arXiv subjects

Vinu Thomas

Publications and source records attributed to Vinu Thomas.

3 recordsLinked to original sources

arXiv2026

Model-Free Control for Multi-Time Scale Dynamics of Grid-Connected Power Converters

Controller synthesis in power electronics-based systems depends predominantly on the mathematical model of the system, which is a limitation when the actual system is complex and the mathematical model cannot capture all its dynamics. Model-free control addresses this limitation by using an ad-hoc simple model which is compensated by high-rate evaluation of dynamics in terms of their derivatives. However, application of the model-free control strategy to power electronics-based multi-time scale dynamical systems is challenging because of the derivative action needed to implement such control. Grid-connected power converters are examples of such systems, yet experimental validation has not been adequately addressed in the literature. This letter presents the validation of such control including the hardware implementation level. An intelligent proportional-integral (iPI) controller is synthesized and validated on a 16 kW experimental test bench. This proves the benefits of the approach in control of grid-connected power converters, among which their participation in the secondary voltage control.

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arXiv2026

Critical Clearing Time Enhancement of Droop-Controlled Grid-Forming Inverters with Adaptive Function-Based Parameters

With the increasing penetration of renewable energy sources, grid-forming (GFM) inverters are becoming essential for voltage and frequency regulation. However, the transient stability of GFM inverter is critically affected by the current limiters that are embedded with the standard control schemes. This paper proposes a novel adaptive function to enhance the transient stability of droop-controlled GFM inverters. The proposed method autonomously adjusts the active power reference and the droop gain based on the terminal voltage of the inverter. Also, the acceleration of the phase angle is prevented, leading to the maximization of critical clearing time (CCT). The proposed method is benchmarked against two state-of-the-art GFM inverter CCT enhancement methods. Effectiveness of the proposed method is validated through electromagnetic transient (EMT) simulations in MATLAB/Simulink\textsuperscript{\textregistered}.

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arXiv2022

A Decentralised Control Strategy for Secondary Voltage Regulation

This paper proposes a decentralised secondary voltage control strategy that has several benefits over the existing centralised strategies. For that, a new structure for the control is proposed in terms of an inner and outer loops for each generator. The individual generators of a particular zone participate in the secondary voltage control by aligning their reactive powers with respect to the pilot point voltage reference. The decentralised nature of the proposed control strategy enables plug and play operation: run with different numbers of generators without any need of regulators reconfiguration, resilience in case of generator failure. This allows one to use such control to integrate renewable generators to existing secondary regulations alongside with the classic generators. The proposed control strategy is implemented using a model-free control scheme that does not require a higher order complex model of the power grid. The deployment of a discrete-time intelligent proportional controller simplifies the tuning of the controller gains. The proposed strategy is validated on a four generator power system model in MATLAB/ Simulink/Simelectrical environment. Simulation results are presented to show the effectiveness of the proposed strategy along with different case studies such as load perturbation, transmission line perturbation, generator disconnection and delay in pilot point voltage measurement to highlight its robustness.

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