فهرست مطالب

  • Volume:8 Issue: 4, 2020
  • تاریخ انتشار: 1399/01/09
  • تعداد عناوین: 6
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  • Habib Benbouhenni* Pages 1-10

    In this article, the author proposes a sensorless direct torque control (DTC) of permanent magnet synchronous motor (PMSM) fed by four-level neutral point diode clamped (NPC) inverter using a neural networks (NNs) technique. neural PI (PIN) regulator is used for controlling the rotor speed of PMSM and NN controller applied in switching select stator voltage. The technique proposed in this article can minimize the stator flux ripple, electromagnetic torque ripple and harmonic distortion of stator current, and especially improve system good dynamic performance and robustness in high and low speeds.

    Keywords: DTC, PMSM, NNs, NPC, PI, PIN
  • Nabi Neisi*, AliReza Tavakoli Pages 11-17

    In this paper, a new method for controlling electric dynamometer based on fuzzy control is presented. Due to the advantages of squirrel cage induction motors, such as simple structure, good reliability and low maintenance cost, these motors are suitable for use as dynamometer to provide dynamic load for torque-speed or speed-power curve characteristics. In order to obtain better torque control performance and induction motor speed, Direct Torque Control (DTC) method is implemented based on space vector modulation (SVM) technique with fuzzy method. The fuzzy method is used instead of PI or hysteresis Torque and flux comparators. For the dynamometer simulation, a 200-horsepower squirrel cage induction motor is connected to a 200-hp direct current motor via the shaft model. The performance simulations of the proposed dynamometer system were evaluated in three study modes for each of the hysteresis direct torque control, PI torque control and fuzzy direct torque control approaches by Matlab / Simulink software. The simulation results show the significant effect of the fuzzy method on reducing the response speed fluctuation and reducing the torque ripple. The results show that it is possible to use high power motor for electric dynamometer.

    Keywords: Electric Dynamometer, Direct Torque Control, Space Vector Modulation, Fuzzy Control, Induction Motor Drive
  • Reyhaneh NasrAzadani*, Akram Mehvari, Mohammadbagher Tavakoli Pages 19-24

    Optical spectrum is a set of wavelengths which is created by a light source. Radiation of each element or composition can be absorptive or reflective and unique. For measurement of these spectra, an apparatus known as spectrometer can be used. In reality, spectrophotometer is a machine which measures the intensity of the absorbed light as a function of wavelength. Owing to the extensiveness of the radiational energy amplitude, various spectrophotometers are used for different purposes. The main purpose of this research is to use spectrophotometer and design of a spectrometer for diagnosis and evaluation of icterus in children and measurement of blood sugar in people suffering from diabetes. Statistical population of research includes 80 newborns suffering from icterus and 160 diabetic people in Al-Zahra hospital which are selected randomly. In this method, all of the samples are evaluated with regard to the absorbed light. Results imply to the 78% accuracy for diabetes and 84% accuracy in newborns.

    Keywords: Icterus, Diabetes, Spectrophotometer, Accuracy
  • Ahad FarajiNaghibi*, Amangalidi Koochaki, Mehdi Gatabi Pages 25-31
    Objectives

    The ability of the frog algorithm to optimize overcurrent relays. 

    Methods/Statistical Analysis:

     Adjusting the over-current relay is different in the multi-grid arrangement. If directional overcurrent relays are set for a micro-grid arrangement, no longer is this relay setting suitable for other microgrid arrangements By limiting current changes by FCL in different makeup and considering a setting for all the relays, micro-grid protection coordination can be maintained in all make-ups.

    Findings

    The ability of the frog algorithm to optimize overcurrent relays is evaluated. It is also compared to its ability to solve the optimization problem by genetic algorithm. The objective function of this problem is to optimize the total operating time of all relays in all arrangement. Also, the main concern is the protection distance between the primary relay and the backup relay. The problem of over-current relay coordination tested by the method of shuffled frog leaping algorithm (SFLA) on a 9-BUS system in two different scenarios and compared with the results of the work in the method of genetic algorithm. In this paper, the results show that the convergence rate in SFLA is greater than GA, and the convergence time in SFLA is less than GA. Application/Improvements: The proposed method can also be adapted to optimize the total operating time in the distribution section of the IEEE standard 30-bus system in the future.

    Keywords: Index Terms-Directional Overcurrent Relays, Fault Current Limiters (Fcls), Microgrid, Shuffled Frog Leaping
  • Mohammad Janali*, AmirHossein Zaeri Pages 33-40

    In this paper, the model predictive control is designed to control the frequency in a micro grid in the island mode with respect to the disturbances entered into the system. One of the important issues in the micro grid is controlling the frequency in it. In case of turbulence in the micro grid, when the micro grid is connected to the network, and also in island mode, it changes the frequency of the system. The proposed micro grid is intended for three areas and in order to improve its efficiency, the particle swarm optimization algorithm is used to determine the controller parameters such as prediction horizon, control horizon, sampling time and etc…

    Keywords: Micro Grid, Frequency Control, Particle Swarm Optimization Algorithm, Model Predictive Contro
  • Venkat Ramana, A Pandian* Pages 41-45

    This paper presents a new functional, powered boost adjusted inverter with improved voltage gain by incorporating an anti-parallel switch with a capacitor that allows two operating modes. These are Continuous Mode of Conduction and Discontinuous Operating Mode. In the proposed Quasi Z-source inverter (QZSI) voltage gain is significantly increased without the use of passive components by adding auxiliary switch. The two operating modes are distinguished by varying switched capacitor qZSI inductances and load conditions. The improvement potential of the proposed CC-qZSI can be expanded further (n-stages) by connecting Diodes and Capacitors in n No.of stages. The limiting conditions for CCM / DCM were derived. Detailed analysis of the voltage control power, current inductance ripples, stresses and converter losses on switching devices for CCM and DCM has been carried out. Both modes of operation are simulated and experimentally verified and validated.

    Keywords: Quasi Z source inverter_CCM_DCM_ZSI