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Open access

M. Abdullah Eissa

Abstract

This paper proposes a newly adaptive single-neuron proportional integral derivative (SNPID) controller that uses fuzzy logic as an adaptive system. The main problem of the classical controller is lacking the required robustness against disturbers, measurement noise in industrial applications. The new formula of the proposed controller helps in fixing this problem based on the fuzzy logic technique. In addition, the genetic algorithm (GA) is used to optimize parameters of the SNPID controller. Because of the high demands on the availability and efficiency of electrical power production, the design of robust load-frequency controller is becoming increasingly important due to its potential in increasing the reliability, maintainability and safety of power systems. So, the proposed controller has been applied for load-frequency control (LFC) of a single-area power system. The effectiveness of the proposed SNPID controller has been compared with the conventional controllers. The simulation results show that the proposed controller approach provides better damping of oscillations with a smaller settling time. This confirms its superiority against its counterparts. In addition, the results show the robustness of the proposed controller against the parametric variation of the system.

Open access

Leszek Jarzebowicz

Abstract

Pulse width modulation (PWM) of inverter output voltage causes the waveforms of motor phase currents to consist of distinctive ripples. In order to provide suitable feedback for the motor current controllers, the mean value must be extracted from the currents’ waveforms in every PWM cycle. A common solution to derive the mean phase currents is to sample their value at the midpoint of a symmetrical PWM cycle. Using an assumption of linear current changes in steady PWM subintervals, this midpoint sample corresponds to the mean current in the PWM cycle. This way no hardware filtering or high-rate current sampling is required. Nevertheless, the assumption of linear current changes has been recently reported as over simplistic in permanent magnet synchronous motor (PMSM) drives operating with low switching-to-fundamental frequency ratio (SFFR). This, in turn, causes substantial errors in the representation of the mean phase currents by the midpoint sample. This paper proposes a solution for deriving mean phase currents in low SFFR PMSM drives, which does not rely on the linear current change assumption. The method is based on sampling the currents at the start point of a PWM cycle and correcting the sampled value using a model-based formula that reproduces the current waveforms. Effectiveness of the method is verified by simulation for an exemplary setup of high-speed PMSM drive. The results show that the proposed method decreases the error of determining the mean phase currents approximately 10 times when compared to the classical midpoint sampling technique.

Open access

Paweł Ewert

Abstract

The paper presents the possibility of using neural networks in the detection of stator and rotor electrical faults of induction motors. Fault detection and identification are based on the analysis of symptoms obtained from the fast Fourier transform of the voltage induced by an axial flux in a measurement coil. Neural network teaching and testing were performed in a MATLAB-Simulink environment. The effectiveness of various neural network structures to detect damage, its type (rotor or stator damage) and damage levels (number of rotor bars cracked or stator winding shorted circuits) is presented.

Open access

Youssef Agrebi Zorgani, Mabrouk Jouili, Yassine Koubaa and Mohamed Boussak

Abstract

A sensorless indirect stator-flux-oriented control (ISFOC) induction motor drive at very low frequencies is presented herein. The model reference adaptive system (MRAS) scheme is used to estimate the speed and the rotor resistance simultaneously. However, the error between the reference and the adjustable models, which are developed in the stationary stator reference frame, is used to drive a suitable adaptation mechanism that generates the estimates of speed and the rotor resistance from the stator voltage and the machine current measurements. The stator flux components in the stationary reference frame are estimated through a pure integration of the back electro-motive force (EMF) of the machine. When the machine is operated at low speed, the pure integration of the back EMF introduces an error in flux estimation which affects the performance torque and speed control. To overcome this problem, pure integration is replaced with a programmable cascaded low-pass filter (PCLPF). The stability analysis method of the MRAS estimator is verified in order to show the robustness of the rotor resistance variations. Experimental results are presented to prove the effectiveness and validity of the proposed scheme of sensorless ISFOC induction motor drive.

Open access

R. Anand, B. Gayathridevi and B. K. Keshavan

Abstract

Permanent magnet motor drive is a widely used technology, offering many advantages, such as exceptional speed, torque control and greater flexibility. Improvement of reliability and efficiency has become a great research interest. Towards this direction and taking into account the major developments in permanent machine technology over the recent years, the use of energy recovery converters has been introduced in various industrial applications. In this paper, the effects of harmonics on a three-phase motor controlled by a drive are analysed, and the behaviours of the filter topology after adopting regenerative drives are studied. The main contribution of this study is a methodology to foresee the standards that can be achieved with the use of an active front end system topology with filters. Moreover, the use of an optimum filter that eases the power system distortion is presented. The analysis presented in this paper is validated experimentally.

Open access

Honoriu Valean, Cola Cristian, Andrei Wegroszta and Cristinel Costea

Abstract

This paper discusses mobile notifications in the context of health monitoring system that measure and store vital signs of the patient that are included in this program. The values measured are temperature and cardiac rhythm. This has two Android application, one is used by the patient to monitor his vital signs and the other is used by the physician to be able to see and receive push notifications of each individual patient. The sensors are connected to a Raspberry Pi and these devices send information to the Android smartphone via Bluetooth. The physician can monitor patient data in real time. All the information that is gathered by the smartphone from the sensors are sent to the cloud, can project a history and can detect some anomalies, for example, if the cardiac pulse is not within the limits of an accepted interval.

Open access

Mateusz Dybkowski

Abstract

In the paper, the concept of universal speed and flux estimator with additional parameters estimators is presented. Proposed solution is based on the Model Reference Adaptive System (MRAS) type flux and speed estimator and can be used in different industrial systems (especially in the automotive applications). Induction Motor (IM) parameters are estimated using the systems based only on simple simulators and adaptive systems (voltage model and current model). Proposed system was tested in the sensorless induction motor drive with the Direct Field Oriented Control (DFOC) algorithm. Simulation and experimental results are presented in the paper.

Open access

Alexandru Lodin, Lacrimioara Grama and Corneliu Rusu

Abstract

Recently have been reported methods to deliver a digital filter from an analog active filter, described only by its circuits diagram. The proposed approaches have been implemented in MATLAB and Python, and they were based on state-space conversion from analog to digital domain. Based on the Python approach, we show in this paper how to compute the transfer function of a large order analog active filter. The analog filter is described only by its circuits diagram. Finally, the analog filter is converted to the corresponding digital filter, having similar frequency gain and phase characteristics.

Open access

Maciej Chojowski

Abstract

The purpose of the article was to present the idea of space vector pulse width modulation (SVPWM) and implementation in Nios II softcore processor. The SVPWM module was described in a classical method in hardware description language both as an independent structure and as an additional component to softcore processor. The available methods were compared, and the experiment was carried out in the laboratory to test implemented SVPWM algorithm using high-speed induction motor.

Open access

Maciej Chojowski

Abstract

The purpose of this paper was to present a method for the estimation of the rotor speed and position of brushless DC (BLDC) motor. The BLDC motor state equations were developed, and the model was discretised. Extended Kalman filter has been designed to observe specific states from the state vector, needed for the sensorless control (rotor position) and to determine the speed, which may be useful to use as a feedback for the controller. A test was carried out to determine the noise covariance matrices in a simulation manner.