The three-level neutral-point-clamped (3L-NPC) converters have been widely applied in several applications including motor drives and grid integration such as wind and solar energy systems. Key performance metrics of the 3L-NPC converters like power quality, efficiency, power density and reliability are strongly affected by the used control methods. Therefore, different control methods have been proposed for the 3L-NPC topology to address certain aspects.
This seminar aims to address basic concepts and control design challenges of NPC converter applications. It will start with basic operating principles of the topology and their control challenges such as neutral point voltage balancing and thermal stress distribution. Then, two different control approaches will be presented: 1) carrier-based PWM techniques and 2) model predictive control techniques. For each control technique, basic concept and step-by-step implementation guideline will be provided, followed by more application-oriented examples and implementation challenges.
An approach to analyze the reliability of power electronics converters will also be introduced, which includes thermal stress modeling, lifetime prediction, and reliability evaluation (Monte Carlo simulation). It will be demonstrated that control algorithm selection has a major impact on the reliability of semiconductor devices and DC-link capacitors in NPC converters.
