Integral Sliding Mode Controlled 3L-ANPC Based Bidirectional AFE Converter for DC Microgrids

Abstract

In this paper, an integral sliding mode controller is proposed for a bidirectional 3-level ANPC-based Active Front End (AFE) converter. An integral error term is added to the control law to reduce the steady state error and chattering. Thus, the reference tracking performance of the controller is improved. The high-frequency space vector PWM technique is used for the bidirectional 3-level AFE. Considering the output waveforms with low THD of the 3-level ANPC, only L filters are used at the converter output. The whole system is simulated in MATLAB/Simulink environment. The obtained simulation results show that the proposed system provides high transient response and zero steady state error. Besides, the grid current harmonics are low in both directions of operation.