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EPE Journal Volume 21-4 - Papers
- Programmable analog filter in the discrete time for the control of PWM power converters
- Capacitor Voltage Control Techniques of the Z-source Inverter: A Comparative Study
- Soft Direct Power Control Reconfiguration from no-load to Grid Connected mode of DFIG based Wind System
- Four Active Filter Topologies to Compensate Different Kinds of Distortion Sources
EPE Journal Volume 21-4 - Editorial
By Remus Teodorescu; Philip C. Kjaer
The editorial of EPE Journal Volume 21-4: EPE Joint Wind Energy and T&D Chapters Seminar 2012. The Utzon Centre & Aalborg University, Aalborg, Denmark. Thursday-Friday 28th-29th June 2012, written by: Remus Teodorescu & Philip C. Kjaer
EPE Journal Volume 21-4 - Papers
By F. Belloni; D. Della Giustina; P.G. Maranesi; M. Riva
The possibility of changing the transfer function of a frequency compensation filter, without modifying its topology, allows to synthesize a feedback regulator of power converters that can be used in a wide variety of applications. By programming the transfer function, the dynamics of the filter can be optimized for each power cell obtaining the desired closed loop behavior. In principle, the filter can be integrated within the power cell and programmed according to specific needs.
Digital filters own this characteristic. Common analog filters, instead, does not offer such a possibility, since their transfer function depend upon their topology. A recursive linear filter in the discrete time, with programmable gains, allows its implementation, offering the same advantages of digital controllers, while avoiding some of their limitations. This paper considers a possible solution based upon switched capacitor circuits, made programmable by multiplying digital to analog converters. In some cases, this solution can be an alternative to digital controls. An analytic model in Z-transform domain and relevant forecasts of frequency responses are provided in the paper. A prototype is employed as external feedback network of a buck converter. Dynamic performances and output voltage transient responses to load variations are shown.
By Omar Ellabban; Joeri Van Mierlo; Philippe Lataire
The Z-source inverter (ZSI) is a recently proposed single-stage power conversion topology. It adds voltage boost capability for complementing the usual voltage buck operation of a traditional voltage source inverter (VSI) with improved reliability. In this paper, a single-loop and dual-loop capacitor voltage control techniques for the ZSI are digitally designed based on a third order small signal model of the ZSI, implemented using a digital signal processor (DSP) and compared. Simulation and experimental results of a 30 kW ZSI during input voltage changes, load disturbances and steady state operations are presented and compared. The results show that the dual-loop capacitor voltage control technique achieves better steady state and transient performance and enlarge the stability margins of the ZSI compared to the single-loop capacitor voltage control technique.
By M. Jebali-Ben Ghorbal; J. Arbi; I. Slama-Belkhodja
This paper presents a novel grid-connection control strategy of a doubly fed induction wind power generator using an improved DPC approach. This control method is similar to the widely known DPC but is more flexible due to the fact that it enables in one hand direct active and reactive power control after grid connection and, on the other hand, a soft and fast grid connection stage. The main advantages of this method are that it is less complex than vector control scheme for connection and does not need any external control loop. A theoretical analysis of the method principles is presented and tested by simulation tools. The results show the effectiveness of the control that ensures a very good synchronization of the stator and grid voltages. Experimental results are carried out and tested on a 4 kW-DFIG prototype to prove the excellent performance of the control method using Field Programmable Gate Arrays (FPGA) technology.
By P. Salmerón; S. P. Litrán; R.S. Herrera; J. R. Vázquez
Along the last years, the practical use of active filters to mitigate harmonics has been extended in electric power systems. Different configurations of series active filters versus shunt active filters have been proposed, among them, hybrid topologies which combine active and passive filters. Nevertheless, there is not any clear accordance about the most suitable configuration for each type of harmonic sources. In this paper, four different topologies of active power filters to eliminate harmonics have been analyzed. It has been implemented an experimental prototype corresponding to each configurations more used and they have been submitted to different performance tests. With this objective, a test bank has been developed, which includes voltage-source nonlinear loads, current-source nonlinear loads, and other whose behavior is between both. The analysis of experimental results obtained allows the most suitable active filter power topology to be determined for each type of load.
EPE Journal Volume 21-4: Books
By B. Sneyers
Electricity Production from Renewables Energies
Vector Control of Induction Machines Desensitisation and Optimisation Through Fuzzy Logic