283 research outputs found
Modelling, Harmonic Compensation, and Current Sharing Between Winding Sets of Asymmetric Nine-Phase PMSM
No full textSeveral modelling approaches of multiphase machines have been proposed in literature to control the machine in healthy or faulty conditions. The variety of the models may confuse the researchers to select the proper ones. In this paper, vector space decomposition (VSD), multi-star (MS), and decoupled MS (DMS) models are developed with detailed explanations for triple three-phase (or asymmetric nine-phase) permanent magnet synchronous machine (PMSM). It is shown that the machine differential equations are not fully decoupled in DMS modelling. The presented approaches can be extended to any types of multiple three-phase PMSM. Also, two new models are introduced with the use of specific transformation matrices in order to provide the current sharing between different three-phase winding sets and for compensation of current harmonics arising from inverter nonlinearities or machine structure. These models are necessary to design the parameters of the control system in order to have the optimum dynamic response
DC Current Elimination for MPC for CHB-STATCOM Employing Current Transformer Sensors
No full textCurrent transformers are widely used as sensors in high-power converters. However, they are incapable of handling DC components, resulting in potential malfunctions. This paper shows that, in a cascaded H-bridge static synchronous compensator with finite control set model predictive control, they can be easily suppressed by adding a cluster balancing optimization algorithm. Experimental evidence is provided by implementing the proposed cluster balancing optimization algorithm on a three-phase, 5-level STATCOM
Enhancing Voltage Gain and Assessing Current THD in Transformer of Photovoltaic Applications through a New Triple Active Bridge Converter
No full textA novel Triple Active Bridge converter is proposed delivering a considerably higher voltage gain and lowering transformer's Total Harmonic Distortion compared to the conventional Dual Active Bridge. The design of the converter, circuit operation modes, and its steady-state behavior are all thoroughly examined in this work. The converter optimizes the control system adding an extra degree of freedom, useful to control the voltage gain by combining the fundamental PWM method with the proposed architecture, which also increases efficiency and reduces THD.The efficacy of the proposed approach is validated by simulations
Time Domain Approach Compared with Direct Method of Lyapunov for Transient Stability Analysis of Controlled Power System
No full textThis paper attempts to study the transient stability of a two machine infinite bus system when affected by large disturbances, by comparison of time domain approach vs. transient energy function. Then the decentralized nonlinear controller is embedded within the power system and simulation results show that the transient stability has been greatly enhanced. Based on the existing transient energy function of uncontrolled power system, the controlled power system has been represented as a forced Hamiltonian system. The Lyapunov function which is suitable for transient stability analysis of this controlled power system has been used for stability assessment.
Simulations in different operating points show the enhancement of transient stability of power system with
controller in both time domain approach and energy function method
Analytical formula for harmonic elimination problem in multilevel inverter
No full textThis paper presents a solution of the selective harmonic elimination problem in multilevel converters based on an analytical formula. Three phase l-level cascaded H-bridges (CHB) inverters with l = 2s + 1, s = 2n number of both dc sources and switching angles are considered to delete n harmonics, arbitrarily chosen, and their multiple from output voltage waveform, imposing the amplitude of the fundamental harmonic. The procedure calculates the unknown switching angles depending on modulation index
Propuesta para la mejora de los procesos de vinculación en la institución CECATI
No full textTrabajo que presenta la intervención realizada en el Centro de Capacitación para el Trabajo Industrial (CECATI) que tuvo como objetivo mejorar los procesos de vinculación entre la institución y los diferentes sectores de la población. El proyecto propuso contar con una agenda de posibles empleadores e instituciones educativas tecnológicas para detectar sus necesidades de capacitación, valorar cuáles pudieran interesarse en los servicios que ofrece el CECATI y establecer un calendario de trabajo con los posibles interesados para difundir los cursos oficiales que se ofertan y/o para diseñar cursos de capacitación personalizados
Efficiency Optimization of Induction Motor by Automatic Voltage Regulator of Synchronous Generator Based on Search-based Method
No full textThis article proposes a new method to optimize the efficiency of a 7.5 kW induction motor connected to a synchronous generator. The Synchronous generator is a part of an emergency power system supposed to provide power for the induction motor. In this proposed method, the efficiency of induction motor is optimized by the automatic voltage regulator of synchronous generator under different loads. The centerpiece of automatic voltage regulator is a DC/DC buck converter which feeds excitation winding. Due to improvement of induction motor efficiency, the cost of generation is significantly reduced. In the proposed method, a search-based method is utilized to adjust the output voltage of synchronous generator in order to find the maximum efficiency of induction motor. Furthermore, losses equations are presented which are applied in efficiency calculation. As a result of not using speed sensor, the motor equations arc used to estimate the motor slip in each step of search method. Results of the proposed method is presented to verify the method performance using MATLAB/Simulink
Test cycle simulation of an electric car with regenerative braking
No full textIn the near future electric cars will be ubiquitous thanks to their wider functionalities and to their much lower tailpipe emissions to the environment. However, at present, there are still problems concerning the storage of energy for long range operation. It is therefore important to employ strategies to preserve the State of Charge (SoC) of batteries as much as possible. The first important strategy is related to the driving style in order to minimize frequent acceleration-braking sequences. Once this condition has been met, the next strategy could be the partial recharge of battery during braking, recovering the kinetic energy of the car mass. This paper presents the simulation of a simple mechanical quarter-car model whose wheel is driven by a Permanent Magnet Synchronous Motor (PMSM) motor. The focus is on the electric control of the motor and on the energy recovery. The PMSM could accelerate and brake the car in all conditions, but this solution depletes the battery also in braking. There is a better strategy that use a combination of regenerative braking (battery recharge) and dissipative mechanical braking. In order to produce meaningful results, the simulations follow the class 3 time-speed data points of the Worldwide Harmonized Light vehicles Test Cycles (WLTC) developed for Pure Electric Vehicles (PEV)
Mathematical proof of a harmonic elimination procedure for multilevel inverters
No full textIn this paper, a single phase cascaded H-bridge inverter with s variable dc sources (s≥2), l=2s+1 levels has been considered. A mathematical proof is presented to demonstrate that, under a particular choice of the switching angles, which number corresponds to the number of dc sources i.e. s, and of the dc voltages, all harmonics are eliminated from the output voltage waveform, except those of order n=4p⋅s±1, p=1,2,.... With this method, the dc voltage sources vary linearly according to the modulation index m, while the switching angles do not depend on m. The resulting output voltage has low total harmonic distortion, that remains independent on m. Compared to a conventional selective harmonic elimination procedure and to a pulse amplitude method, the proposed procedure reduces distortion in a wide range of modulation index
A comparison between real-time harmonic elimination procedures for single phase CHB 5-level inverter
No full textIn this paper, single phase cascaded H-bridge (CHB) 5-level inverters are considered and a pulse amplitude modulation (PAM) procedure operating at fundamental frequency, ables to remove the third and fifth harmonics and their respective multiple, is proposed. Each H-bridge is fed by equal voltage sources linearly dependent on modulation index. This procedure is compared with another PAM procedure that uses disequal dc voltage sources and with the classical selective harmonic elimination (SHE) technique working at fundamental frequency. The presented procedure eliminates more harmonics, therefore it returns lower Total Harmonic Distortion (THD) in comparison to the other considered strategies. Experimental results are shown, confirming the validity of the proposed procedure
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