Efficient Modeling of Adjustable Speed Drive Systems for Offline and Real-Time EMT Simulators

Abstract

Adjustable speed drives (ASDs) comprised of inverter-driven induction machines are now widely used in many applications. Design and analysis of such systems require accurate and efficient models of induction machines (IM) and voltage source inverters (VSI). Such studies are often done in real-time or offline multiple times for tuning/optimizing controller parameters. Usually, simulations of such systems are carried out using detailed switching models of VSI and qd IM models, which are readily available as built-in library components in many electromagnetic transient (EMT) simulation programs. However, detailed switching models of converters with qd IM models typically require interfacing snubbers and small time steps, making them computationally expensive. As an alternative, this paper extends the prior work and presents an efficient simulation method using the average-value model of VSI and decoupled constant-parameter voltage-behind-reactance (DCPVBR) model of IM. Simulation studies carried out using MATLAB-Simulink and real-time OPALRT5700 simulator demonstrate the computational advantages of the proposed method over existing approaches.