Smooth Switching Method for Multi-Mode Synchronous Space Vector Modulation of NPC Three-Level Inverter

To meet the requirements of output harmonic distortion neutral point clamped (NPC) three-level inverter under low switching frequency conditions, multi-mode synchronous space vector modulation is usually adopted. When between different pulse patterns, there will be oscillation in current. This paper proposes a smooth method for modulation. compensates phase angle reference voltage vector, order to make flux trajectories continuous before and after switching. Multi-position can realized fundamental period, no delay Compared with direct switching, total rate current during reduced. The calculation compensation value not affected by specific parameters operating conditions motor, carried out offline. Finally, experiments are on 7.5 kW induction motor fed NPC three level verify feasibility effectiveness proposed method.