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Induction heating system is the most important component in domestic induction cooker. The system is usually required a full-bridge rectifier and a resonant inverter to generate medium-frequency power source to the induction coil. In order to simplify and reduce the operating procedure, we propose a design of the system by using a Class-E direct AC-AC converter with only one capacitor and one inductor. The design principle is based on the zero-voltage derivative switching (ZVDS) of the Class-E inverter with a parallel network. Thus, this study provides a more systematic scheme to design a Class-E direct AC-AC converter for domestic induction cooker than the conventional methodology. The results from our design are then compared with experimental results from a 1,300 W prototype operated at 220 V and 50 Hz.

This article introduces voltage feedback controlling using the PI controller tuned gains by metaheuristic optimizations for a four-phase interleaved boost converter. The metaheuristic optimizations, particle swarm optimization (PSO), genetic algorithm (GA), and Tabu search (TS) are applied to find the optimal gains for the proposed control system. In experiment, the designed control system is implemented on the DSP board TMS320F28335 with MATLAB/Simulink. In this paper, there are two conditions of the control system in the test, without load and with load. The response result of the proposed control system tuned gains by PSO is no overshoot and approaches to the steady state better than GA and TS methods. Moreover, it is able to maintain the output voltage feedback at a constant level according to the control signal both without load and with load conditions. As a result, the four-phase interleaved boost converter is regulated by the PI controller tuned gains with PSO which could efficiently maintain the voltage of both levels.

This study presents voltage control with PI controller for four phase interleaved boost converter. The control of voltage control is done by using PI Controller to control output voltage of the four sets of boost converter parallel connected. Each set works interleaving with 90 degree of distance using 586 microhenry inductor, inner resistance of inductor 0.4 ohm/phase, 400 microhenry capacitor, resistance load at the beginning 10 ohm, lowest resistance 2 ohm, input voltage 13.8 volt, output voltage 24 volt. The result of the experiment shows that the circuit maintain the level of output voltage required which is 24 volt, both while changing 10 ohm resistant load to 2 ohm and interchanging. The circuit also still maintain the level of output voltage at 24 volt same.

The four phase interleaved boost converter has been widely implemented in various studies, for example, solar cell application, fuel cell energy and application with electric motor driving. Due to various applications of the four-phase interleaved boost converter, this study presents another possible simulation of four-phase interleaved boost converter with inductor $586.5 \mu \mathrm{H}$ and inner resistant of inductor $0.4 \Omega /$ phase, capacitor $400 \mu \mathrm{F}$, resistant load when start $10 \Omega$, lowest resistant load $2 \Omega$, input voltage 13.8 volt, output voltage 24 volt, duty cycle for mosfet switching 42.5% and frequency switch 25 kH z for reducing ripple of input current, ripple of output current, ripple of output voltage. This is also to support the increasing of load power. The results compare two types of boost and another type of single phase boost converter using large inductor. It found that the four-phase interleaved boost converter can reduce the ripple of input, output current and output voltage like using a large inductor and also provided the circuit response faster than traditional single phase boost converter. In summary, the proposed system is capable of simulating for the circuit operation.

In various industries, the high efficiency and endurance of a Brushless DC (BLDC) motor. It is an important component in control system of electromechanics speed. A Brushless DC motor has been commonly used in various industries because of its high efficiency, endurance. Appropriate controller design in the response mode of BLDC motor speed enhances the efficiency in controlling motor speed. The objective of this research is to propose the Proportional Integral (PI) controller to stabilize the motor speed. A PI controller can be formulated in terms of K P and K I , a proportional and an integral gain parameters, respectively. The increase in proportional gain results in the system’s response is increasing. For suitable integral gain parameter of system, the exceeding steady-state error in the system can be eliminated by the increase of integral gain. The increase of high efficiency of motor’s response to control the motor can be applied to DSP TMS320F28335 board. For testing and simulation of controlling BLDC motor speed, the experiment’s parameters were determined as follows: 24 V, 350 W, and rotational speed of motor 3,000 rpm. The experiment of the system was based on state space model. The experimental result showed that controlling non-load motor speed would be adjusted by PI controller during steady state with reference signal varying with time. When the load was supplied the motor, the rotational speed of motor would decrease and return to its steady state in which the motor response was faster active in the reference signal system. Consequently, the PI controller of controlling BLDC motor’s rational speed is an alternative and efficiency.

