This paper presents a DC-link capacitor lifetime improvement method for three-level photovoltaic (PV) hybrid active neutral-point clamped (ANPC)
inverters in full modulation index range. The capacitors are one of the components with vulnerable reliability in a power conversion system. The DC-
link capacitor current ripples lead to temperature rise and wear-out failure of the capacitors. The accumulated thermo-mechanical damages from the
temperature rise reduce the capacitor lifetime and reliability of the system. The proposed modulation method suppresses effectively the DC-link
capacitor current ripple to improve the capacitor lifetime. In this paper, the proposed method is discussed via a comparison with conventional space-
vector pulse width modulation (SVM) in full modulation index range. The modulation index range is divided into two regions, namely medium-vector
modulation and hybrid modulation region. The capacitor lifetime is evaluated by the capacitor lifetime model according to the modulation methods
and modulation regions. The effectiveness of the proposed modulation method is verified through simulation and experimental results.