Direct Torque Control of PV-Wind-Battery-Grid Connected 5L-NPC Inverter for Medium Voltage Based Induction Motor Drive

Medium voltage induction motor drives (IMDs) are used for many applications in industries. Ripples in the torque must be reduced for high power medium voltage IMDs to exhibits its higher performance under various operating conditions. To achieve this, a 5 -level neutral point clamped (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$5 ~\mathrm{L}$-</tex> NPC) three-phase inverter is utilized to operate the moor through operate the induction motor through direct torque control (DTC). In addition, a hybrid photovoltaic (PV) -wind power production system along with a battery bank is incorporated to ensure a continuous power supply during offgrid conditions. In normal condition, grid is providing supply to IMD through 24 pulse converter for providing smooth dclink voltage. A consistent voltage at dc-link (Vdc) is obtained by utilizing a dc/dc bidirectional converter that is arranged between the dc-link and battery bank. To achieve smooth operation of IMD, a stable and smooth Vdc must be supplied. However, both irradiance and wind speeds are unpredictable and rapidly varying. Hence, a novel control methodology is proposed on bidirectional dc to de device of the battery bank to supply constant and stable Vdc. This paper presents realistic responses by implementing hardware-in-the-loop (HIL) by OPAL-RT modules.