A series-stacked ac-to-dc converter integrated into a multi-port permanent-magnet-synchronous generator has been shown to be beneficial in achieving high conversion efficiency while reducing the size and rating requirements for the active rectifier . The major drawback of this architecture is the bulky filter capacitors used at the passive rectifiers. These filters increase system size, weight and cost, reduce the overall reliability and cause a low power factor at the passive rectifier ac-port. This paper presents an alternative approach: using the active rectifier to compensate the capacitor-less passive rectifier voltage ripple. Simulation on a 6.25 kV, 3 MW dc bus system shows that by active compensation, the dc-bus voltage ripple is reduced to 2.4% of the dc-bus voltage. In addition, the passive rectifier ac-source power factor is improved to 0.95 compared to 0.8 using the conventional method with filter capacitors. Experimental results show the effectiveness of the proposed method for voltage ripple compensation.