The onset of electroconvection in binary mixtures of a bent-core and a rodlike nematic has been characterized by measuring the threshold voltage U(c) and the critical wave number of the pattern in a wide range of frequencies f. In the mixtures rich in bent-core molecules, a "conductive-prewavy2-patternless-prewavy1" morphological sequence has been detected with an unusual negative slope of U(c)...

monte carlo method is a very accurate method to optimize medical diagnostic radiology spectra and simulation of radiation transportation. using mcnp code, radiology and mammography attenuated x-rayspectraweresimulated.the ipem report number 78 was used as a reference to compare with the geant4 and mcnp simulations because of its popularity and wide availability. the results of geant4 in 40kev s...

microgrids are nowadays used to produce electric energy with more efficiency and advantage. however, the use of microgrids presents some challenges. one of the main problems of the microgrids widely used in electrical power systems is the control of voltage, frequency and load sharing balance among inverter- based distributed generators (dgs) in islanded mode. droop method performance degrades ...

microgrids are small-scale, low voltage (lv) power networks which employ renewable distribution energy resources (ders) with power electronic interfaces (peis). microgrids as single controlled units and active distribution networks require flexible control systems to ensure reliable and secure operation in different modes. these various operations of microgrid cause variations in voltage and fr...

Linear AC power supplies can be replaced by their nonlinear switching counterparts due to the lower voltage drops and higher efficiency and power density of switching-mode inverters. Multilevel cascaded H-bridge (CHB) converters are the preferred inverter structure because of modular configuration, control, and protection. The output voltage quality in CHB converters depends on the number of ou...

In this paper, a voltage-current mode controller is proposed to adjust both the input current and DC voltage of a boost-inverter in order to improve the performance of the photovoltaic (PV). The proposed system is based on fuzzy-making-decision predictive voltage-current controller (FPVCC). The simulation results show that in case of using the proposed FPVCC, the input current of a PV array is ...

In this paper a new topology for Dynamic Voltage Restorer (DVR) with high frequency link is proposed. This topology is able to compensate different types of voltage disturbances such as voltage sag, voltage swell and voltage harmonics. According to the obtained equations, this topology operates as a controllable current source to charge the series capacitor. Due to using High Frequency Transfor...

This paper develops an effective control framework for DC voltage control and power-sharing of multi-terminal DC (MTDC) grids based on an optimal power flow (OPF) procedure and the voltage-droop control. In the proposed approach, an OPF algorithm is executed at the secondary level to find optimal reference of DC voltages and active powers of all voltage-regulating converters. Then, the voltage ...

In this paper, a new topology for cascaded multilevel inverter based on quasi-Z-source converter is proposed. In the proposed topology the magnitude of output DC voltage is not limited to the sum of magnitude of DC voltage sources. Moreover, the reliability of the circuit due to capability of short circuit by Z-source network is increased. The quasi-Z- source converter in different modes is ana...