Control of a Hybrid Asymmetric Multi-Level Inverter for Competitive Medium-Voltage Industrial Drives

Hybrid asymmetric multi-level inverters promise significant improvements for medium-voltage industrial drives. Floating sub inverters without feeding can only supply reactive power. An on-line non-linear model-predictive controller stabilizes their intermediate-circuit voltages in steady-state and during transients, as demonstrated by simulations and measurements. A pre-charge method assures converter start-up without additional equipment.