Integration of Boost-Type Active Power Decoupling Topology With Single-Phase Switched Boost Inverter
Pramit Nandi, Ravindranath Adda
Abstract
In this article, ripple energy of a single-phase switched boost inverter (SBI) is analyzed, and the amount of low-frequency ripple present in the switch-impedance network parameters is estimated. It is found that larger passive components are required to maintain smaller ripples resulting in poor power density. Therefore, integration of the single-phase SBI with an independent boost-type active power decoupling (APD) topology is proposed to deflect the low-frequency ripple to an auxiliary capacitor. Thus, the low-frequency ripple on inductor current and capacitor voltage of the switch-impedance network is significantly reduced, and much smaller passive elements are required only to filter high-frequency ripple. A passive element selection procedure for the switch-impedance network and the APD topology is presented to reduce ripple power. To properly mitigate the low-frequency ripple for varying ac loads of the SBI and also to avoid overcharging of the auxiliary capacitor, a closed-loop control strategy is developed for the APD topology. The proportional-resonant (PR) current controller is chosen due to its low steady-state error while tracking ac signals. The parameters of the PR controller are designed based on the small-signal analysis of the APD topology. A hardware prototype of the proposed system is fabricated, and its performance is demonstrated.