A Charge Injection Loss Compensation Method for a Series-Stacked Buffer to Reduce Current and Voltage Ripple in Single-Phase Systems

Single-phase rectifier and inverter applications require an additional reactive circuit branch tied to the dc-link in order to remove the twice line frequency power pulsation that couples to the dc bus. The series-stacked buffer (SSB) has been identified as an active buffer topology that buffers this reactive power with a high energy utilization factor. However, the SSB requires an additional loss compensation control that injects real power into the SSB branch. Consequently, residual ac current and voltage ripple remain coupled to the dc-link. This paper proposes a novel loss compensation method featuring augmented hardware and control that introduces charge injection which eliminates this twice line frequency ripple from the dc-link. A 1.5 kW hardware prototype was built and tested to verify the effectiveness of the newly proposed charge injection method.