Comparison Between Discretization Techniques on HIL Fractional-Order Controllers

Nowadays hardware in the loop (HIL) is a common tool in the development of high-performance power electronic converters (PEC). Accelerating design and flexibility into the model-based design process are some of their principal characteristics. Indeed, analysis, implementation, and evaluation of traditional and smart control techniques in HIL on PEC have been reported. However, little attention has been done in the HIL development of digital fractional order controller (FOC). Therefore, in this work are compared seven indirect discretization methods applied on a digital FOC, and as a testbed a Buck converter is considered. The Buck converter is practically emulated into a Typhoon HIL 402, and the digital controllers are implemented on a DSP Piccolo F280049C. A traditional frequency analysis was performed, and practical evaluation responses were acquired and compared. It was noticed that Bilinear approximation is not always the best approximation method in the development of FOC for PEC applications.