Enhancement of power quality using double-band hysteresis controller for the grid integrated renewable energy system

Development of control technologies facilitates the integration of renewable energy sources to the grid through power electronic converters. In this study, the inverter acts as shunt active power filter along with the power conversion operation. Various sliding mode control (SMC) techniques namely relay and signum method, hysteresis method and equivalent control method are implemented to control the real, and reactive power flow between Renewable Energy System (RES), load and grid using an inverter. To reduce the complexity, the control law (u eq) for equivalent control method is derived using a simple single-phase equivalent circuit of a three-phase voltage source inverter. In this study, the robustness is enhanced by choosing the integral sliding surface. These controllers are used to reduce the total harmonic distortion (THD) and to ensure unity power factor (PF) in the grid during balanced and unbalanced grid voltage conditions even in the existence of nonlinear loads. The SMC using equivalent control function outperforms the other methods in terms of chattering, THD and PF. To illustrate the effectiveness, three different modes are considered: (i) no RES power, (ii) insufficient RES power and (iii) excess RES power. The performance of controllers is validated by the simulation and experimental results.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-rpg.2019.1305

Sliding mode controller-based voltage source inverter for power quality improvement in microgrid

Practical systems such as hybrid power systems are currently implemented around the world. In order to get the system to work properly, the systems usually require their behavior to be maintained or state values to stay within a certain threshold. However, it is difficult to form a perfect mathematical model for describing behavior of the practical systems since there may be some information (uncertainties) that is not observed. Thus, in this article, we studied the stability of an uncertain linear system with a non-differentiable time-varying delay. We constructed Lyapunov-Krasovskii functionals (LKFs) containing several symmetric positive definite matrices to obtain robust finite-time stability (RFTS) and stabilization (RFTU) of the uncertain linear system. With the controller and uncertainties in the considered system, there exist nonlinear terms occurring in the formulation process. Past research handled these nonlinear terms as new variables but this led to some difficulty from a computation point of view. Instead, we applied a novel approach via Cauchy-like matrix inequalities to handle these difficulties. In the end, we present three numerical simulations to show the effectiveness of our proposed theory.

https://www.mdpi.com/2073-8994/12/4/680/pdf

Robust Finite-Time Control of Linear System with Non-Differentiable Time-Varying Delay

Control of power in the grid integrated solar photovoltaic system using linear quadratic regulator

A Comparison of Instantaneous and Extension p-q Methods for Current Controlled Voltage Source Inverter in Microgrid

This paper presents an optimal control strategy using linear quadratic regulator (LQR) applied in current-controlled voltage source inverter (CCVSI) to control the real and reactive power flow betw...

Power Quality Enhancement Using Linear Quadratic Regulator Based Current-controlled Voltage Source Inverter for the Grid Integrated Renewable Energy System

Immanuel Selwynraj Arunodayaraj

Papers

Power Quality Enhancement Using Linear Quadratic Regulator Based Current-controlled Voltage Source Inverter for the Grid Integrated Renewable Energy System