Electrocardiographically Signal Simulator Based on a Sliding Mode Controlled Buck DC-DC Power Converter

The aim of this study is to design a controlled continuous signal generator of electrocardiographic (ECG) signals using a buck direct-current power converter. The application of sliding mode control on a buck type DC-DC power converter yields the production of continuous variations of the output DC voltage to reproduce the required simulated ECG. The application of the equivalent control strategy generates the design of a cascade sliding mode controller regulating both current and voltage loops to enforce the tracking of the reference ECG voltage. For the proposed controller, the current control is first exerted, and then the corresponding output voltage is fixed by regulating the switching sequence at the electrical device. The proposed controller was able to operate robustly concerning perturbations in both the input and voltage dynamics. The estimation of the requested gain for the sliding mode controller is solved considering the amplitude of the reference ECG signal and its time derivative with respect to time. A reference signal was proposed to evaluate the suggested controllers in either numerical simulation or experimental validation. In both cases, the proposed reference signals were successfully reproduced.