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Effects of Grid Disturbances on Current Source Rectifier Controlled by FCS-MPC Algorithm

Abstract

Nowadays, the increasing number of non-linear loads influences the grid, causing grid voltage disturbances. These disturbances may be very dangerous for the equipment and can create faults in converter behaviour. However, the right control algorithm can improve the reliability of the work. For a current source rectifier, the finite control set model predictive control has been proposed. This method is very flexible because of the variety of the possible cost function forms. It has been examined under grid voltage disturbed by the higher harmonics and the voltage drop. Simulation results prove the ability to damp the distortions and to ensure the unity power factor. Summing up, the algorithm is a very good solution for use in applications such as battery charging, active power filtering and low-voltage direct current load feeding.

Open access
Estimation of Power and Delay in CMOS Circuits using Leakage Control Transistor

Abstract

With a rapid growth in semiconductor Industry, complex applications are being implemented using small size chips, with the use of Complementary Metal Oxide Semi-Conductors (CMOS). With the introduction of new Integrated Circuit (IC) technology, the speed of the circuits has been increased by around 30%. But it was observed that for every two years, the power dissipation of a circuit doubles. The main reason for this power dissipation is leakage currents in the circuit. To reduce these leakage currents, we can reduce the width of the device. In addition to this, we can use lector techniques that use Leakage Control Transistors (LCT) and High Threshold Leakage Control Transistors (HTLCT).In this paper; we present a circuit technique that uses 130 nano-meter CMOS VLSI circuits that use two extra transistors to mitigate the leakage currents. The proposed technique overcomes the limitations posed by the existing methods for leakage reductions an average leakage reductions is 82.5%.The estimation of power and delay will be discussed using LCT’s and HTLCT’s.

Open access
Extended Kalman Filter Based Speed-Sensorless Load Torque and Inertia Estimations with Observability Analysis for Induction Motors

Abstract

This paper aims to introduce a novel extended Kalman filter (EKF) based estimator including observability analysis to the literature associated with the high performance speed-sensorless control of induction motors (IMs). The proposed estimator simultaneously performs the estimations of stator stationary axis components of stator currents and rotor fluxes, rotor mechanical speed, load torque including the viscous friction term, and reciprocal of total inertia by using measured stator phase currents and voltages. The inertia estimation is done since it varies with the load coupled to the shaft and affects the performance of speed estimation especially when the rotor speed changes. In this context, the estimations of all mechanical state and parameters besides flux estimation required for high performance control methods are performed together. The performance of the proposed estimator is tested by simulation and real-time experiments under challenging variations in load torque and velocity references; and in both transient and steady states, the quite satisfactory estimation performance is achieved.

Open access
Extended T-type Inverter

Abstract

This paper presents a new concept for a power electronic converter - the extended T-type (eT) inverter, which is a combination of a three-phase inverter and a three-level direct current (dc)/dc converter. The novel converter shows better performance than a comparable system composed of two converters: a T-type inverter and a boost converter. At first, the three-level dc/dc converter is able to boost the input voltage but also affects the neutral point potential. The operation principles of the eT inverter are explained and a simulation study of the SiC-based 6 kVA system is presented in this paper. Presented results show a serious reduction of the DC-link capacitors and the input inductor. Furthermore, suitable SiC power semiconductor devices are selected and power losses are estimated using Saber software in reference to a comparative T-type inverter. According to the simulations, the 50 kHz/6 kVA inverter feed from the low voltage (250 V) shows <2.5% of power losses in the suggested SiC metal oxide-semiconductor field-effect transistors (MOSFETs) and Schottky diodes. Finally, a 6 kVA laboratory model was designed, built and tested. Conducted measurements show that despite low capacitance (2 × 30 μF/450 V), the neutral point potential is balanced, and the observed efficiency of the inverter is around 96%.

Open access
Introduction to the Special Section on State and Parameter Estimation Methods for Sensorless Drives

Abstract

This short article constitutes an introductory part of the Special Section (SS) on State and Parameter Estimation Methods in Sensorless Drives. In the current issue of the journal, the first part of this section is published. Accepted articles are focussed mainly on estimation of the state variables and parameters for vector-controlled induction motor (IM) drives, using different concepts, such as different types of Kalman filters (KFs) and model reference adaptive systems (MRASs). The KF was also proposed for brushless DC motor (BLDC). Also, neural networks (NNs) have been proposed for mechanical state variables’ estimation of the drive system with elastic couplings.

Open access
Model Predictive Control of Four-Leg Three-Level Flying Capacitor Converter: Influence of Model Parameter Mismatch

Abstract

This paper presents a control method for a four-leg three-level flying capacitor converter (FCC) operating as a shunt active power filter (SAPF), based on model predictive control with finite number of control states (FS-MPC). Current control and capacitor voltage balancing are described. Influence of the mismatch of the inductive filter model parameters on the current control precision is analysed. Results are supported by the experimental waveforms obtained with a 10kVA set-up.

Open access
Neural Network Estimation of Tourism Climatic Index (TCI) Based on Temperature-Humidity Index (THI)-Jordan Region Using Sensed Datasets

Abstract

Jordan which is located in the heart of the world contains hundreds of historical and archaeological locations that have a supreme potential in enticing visitors. The impact of clime is important on many aspects of life such as the development of tourism and human health, tourists always wanted to choose the most convenient time and place that have appropriate weather circumstances. The goal of this study is to specify the preferable months (time) for tourism in Jordan regions. Neural network has been utilized to analyze several parameters of meteorologist (raining, temperature, speed of wind, moisture, sun radiation) by analyzing and specify tourism climatic index (TCI) and equiponderate it with THI index. The outcomes of this study shows that the finest time of the year to entice tourists is “ April” which is categorized as to be “extraordinary” for visitors. TCI outcomes indicates that conditions are not convenient for tourism from July to August because of high temperature.

Open access
Neural State Estimator for Complex Mechanical Part of Electrical Drive: Neural Network Size and Performance of State Estimation

Abstract

This paper presents the results of simulation research of an off-line-trained, feedforward neural-network-based state estimator. The investigated system is the mechanical part of an electrical drive characterised by elastic coupling with a working machine, modelled as a dual-mass system. The aim of the research was to find a set of neural network structures giving useful and repeatable results of the estimation. The mechanical resonance frequency of the system has been adopted at the level of 9.3-10.3 Hz. The selected state variables of the mechanical system are load, speed and stiffness torque of the shaft.

Open access
Novel Converter for Voltage Balance in Series-Connected Capacitors and Batteries

Abstract

This paper presents a novel concept of a circuit for voltage balance of three series-connected capacitors or batteries, as well as the research results. The problem is related to the control of voltage sharing on series capacitors, supercapacitors or battery banks in energy storage systems or direct current (DC)-link of four-level neutral-point-clamped inverters. The proposed circuit is a switched-capacitor (SC) resonant converter composed of a single capacitor and seven transistor switches. Control of the converter makes it possible to transfer energy between any capacitors, by switching selected transistors. This paper presents the basic concept of the converter, an analysis of control strategies and the simulation results for various cases of voltage balancing.

Open access
PMSM Servo-Drive Fed by SiC MOSFETs Based VSI

Abstract

The article presents modern PMSM servo-drive with SiC MOSFETs power devices and microprocessor with ARM Cortex core. The high switching frequency is obtained due to the application of high efficient power switching components and powerful microprocessor. It allows to achieve good dynamical properties of current control loop, proper disturbance compensation and silent operation of servo-drive. Experimental tests results obtained for two different control schemes (i.e., cascade control structure and state feedback position control) are presented.

Open access