Super Twisting SMC Based 5L-NPC for Medium Voltage Grid Connected PV-Battery System

Medium voltage drives, particularly those for induction motors, are regularly using in various industrial tasks. The efficient management of induction motors is crucial in nuclear power plants. Induction motors are often controlled using direct torque control (DTC) to achieve smoother speed torque characteristics in comparison to other available control methods. Nevertheless, traditional DTC encounters numerous challenges due to the need to uphold a consistent reference flux across all speed ranges. Therefore, this paper presents the implementation of two innovative super twisting sliding mode (STSM) controllers in a novel DTC system. The induction motor is driven by a 5L-NPC: five level neutral point clamped inverter operating in three phases. The connection to the dc-link is made via a 36-pulse converter. Additionally, a photovoltaic (PV) system is added with a battery bank to ensure uninterrupted power supply in off-grid situations. A constant dc-link voltage is maintained through the use of a dc bidirectional circuit that links the dc-bus with the battery. The suggested regulation of the dc bidirectional converter has the potential to minimize the oscillations and ripples in the dc-link caused by the 36 pulse converter when the grid voltages are unbalanced. In order to identify best vector location, whale optimization methodology has been implemented. This paper presents practical responses by implementing hardware-in-the-loop (HIL) using OPAL-RT circuits. The results obtained from HIL are examined across multiple case studies.