DC-link capacitor voltage balancing in five-level neutral point clamped Inverters using space vector modulation

摘要

DC capacitor voltage imbalance is an inherent problem limited the further development of multi-level Neutral Point Clamped (NPC). In this paper, a new hybrid control method based on Space Vector Pulse Width Modulation (SVPWM) for five-level NPC at high modulation index and high power factor is presented. By choosing appropriate switching pattern in lower modulation index sectors and collocating different space voltage vectors in higher modulation index sectors, the advantages of multi-level inverter will not be diminished and the problem of the DC-link capacitor voltage imbalance will be solved. Simulation and prototype test verifies the correctness and reliability of the control method.