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EPE Journal Volume 25-1 - Papers
- Determination of Wound Core Transformer Losses and Temperature Rise
- A Comprehensive Study of Direct Torque Control (DTC) and Predictive Torque Control (PTC) for High Performance Electrical Drives
- New Rogowski Coil Design with a High dV/dt Immunity and High Bandwidth
- Novel Feedback-Based Selected Harmonic Elimination Technique for Single-Phase Symmetric PWM Inverters
- Modeling and Analysis of Different Control Techniques of Electric Motor for Electric Vehicle Powertrains
EPE Journal Volume 25-1 - Editorial
By Martin Doppelbauer
The editorial of EPE Journal 25-1, Welcome to EPE'16 ECCE - Europe, written by Prof. Martin Doppelbauer, Local Conference Chair of EPE'16 ECCE Europe
EPE Journal Volume 25-1 - Papers
By Amir Baktash; Abolfazl Vahedi
Recently tape wound cores are widely used in transformers for power electronics applications. The spiral structure of theses cores affects the flux distribution inside the core and causes complication of magnetic analysis. In this paper, a model based on reluctance networks method is used for analysis of magnetic flux in toroidal wound cores and losses calculation. A Preisach based hysteresis model is included in the model to consider the nonlinear characteristic of the core. Magnetic losses are calculated by having the flux density in different points of the core and using hysteresis model. Additionally a thermal equivalent circuit is applied to determine the temperature rise in transformer due to the magnetic and electric losses. A transformer for using in a series resonant converter is modeled and the results are compared with experimental measurements to evaluate the validity of the model. Comparisons show accuracy of the model besides simplicity and fast convergence.
By Fengxiang Wang; Zhe Chen; Peter Stolze; Mauricio Trincado; Jose Rodriguez; Ralph Kennel
This paper presents an experimental evaluation between Direct Torque Control (DTC) and Finite Control State Predictive Torque Control (FCS-PTC) applied to induction machines. Both control strategies have features in common: absence of a modulator, fast dynamics. Regarding the conceptual understanding and system constraints the PTC method shows advantages compared to the DTC method. However, compared to PTC, DTC method has lower calculation time. An experimental comparison is carried out in this work. The same average switching frequencies at specific operating points for two control methods are taken into account in order to reach a fair comparison. The experiments confirm that both PTC and DTC methods reach good results and achieve very comparable performance both in steady and transient states.
By Stefan Hain; Mark-M. Bakran
With the fast development of modern power semiconductors in the last years, the development of current measurement technologies has to adapt to this evolution. The challenge for the power electronic engineer is to provide a current sensor with a high bandwidth and a high immunity against external interferences. Rogowski current transducers are popular for monitoring transient currents in power electronic applications. But the trend of even higher current and voltage gradients generates a dilemma regarding the Rogowski current transducer technology. On the one hand, a high current gradient requires a current sensor with a high bandwidth. On the other hand, high voltage gradients forces to use a shielding around the Rogowski coil in order to protect the measurement signal from a capacitive displacement current caused by an unavoidable capacitive coupling to the setup, which reduces the bandwidth substantially. This paper presents a new Rogowski coil design which allows measuring high current gradients close to high voltage gradients without interferences and without reducing the bandwidth by a shielding. With this new measurement technique, it is possible to solve the mentioned dilemma and to get ready to measure the current of modern power semiconductors such as SiC and GaN with a Rogowski current transducer.
By Hassan Fathabadi
This paper presents a novel feedback-based selected harmonic elimination (SHE) technique for using in single-phase symmetric pulse-width modulation (PWM) inverters. The novelty of the proposed technique is that it is implemented as a closed loop system. It means that it uses the solution of a set of transcendental equations as the initial optimal switching angles to start an exact smart feedback-based process to compensate the probable differences between the actual optimal switching angles and the theoretical computed optimal switching angles. For first time, the proposed technique can completely eliminate the selected voltage harmonics for both resistive and inductive loads. To check the theoretical results, the proposed technique is implemented as a simulated circuit in Proteus 6 software environment. Based on the simulated circuit, an experimental prototype of the circuit is constructed to verify the theoretical and simulation results. There are not any limitations for the maximum output power and loads of the inverter and furthermore, it complies with international standards such as IEEE 519, ER G5/4-1 and IEC 555-2. A comparison between the results of this work and other works is presented which explicitly proves the superiority of the proposed technique.
By Omar Hegazy; Philippe Lataire
Electric Motors (EMs) and their control methods play an essential role in the development of energy-efficient drivetrains, particularly electric vehicle (EV) powertrains. It should be pointed out that the electric motors and their control methods are one of the key aspects in all EV propulsion systems. Thus, in this article, different motor control methods (i.e. Indirect Field-Oriented Control (IFOC), Hybrid IFOC and PWM voltage scheme, IFOC based on SVPWM, Direct Torque Control (DTC), and DTC based on SVPWM) are designed and investigated in detail by using Matlab/Simulink. This article also presents the dynamic modeling of electric motor taking into account its core losses. Based on the developed loss model, the IFOC based on PWM voltage and PSO is proposed to enhance the motor efficiency especially at low load conditions. A comparative study of these motor control methods is provided in this paper in order to select the proper motor control strategy. The obtained results have demonstrated that the proposed PSO algorithm significantly minimizes the motor losses at any operating condition by selecting the optimal flux level. The simulation and experimental results are provided and discussed.
EPE Journal Volume 25-1: In memoriam
By B. Sneyers
In Memoriam José Millán