In recent years, a lot of effort has been made to develop various advanced control techniques in electric motors drive for industrial applications. Induction motors are the most common motors used in motion control systems. Simple and robust design, cheap price and low maintenance cost are the main advantages of induction motors. In this article, the three-phase induction motor drive is selected as a suitable electric drive according to the wide range of speed control and its performance in classical controls is examined. The main goal of this paper is to provide a robust control method for three-phase induction electric drive. The presented control method is capable of better starting the motor in a wide range of speed and torque. Also, the use of fuzzy controller has improved the stator flux and reduced the steady state fault of the drive. The performance of the proposed engine and drive is analyzed using MATLAB/Simulink software and the results are shown in different conditions. تفاصيل المقالة

Due to the variable and non-uniform nature of wind speed, using the variable speed wind power plants equipped with induction generators has advantages over the fixed speed wind power plants; however, it also contains some disadvantages such as consuming a large amount of reactive current in the power grid and causes voltage drop and instability. The use of static synchronous compensator or STATCOM is one of the key methods to improve the power profile in wind farms. STATCOM can control the voltage dynamics, improve transient stability, eliminate power fluctuations in the transmission network, and control the real and reactive power. Regarding to the fluctuations in electricity generated in wind farms, the presented case study proposed methods to improve the active power and compensate reactive power using the STATCOM in wind systems by modeling in Simulink environment of MATLAB software. According to the simulation results, by applying the STATCOM to the studied system, changes in active power and reactive power generated from the wind farm are significantly reduced. In addition, studies in terms of total harmonic distortion (THD) show that by employing STATCOM, the amount of output voltage distortion is vastly decreased. تفاصيل المقالة

Today, three-phase induction motors are widely used in industry due to advantages such as lower maintenance requirements, higher reliability, lower design costs, and the ability to operate in dusty and explosive environments. Vector control and direct torque control are two common methods for controlling induction motors. The control algorithm of the two methods is almost the same in some cases and completely different in others. Each of the control methods has advantages due to their general structure, which lead to a better response compared to other methods. The vector control method contains a good steady state response however offers relatively less speed dynamic responses and steady state time. Several methods have been proposed to solve this problem. In this paper, a switching table is used to select the appropriate switching modes for the induction motor drive to improve the output dynamic response. Comparison of the results obtained from the performance of the drive under test with the vector control and direct torque control methods illustrates that the response of the drive system to the vector control includes faster dynamics with less constant state fluctuations. In order to validate the performance of the drive system, MATLAB software has been utilized for modeling and simulation. تفاصيل المقالة

Nowadays, among the renewable energy resources, wind energy is more economically viable than other new sources. To achieve the maximum power at different wind speeds, the turbine speed must be variable over a wide range. Electricity generation from wind is performed by different models of wind turbines with different generators. Due to the capabilities and advantages such as relatively high power density, low noise, high efficiency, high reliability and low maintenance costs, wind turbines equipped with permanent magnet synchronous generator (PMSG) are in increasing use. This paper presents a method for modeling and controlling the stability of PMSG-equipped power systems using static synchronous compensator (STATCOM). STATCOM is a static synchronous generator that is installed in parallel with the power grid and is used as a reactive power compensator which plays an effective role in voltage stability. The main goal of this study is to develop a reliable control strategy for wind farms and STATCOM to investigate the effect of reactive power losses under constant and sub-fault conditions. Furthermore, to increase the attenuation of the synchronous generator of single-machine system with infinite bus, STATCOM with PID controller is connected to the studied system to rise the dynamic stability of the PMSG based wind turbine. تفاصيل المقالة

Due to the variable and non-uniform nature of wind speed, using the variable speed wind power plants equipped with induction generators has advantages over the fixed speed wind power plants; however, it also contains some disadvantages such as consuming a large amount of reactive current in the power grid and causes voltage drop and instability. The use of static synchronous compensator or STATCOM is one of the key methods to improve the power profile in wind farms. STATCOM can control the voltage dynamics, improve transient stability, eliminate power fluctuations in the transmission network, and control the real and reactive power. Regarding to the fluctuations in electricity generated in wind farms, the presented case study proposed methods to improve the active power and compensate reactive power using the STATCOM in wind systems by modeling in Simulink environment of MATLAB software. According to the simulation results, by applying the STATCOM to the studied system, changes in active power and reactive power generated from the wind farm are significantly reduced. In addition, studies in terms of total harmonic distortion (THD) show that by employing STATCOM, the amount of output voltage distortion is vastly decreased. تفاصيل المقالة

Three-phase induction motors as widely used electric drives in industry, automation, transportation and electric vehicles are mainly controlled by two conventional methods, vector control (VC) and direct torque control (DTC). The vector control method has a suitable steady state response, but in terms of dynamics and time to reach the steady state, it provides a relatively slower response. In contrast, the direct torque control method works almost the opposite way and provides a better dynamic response. Therefore, providing a control strategy that combines the advantages of the two mentioned methods as much as possible improves the driving performance of the induction motor. This paper presents a hybrid control method based on the optimal keying table to select the appropriate keying modes for the induction motor drive converter to improve the output dynamic response. To reduce current and torque ripples in different operational states, the space vector modulation technique has been used in the proposed drive system. The efficiency of the drive system presented with the hybrid control strategy has been compared with the conventional DTC and VC control methods, and the results illustrate a faster dynamic response of the proposed drive system with less steady-state ripples than the two conventional methods. Modeling and implementation of the proposed drive system have been performed in MATLAB/Simulink software. تفاصيل المقالة

This paper introduces a new application of the Rotor based-current MRAS observer (RCMO) method for Doubly fed induction generator (DFIG) sensorless control in the condition of network voltage drop. DFIG control is Field oriented control (FOC) vector and Model reference adaptive system (MRAS) observer is used instead of speed and position sensor based on rotor current. It is possible to estimate the speed and position of the rotor. Simulation and analysis have been done based on 10% balanced voltage drop in the wind power plant terminal. The results of the simulation show the estimated speed (ω̂r), accurate and appropriate sequence of speed has real (ωr). Also, the graph of the machine variables in the state of balanced three-phase voltage drop in the state sensored is obtained and compared with the state sensorless, which shows the lack of influence of the estimated speed fault on the simulation results and the acceptability of using the RCMO method in estimating the speed in the condition of balanced voltage drop. Finally, the effect of various voltage drops on the estimated speed fault has been investigated. تفاصيل المقالة

This article presents comparative studies for dynamic performance evaluation of vector- and scalar-controlled asynchronous (induction) motor (ASM) drives based on improved control baselines. To compare the ASM drive responses, four control strategies including improved direct torque control (DTC), improved indirect field-oriented control (IFOC), feedback (FB) linearization, and scalar vectorized Volt per Hertz (VV/Hz) are considered with their enhanced versions based on the space vector pulse-width modulation (SVPWM) switching technique. The main objective of this work is to implement feasible dynamic computer functions of the ASM drive to assess its torque and speed responses over the variable low and high speeds for pure or hybrid electric vehicle traction drive applications using MATLAB/Simulink software. To validate the overall performance of the ASM drive, several case studies are developed to evaluate the transient behavior of the system from the starting stage to the steady state over the variable load conditions. تفاصيل المقالة