feasibility and effect.
