S. Saadate

Active filtering capability of WECS with DFIG for grid power quality improvement

A doubly fed induction generator (DFIG) with active filtering capability is presented. We proposed to make use of the DFIG and the associated rotor side converter (RSC) to control stator active and reactive power and simultaneously compensate the most significant and troublesome harmonic currents of the utility grid. We presented a new high selectivity harmonic isolator based on self tuning filter (STF). Simulation results when filtering the harmonic component of the grid current validate the performances of the harmonic isolator principle and the active filtering capability of the DFIG.

Fault-tolerant Power Electronic Converters: Reliability Analysis of Active Power Filter

The aim of fault tolerant control (FTC) is to preserve the ability of the system to reach performances as close as possible to those which were initially assigned to it. The main goal of this paper is to develop a FTC system, based on reliability analysis dedicated to an active power filter. Once a fault has been detected and isolated, all possible structures of the system that preserve pre-specified performance are analyzed and the highest reliability indicate the optimal structure.

A fault tolerant converter topology for wind energy conversion system with doubly fed induction generator

This paper presents a novel fault tolerant converter topology for grid connected Wind Energy Conversion System (WECS) with Doubly Fed Induction Generator (DFIG). This topology allows fault detection and compensation of one of the semiconductors or drivers by using isolating and connecting devices. It is based on a unique redundant leg for both back to back converters. We present a new detection algorithm, robust to false fault detection due to semiconductor switching. Simulation results are presented for two open circuit cases on both back to back converters.

A New Control Scheme of Hybrid Active Filter Using Self-Tuning-Filter

This paper presents a new control scheme using Self Tuning Filter placed in both feedback and feedforward control of a parallel hybrid active filter. This hybrid active filter is intended for harmonic compensation of a diode rectifier. The use of self tuning filters simplifies the control scheme by reducing the number of extraction filters, used in classical feedback and feedforward loop. More, in this case, no Phase Locked Loop is necessary for the feedforward loop. The studied hybrid active filter consists of an active filter and three phase tuned LC filters for 7th harmonic frequency. The non linear load is a diode rectifier feeding a (R, C) parallel load. The effectiveness of the new proposed scheme has been verified by computer simulation and the results are compared with the classical control scheme.

Hardware implementation of a three-phase active filter system with harmonic isolation based on self-tuning-filter

This paper presents the hardware implementation of a new control method based on an improved harmonic isolation for active filter systems. The harmonic generation is based on Self Tuning Filters for the harmonic isolation and on a modulated hysteresis current controller for the current control technique. This active filter is intended for harmonic compensation of a diode rectifier feeding a RL load. The study of the active filter control is divided in two parts. The first part deals with the harmonic isolator which generates the harmonic reference currents and is implemented into a Dspace DS1104 prototyping card. The second part focuses on the generation of the switching pattern of the IGBTs of the inverter by the modulated hysteresis current controller, implemented into an analogue card. The use of Self Tuning Filters instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the alpha-beta axis at high performances, without any Phase Locked Loop. The effectiveness of the new proposed method is verified by computer simulation and validated by experimental study.

A fast and reliable fault diagnosis method for fault tolerant shunt three-phase active filter

This paper proposes a fault tolerant shunt three phase active filter topology. It mainly details converter reconfiguration and examined a fast and reliable optimised fault diagnosis method. This method avoids spurious semiconductor fault detection due to semiconductor switching. The converter topology is based on classical three-leg active power filter topology but includes bi-directional switches for converter reconfiguration after fault detection. The resulting post fault power structure is a two-leg topology with fault leg connected to the middle point of the filtering capacitor. A new fault diagnosis method is proposed, based on classical voltage measurements. It includes combinatory logic to analyse and validate error signals. An unique control is applied before and after fault detection, which avoids any controller reconfiguration. Simulation results obtained with Saber CAD tools validate the theoretical study and the modelisations

Fault tolerant operation of single-ended non-isolated DC-DC converters under open and short-circuit switch faults

Fault tolerant operation of single-ended non-isolated DC-DC converters used in embedded and safety critical applications is mandatory to guaranty service continuity. This paper proposes a new, fast and efficient FPGA-based open and short-circuit switch fault diagnosis asssociated to fault tolerant converter topology. The results of Hardware-In-the-Loop and experimental tests are presented and discussed.

Study and experimental validation of harmonic isolation based on High Selectivity Filter for three-phase active filter

This paper presents the hardware implementation of a new control method of three-phase active power filters based on improved harmonic isolation. The harmonic isolator is based on high selectivity filters and the current control technique consists in a modulated hysteresis current controller. This active filter is intended for harmonic compensation of a diode rectifier feeding a RL load. The study of the active filter control is divided in two parts. The first part deals with the harmonic isolator which generates the harmonic reference currents and is implemented into a DSPACE DS1104 prototyping card. The second part focuses on the generation of the switching pattern of the IGBTs of the inverter by the modulated hysteresis current controller, implemented into an analogue card. The use of high selectivity filters instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the alpha-beta axis at high performances. The effectiveness of the new proposed method is verified by computer simulation and by experimental study.

FPGA-based real time current sensor failure diagnosis for shunt active power filters

The performances of conventional shunt active power filters heavily depend on accurate active filter current sensing. A sudden failure in one of the active filter current sensors decreases the filter performances. Moreover, if the fault is not detected and compensated for quickly, its effect leads to disconnection or hard failure of the active filter. Hence, to reduce the failure rate and to prevent unscheduled shutdown, a real-time fault detection, isolation and compensation scheme could be adopted. This article introduces a new fast and robust current sensor fault detection and compensation method for three-phase shunt active power filters. The proposed current sensor fault detection is achieved with a predictive model associated with a logical decision. The satisfactory performances obtained by experimental ‘FPGA in the loop’ prototyping validate the effectiveness of the proposed method.

A New Control Method of Hybrid Active Filter Using a Feedforward Loop Tuned at 5 th and 7 th Harmonic Frequency

In this paper, we proposed a new control method for a three-phase hybrid active filter, consisting of a classical active filter connected in series with a passive filter. The non linear load is a diode rectifier feeding a (R, C) parallel load. The proposed method is based on two self tuning filters placed in both feedback and feedforward loops dedicated to eliminate the 5th and the 7th harmonics frequency. The feedforward loop consists in two branches, one to remove the 5th harmonic and the other one to remove the 7th harmonic frequency. The use of self tuning filters simplifies the control scheme by reducing the number of extraction filters used in classical feedback and feedforward loops. More, in this case, no phase locked loop is necessary for the feedforward loop. The effectiveness of this new proposed scheme has been verified by computer simulation.