abstract: in this paper a control scheme for grid-connected operation mode and the island state of distributed generation is presented. in normal conditions, every inverter dg system in micro-grids to supply a preset power, normally operate in a constant current control mode. when micro-grids removed from the network, dg inverter of each system must recognize the island and change position to v...

in this paper, we investigated the necessity and effects of optimal control methods in the stability and performance of a micro-grid that operates in islanded mode. the micro-gird is consisted of a combine heat and power (chp), a capacitor bank (cb), photovoltaic panel (pv) as power generation sources. in addition, battery and the building electricity and thermal load are placed on the load sid...

when power systems are expanded and connected together with weak tie lines, the low-frequency oscillations are increased and the stability margin of the power system decreases. therefore, when designing the transmission system to be used, it is necessary to maintain the dynamic stability of the power system, and to make sure to have the most possible stability margin. sssc is a facts device con...

In this paper, an adaptive control strategy is proposed for the inverters of renewable energy source (RES) to simultaneously control the load voltage, grid current and the amount of instantaneous injected power to the grid in the presence of grid voltage distortions and nonlinearity of load current. In the proposed control strategy, the power quality of the local load can be settled based on th...

In this paper, a new embedded Z-H (EZ-H) buck-boost converter is proposed. In this topology, two identical dc voltage sources are embedded in a LC network in a series connection with the inductors. The proposed converter eliminates the shoot-through (ST) switching state and there is no need for a front-end diode. Other advantages of the proposed topology are having capability of buck and boost ...

In this paper, a series Z-source inverter based on switched inductors cell is proposed for the first time. This inverter is able to increase the voltage gain in comparison to the conventional Z–source inverters in additon to solve the ST (shoot-through) state’s problems. In this inverter, the value of voltage gain is increased by increasing the number of used diodes and inductors in the switche...

Voltage sag/swell is one of the most frequently power quality problems which affects the power systems with sensitive loads. The unified power quality conditioner (UPQC) is capable of mitigating the effect of voltage sag/swell at the load or point of common coupling (PCC). In this paper, a new control of UPQC is proposed based on combining the sag detection and voltage injection established on ...

The Dynamic Voltage Restorer (DVR) is a commercially available, popular device to eliminate voltage sags and swells in the distribution lines. Its basic function is to inject the voltage difference (difference between the pre-sag and sag voltage) to the power line and maintains the pre-sag voltage condition in the load side. The efficiency of the DVR depends on the performance of the efficiency...

Voltage control is one of the imperative issues in the smart distribution control system. While traditional distribution network is equipped with communication and monitoring equipment, the online voltage control can be perfectly achieved. With using these smart grid technologies, the distribution voltage control schemes should carry out intelligently and cover the undesirable effect of high pe...

A high accurate and low-voltage analog CMOS current divider which operates with a single power supply voltage is designed in 0.18µm CMOS standard technology. The proposed divider uses a differential amplifier and transistor in triode region in order to perform the division. The proposed divider is modeled with neural network while TLBO algorithm is used to optimize it. The proposed optimiza...