Zelmira Ferkova

Optimal Input Vector Based Fuzzy Controller Rules Design

The paper deals with the method of design of a fuzzy controller the rules of which are based on generating the optimal input vector using a genetic algorithm. The method is first demonstrated on a simple linear system and is then applied to the start-up of a drive with a three-phase asynchronous motor with constant torque, representing a strongly nonlinear fifth order dynamic system. The proposed controller is verified through simulation using the MATLAB software package. Achieved results present a simple applicability of this proposed procedure for a wide class of nonlinear dynamic black-box systems.

Flywheel energy storage system for city railway

This article makes an effort to explain practice using of stationary energy storage system based on flywheel (FESS). We are introducing two fundamental methods of utilization of the FESS for the tram transportation or trolleybus lines. The main goal of these methods is to save non-utilized energy from the DC railway and use it for covering the consumption peaks and to decrease the total power load of the traction substation from the viewpoint of the power grid. The ideal case is complete smoothening of the course of used energy. The principle of these methods is demonstrated on real data measured during the operation of the tramcar in Liberec.

3D EM modelling of DC traction motors for pairing of motors in tram undercarriages

The article deals with modelling of tram DC series motors. The finite element method in 3D and 2D ANSYS / Maxwell program is used. The main objective is to focus on the effects of the electromagnetic imbalances or imperfections that they arise in the maintenance and repair of DC series motors.

Modelling of switched reluctance motor drive based on ANSYS simplorer

The paper presents a nonlinear model of switched reluctance motor with a number of poles 2p1/2p2 = 6/4. The model of SRM is based on the multidimensional look-up table, and it was created using software ANSYS Simplorer. The basic control algorithm and direct torque control method are described below. Simulation results using the ANSYS Simplorer are included in this document as well.

Dynamic emulation of mechanical loads — Analysis and implementation into industrial drive

The paper presents an approach to the dynamic emulation of mechanical loads. The main goal was to implement known control algorithm to the industrial converter SINAMICS S120 with the control unit CU320 using Drive Control Chart programming tool. The reference torque of a load machine is calculated through the closed-loop control algorithm using PI estimator. Proposed implementation enables the user the emulation of various mechanical loads with the industrial drive dynamometer, although only variation of the inertia and the viscous friction is reported here.

Magnetic shield optimization for the multi-motor assembly

Electric motor influences its surroundings by stray magnetic fields. Their intensity is usually small compared to the intensity inside the motor due to a closed magnetic circuit. However, there are other open motor constructions where the influence of stray magnetic fields cannot be neglected. This paper analyses a particular case of influence of stray magnetic fields of a motor in the multi-motor assembly. Three bipolar two-phase stepping motors with permanent magnets are arranged close to each other. The rotor position of each motor is affected by stray magnetic fields of nearby motors. Therefore the magnetic shielding is placed between rotors to reduce the position shift of the rotor due to the rotation of neighbouring rotors. The dimensions, namely diameter and thickness, of the shielding element are design variables of optimization. The objective function is a sum of squared deviations of a rotor position from each desired step angle and should be minimized. The value range of diameter and thickness is restricted by motor dimensions. Step angles are calculated by Finite element method. For this purpose, a MAXWELL ANSYS 3D model of multi-motor assembly was built, and a dynamic rotor angle response was simulated. The steady state angle for each half step is retrieved from simulation and is used for the objective function evaluation. Response surface of the objective function, as well as optimal dimensions of the magnetic shield subject to optimization constrains, is showed.

Physical and energy analysis of therapy applying low-dynamic magnetic fields

This article makes an effort to explain physical and energy aspects of practice using magneto therapy in physiotherapy and rehabilitation. We are presenting the principles of electromagnetic induction in muscle tissue as a typical example of parts of human body. The main goal of these analyses is to warn about physical and energy differences among individual types of power sources of magnetic field and their dynamic behaviour. In theory the problems are indicated with modelling of low dynamic magnetic field in the living tissue.

Measurement of switched reluctance motor parameters

Torque ripple presents the main disadvantage of switched reluctance motor. Advanced control methods allow to minimize the torque ripple, which requires knowing the motor parameters — inductance and torque characteristics. The paper presents parameter identification of switched reluctance motor with 2p1/2p2 = 12/8 number of poles. Included in this document are results of inductance and torque measurements. Industrial components were used to measure torque characteristics. Characteristics are compared with finite element analysis model.

Analysis of tram DC traction motors pairing

The presented article deals with analysis of the motor pairing procedure and presents a computer model of the testing dynamometer including motor and dynamo non-linearity created in Matlab/Simulink. The model was used in the one-factor-at-a-time sensitivity analysis to determine which of the measured values has the greatest impact on the motor torque characteristics. An optimal pairing procedure is discussed.

Analysis of mutual influence of rotors in multi-motor assembly

Electric motor influences its surroundings by stray magnetic fields. This influence does matter in certain cases hence reduction of the field intensity outside the motor is a part of the motor design. The primary objective is to provide a safety region for humans, reduce a low-frequency electromagnetic emission, or produce magnetically silent electrical machines for propulsion of some military or oceanographic ships where low magnetic stray fields are required. This paper analyses the particular case of influence of stray magnetic fields of a motor in the multi-motor assembly of several stepper motors. The rotor position of each motor is affected by stray magnetic fields of nearby motors. Finite element analysis of mutual influence is provided, and construction change is suggested to reduce the position shift of the rotor due to the rotation of neighbouring rotors.