Single DC-Source Seven-Level Inverter with Extended Linear Modulation for Induction Motor Drives

The research introduces an innovative seven-level inverter design featuring 24 switches, all powered by a single DC source. The topology of this inverter offers benefits in terms of sensor-less capacitor balancing fault tolerance, and increased DC bus utilization with extended linear modulation range till full base speed. In this paper, the balancing of capacitor voltages relies solely on measuring their voltage, eliminating the need for additional current sensors. The capacitor balancing focuses on minimizing the dependencies on current sensors to determine the direction of capacitor currents. By using these measured values, logical variables and equations are created. These logical expressions remain effective across linear and extended linear modulation ranges, eliminating all lower-order harmonics.The modulation technique used is space vector pulse width modulation (SVPWM). The simulation results show how well a state-of-the-art seven-level inverter can operate an induction motor (IM) drive.