Optimum Firing Angle Research Articles

Eleven level multi-level inverter simulation platform

Finding the optimal firing angles that minimize the amount of harmonics in a multilevel inverter is an optimization problem. However, since these values are available, testing them in an inverter is not something that can always be done since there is not always a physical inverter to carry out the tests. This paper proposes the development of a Simulink script that allows, from the input angles, to determine the typical ladder output waveform, as well as the harmonic content of an 11-level triphasic multilevel inverter. This will be done by designing the inverter by implementing Simulink IGBTS modules in a configuration of 5 H-bridges in series per phase. Furthermore, Fourier analysis of these waves is carried out in order to characterize the harmonic content of the generated signals.

Optimum Firing Angles Control for Switched Reluctance Motor Based on IPSO at Steady State

To avoid the control error caused by the inaccuracy of the analytical model as used in traditional method, in this paper, a novel model free scheme based on intelligent optimum algorithm - improved particle swarm optimization (IPSO) to search the optimum firing angles of switched reluctance motor (SRM) drives online is proposed. The optimum firing angles can be searched by the proposed scheme online with fast convergence speed and high probability according to the criterion of minimum the phase current when the SRM operated at a constant speed and load torque in single pulse model. For cumbersome and complicated process to calculate or measure flux or inductance to decide firing angles value is not needed, only the RMS phase current needs to be measured as guidance, the proposed optimum method is easy to implement. It is also not affected by system parameters variation and the dynamic performance is not influenced. The impact of saturation of core, back-EMF, fringing effect, iron loss and power switch loss has been considered in the proposed method, but the traditional methods cannot. Experimental and simulation results are carried out to verify the effectiveness and high performance of the proposed optimum firing angles control algorithm.

Investigation on load harmonic reduction through solar-power utilization in intermittent SSFI using particle swarm, genetic, and modified firefly optimization algorithms

A new Symmetric Solar Fed Inverter (SSFI) proposed with a reduced number of components compared to the classical, modified, conventional type of Multilevel Inverter (MLI). The objective of this architecture is to design fifteen-level SSFI, this circuit uses a single switch with minimizing harmonics, and Modulation Index (MI) values. Power Quality (PQ) is developed by using the optimization algorithms like as Particle Swarm Optimization (PSO), Genetic algorithm (GA), Modified Firefly Algorithm (MFA). It’s determined to generate the gating pulse and finding optimum firing angle values calculate as per the input of MPP intelligent controller schemes. The proposed circuit is solar fed inverter used for optimization techniques governed by switching controller approach delivers a major task. The comparison is made for different optimization algorithm has significantly reduced the harmonic content by varying the modulation index and switching angle values. SSFI generates low distortion output uses through without any additional filter component through utilizing MATLAB Simulink software (2020a). The SSFI circuit assist Xilinx Spartan 3-AN Filed Program Gate Array (FPGA) tuned by optimization techniques are presented for the effectiveness of the proposed model.

Wide Range Reactive Power Compensation for Voltage Unbalance Mitigation in Electrical Power Systems

In this work, a wide range of reactive power compensation is achieved for voltage unbalance mitigation in 500 km electrical power systems. An Optimal Control Technique (OCT) is proposed to encompass the unbalance load changes at a wide range of Voltage Unbalance Factor (VUF), between 3.33% and 12.4601%, and to minimize it to an acceptable value (at average less than 2%). The technique uses a combination of Particle Swarm Optimization (PSO) and Artificial Neural Networks (ANN) in three stages. In the first stage, the PSO finds the optimal firing angles of the Thyristor Controlled Reactor (TCR) and the optimal number of bank capacitors for the Thyristor Switched Capacitor (TSC) to restore the voltage balance. In the second stage, the voltage unbalance evaluations obtained by the PSO algorithm are used to train the ANN. In the third stage, the ANN is connected to the system to control and overcome the voltage unbalance problem accurately and quickly. Results are compared with other techniques available in the literature to confirm the superiority of the OCT performance. Furthermore, a laboratory model for the electrical power system is built and the proposed OCT for real voltage unbalance mitigation is validated.