This paper proposes a design of optimal PI(D) controller for brushless DC (BLDC) motor speed control by the particle swarm optimization (PSO), one of the powerful metaheuristic optimization search techniques. The proposed control system is implemented on the TMS320F28335 DSP board interfacing to MATLAB/SIMULINK. With Back EMF detection, the proposed system is considered as a class of sensorless control. This scheme leads to the speed adjustment of the BLDC motor by PWM. In this work, the BLDC motor of 100 watt is conducted to investigate the control performance. As results, it was found that the speed response of BLDC motor can be regulated at the operating speed of 800 and 1200 rpm in both no load and full load conditions. Very satisfactory responses of the BLDC system can be successfully achieved by the proposed control structure and PSO-based design approach.

A Brushless Direct Current (BLDC) motor has been widely used due to the high efficiency, durability, easy maintenance, and winding dynamically faster than a brushed direct current motor. The objectives of this research are to investigate and analyze the efficiency of function and the response of BLDC motor in the neighbor of speed response. The simulation of BLDC motor was established in the mathematical model as the state space model which was in the first order of differential equations as well as the analysis in time domain and in the signal with Multi MIMO simulation. The investigation in the behavior of BLDC motor is classified to two cases, load motor and non-load motor, with testing for BLDC motor, rated voltage (24 V), rotational speed (3,000 rmp). The simulation results showed that the load supply for motor resulted in the decrease in the rotational speed but the increase in the current. Therefore, the load supplied for BLDC motor affects the motor's response behavior in term of rotational speed decreasing and current increasing.

This paper presents a design and implementation of Brushless DC (BLDC) motor speed control based on the TMS320F28335 DSP board interfacing to MATLAB/SIMULINK. To obtain the optimal tracking and regulating responses, the PI controller is conducted and designed by pole placement technique. With Back EMF detection, the proposed system is considered as a class of sensorless control. This scheme leads to the speed adjustment of the BLDC motor by PWM. This experiment aims to examine the effectiveness of BLDC motor by testing the BLDC motor of 100 watt. It was found that the speed response of BLDC motor can be regulated at the operating speed of 700 rpm and 1400 rpm at no load and full load conditions.

Wind energy is a sustainable renewable source of energy since the wind will be around as long as the sun keeps shinning. Wind energy is mainly used to generate electricity. A wind turbine uses kinetic motion to generate clean and renewable energy. In the case of a wind turbine, the turbine blades are designed to capture the kinetic energy in wind. In this paper, the wind turbine is based on Permanent Magnet Synchronous Generator (PMSG) to transform mechanical energy into electrical energy for three-phase of grid connected. The filter is designed in a control system with PI to control the active power (P) and reactive power (Q). The experimental design has connected to the electrical power system with voltage at 380 V and 50 Hz. The simulated results have shown that at 0.1 second, it found that the grid connected system can improve oscillation and reduce maximum overshoot in a life time. As a result, the power system can transfer active and reactive power in grid connected with PMSG, effectively.

Renewable energy is clean and effectively infinite. Wind is as sources of sustainable energy. Accessing wind power, it can reduce electric cost for urban building. Wind power generates electricity by converting kinetic energy in wind to generate electricity. In this paper, wind energy is measured on urban building in Bangkok at Pathumwan Institute of Technology (PIT) which is the height from the ground at 25 meters. Approximating a wind power, the weather data consists of wind speed, wind direction, temperature and humidity. The datasets are collected in a minute and converted into database system (PITWeatherDB). Artificial Neural Network (ANN) has been applied to estimate the potential wind energy in short-term. The performances of ANN are considered by mean square error (MSE) and the correlation between ANN output and observed data from PITWeatherDB are measured. The experimental results show that the topology of six neuron nodes in input layer, ten neuron nodes in hidden layer and a neuron node output is trained by Levenberg–Marquardt algorithm. It has high correlation and minimum MSE.

Thailand has limited resources to generate the electric power. In developing countries, the electrical demand is growing continuously. Power system planning is very important issues. There are three major components of the electrical power system namely, generation, a high voltage transmission line, and a distribution system. The hourly power variables, at Bamnet Narong substation in northeastern Thailand is fed to artificial neural network models for the short-term load forecasting. The training dataset in ANN is from measurement data of Supervisory Control and Data Acquisition (SCADA) system such as true power, reactive power and voltage source. The training methods with optimized weights in the ANNs, Levenberg-Marquart algorithm (LMA) and Gradient Descent algorithm (GDA), are applied. The results have shown that the ANN with LMA is more effective than GDA.

