A Second-Order Sliding Mode Voltage Oriented Control of Three-Phase Active Front End Rectifier

This paper presents a cascaded proportional-integral and second-order sliding mode Voltage Oriented Control (VOC) for a three-phase Active Front End (AFE) rectifier in presence of operational constraints. The inner-loop is based on Sliding Mode Control (SMC) which controls the direct and quadrature components of line current in order to maintain the input power factor at unity. A proportional-integral (PI) control is employed to regulate the de-link voltage at its reference value. The SMC exhibits an excellent dynamic performance over the complete operating range due to its nonlinear nature and robustness to parametric variations. Moreover, it provides a chattering free control action with finite-time convergence. The performance of the developed controller is verified using simulations in MATLAB/Simulink on a 30kW three-phase AFE for a switching frequency of 5kHz. The results show an excellent dynamic performance both in terms of transient response and steady-state performance.