Switched-Capacitor-Based Active-Neutral-Point-Clamped Seven-Level Inverter with Natural Balance and Boost Ability

Abstract

This paper proposes a new active-neutral-point clamped (ANPC) seven-level inverter based on switched-capacitor technique. The proposed seven-level inverter employs only nine switches and one floating capacitor. With the input amplitude of V_{\mathrm {DC}} , the peak output of the proposed topology can reach 1.5V_{\mathrm {DC}}. Its boost ability indicates a wider range of output compared with other APNC converters. Needless for auxiliary control methods, the voltages of capacitors in dc link can naturally maintain at 0.5V_{\mathrm {DC}} , and the floating capacitor can get self-balance at V_{\mathrm {DC}}. The mechanism of natural balance for capacitors and the operation principle of the proposed topology are described in detail. The merits of the proposed topology on reduced components, lower overall voltage stress, natural balance, and boost ability are also demonstrated through the comparison against the latest similar topologies, showing its suitability for distributed generation, electric vehicle, and other applications. Definitively, the simulation and experimental prototype are implemented to verify the feasibility and performance of the proposed topology. The voltage balance of capacitors has been fully demonstrated through multiple transient experiments.