A Developed H-Bridge Cascaded Multilevel Inverter with Reduced Switch Count

Multilevel Inverter integrates several Direct Current (DC) sources to produce a single-phase Alternating Current (AC) waveform that can be used to meet the domestic and commercial power demand. This article introduces a novel Multi Source Cascaded Multilevel Inverter with a reduced number of switches for the efficient use of DC voltage sources. The conversion efficiency can be increased by the presented topology which is simple in design to overcome the significant switching losses in the power electronics devices. Optimal Firing Angle and Phase Opposition Disposition Pulse width Modulation Techniques were used to reduce the harmonics at the desired output of the inverter and also to improve the power quality of the presented topology. This article also proposes two Asymmetric Multilevel Inverter Topologies. A comparison has been made, on the number of switches required and the efficiency of the inverters to differentiate the presented Topologies from other topologies of the multilevel inverter. Finally, the performance characteristics of the presented topologies have been designed and investigated using MATLAB Simulation. Simulation results were validated using an experimental setup.

Proposing and Evaluation of SC Techniques for Variable Speed High-Power Operation of SEIG

This work presents a novel methodology for variable speed high power Transfer Capability of a self-excited induction generator (SEIG). The proposed methodology is based on the selection of a suitable firing angle of Fixed Capacitor-Thyristor Controlled Reactor (FC-TCR) for achieving constant rated stator current. WDSEIG would produce a variable speed high power without overheating under variable wind speed and connected load. The analytical approach for the proposed methodology has been implemented to predict the optimal operating firing angle of FC-TCR for full load stator current achievement within the allowed operating range of load and prime mover speed. Also, Soft Computing (SC) techniques have been implemented based on Harmony Search Algorithm (HSA), Flower Pollination Algorithm (FPA), and Moth-Flame Optimization (MFO) algorithm to achieve the proposed methodology. A comparison between different SC techniques, analytical approach and experimental work are given and evaluated to verify SC techniques accuracy. This evaluation study can be useful in specifying the appropriateness of the SC techniques for High Power Transfer Capability for a SEIG.

THD Analysis of Novel Envelop with a T type (E-T) Multilevel Inverter with reduced number of switches

Multilevel inverters are a good choice for medium and low power applications. Multilevel inverters have found a wide place in the market for their good power quality output. This paper proposes a new Envelope with T type Novel Multilevel inverter with unequal sources and with reduced switch count. Working of the circuit is explained. Firing angle calculations are done using simple nested looping technique and later Genetic Algorithm is used to obtain optimum firing angles for Selective Harmonic Elimination technique and improve the THD of the output voltage. Comparison is made between different types of inverters. The proposed inverter can be used for speed control of drives

Design and Simulation of a Novel Nine Level Inverter Topology for Motor Application

In the couple of years, the demand of multilevel inverter has expeditiously increased in the field of utilization of electrical energy. Because the multilevel inverter is a key technology to integrate the different renewable energy sources (wind, solar etc) with the grid. In this research work, authors have configured a novel topology of nine level multilevel inverter has less number of switches with dc voltage sources. The presented approach has been designed to 9-level inverter with seven unidirectional switches with voltage sources. It comprises of an H-bridge which synthesize to ac voltage by utilizing almost all possible additive and subtractive cases of the voltage sources with its combinational power switches and generated optimal firing angles using selective harmonic elimination method with Genetic Algorithm to decrease the lower order harmonic present in the output voltage of the, which supplied by the presented nine-level inverter. It has been concluded that presented approach use a less number of power switches in drive circuit and the number of dc voltage sources also make a simple circuit and enhance the efficiency of the complete system.

Maximum Output Torque Control in Improved Flux Path Homopolar Brushless DC Motor With Axillary Field by Using Optimal Control of Turn-ON and Turn-OFF Angles in Variable Speed Applications

This paper presents the principles of operation, electromagnetic behavior analysis, and a search technique based on the finite-element analysis in order to determine the optimum control parameters of an improved flux path Homopolar brushless dc motor (IFP-HBLDC). In the proposed IFP-HBLDC structure, a permanent magnet is replaced by a dc excited assisted field coil to control and regulate the flux. In this paper, for different values of speed, maximum torque is determined by calculating the optimal turn-on and turn-off angles and the optimal field current which provides more flexible control over wide ranges of speed. To such aim, the behavior of the commutation angles is analyzed first by a numerical technique using the 3-D electromagnetic field analysis, in which the analysis of the collected data has shown that the commutation angles providing the maximum electromagnetic torque. The technique was successfully used offline to determine the optimum firing angles for achieving the highest drive efficiency to maximize the electromagnetic torque in a prototype 1.5-kW three-phase IFP-HBLDC motor drive intended for variable speed application. The performance prediction and test results are found in good correlation.

