Coordinated control of regenerative three-level neutral point clamped PWM voltage source inverters

This paper studies the coordinated control strategy between the source and load controllers for regenerative back-to-back three level neutral-point-clamped PWM voltage source inverters. The focus is on the coordinated dc link voltage control through a feed-forward power flow control and the coordinated dc link neutral point control. The paper also covers various neutral point control methods including a new linear control scheme. The simulation and experiment results show that, compared with independent source and load control approach, the coordinated approach can significantly improve system response, reduce component stress, and help eliminating nuisance trips.