The brushless DC motor is widely used in various industrial fields because of low maintenance, high power density and high efficiency. The permanent magnets in the rotor generate a constant magnetic flux which is limited by the motor speed range. Mathematical modelling of brushless DC motor is necessary for realizing the dynamic behaviour. This paper presents a phase advanced angle for brushless DC motor to extend speed range of brushless DC motor beyond the rate top speed. The experimental designed system is simulated. The simulated results show that a phase advanced angle in the designed system can extend speed range. Finally, it can improve the ability of the proposed system, efficiently.

This paper presents the electrical power conversion system which is developed for a self-excited induction generator in order to apply with wind turbine. In the wind energy conversion system, a self-excited induction generator is converted the mechanical energy into electrical energy. A B6 rectifier and capacitor are utilized to maintain constant intermediate DC voltage. The average power is converted entirely by the PWM converter, consists of B6 voltage-source inverters. Output currents and active power of switch mode voltage source inverter are flowed into utility grid by current control and PQ theory technique. For the hardware implementation, the system consists of 1kW four poles self excited induction generator and the voltage source inverter controlled output current by hysteresis controller(bang-bang) method. The algorithm is implemented in a dSPACS ds1104DSP together with MATLAB/SIMULINK program. The validity of the proposed method is verified by both simulation and experimental results under power transferred into grid in term of power quality such as real power, reactive power, total harmonics distortion, and so on.

Permanent magnet synchronous generator (PMSG) can convert the mechanical energy to electrical energy. PMSG is the one of widely used and consists of rectifier and capacitor to maintain direct current (DC) voltage to be constant. Pulse width modulation (PWM),converting DC to alternating current (AC) power is the method to control the voltage source inverter and transfers the electrical energy to grid connected. The objective in this study is to control the electrical power and purpose the method to control the current. To Measurement of voltage terminal on the grid, it is converts command current to control active power (P) and relative power (Q) theory technique. There are two modes in the simulation experiment that are rectifier and inverter modes. The initial condition of DC bus for the simulation is 600 VDC and step command of the active power from 1 kW to -1 kW in the relative power of zero constant. The results show that the electrical power can be transferred and received to the grid connected by vo...

The objective of this paper is to present the simulation of field oriented control using dynamic three-phase induction motor model that developed by MATLAB/Simulink, fed by Pulse Width Modulation (PWM) inverter to be studied, understood and observed the response of the control system such as speed, torque and phase current with step input command signal. The motor control is divided into two control loops, inner current loop and outer speed control loop using proportional plus integral (PI) controller. In the current loop, the first current control loop generates stator flux and another one generates rotor torque of the induction motor. The rotor flux quantities are estimated using computational rotor time constant, rotor angular velocity and stator current. The performance of the feedback control system is tested under different speed command and load disturbances..

This paper introduces the performance improvement of a slip energy recovery drive system for the speed control of a wound rotor induction motor by a voltage-controlled technique. The slip energy occurred in the rotor circuit is transferred back to ac mains supply through a reactor instead of a step up transformer. The objective of the voltage-controlled technique is to increase power factor of the system and to reduce low order harmonics of the input line current. The drive system is designed and implemented using a voltage source inverter in conjunction with a boost chopper for DC link voltage, instead of a conventional drive using a 6 pulse converter or a Scherbius system. The slip power is recovered by the help of a voltage source inverter (VSI) based on a space vector pulse width modulation (SVPWM) technique. In order to keep the speed of the wound rotor induction motor constant over a certain range of operating conditions, the servo state feedback controller designed by a linear quadratic regulator (LQR) is also introduced in this paper. The overall control system is implemented on DSP, DS1104’TMS320F240 controller board. The performance improvement of the proposed system is tested in comparison with the conventional Scherbius system and the modified conventional Scherbius system by a 12 pulse converter in conjunction with a chopper at steady state and at dynamic conditions. A 220 W wound motor is employed for testing. It is found that the motor speed can be controlled to be constant in the operating range of 450–1200 rpm at no load and full load. It is also found that the efficiency of the proposed system is remarkably increased since the harmonics of the input ac line current is reduced while the ac line input power factor is increased.

