Digital Control in Power Electronics

Abstract: The tutorial addresses several latest issues related to the modeling, design, implementation of digital control in Power Electronics, with a specific focus on high-frequency switching converters. The tutorial first... [ view full abstract ]

Abstract: The tutorial addresses several latest issues related to the modeling, design, implementation of digital control in Power Electronics, with a specific focus on high-frequency switching converters. The tutorial first describes some basics related to the modeling and implementation of digitally controlled power converters. The analysis of the delay introduced by the sampling process and the uniformly sampled PWM is discussed. The effect of oversampling on the reduction of the control delay and on the achievable dynamic response is also investigated. Then a number of digital control design criteria are presented, starting from the standard equivalent analog representation and then moving to the discrete time analysis with some illustrative design compensation examples. The tutorial then moves to non-linear action (such as the time-optimal approach) to highlight the benefits of the digital approach. To complete the overview of some high-performance digital control, the digital hysteresis modulation, the time-event control and the oversampled control are presented. Finally a set of auto-tuning techniques are addressed. The final part of the tutorial addresses some examples of grid-connected power converters, to illustrate how some of the proposed analysis can be applied also to power converters connected to the utility grid.