Design of Computational Experiment for Performance Optimization of a Switched Reluctance Generator in Wind Systems

This paper presents as a new contribution a proposal to optimize the performance of a switched reluctance generator (SRG) in a variable wind energy conversion system. An approach based on the design of computational experiment is applied to determinate the optimal firing angles and the optimal dc link voltage that guarantee the best system behavior for each rotor speed. A third-order response surface model based on space-filling designs is applied to build a multiobjective function considering efficiency improvement and torque ripple reduction. An interior point method is applied to find the minimum of the surface, optimizing the process. Direct power control is used to obtain the maximum power as a function of the rotor speed, employing the optimal parameters. Hysteresis and single-pulse current control are applied for low- and high-speed operation, respectively. Simulation and experimental results have shown that the proposed approach returned a good compromise between SRG high efficiency and low torque ripple. Moreover, the presented technique reduces computational effort and provides a clear massive data simulation framework.

Initial Firing Angle Control of Parallel Multi-Pulse Thyristor Dual Converter for Urban Railway Power Substations

This paper presents an optimal initial firing angle control based on the energy consumption and regenerative energy of a parallel multi-pulse thyristor dual converter for urban railway power substations. To prevent short circuiting the thyristor dual converter, a hysteresis band for maintaining a zero-current discontinuous section (ZCDS) is essential during mode changes. During conversion from the ZCDS to forward or reverse mode, the DC trolley voltage can be stabilized by selecting the optimal initial firing angle without an overshoot and slow response. However, the optimal initial firing angle is different depending on the line impedance of each converter. Therefore, the control algorithm for tracking the optimal initial firing angle is proposed to eliminate the overshoot and slow response of DC trolley voltage. Simulations and experiments show that the proposed algorithm yields the fastest DC voltage control performance in the transient state by tracking the optimal firing angle.

Approach for performance optimization of switched reluctance generator in variable-speed wind generation system

In this paper, algorithms are proposed to get optimal parameters of a switched reluctance generator (SRG) when applied in variable speed wind generation systems. The driver’s parameters affect power generated, torque ripples, iron losses, and electric losses. Therefore, the optimal values of the drive activation must be defined for SRG’s operation in a wide speed range. Thus, knowing the operating points of the wind turbine (speed and power), algorithms that perform dynamic simulations of the operation at low and high speed were developed. Driver’s parameters of the SRG are obtained through cost functions, which are defined such that the balance between torque ripples, iron losses, and electric losses are maintained. With simulations results, the cost functions were minimized to get SRG’s optimal firing angles according to the operating speed. Simulation and experimental tests were performed emulating a wind turbine system. The results confirmed the efficiency of the methodology proposed in this paper.

FPGA-based genetic algorithm implementation for AC chopper fed induction motor

ABSTRACTGenetic algorithm (GA)-based harmonic elimination technique is proposed for designing AC chopper. GA is used to calculate optimal firing angles to eliminate lower order harmonics in output voltage. Total harmonic distortion of output voltage is taken for the fitness function used in the GA. Thus, the ratings of the load are not mandatory to be known for calculating the switching angles using proposed technique. For the performance assessment of GA, Newton–Raphson (NR) method is applied in this present work. Simulation results show that the proposed technique is better in terms of less computational complexity and quick convergence. Simulation results were verified by field programmable gate array controller-based prototype. Simulation study and experimental investigations show that the proposed GA method is superior to the conventional methods.

OPTIMIZATION TECHNIQUES FOR HARMONICS MINIMIZATION IN CASCADED HYBRID MULTILEVEL CONVERTERS: A REVIEW

Recent advancements in the field of power electronics have made possible the worldwide application of converters in dc power source utilization, uninterruptible power supplies, electric motor speed control, switched mode power supplies, flexible alternating current transmission systems devices including static synchronous compensator and their controls. Power semiconductor devices such as converters have been emerged as powerful devices in the power industries. As such, harmonics free output of inverters is assuming extreme importance. Over the past decades, depending upon the topologies and control strategies, numerous optimization techniques have been proposed for desired output waveform. This paper presents a review of optimization techniques used for multilevel inverters. The pros and cons of optimization techniques are discussed. The objective of these optimization techniques is to find out the optimum firing angles of multilevel inverters, which results in minimum harmonics. As a preferred option for proposed work, reduction of total harmonic distortion with the aid of particle swarm optimization technique to multilevel inverters is suggested.

Design and implementation of AC voltage controller-fed induction motor starting through particle swarm optimisation

This paper analyses the starting performance of AC voltage controller fed-induction motor drive to find out an optimum firing angle for the AC voltage controller using particle swarm optimisation(PSO). Investigations on dependence of optimum firing angle on motor parameters and the effect of variation of motor parameters on the starting performance of motor are also made in this work. About nine machines grouped into four, with each group consisting of equally rated machine with different motor parameters are used for the study. Optimum firing angle is first obtained through graphical method and then through the PSO algorithm. Experimental evaluation is done using DSP TMS320F2812 as the controller. All the results show that optimum firing angle obtained through graphical method and PSO is matching and there is a good agreement with the simulation and hardware results. Results also show that, though the machines have same rating, their optimum firing angles are different due to the difference in motor parameters.

