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EPE Journal Volume 16-4 - Papers
- Single-Phase Resonant Converter in Three-Phase System in Modular Approach
- Computer Aided Control Optimization of Power Converters
- A Novel Split Phase Induction Motor Drive without Harmonic Filters and with Linear Voltage Control for the Full Modulation Range
- Sensorless Direct Instantaneous Torque Control for Switched Reluctance Machines
- Control of a Stand-Alone Variable Speed Constant Frequency Generator Based on a Doubly-Fed Induction Generator
- Steady State Electrical Design, Power Performance and Economic Modeling of Offshore Wind Farms
EPE Journal Volume 16-4 - Editorial
By B. Sneyers
Planning the year 2007, the editorial of the EPE Journal 16-4, October - December 2006.
EPE Journal Volume 16-4 - Papers
By M. R. Ramteke; H. M. Suryawanshi; K. L. Thakre
A three-phase AC-to-DC high voltage, high frequency, zero-voltage switching resonant converter using single-phase con-verters in modular approach is presented. Modified series-parallel resonant converter (MSPRC) for modular approachis simulated and experimental prototype converter is developed. The proposed converter has many advantages like powerfactor correction, simple control and power expandability. The results are obtained and compared for three-wire and four-wire systems. Experimental results are in good agreement with simulation results. The power factor in three-wiremodular converter system is very good compared to four-wire system.
By F. Belloni, P. Maranesi, M. Riva
The paper describes an improved automatic technique for the dynamic modelling of PWM DC-DC converters. It makeseasier and more accurate the control optimization. Since the operating ranges of the load current and of the input voltage are generally wide,the usual recourse to a single linear model provides an information inadequate,in manycases. Such insufficiency is heavy when different operating modes are involved,f.i. DCM/CCM,whose dynamic performances can be very dissimilar. The proposed technique makes reference to a full set of models in the ranges of the input variables. Automatic modelling in the state space discrete time,by means of suitable software tools,cuts the drawback of implementing a large number of models. It gets the full set of the dynamic descriptions in a short time andprovides a bundle of frequency responses as shown in the Fig. 1s.
The case of a phase-shift controlled PWM converter is studied. The open loop frequency responses are provided first,withindications for the feedback optimization. After assigning the feedback compensation networks the closed loop behaviourover the whole operating range is shown. The compliance of the model forecasts with the real life is very good.
By K. K Mohapatra, K. Gopakumar
A modulation scheme for a split phase (six phase) induction motor is presented in this paper. For a six phase inductionmotor drive harmonics of the order 6n ±1 (n = 1,3,5 etc.,) will not contribute to the air gap flux and hence these har-monic currents are limited by the stator impedance only. So harmonic filters are needed for the suppression of these (6n ±1( n = 1,3,5 etc.,) high amplitude harmonic currents,when a six phase induction motor is used for variable speedapplication. In the proposed scheme,a modulation technique to eliminate the 6n ±1 (n = 1,3,5 etc.,) harmonic currents,without the need for harmonic filters,from the stator phases of a six phase induction motor drive is explained. An open-end winding drive configuration with appropriate DC-link voltages,is chosen in such away that a 12-sided polygonalvoltage space phasor combinations are achieved for each 3-phase group,independently. A modulation scheme based on12-sided polygonal voltage space phasors cancel the 6n ±1 (n = 1,3,5 etc.,) harmonic voltages from all the motor phases and hence currents due to these harmonics can not flow in the motor phases of the six phase machine. For thesame flux level of operation,nearly 11.5 % increase in modulation range is possible from this proposed drive (while stillbeing in the linear PWM range),which is more than that of a six-step over modulation region in a conventional 3-phaseinduction motor drive. The proposed drive scheme is experimentally verified,for variable speed application,using a 1.5 kW six-phase induction motor drive.
By N. H. Fuengwarodsakul, S. E. Bauer, C. P. Dick, R. W. De Doncker
This paper presents a position-sensorless torque controller for Switched Reluctance Machines (SRMs) based on DirectInstantaneous Torque Control (DITC). An indirect position estimation is developed based on a current-flux-linkagemethod to eliminate the need of the position encoder. The current-flux-linkage method has advantages of simplicity andrequires a relatively short computation time. Therefore,the controller can be implemented with a high control bandwidth.The accuracy of position estimation and influences of estimation errors are studied. The functionality of the developedcontroller and its performance are investigated and verified by experiments over a wide operating range.
By N. Patin; J-P. Louis; E. Monmasson
Variable speed and constant frequency (VSCF) generators are widely used in industry (e.g. embedded applications andrenewable energy systems). Doubly-fed induction generators (DFIG) allow a such operation. Moreover,this kind ofmachines can be driven by a low power converter in comparison to the power provided to the grid. But on isolated grid,an efficient controller is needed in order to maintain quasi-sinusoidal voltages with an important amount of non-linearload and with a small passive filter. The aim of this paper is to present a new design methodology based on the inversionof the dynamical model of the system. It also uses an original representation of the system called dynamical equivalentcircuit. Thus,a hierarchical controller is designed and validated by simulation and experimental results.
By M. Damen; P. Bauer; S. W. H. de Haan; J. T. G. Pierik
A load flow model has been developed for the evaluation of thirteen different electrical architectures for large offshorewind farms. In a case study,these architectures have been evaluated for two wind farm sizes (100 and 500 MW) and twodistances to shore (20 and 60 km). The case study has shown that systems C1 (string layout) and C2 (star layout),havethe lowest contribution of the electrical system to the price per kWh (Partial Levelized Production Cost PLPC). C1 andC2 system prices are 19.7 and 24.9 MEuro (100 MW,20 km),36.9 and 42.1 MEuro (100 MW,60 km),91.7 and 109.5MEuro (500 MW,20 km) and 132.9,150.7 MEuro (500 MW,60 km). For comparison another case study with prolongedlife-time and predicted price decrease of power electronic components is shown too.