Faculty Publications

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Author: search.filters.author.Manjarekar, N.S.Has files: No

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    Steady-state Initialization of Doubly Fed Induction Generator Based Wind Turbine Considering Grid Side Filter
    (IEEE Computer Society, 2021) Karthik, D.R.; Kotian, S.M.; Manjarekar, N.S.
    In this paper, a steady-state initialization method for a doubly fed induction generator (DFIG) based wind turbines including grid side (GS) filter equations is discussed. The approach employed considers factors like non-zero grid side converter (GSC) reactive power and GS filter losses. As per the recent grid code requirements, DFIG should be able to participate in reactive power support to maintain voltage stability during faults. Also GSC acts as STATCOM by its structure and supports in damping inter-area oscillations. Above conditions mandates to consider the non-unity power factor operation of GSC. The approach employed also considers GS filter losses, by which an accurate initial values can be obtained. Dynamic evaluation of the steady-state values obtained are performed using eigenvalues and time-domain simulations. The studies are performed on a single-machine-infinite-bus (SMIB) system and the results are compared with dynamic results with a case wherein GS currents are considered as dummy states. © 2021 IEEE.
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    An Accurate Method for Steady State Initialization of Doubly Fed Induction Generator
    (Institute of Electrical and Electronics Engineers Inc., 2022) Karthik, D.R.; Kotian, S.M.; Manjarekar, N.S.
    In this paper, an accurate method for calculation of steady-state values of a doubly fed induction generator (DFIG) is proposed. The assumption of active power (P) and reactive power (Q) or terminal voltage (Vt) as constant variables at DFIG bus may not yield accurate results as wind speed is variable in nature. So, an initialization strategy considering input wind speed (Vw) as known variable, is employed in the present work, which is an accurate way to start with initialization. The approach followed in this paper also considers grid side filter losses, and non-zero reactive power flow through grid side converter (GSC). The steady-state values obtained from the approach followed in this paper is dynamically tested on SMIB system by conducting modal studies and time domain simulations. © 2022 IEEE
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    Design and performance comparison of interconnection and damping assignment passivity-based control for vibration suppression in active suspension systems
    (SAGE Publications Inc., 2021) Sistla, P.; Figarado, S.; Chemmangat, K.; Manjarekar, N.S.; Kallu Valappil, G.
    This study presents the design of interconnection and damping assignment passivity-based control for active suspension systems. It is well known that interconnection and damping assignment passivity-based control’s design methodology is based on the physical properties of the system where the kinetic and potential energy profiles are shaped, and asymptotic stability is achieved by damping injection. Based on the choice of control variables, special cases of the control law are derived, and tuning of the control law with the physical meaning of the variables is demonstrated along with their simulation results. The proposed control law is experimentally validated on a scaled model of a quarter-car active suspension system with different road profiles, varying load conditions, and noise and delay in the sensor measurements and actuator respectively. The results are compared with that of an uncontrolled system with linear quadratic regulator and sliding mode control. © The Author(s) 2020.
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    Computation of steady-state operating conditions of a DFIG-based wind energy conversion system considering losses
    (Springer Science and Business Media Deutschland GmbH, 2023) Karthik, D.R.; Manjarekar, N.S.; Kotian, S.M.
    In this paper, steady-state operating conditions of a doubly fed induction generator (DFIG) are computed considering losses of grid-side (GS) filter. Two different cases are studied for steady-state initialization of the DFIG-based wind turbine systems (WTS). In the first case, active power (P) and reactive power (Q) at DFIG terminals are assumed to be known. In the other case wind speed (Vw), Q is assumed to be known. Apart from considering losses of the DFIG and GS filter, both the cases also consider the non-unity power factor operation of the grid side converter (GSC). For the first case, steady-state operating conditions are calculated by iterative method as well as by non-iterative method. For the second case, iterative method is used to calculate steady-state operating conditions. Calculation of steady-state values of other subsystems of DFIG-based WTS like drive train, controller and network is also shown. The initial values calculated are validated and compared by performing modal analysis and time-domain simulations. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.