Differential evolution method‐based output power optimisation of switched reluctance generator for wind turbine applications

The use of wind energy for electric power generation provides a clean and renewable source. Therefore there is an increasing interest in developing and exploiting natural energy generation system. Switched reluctance generators (SRGs) have the potential to be a robust and highly efficient electrical conversion system for variable-speed wind applications. This study presents a new approach for optimising performance of a SRG intended for variable-speed direct drive wind turbine applications. DC bus voltage level and phase voltage switching angles have been identified as control variables affecting power generation. Owing to highly non-linear characteristics of SRG, iterative simulation of the generator model on the range of control variables can be used for finding output power profile. Since it is a multidimensional search space, the number of iterations is very big. Differential evolution (DE) strategy has been introduced to find optimal firing angles and DC bus voltage level under multiple operating conditions. Optimisation of the control variables is performed using a machine model based on the measured characteristics. Selected operating points are experimentally tested using a 4 kW 1500 rpm SRG prototype. DE algorithm is a viable alternative for generating optimal control in multidimensional optimisation of SRG wind energy generation.

Starting performance optimisation of two-leg AC voltage controller-fed three-phase induction motor drive

This paper analyses the starting performance of two-leg AC voltage controller-fed three-phase induction motor drive and establishes that optimum value of firing angle combination for the voltage controller depends on the motor parameters. Identically rated machines with different motor parameters are used for the work. Optimum firing angle combination is obtained from the simulation, which gives zero negative torque pulsations with minimum acceleration time and other electrical characteristics like peak positive electrodynamic torque pulsations, peak starting current are having satisfactory values. Results show that cost effective two-leg controller is giving an improved performance with the optimum firing angle combination and is found to depend on motor parameters.

Multi-Objective Differential Evolution Based PerformanceOptimisation for Switched Reluctance Motor Drives

The simple structure, low manufacturing cost, rugged behavior, high torque per unit volume, and wide torque-speed range make a switched reluctance motor (SRM) very attractive for industrial applications. However, these advantages are overshadowed by its inherent high torque ripple, acoustic noise, and difficulty to control. The controlled parameters in SRM drives can be selected as the turn-on angle, the turn-off angle, and the current reference. This paper investigates the problem of optimal control parameters considering the maximum average torque, minimum copper losses, and minimum torque ripple as the main objectives in SRM drives. The use of evolutionary algorithms (EAs) to solve problems with multiple objectives has attracted much attention recently. Differential evolution (DE) is an EA that was developed to handle optimization problems over continuous domains. A multiobjective DE (MODE) technique is introduced here to find the optimal firing angles under multiple operating conditions. The simulation results carried out on a 4-phase 8/6 pole SRM show that the proposed MODE can be a reliable alternative for generating optimal control in the multiobjective optimization of SRM drive systems.

Simulation of Switched Reluctance Generator in Low and Medium Speed Operations for Wind Energy Application

This paper provides a new approach to maximize the amount of power generated by the switched reluctance generator (SRG) in the low and medium speed operations. There are many control variables which affect the power generated such as: firing angles, reference current, speed and voltage. It will incur high costs and time consuming to modify the variables using experimental set up. Hence, to minimize time, cost and aid in the manufacturing industry, a simulation model of the overall SRG drive is developed. The objective of the work is to identify the optimal parameters and characterize them under closed loop control. The study indicates that there is an optimal voltage, firing angles and reference current at each speed range. Also, the percentage of the power generated can be categorized as a function of dwell angle and speed at optimal voltage level. The optimal dwell angle is determined using the least square method. Within the closed loop system, the high percentage of power generated can be maintained by adjusting the voltage level. It allows operation in single pulse mode as opposed to the conventional current chopping during the low and medium speed.

Neuro-fuzzy Controller for High Performance Induction Motor Drives

This paper presents development of a neuro-fuzzy system for performance enhancement of a.c.voltage controller fed induction motor drives. Improvement in motor efficiency and power factor is achieved by suitably adapting the motor flux to optimum point by stator voltage control. The optimum SCR firing angle for each operating point is readily estimated by the neuro-fuzzy system. Extensive simulation is carried out with the proposed technique and the results are presented.