This paper introduces a modified slip energy recovery drive system for speed control of a wound rotor induction motor offering improvement of drive performance, particularly line power factor and overall system efficiency. A 12-pulse line commutated thyristor converter operating in an inverter mode in conjunction with an additional IGBT shunt chopper is employed to transfer slip energy back to ac mains supply via three phase transformers. This approach offers motor speed control by varying the duty cycle of the chopper instead of changing the inverter firing angle. As a consequence, supply power factor can be improved. The servo state feedback designed by linear quadratic regulator (LQR) with observer is also included in order to keep motor speed to be constant over a certain range of operating conditions by using the estimated dc link current derived from motor speed. The advantage of this technique is absence of current transducers for current feedback control loop. The overall control system is implemented on DSP, DS1104’TMS320F240 controller board. Experimental results are illustrated in order to validate performance of the proposed system.

The intensified current search (ICS) is one of the newest metaheuristic optimization search techniques for solving the continuous optimization problems. It is the latest modified version of the original current search (CS). In this paper, the algorithms of the ICS is proposed and the performance evaluation of the ICS is investigated via five well-known surface optimization problems. The ICS is then applied to design an optimum PID controller for the AVR widely used in power systems. Based on the optimization context, the sum of absolute errors between reference input and output response of the system is performed as the objective function to be minimized. This paper demonstrates how to conduct the ICS to search efficiently the optimum PID controller parameters of the AVR system. As results, the optimum PID controller for the AVR system is successfully and rapidly obtained by the ICS. Moreover, the ICS-based design approach performs high robustness once parameter variations are occurred in the control loop.

This paper presents design and implements the state feedback controller to design using Matlab/simulink for a speed control system of DC motor. The proposed controller will be a state feedback with state observer controller incorporating integrator. The controller design by pole placement technique is also introduced to the system for regulates and tracking speed response. The overall control system is implemented on dSPACE DSP DS1104 controller board. This scheme leads to be able to adjust the speed of the motor by control the input voltage of power amplified. The experimental results in testing the 48 watt DC motor system from no load condition to rated condition show the effectiveness of the proposed control scheme. It is found that the motor speed can be controlled to be constant in the operating range of 0-3200 rpm at no load and full load.

This paper presents the comparison power quality of the voltage source inverter type a space vector pulse width modulation (SVPWM) and sinusoidal pulse width modulation (SPWM) technique for adjust speed of the induction motor. All the drives are implemented on real-time Simulink model of three phase variable magnitude of voltage and variable frequency type are used the drive voltage source inverter system. This scheme leads to be able to adjust the speed of the motor by control the frequency and amplitude of the model. The ratio of input stator voltage to frequency should be kept constant. The overall control system is implemented on dSPACE DSP DS1104 controller board. The power quality of voltage source inverter are measured and compared to supply the 120 watt induction motor full load condition.

This paper presents design and implements the two degree of freedom (T-DOF) technique to design using Matlab/simulink for a reactive power and voltage control system of the synchronous generator. The proposed controller will be a Proportional Integral Derivative(PID) controller. The T-DOF PID controller design by root locus technique is also introduced to the system for regulates and tracking terminal voltage response. The overall control system is implemented on dSPACE DSP DS1104 controller board. This scheme leads to be able to adjust the output voltage of the generator by control the input voltage of exciter. The experimental results in testing the 300 watt generator system from no load condition to rated condition show the effectiveness of the proposed control scheme. It is found that the output phase voltage can be controlled to be constant in the operating range of 80-110 volt of a resistive, inductive and capacitive load.

This paper presents the approach to design the Auto- Tuning PID controller for interactive Water Level Process using integral step response. The Integral Step Response (ISR) is the method to model a dynamic process which can be done easily, conveniently and very efficiently. Therefore this method is advantage for design the auto tune PID controller. Our scheme uses the root locus technique to design PID controller. In this paper MATLAB is used for modeling and testing of the control system. The experimental results of the interacting water level process can be satisfyingly illustrated the transient response and the steady state response., {"references":["L, Ljung, System Identification Theory for the User, Englewood\nCliffs, NJ, Prentice-Hall 1987.","J.G. Ziegler and N.B. Nichols, \"Optimum settings for automatic\ncontrollers\", Trans. ASME, vol.65, 1943, pp.433-444.","K.J. Astrom and T. Hagglund, \"Automatic tuning of simple regulators\",\nProceeding of IFAC 9th World Conger.,Budapest, Hungary, 1984, 1867-\n1872.","J. Dorsey, Continuous and Discrete Control Systems, McGraw Hill,\n2002.","Numsomran A.,\"2-DOF Control System Designed by Root Locus\nTechnique\", Proceeding of KACC control 15th,Korea, October 2000."]}

