Active Modulation Strategy for Capacitor Voltage Balancing of Three-Level Neutral-Point-Clamped Converters in High-Speed Drives

In this article, the equivalent relationship between nearest-three-virtual space vector and carrier-based pulsewidth-modulation scheme is established based on coordinate for a three-level neutral-point-clamped (3L-NPC) converter. Moreover, to solve neutral-point voltage imbalance problem of studied 3L-NPC converter-fed high-speed drives, an active modulation strategy with generalized bias-offset injection technique proposed. Meanwhile, excessive computational burden significantly overcome by fast calculation approach. The effectiveness proposed algorithm validated through both simulation experimental results obtained from 45 kW, 32 kr/min aircraft electric starter/generator prototype system.