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This paper proposes a modified distribution static compensator (DSTATCOM) with the voltage controller. The modified DSTATCOM is incorporated in a three-phase four-wire distribution network. The design criteria of the modified DSTATCOM parameters is introduced. The Hysteresis Voltage Controller (HVC) is used to drive the Voltage Source Converter (VSC) and its reference voltage signal is generated based on the Instantaneous Symmetrical Components Theory (ISCT) to provide the proper compensation to stabilise the system voltage, improve the power factor and mitigate the harmonic distortion. Matlab/Simulink software is used to verify the performance of the modified DSTATCOM with the used controller under different load types and supply voltage conditions. The control algorithm ensures that the bus voltage is maintained at its rated value during different connected loads and supply conditions. Also, it compensates the non-linear and unbalanced supply currents and reducing the Total Harmonic Distortion (THD) of both current and voltage. The proposed modified DSTATCOM gives better results in comparison with the conventional DSTATCOM. [ABSTRACT FROM AUTHOR]

Secondary voltage control of islanded microgrid is one of the main needs of microgrid hierarchical control from one perspective and the realization of stable smart grids from another aspect. This article aims to achieve several goals simultaneously: First, it provides a decentralized structure for controlling and regulating the voltage of DGs, in which the effects of nonlinear terms on the dynamics of the microgrid system are considered without elimination or linearization. The fuzzy method has been used to approximate the uncertainties, the interactions of agents and nonlinear terms, and the adaptive method has been used to obtain the optimal fuzzy approximation gains. Sliding mode rules are also used to obtain a control signal and using Lyapunov's theory, the finite time and robust stability of the closed-loop control system is guaranteed. The finite time approach ensures the achievement of convergence in a finite and definite time, and the robust approach realizes the dynamic stability of the system against uncertainties and disturbances. The results of the microgrid system simulation show well the proposed controller capability in different operating conditions. [ABSTRACT FROM AUTHOR]