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In this study, a novel Power Factor Correction System based on Sliding Mode Fuzzy Control is presented. This structure is used as an AC/DC/AC drive system for asynchronous machine. Non-sinusoidal source current of the system is improved to a sinusoidal waveform by the novel Power Factor Correction System controlled by Sliding Mode Fuzzy Controller. Sliding mode control technique (variable structure control) is preferred because of its robustness. Additionally, fuzzy control algorithm is adapted to Sliding Mode Control for eliminating or reducing chattering problem. A DC–DC boost converter is used to provide DC-link voltage to the inverter Three-phase voltages for Space Vector Pulse Width Modulation technique are represented by a voltage space vector in α-β space using the Clarke transformation for two-level voltage source inverter. The harmonic performance of the AC/DC/AC drive system, source side and load side current waveforms, and total harmonic distortion (THD) values are given in figures. Experimental results show the significant improvement in source current with eliminated harmonics and increased power factor from 0.63 to 0.998 value. [ABSTRACT FROM AUTHOR]

This paper presents a high-performance vector control strategy for Multilevel Inverter (MLI) fed induction motor drive system. In the proposed drive system, an adaptive and online trained sugeno type neuro-fuzzy speed controller is used to improve the speed tracking performance. The generation of Pulse Width Modulation (PWM) patterns for multilevel inverter is obtained using space vector PWM algorithm. The complete drive system is implemented in real time using DS1104 controller card. Using the experimental setup, the performance of the proposed drive system is tested under different speed commands, mechanical parameter variations and load disturbances. The experimental results show that control performance of the proposed drive system is satisfactory. [ABSTRACT FROM AUTHOR]

In this paper, the effect of carrier waveform variations on inverter output voltage in multilevel inverters is examined. For this aim, carrier waveforms with various frequency and amplitude are constructed and compared with the reference sinusoidal signals. The obtained PWM waveforms are then applied to the power switches of the inverter. A five-level inverter prototype implemented and the real-time signals are produced using dSPACE DS1103 controller board and software's. The proposed multilevel sinusoidal PWM (SPWM) strategy is tested experimentally and the results obtained are presented. [ABSTRACT FROM AUTHOR]

In this study, Pulse Width Modulation (PWM) signals of 1-16 kHz variable frequencies and variable duty cycles are produced by using Xilinx XC3S500E-4FG320 Field Programmable Gate Arrays (FPGA). VHDL (Very High Speed Integrated Circuit Hardware Description Language VhsicHDL), hardware description language, is used for programming FPGA. The produced PWM signals are applied to the drive circuit of a direct current motor and thus, the defined operation speeds are achieved. The motor speed is obtained by a disc attached motor shaft and an optic transducer, and is processed by FPGA then displayed on digital display (LCD). The produced PWM signals are both simulated using Xilinx programming interface unit and validated by observing the oscilloscope screen. [ABSTRACT FROM AUTHOR]

In this paper, a sliding mode controller is designed for active shaping of the input current in the boost converter. Robustness of the designed controller is tested with variable output voltage references, different loads and network voltage variations. For the simulations, MATLAB/Simulink programme is used. From simulation results, the same phase was provided between input current and input voltage and nearly unity power factor was obtained. [ABSTRACT FROM AUTHOR]

Coronavirus disease (Covid-19) has recently emerged as a serious public health threat, spreading rapidly worldwide and threatening millions of lives. With an increasing number of cases and mutations, medical resources are being drained daily owing to the rapid transmission of the disease, and the health systems of many countries are negatively affected. Therefore, it is important to use the available resources appropriately and in a timely manner to detect and treat the disease. In this study, VGG16 and ResNet50 deep learning models were used to quickly evaluate x-ray images and perform a prediagnosis of Covid-19, and an alternative model (IsVoNet) was proposed. Following model training, success accuracies of 99.92%, 99.65%, and 99.76% were achieved in the VGG16 model, ResNet50 model, and proposed model, respectively. According to the results, the models classified the Covid-19 and normal lung x-ray images with high accuracy, and the proposed model showed a high success rate at a lower time complexity than the other models. [ABSTRACT FROM AUTHOR]

In this paper, experimental setup of three-level cascaded inverter based 380V/±25kVAR D-STATCOM using decoupled indirect current control method (DICC) is realized. AC and DC side of D- STATCOM is modelled in dq-axis on account of D-STATCOM's controlling. DICC is used for control of D-STATCOM's dq-axis currents independently. Gate pulses for inverter are generated with multilevel sinusoidal pulse width modulation (SPWM) technique. In this study, controller card used for signal processing is dSPACEs DS1103. The control algorithm is prepared by the help of MATLAB/ Simulink® software. This algorithm is converted to C language by using Matlab/Real-Time Workshop and downloaded to DS1103's program memory by dSPACE/Real-Time Interface. Implemented experimental setup is tested by changing reference reactive current (iqref) +20A to -20A and obtained results from this test are given. [ABSTRACT FROM AUTHOR]

A distribution static compensator (D-STATCOM) is a custom power device connected in parallel to a power system to address electric power quality problems caused by reactive power and harmonics. To obtain high performance from a D-STATCOM, the D-STATCOM's dq-axis currents must be controlled in an internal control loop. However, control of the D-STATCOM's currents is difficult because of its nonlinear structure, cross-coupling effect between the dand q-axis, undefined dynamics, and fast changing load. Therefore, the controller to be preferred for a D-STATCOM should have a nonlinear and robust structure. In this study, a neuro-fuzzy controller (NFC), which is a robust and nonlinear controller, is proposed for dq-axis current control of a D-STATCOM. A DSP-based experimental setup is built for real-time control. The basic building block of the experimental setup is a three-level cascaded inverter. This inverter is constructed by using three IPM intelligent modules. A DS1103 controller card is used for real-time control of the D-STATCOM's experimental setup. The control algorithm is prepared in MATLAB/Simulink software and loaded to the DS1103 controller card. The performance of the NFC current-controlled D-STATCOM is tested for different load conditions: no load to full inductive, no load to full capacitive, full inductive to full capacitive, and full capacitive to full inductive. For this aim, the reactive current setpoint is changed as a step. The experimental results are presented to show the efficiency of the proposed controller under different load conditions. [ABSTRACT FROM AUTHOR]

Distribution Static Synchronous Compensator (D-STATCOM) is an inverter based custom power devices used to improve power quality problems in distribution systems. In this paper, design of inverter, measurement, protection and dead-time circuits needed to build experimental setup of three-level H-bridge inverter based D-STATCOM is explained in detail. In addition, selection of passive elements which are coupling inductance and dc-link capacitor being important for dynamic response of compensator is given. In experimental study, DS1103 controller card from dSPACE firm is used to transfer data between D-STATCOM and computer. D-STATCOM's ability for reactive power support is tested in experimental setup by changing of iqref as on-line and some results are given. [ABSTRACT FROM AUTHOR]