A Modified Second Order Sliding Mode Control Technique for the Operation and Control of a 3-Level Bidirectional NPC Converter

This paper presents a novel Modified Second Order Sliding Mode Control (MSOSMC) strategy for a bidirectional 3-Level Neutral Point Clamped (3-LNPC) converter. In the control circuit of the proposed system there are three closed loops; external voltage loop, inner current loop and capacitor voltage balancing loop. MSOSMC strategy is incorporated in all the three control loops with various error based adaptation laws. The controllers are designed to work under bidirectional power flow condition. Chattering effect is curbed by the proposed adaptive MSOSMC strategy without affecting the robust dynamics of the system response. The efficacy of the proposed control strategy is authenticated through MATLAB simulation.