Online System Identification of DC-DC Converter for RFPA

This paper describes non-parametric system identification of a DC-DC converter based on spectral analysis correlation method. The used technique identifies the open-loop characteristics of a DC-DC converter online while the unit operates in closed-loop. A digital controller is used to perform both the closed-loop control of the converter and to periodically identify the converter by injecting a pseudo-random binary perturbation. Experimental results are provided for an example buck-boost converter to demonstrate accurate identification of the converter control-to-output frequency response. Experimental results have revealed stable operation of the converter during identification while meeting severe transient response requirements. This technique is advantageous for developing wide-input range/wide-output range converters which are vital for RF power amplifiers used in space and telecommunication applications. Keywords: System Identification, Adaptive Control, DC-DC converter, RFP