Adaptive control of a buck converter with an ARM Cortex-M4

The capability of dealing with unpredictable variations of a process under manipulation is one of the most sought features when implementing digital control loops. Self tuning regulators are one type of control systems with such capability, existing several successful application of it in industry. However implementations of such systems are typically based on computationally intensive algorithms that, when applied to processes with fast dynamics, require high performance but complex and expensive embedded systems to cope with the required control-loop turnaround times. With the performance improvements brought by the new ARM Cortex M4, general purpose microcontrollers and advanced digital signal processing are no longer disjoint domains, becoming now possible to develop more versatile and robust control algorithms on affordable embedded systems with less restrictive computational limitations. Taking advantage of this architecture, this paper will present a real-time embedded adaptive controller applied to a Buck DC-DC converter. To assess the capabilities of this new architecture, comparative measurements of the algorithm´s CPU usage under different system configurations and results relative to the setpoint tracking capability of the adaptive controller under time-varying dynamics will be presented.