A generalized switched‐capacitor‐based modular T‐type inverter topology with reduced switch count

摘要

Summary Switched‐capacitor (SC)‐based multilevel inverters (MLIs) have gained great attention in renewable energy applications owing to their self‐balancing of capacitor voltage and ac voltage boosting. Using SCMLI, single‐stage dc–ac power conversion is made possible without needing a front‐end dc–dc boost converter that improves overall system efficiency, reliability, and power density. However, in most existing SCMLIs, the discharging duration of the rear‐end SCs is much longer than its charging duration, especially when a high number of SC units are adopted. While a high number of level generation is expected to produce a better resolution ac voltage, a significant increase in capacitor's voltage ripple, in contrast, distorts the ac voltage despite using large capacitors. Recently, the switched‐capacitor modular t‐type inverter (SC‐MTI) topology resolved the problem by extending the charging period of all SCs to at least half of the fundamental switching period. However, the high switch count of SC‐MTI introduces a trade‐off in terms of efficiency and cost. In this paper, a new SCMLI topology that retains the good traits of SC‐MTI with switch count reduction is proposed. The merits and feasibility of the proposed SCMLI are verified through simulation and further validated through experimental results for seven‐level considering various operating conditions.