This paper presents design and implements the T-DOF PI controller design for a speed control of induction motor. The voltage source inverter type space vector pulse width modulation technique is used the drive system. This scheme leads to be able to adjust the speed of the motor by control the frequency and amplitude of the input voltage. The ratio of input stator voltage to frequency should be kept constant. The T-DOF PI controller design by root locus technique is also introduced to the system for regulates and tracking speed response. The experimental results in testing the 120 watt induction motor from no-load condition to rated condition show the effectiveness of the proposed control scheme., {"references":["Andrzej M. Trzynadlowski, Introduction to Modern Power Electronics,\nJohn Wiley & Sons, 1998.","Bimal K.Bose, Modern Power Electronics and AC Drives, ┬® Prentice\nHall PTR, 2002.","W. Leonhard, Control of Electrical Drives, Springer-Verlag Berlin\nHeidelberg, New York, Tokyo, 1985.","Numsomran A.,\"2-DOF Control System Designed by Root Locus\nTechnique\", in Proc. 15th KACC control ,Korea, October 2000","Bimal K. Bose, Modern Power Electronics and AC Drives, Prenti Hall\nPTR, 2002","DSP Based Electric Drives Laboratory User Manual : Frequency\nControl of AC-Motor Drives., Department of Electrical and Computer\nEngineering University of Minnesota.","Introduction Getting Started with dSPACE DSP Based Laboratory of\nElectric Drives., Department of Electrical and Computer Engineering\nUniversity of Minnesota.","Tunyasrirut S., \"Implementation of a dSPACE based Digital State\nFeedback Controller for a Speed Control of Wound Rotor Induction\nMotor\", in Conf. 2005 IEEE Int. Conf. Industrial Technology, 14-17\nDec.2005, pp. 1198-1203.","Satean Tunyasrirut, Sompong Srilad and Tianchai Suksri, \"Fuzzy Logic\nControl for a Speed Control of Induction Motor using Space Vector\nPulse Width Modulation\", Transaction on Engineering, Computing and\nTechnology Volume 19 January 2007 ISSN 1305-5313, pp 71-77.\n[10] Satean Tunyasrirut and Sompong Srilad \"Speed Control with Slip\nRegulation of Induction Motor Drives with Space Vector Pulse Width\nModulation Technique\", Proceeding of the Third IASTED Asian\nConference Power and Energy Systems\" April 2-4, 2007, Phuket,\nThailand, ISBN CD: 978-0-88986-657-7, pp 12-16.\n[11] Sompong Srilad, Satean Tunyasrirut and Tianchai Suksri,\n\"Implementation of a Scalar Controlled Induction Motor Drives\" SICEICASE\nInternational Joint Conference 2006, Oct. 18-21, 2006 in Bexco,\nBusan, Korea, pp 3605-3610."]}

This paper presents design and implements a voltage source inverter type space vector pulse width modulation (SVPWM) for control a speed of induction motor. This scheme leads to be able to adjust the speed of the motor by control the frequency and amplitude of the stator voltage, the ratio of stator voltage to frequency should be kept constant. The fuzzy logic controller is also introduced to the system for keeping the motor speed to be constant when the load varies. The experimental results in testing the 0.22 kW induction motor from no-load condition to rated condition show the effectiveness of the proposed control scheme., {"references":["Andrzej M. Trzynadlowski, Introduction to Modern Power Electronics,\nCopyright┬® 1998 by John Wiley & Sons, Inc. All rights reserced.","Bimal K.Bose, Modern Power Electronics and AC Drives, ┬® 2002\nPrentice Hall PTR.","W. Leonharn, Control of Electrical Drives, Springer-Verlag Berlin\nHeidelberg, New York, Tokyo, 1985.","F. Ashrafzadeht, E.P. Nowickit, and J.C. Samont, \"A Self-Organizing\nand Self-Tuning Fuzzy Logic Controller for Field Oriented Control of\nInduction Motor Drives\", 0-7803-3008-0/95 $4.00┬® 1995 IEEE, pp.\n1656-1662.","Zdenko Kovaccic and Stjepan Bogdan, Fuzzy Controller design Theory\nand Applications, ┬® 2006 by Taylor & Francis Group. International,\n2002.","Hoang Le-Huy and Maher Hamdi, \"Control of Direct-Drive DC Motor\nby Fuzzy Logic\", 0-7803-1462-x/93$03.00 ┬® 1993 IEEE, pp. 732-738.","DSP Based Electric Drives Laboratory User Manual, Frequency Control\nof AC-Motor Drives, Department of Electrical and Computer\nEngineering University of Minnessota.","University of Minnesota, Introduction Getting Started with dSPACE,\nDSP Based Laboratory of Electric Drives.","Katsuhiko Ogata ,Modern Control Engineering Fourth Edition, Prentice\nHall International, 2002.\n[10] Satean Tunyasrirut, \"Implementation of a dSPACE-based Digital State\nFeedback Controller for a Speed Control of Wound Rotor Induction\nMotor\",0-7803-9484-4/05/$20.00┬®2005 IEEE, pp.11981203.\n[11] Control Desk Experiment Guide, dSPACE, May 2002."]}

