Performance Studies of Static Synchronous Compensator and Static Synchronous Series Compensator Modes for Convertible Static Compensator

This thesis presents an overview of the emerging Flexible AC Transmission System (FACTS) and Convertible Static Compensator (CSC) technologies. CSC, the flexible multifunctional compensator is an innovation fi-om FACTS technology. These technologies are fully utilized the existing transmission system assets, that improve transmission nationality for economical and environmental reasons. The CSC can occupy as shunt and/or series compensation devices providing various modes. The CSC can operate in 11 different configurations depending on control objectives, for voltage control at bus system as well as power flow control on two existing transmission lines. The CSC can function as a Static Synchronous Compensator (STATCOM), Static Synchronous Series Compensator (SSSC), Unified Power Flow Controller (UPFC) and Interline Power Flow Controller (IPFC). This research work focused on STATCOM and SSSC for CSC as shunt and series controller, respectively. The basic operation of the controllers is explained, together with the circuit configurations and general control strategies. The STATCOM and SSSC are based on a voltage-sourced converter (VSC) which consist of Gate Turn- Off (GTO) Thyristor as the switching devices, are used in this research work to study the performance of the controllers. An 11-bus system as the test system is used throughout the study to verifL the proposed models and its control strategies. The model of the controllers and its control are then validated through PSCAD/EMTDC simulation. Steady-state analysis is done to demonstrate the capability of the controllers designed for improving voltage regulation and power flows in the transmission systems. The result obtained from the simulations clearly showed that the designed STATCOM and SSSC controllers are capable in regulating voltage and increased the transmitting powe

A Simple THD Minimization Technique for Transistor-Clamped H-Bridge-Based Cascaded Multilevel Inverter

This paper presents a simple modulation technique that minimizes the output voltage total harmonic distortion (THD) without eliminating the lowest order harmonics. It uses the voltage-angle equal concept of sinusoidal reference waveform to generate the step output voltage of a single-phase transistor-clamped H-bridge (TCHB)-based cascaded multilevel inverter. The real implementation of the modulation technique for a various range of modulation indices is built using an Altera field-programmable gate array (FPGA). It is found that the proposed modulation method resulted in a dramatic decrease in the inverter’s output voltage THD when increasing the number of output steps up to thirteen levels

Particle Swarm Optimization (PMO) Algorithm With Reduced Number Of Switches In Multilevel Inverter (MLI)

In this work, a three-phase of multilevel inverter (MLI) with reduced number of switches components based on Newton Raphson (NR) and Particle Swarm Optimization (PSO) techniques were presented. The Selective Harmonic Elimination Pulse-Width Modulation (SHE-PWM) is a powerful technique for harmonic minimization in multilevel inverter within allowable limits. NR and PSO techniques were used to determine the switching angles by solving the non-linear equation's analysis of the output voltage waveform of the modified CHB-MLI in order to control the fundamental component. A comparison has been made between NR and PSO techniques related to optimization in order minimize harmonic distortion. The main aims of this paper cover design, modeling, construction the modified topology of the CHB-MLI for a three phase five levels inverter. The controllers based on NR and PSO were applied to the modified multilevel inverter. The inverter offers much less THD using PSO scheme compared with the NR scheme. The performance of the proposed controllers based on NR and PSO techniques done by using MATLAB/Simulink of results are compared

A Modified Cascaded H-Bridge Multilevel Inverter Based On Particle Swarm Optimisation (PSO) Technique

In this paper, modified multilevel inverter, via addition of an auxiliary bidirectional switch, based on Newton Raphson (NR) and Particle Swarm Optimization (PSO) techniques is presented. The NR and PSO techniques were employed for selective harmonics elimination (SHE) solution in a modified Cascaded H Bridge Multilevel inverter (CHB-MLI). The Selective Harmonic Elimination Pulse-Width Modulation (SHE-PWM) is a powerful technique for harmonic minimization in multilevel inverter. The NR and PSO techniques were used to determine the switching angles by solving the nonlinear equations of the output voltage waveform of the modified CHB-MLI in order to control the fundamental component and eliminate some low order harmonics. The proposed NR and PSO techniques are capable to minimize the Total Harmonic Distortion (THD) of the output voltage of the modified inverter within allowable limits. This paper aims to modeling and simulation by MATLAB of the modified topology of the CHB-MLI for a single-phase prototype for 13-levels. The inverter offers less THD and greater efficiency using PSO control algorithm compared with the NR algorithm. The performance of the proposed controllers based on NR and PSO techniques is verified through simulation

Features identification and classification of alphabet (ro) in leaning (Al-Inhiraf) and repetition (Al-Takrir) characteristics

