Saji Chacko

Genetically Tuned STATCOM for Voltage Control and Reactive Power Compensation

—In this paper Static Synchronous Compensator (STATCOM) is used for voltage stability and the compensation of reactive power. The STATCOM contains an Insulated Gate Bipolar Transistor (IGBT) based voltage source converter for voltage control and reactive power compensation. The STATCOM is used to control the reactive power with the voltage source converter in combination with a DC voltage source. The values of the DC link capacitor and battery source were optimized using the Genetic Algorithm technique and the simulations results for the same were observed under the inductive as well as capacitive load conditions. The comparison of voltage compensation for various conditions show that the performance of STATCOM tuned with GA was the best and closest to the nominal value of voltage. The simulation is done in MATLAB for STATCOM and Voltage Source Converter (VSC).

TS -Fuzzy controller based rotor resistance estimation for indirect field oriented controlled IM drive utilizing rotor flux

Induction motor with indirect field oriented control is well suited for high performance applications due to its excellent dynamic behavior. But, the indirect field oriented controller is sensitive to variations in rotor time constant, especially variation in rotor resistance. In this paper a scheme based on the Rotor flux Model Reference Adaptive Controller is designed for estimating the rotor resistance. The rotor flux estimation based on the measurement of motor terminal voltage and current although depends on the motor stator resistance, however its compensation easier and the overriding feature of this estimation technique is that identification of rotor resistance when the drive is operating at full load and at zero motor speed condition is possible. The effectiveness of the TS fuzzy controller based rotor flux adaptive scheme for four quadrant operation of motor drive is investigated and compared with the conventional PI and Mamdani fuzzy controller inMatlab/Simulink environment.

Performance and investigation of hybrid filters for Power Quality Improvement

In this paper the simulation results of hybrid filter system for non-linear load are presented. The adopted hybrid filter consists of shunt passive filters & shunt active filters. The entire filter is used by filtering higher order harmonics as the dominant harmonics gets filtered by the passive filter. According to Power Quality Standards (IEEE-519), the total harmonic distortion (THD) caused by power electronic equipment must be within the acceptable range (i.e. 5%). The effectiveness of the proposed topology has been verified by MATLAB/Simulink simulation of instantaneous reactive power theory based hybrid filter.

PSO based online tuning of PI controller for estimation of rotor resistance of indirect vector controlled induction motor drive

In industries where the operating condition are stringent and which requires excellent dynamic and steady state performance, the most preferred drive is the three phase induction motor with indirect field oriented control. However, its performance is prone to variation in rotor resistance, which needs to be estimated online. Conventionally, the model reference adaptive system with proportional integral controllers is used as adaptation mechanism for estimation of rotor resistance. This mechanism works satisfactorily for one particular operating condition and invariably fails under variable operating condition. Therefore the need arises for an adaptive controller for robust response of a drive with parameter variation. In this paper, the particle swarm optimization based proportional integral controller was applied to estimate the variation in rotor resistance. The proposed system under study is implemented in MATLAB/Simulink environment. The results shows that the estimation of rotor resistance by the proposed controller under all motor operating condition is better than the conventional fixed gain proportional integral controller.

Comparative Analysis of DTC Induction Motor Drives with Firefly, Harmony Search, and Ant Colony Algorithms

In industries, induction motor drives are more popular due to their brushless structure, low cost, low maintenance, and robust performance. Direct Torque Control (DTC) drive performance gained more importance due to its fast dynamic response and simple control structure. In order to enhance the performance of the speed control of DTC drives, this paper implements different optimization techniques to tune the speed PI controller. The simulation is carried out using MATLAB, and the results of genetic algorithm, ant colony, harmony search, and firefly optimization process are compared for different speeds of the DTC drive, with respect to peak overshoot and settling time.

Torque ripple reduction of DTC IM drive using artificial intelligence

Over the past years many kind of control techniques are proposed for induction motor drives. Among them DTC has gained more importance due to fast dynamic response and simple control structures. However it has disadvantage of high ripples in torque and slow response because of hysteresis controllers in torque and flux loop at low speed. To improve the performance of DTC (Direct Torque Control) and to reduce the torque ripples, DTC based Fuzzy logic controller is proposed in this paper. The simulation is carried out using MATLAB and compares the proportional integral (PI) controller tuned with genetic algorithm (GA) and in DTC Fuzzy Logic is implemented and simulated results are shown.

A novel on line rotor resistance estimation technique using EA tuned fuzzy controller for vector controlled induction motor drive

Induction motor with indirect field oriented control is well suited for high performance applications due to its excellent dynamic behavior. But, the indirect field oriented controller is sensitive to variations in rotor time constant, especially variation in rotor resistance. In this paper a scheme based on the Rotor flux Model Reference Adaptive Controller is used for on line identification of the rotor resistance and thus improving the steady state performance of the drive. The estimation of the actual rotor flux depends on the motor stator resistance, however its compensation is easier and the overriding feature of this estimation technique is the accurate identification of rotor resistance both during transient and steady state conditions when the drive is operating at full load and at zero motor speed condition. The effectiveness of the optimal designed Mamdani fuzzy controller based rotor identification scheme for four quadrant operation of motor drive is investigated and compared with the conventional trial and error based fuzzy controller in MATLAB/Simulink environment.

Performance enhancement of Direct Torque Control IM drive using Genetic Algorithm

The speed of three phase Induction Motor (IM) drives are controlled with the help of vector control and scalar control. Direct Torque Control (DTC) is advanced scalar control technique for speed control of IM drives. Fast response, dynamic performance and robustness has made DTC very popular. The Conventional DTC drive requires no coordinate transformation and therefore its control algorithm becomes simple. However it has high torque ripple and slow transient response because of the use of hysteresis controllers in torque and flux loop. In this paper modified DTC scheme for IM drive is proposed where three proportional integral (PI) controllers are introduced to replace the hysteresis controllers. The outer loop having PI speed controller is tuned using Genetic Algorithm (GA) for improving the speed and torque response of the drive.