PERANCANGAN SISTEM PENGATURAN KECEPATAN MOTOR INDUKSI 3 PHASA DENGAN DIRECT TORQUE CONTROL (DTC) MENGGUNAKAN SLIDING MODE CONTROL (SMC) BERBASIS ALGORITMA GENETIKA

Secara umum dalam dunia industri, motor induksi lebih banyak digunakan daripada motor arus searah. Dikarenakan sifat motor induksi yang kokoh, handal, mudah dalam perawatan, dan harga relatif murah. Tetapi pengontrolan pada motor induksi lebih komplek dibandingkan dengan motor arus searah, hal ini disebabkan oleh kompleksitas dinamika motor induksi, sehingga algoritma pengaturannya lebih komplek. Berdasarkan masalah tersebut penulis melakukan penelitian pada motor induksi menggunakan metode Sliding Mode Control (SMC) berbasis Algoritma Genetika, di mana Algoritma Genetika dirancang untuk masalah optimalisasi parameter Sliding Mode Control (SMC) yaitu (gain K) yang optimal, guna untuk mengatasi kekurangan pada Direct Torque Control (DTC) konvensional yang masih menimbulkan fluktuasi ripple fluks dan fluktuasi ripple torsi yang tinggi pada saat kondisi steady state, sehingga dari tujuan metode yang diusulkan, hasil dari sistem yang dirancang dapat mengatur kecepatan putar motor induksi sesuai referensi yang diberikan sebesar 1000 rpm dengan settling time yaitu 0.6282 detik, dan juga dapat meminimalkan fluktuasi ripple fluks dan fluktuasi ripple torsi

Performance Improvement of Grid-Integrated Doubly Fed Induction Generator under Asymmetrical and Symmetrical Faults

The doubly fed induction generator (DFIG)-based wind energy conversion system (WECS) suffers from voltage and frequency fluctuations due to the stochastic nature of wind speed as well as nonlinear loads. Moreover, the high penetration of wind energy into the power grid is a challenge for its smooth operation. Hence, symmetrical faults are most intense, inflicting the stator winding to low voltage, disturbing the low-voltage ride-through (LVRT) functionality of a DFIG. The vector control strategy with proportional–integral (PI) controllers was used to control rotor-side converter (RSC) and grid-side converter (GSC) parameters. During a symmetrical fault, however, a series grid-side converter (SGSC) with a shunt injection transformer on the stator side was used to keep the rotor current at an acceptable level in accordance with grid code requirements (GCRs). For the validation of results, the proposed scheme of PI + SGSC is compared with PI and a combination of PI with Dynamic Impedance Fault Current Limiter (DIFCL). The MATLAB simulation results demonstrate that the proposed scheme provides superior performance by providing 77.6% and 20.61% improved performance in rotor current compared to that of PI and PI + DIFCL control schemes for improving the LVRT performance of DFIG

Induction Motors

AC motors play a major role in modern industrial applications. Squirrel-cage induction motors (SCIMs) are probably the most frequently used when compared to other AC motors because of their low cost, ruggedness, and low maintenance. The material presented in this book is organized into four sections, covering the applications and structural properties of induction motors (IMs), fault detection and diagnostics, control strategies, and the more recently developed topology based on the multiphase (more than three phases) induction motors. This material should be of specific interest to engineers and researchers who are engaged in the modeling, design, and implementation of control algorithms applied to induction motors and, more generally, to readers broadly interested in nonlinear control, health condition monitoring, and fault diagnosis

Control strategies for the More Electric Aircraft starter-generator electrical power system

The trend towards development of More Electric Aircraft (MEA) has been driven by increased fuel fossil prices and stricter environmental policies. This is supported by breakthroughs in power electronic systems and electrical machines. The application of MEA is expected to reduce the aircraft mass and drag, thereby increasing fuel efficiency and reduced environmental impact. The starter-generator (S/G) scheme is one of the solutions from the MEA concept that brings the most significant improvement to the electrical power generation system. A S/G system is proposed from the possible solutions brought by the MEA concept in the area of electrical power generation and distribution. Due to the wide operating speed range, limited controller stability may be present. This thesis contributes to the control plant analysis and controller design of this MEA S/G system. The general control requirements are outlined based on the S/G system operation and the control structure is presented. The control plants are derived specifically to design the controllers for the S/G control scheme. Detailed small signal analysis is performed on the derived plant while taking into consideration the aircraft operating speed and load range. A safe range for the controller gains can then be determined to ensure stable operation throughout the S/G operation. Adaptive gain and a novel current limit modifier are proposed which improves the controller stability during S/G operation. Model predictive control is considered as an alternative control strategy for potential control performance improvements with the S/G system. The technical results and simulations are supported by Matlab®/Simulink® based models and validated by experimental work on a small scaled drive system

Fault tolerant behavior of advanced control schemes of induction machine drives

Power electronics based variable-speed drives offer energy saving solutions, providing precise control and quick response time. They are required for sensitive process control in industrial applications and other emerging technologies such as electric vehicles. This thesis examines two popular advanced control schemes of variable-speed induction machine drive applications. The two advanced control schemes, Indirect Field oriented control (IFOC) and Direct torque control (DTC), are compared by examining their implementation complexity, parameter sensitivity, dynamic responses, steady state performance and, most importantly, under power line fault scenarios. MATLAB-Simulink package is used to develop system models for both control schemes. System studies are done under normal and abnormal operating conditions. In the end, conclusions are drawn based on their behavior and comparison of performance characteristics under dynamic and AC fault (single-line to ground, phase to phase and triple-line to ground) conditions, highlighting the fault tolerant characteristics of the two drive schemes