Browse

81 - 90 of 112 items :

  • Electronics x
  • Engineering x
Clear All
Fuzzy Adaptation in a State Space Controller Applied for a Two-Mass System

Abstract

Application of a state space controller for two-mass system has been examined. However, the classical version of the controller was modified in order to improve properties of the whole system. For this purpose fuzzy model was implemented as an adaptation element for the parameters. The theoretical description of the control structure, numerical tests and experimental results (using dSPACE1103 card) have been presented.

Open access
Parametric-Active Compensation of Earth Fault Current in an It-Type Network

Abstract

The parametric-active compensation of earth leakage currents which minimalized virtual capacitance current in ships of IT-type network has been discussed. The protection is based on automatic compensation of leakage earth currents. The protection system is governed by a controller. The results of simulation tests have been presented. The parametric-active compensation of earth leakage currents which minimalized virtual capacitance current in ships with IT-type network has been discussed.

Open access
Performance Study of a New High Instantaneous Power Impulse Converter with a Switched Capacitor Unit

Abstract

A new high instantaneous power impulse converter (HIPIC) with a switched capacitor unit has been presented. HIPIC generates very short impulses (hundreds of microseconds) of instantaneous power in megawatt range while the average power is much lower (tens of kilowatts). The presented topology is composed of step-down converters, an H-bridge converter and a switched capacitor, adjusted with a new current control. It allows one to achieve the output current impulses with very short rising and falling times and strict peak current control with low ripples.

Open access
Position Tracking Systems for AC Drives Employing Forced Dynamics Control

Abstract

Position tracking systems for AC drives offering high robustness to external load torques have been presented. A triple-loop cascade control structure was employed where the inner loop is a stator current control loop and the middle loop is a speed control loop based on the forced dynamic control and respecting vector control principles. Two alternative outer position control loop designs both of which respect prescribed dynamics and settling time of position have been developed. The former system prescribes also time constant of the speed control loop while the latter one respects time constant of speed control system developed independently. To enhance the tracking abilities of both control systems the dynamic lag pre-compensator has been included. Case studies of the both position control systems for time near-optimal control and energy near-optimal control have been presented. The tracking performances of the designed control systems were assessed based on comparisons of the experimental responses with the simulated responses of the ideal closed-loop system.

Open access
Possibilities for Determining the Interference Between a Power Supply Network and a Converter Fed Drive

Abstract

Measuring instruments, measurement methods, and an exemplary analysis of the impact of chosen operating stages of the converter drive on the power supply network have been presented. The measurements of electrical and mechanical parameters in drive systems used in industry are complex. The task is difficult due to the necessity of connecting a measuring instrument into electric circuits of an active facility with the use of only short non-operational periods of the device. However, a well-chosen model of a drive system allows the multivariate research of the impact of drive parameters and a control algorithm used on voltage and current harmonic content and performance of the system, and therefore on a simulation analysis of the impact of the drive on the power supply network.

Open access
Rotor Fault Compensation and Detection in a Sensorless Induction Motor Drive

Abstract

The compensation and detection analysis of rotor faults in a sensorless induction motor drive system with an additional rotor resistance estimator has been conducted and the influence of the rotor faults on the properties of such system has been examined. The rotor flux vector and rotor speed have been reconstructed by the MRASCC estimator. The drive was tested for various conditions. Simulation tests were performed in the direct field oriented control (DFOC) structure realized in the MATLAB/Simulink software.

Open access
Sliding Mode Speed Control of an Induction Motor Drive Using Time-Varying Switching Line

Abstract

An equivalent sliding mode control method of an induction motor speed has been discussed. The control signal consists of two parts: a continuous and discontinuous one. Very good dynamical response of the drive system has been obtained, which however changes influenced by external and parametric disturbances occurring under various operation conditions. In order to ensure identical dynamic performance of the speed transients and system robustness during the switching line reaching phase, regardless of external and parametric disturbances, the time-varying switching line is proposed. The simulation results have been validated by experimental tests of the induction motor drive system.

Open access
ANTI-WINDUP STRATEGY FOR AN LQ CURRENT CONTROLLER WITH OSCILLATORY TERMS FOR THREE-PHASE GRID-TIE VSCs IN SMES SYSTEMS

Abstract

The paper presents a linear-quadratic current controller with damped oscillatory terms designed for three-phase grid-tie voltage source converters used in SMES systems and operated under distorted grid voltage conditions. Special emphasis is placed on a synthesis of an anti-windup mechanism to prevent wind-up derived from the oscillatory terms by the use of a new active damping loop based on a simple moving average method. As a consequence, the current feedback gain may be increased without unwanted overshoot and overruns, and performance of the system can be improved.

Open access
APPLICATION OF ARTIFICIAL BEE COLONY ALGORITHM TO AUTO-TUNING OF STATE FEEDBACK CONTROLLER FOR DC-DC POWER CONVERTER

Abstract

The article presents an auto-tuning method of state feedback voltage controller for DC-DC power converter. The penalty matrices employed for calculation of controller’s coefficients were obtained by using nature-inspired artificial bee colony (ABC) optimization algorithm. This overcomes the main drawback of state feedback control related to time-consuming trial-and-error tuning procedure. The optimization algorithm takes into account constraints of selected state and control variables of DC-DC power converter. In order to meet all control objectives (i.e., fast voltage response and chattering-free control signal) an appropriate performance index is proposed. Proper selection of state feedback controller (SFC) coefficients is proven by simulation and experimental tests of DC-DC power converter.

Open access
FUZZY ADAPTIVE CONTROL OF NONLINEAR TWO-MASS SYSTEM

Abstract

In the paper, an adaptive control MRAS-based structure for nonlinear two-mass system is proposed. The performance of the control structure is supported by additional compensator. After short introduction a mathematical model of the drive system is presented. In the plant, the additional nonlinearities such as friction and mechanical hysteresis are considered. Then the structure of the fuzzy system is shown. Contrary to the majority of papers the controller considered is based on the II type fuzzy sets. Then the simulation tests showing performance of the proposed structure are presented. The drive is tested at different operation points, including low-speed region where friction plays dominant role. A comparison of classical PI controller with antiwindup and the proposed structure is presented. Then laboratory set-up with DC motor is described briefly. Experimental results are included in the paper. It is shown that the torsional vibrations of two-mass system are damped effectively. The impact of the existing delays of system is discussed. A summary is given at the end of the paper.

Open access