—It is important for Muslim to recite the Quran properly with the correct Tajweed. which includes the use of correct characteristics (sifaat) and point of articulations (makhraj). To this date, there are limited researches done focusing on classifying the Quranic letters according to the characteristics. In this study, the focus is given to the classification of the characteristics of the Quranic letters for the purpose of developing an automated self-learning system for supporting the conventional method of Quranic teaching and learning. The characteristics of Quranic letters, which are the focus in this paper are Leaning and Repeating, where both consists of ر) ro) alphabet. Several methods of feature extractions and analysis were implemented such as Formant Analysis, Power Spectral Density (PSD), and Mel Frequency Cepstral Coefficient (MFCC) to come out with the suitable features that best represent the correct characteristics of the alphabet. Once the features had been identified, Linear Discriminant Analysis (LDA) and Quadratic Discriminant Analysis (QDA) were used as the classifier. The results show that QDA with all 19 features trained achieved the highest percentage accuracy for both Leaning (اإلنحراف – Al-Inhiraf) and ّكرير) Repetition الت– Al-Takrir) characteristics with of 82.1% and 95.8% of accuracy respectivel

Control Of A Super-Capacitor As Energy Storage With Thirteen-Level Inverter

Control of a super-capacitors as energy storage with thirteen-level inverter is presented in this paper. A NR and PSO techniques are presented for selective harmonics elimination (SHE) solution in a modified Cascaded H Bridge Multilevel inverter (CHB-MLI). The Selective Harmonic Elimination Pulse-Width Modulation (SHE-PWM) is a powerful technique for harmonic minimization in multilevel inverter. The proposed design is used to charge the energy storage such as battery, super capacitor.NR and PSO techniques are used to determine the switching angles by solving the non-linear equation's analysis of the output voltage waveform of the modified CHB-MLI in order to control the fundamental component. The proposed techniques, based on NR and PSO techniques, are capable to minimize the Total HarmonicM Distortion (THD) of output voltage of the modified CHB-MLI within allowable limits. A comparison has been made between NR and PSO techniques related to optimization in order minimize harmonic distortion based on super capacitor as super capacitor. The main aims of this paper cover design, modeling, construction and testing of a laboratory the modified topology of the CHB-MLI for a single-phase prototype for 13-levels. The experimental results of the prototype are also illustrated. The controllers based on NR and PSO are applied to the modified multilevel inverter based on super capacitor as super capacitor. The Digital Signal Processing (DSP) TMS320F2812 is used to implement these modified inverters control schemes using NR and PSO method. The proposed controller is then coded into a DSP TMS320F2812 board. The inverter offers much less THD using PSO scheme when compared with the NR schem

Comparison between selective harmonic elimination and nearest level control for transistor clamped H-bridge inverter

Total harmonic distortion (THD) is a key index used to measure the quality of output waveforms in multilevel inverters. In this paper the THD is investigated and compared between two modulation methods; selective harmonic elimination and nearest level control, for 13-level transistor clamped H-bridge (TCHB) inverter. The selected TCHB topology employs a reduced number of DC sources and switches compared with other conventional multilevel inverters, which helps to reduce the size and cost of the inverter. The performance of both modulation methods has been validated through simulations using MATLAB/Simulink. The results show that for selective harmonic elimination, the 13-level output exists for a narrow range of modulation index

A New Algorithm With Different Modulation Index (Mi) In Cascaded H-Bridge Multilevel Inverters (CHB MLIS)

The output waveforms of the multilevel inverters must be maintained smooth and not highly contents of the harmonics.Due to that the research of the multilevel inverters is still relevant to explore. For maintaining sinusoidal of the output waveforms of the multilevel inverters the design of an appropriate controller is crucial, hence the best controllers must be chosen. The suitable and its performance of the controllers will determine whether the output waveforms of the multilevel inverters can reduce the harmonics contains or not. This research aimed to investigate the performance of the Firefly Algorithm (FFA) which is applied to the modified cascaded H-Bridge multilevel inverters (MCHBMLIs) for five levels for harmonics reduction of the MCHBMLIs output waveforms especially for the currents and the voltages with different modulation index (MI). FFA is considered as an easy way which is aims to compute of the switching angle to be optimized for harmonics reduction in the proposed inverters.The concept is based on the Selective Harmonics Elimination (SHE) and the FFA is capable to reduce the lower order harmonics in the output voltages and currents of the waveforms. In order to validate the effectiveness of the proposed algorithm a simulation model has been built up. The parametric model of the simulation to be a benchmark to build up a prototype. Finally the experimental results are a good agreement with the simulation result

A simple THD minimization technique for transistor-clamped H-bridge-based cascaded multilevel inverter

This paper presents a simple modulation technique that minimizes the output voltage total harmonic distortion (THD) without eliminating the lowest order harmonics. It uses the voltage-angle equal concept of sinusoidal reference waveform to generate the step output voltage of a single-phase transistor-clamped H-bridge (TCHB)-based cascaded multilevel inverter. The real implementation of the modulation technique for a various range of modulation indices is built using an Altera field-programmable gate array (FPGA). It is found that the proposed modulation method resulted in a dramatic decrease in the inverter’s output voltage THD when increasing the number of output steps up to thirteen levels