Switched Capacitor Cascaded Multilevel Inverter with Extended Sinusoidal Modulation Range for Drives

Abstract:
The paper presents a cascaded multilevel inverter topology with a switched capacitor designed for an open-ended induction motor load. The multilevel space vector structure extends the linear modulation range with sinusoidal PWM, making it suitable for Electric Vehicles (EV) and other medium voltage drives during flux weakening region operations. Switching state redundancies ensure that both inverters supply real power across the entire modulation range, preventing capacitor voltage imbalance. In this topology, the maximum phase peak fundamental reaches 0.637 times the DC-link voltage within the extended linear modulation range. The proposed topology has been thoroughly analyzed and its performance has been validated using detailed simulation results, demonstrating its effectiveness.