Robust control of switch-mode rectifier considering nonlinear behaviour

This work presents the disturbance observer-based robust current and voltage controls for a digital signal processor (DSP)-based boost-type switch-mode rectifier (SMR) considering nonlinear behaviour. First, a robust current control scheme is developed to let the SMR inductor current waveform closely track its command around zero-crossing points, and hence the SMR possesses improved line drawn power quality. Then a robust voltage two-degrees-of-freedom control (2DOFC) scheme and its systematic design approach are proposed. In determining the power circuit components and the key parameters of the proposed robust control schemes, the compromise between the desired performance and the nonlinear behaviours is considered. Specifically, the adaptation of voltage robust compensation control is made according to the observed nonlinear phenomena. Experimental results confirm that robust and good voltage tracking and regulation responses are obtained by the developed SMR. Furthermore, the developed SMR is successfully applied to serve as a front-end converter of a switched reluctance motor drive, and its effectiveness in vibration reduction and power quality improvement is demonstrated experimentally.