An Energy-Efficient Motor Drive With Autonomous Power Regenerative Control System Based on Cascaded Multilevel Inverters and Segmented Energy Storage

This paper presents a cascaded-multilevel-inverter-based motor drive system with integrated segmented energy storage. A power-distribution strategy among the energy source, the segmented energy storage, and the electric motor is proposed under different operation modes. A design guideline for energy storage is provided to meet the proposed power-distribution strategy. Moreover, the energy storage features not only implementing the harmonic compensation in all operating modes but also providing peak power during acceleration and absorbing regenerative power during deceleration, which improves the energy efficiency of the motor drive system and reduces the size of the energy source. An autonomous power regenerative control system including voltage balancing control of segmented energy storage is developed to perform the smooth power transition between different operation modes and provide accurate speed tracking. A 5.5-kW permanent-magnet synchronous motor (PMSM) drive system has been built in the laboratory. Simulation and experimental results are provided to demonstrate the effectiveness of the proposed motor drive system.