The ISOP SST is a promising candidate for MVAC to LVDC conversion. However, large DC link capacitors are required to smooth the second harmonic voltage ripple. The active power decoupling method can shift away the pulsating power, significantly reducing DC link capacitance and resulting voltage ripple. This paper investigates the feasibility of applying active power decoupling to SST. The active power filter with symmetrical half-bridge circuit is selected. Simulation results show that the active power filter can significantly reduce the second harmonic voltage ripple. A prototype of the active power filter has been built and tested.