This paper presents design and implement a V/F control speed of induction motor. This scheme leads to be able to adjust the speed of the motor by control the frequency and amplitude of the stator voltage, the ratio of stator voltage to frequency should be kept constant, which is known as V/F or scalar control. The PI controller is applied to speed signal model of the inverter and is then downloaded to dSPACE through Simulink. The experimental results are analyzed and compared simulation in testing the 0.22 kW induction motor from no-load condition to rated condition, it's found that the motor speed to be constant when the load varies, as shown the effectiveness of the proposed control scheme.

This paper proposes a design fuzzy logic controller to control the water level in horizontal tank which has diameter 300 mm, long 480 mm, and total volume 33.9 litters. The proposed controller is implemented on a microcontroller MCS-51 by using C language. The performance of the system can be improved even when step inputs is used. The rise time and steady state error of the process response are considered. From the experiment results found that the proposed controller can be effectively used for controlling the level in horizontal tank with and without interrupt load accurately

Fuzzy logic control is considered for speed of wound rotor induction motors with slip energy recovery. The speed is limited at some range of sub-synchronous speed of the rotating magnetic field. By controlling speed by adjusting the resistance value in the rotor circuit the efficiency of power is reduced, because of the slip energy lost when it passes through the rotor resistance. The control system is designed to maintain efficiency of the motor. A fuzzy logic control method is applied for self-tuning the system by keeping the speed constant and adjusting the rotor current appropriate to the load. Good transient response without overshoot can be obtained.

This paper introduces the speed and power control a slip energy recovery drive using voltage-source PWM converter with current-controlled technique. The slip energy occurred in the rotor circuit is transferred back to ac mains supply through a reactor and a step up transformer. The objective of the current-controlled technique is to increase power factor of the system and to reduce low order harmonics of the input line current. The drive system is designed and implemented using a voltage source inverter in conjunction with a boost chopper for DC link voltage, instead of a conventional drive using a 6 pulse converter or a Scherbius system. The slip power is recovered by the help of a voltage source inverter (VSI) based on a current-controlled technique. In order to keep the speed of the wound rotor induction motor constant over a certain range of operating conditions, the servo state feedback controller designed by a linear quadratic regulator (LQR) is also introduced and the PI controller designed by pole placement method is also introduced in control the slip power this paper. The overall control system is implemented on DSP, oller board. A 1 kW wound motor is employed for testing. It is found that the motor speed can be controlled to be constant in the operating range of 600-1200 rpm at no load and full load. It is also found that the harmonics of the input ac line current is reduced while the ac line input power factor is increased.

This paper presents a power thyristors based soft starter strategy for an induction-generator based wind turbine system. Soft-starter is designed to reduce inrush current or surge in current while achieving a proper synchronism between the generator and the grid. The designed soft-starter successfully limits the high inrush current during the connection of the wind-turbine system to the grid. An experimental investigation is done to find out suitable values of the power thyristor for soft-connection of a wind turbine system with the grid. Tests are carried out on a three phase induction generator, based system controller and relays for the system connection/disconnection from the grid. This paper describes the soft-starting principle, the designed soft-starter, application of the soft-starter in wind power generation, and experimental test results.