Mohamed Fouad Benkhoris

Fuzzy logic controller for five-level shunt active power filter under distorted voltage conditions

In this paper, a five-level inverter is used as a shunt active power filter (APF), taking advantages of the multilevel inverter such as low harmonic distortion and reduced switching losses. It is used to compensate reactive power and eliminate harmonics drawn from a diode rectifier feeding a RL load under distorted voltage conditions. The active power filter control strategy is based on the use of self tuning filters (STF) for reference current generation and a fuzzy logic current controller. The use of STF instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the α-β axis without phase locked loop (PLL). This study is divided in two parts. The first one deals with the harmonic isolator which generates the harmonic reference currents. The second part focuses on the generation of the switching pattern of the inverter by using a fuzzy logic controller applied and extended to a five level shunt APF. The MA TLAB Fuzzy Logic Toolbox is used for implementing the fuzzy logic control algorithm. The obtained results show that, the proposed shunt active power filter controller has produced a sinusoidal supply current with low harmonic distortion and in phase with the line voltage.

A new balancing three level three dimensional space vector modulation strategy for three level neutral point clamped four leg inverter based shunt active power filter controlling by nonlinear back stepping controllers

In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK.

Fuzzy logic controller for three-phase four-leg five-level shunt active power filter under unbalanced non-linear load and distorted voltage conditions

This paper presents a five-level inverter which is used as a three-phase four leg shunt active power filter, taking advantages of the multilevel inverter such as low harmonic distortion and reduced switching losses. It is used to suppress harmonic current, compensate reactive power and neutral line current and balance the load currents under unbalanced non-linear load and distorted voltage conditions. The active power filter control is essentially based on the use of self tuning filters for the reference current generation and a fuzzy logic current controller. This study is divided in two parts. The first one deals with the harmonic isolator which generates the harmonic reference currents. The second part focuses on the generation of the switching pattern of the inverter by using a fuzzy logic controller applied and extended to a four leg five level shunt active power filter. The MATLAB Fuzzy Logic Toolbox is used for implementing the fuzzy logic control algorithm. The performance of the proposed shunt active power filter controller is found considerably effective and adequate to compensate harmonics, reactive power and neutral current and balance load currents under distorted voltage conditions.

Embarked electrical network robust control based on singular perturbation model.

This paper deals with an approach of modelling in view of control for embarked networks which can be described as strongly coupled multi-sources, multi-loads systems with nonlinear and badly known characteristics. This model has to be representative of the system behaviour and easy to handle for easy regulators synthesis. As a first step, each alternator is modelled and linearized around an operating point and then it is subdivided into two lower order systems according to the singular perturbation theory. RST regulators are designed for each subsystem and tested by means of a software test-bench which allows predicting network behaviour in both steady and transient states. Finally, the designed controllers are implanted on an experimental benchmark constituted by two alternators supplying loads in order to test the dynamic performances in realistic conditions.

A new Robust torque control of a five Phase Permanent Magnet Synchronous Machine

This paper deals with a Robust H∞ Output Feedback torque control of five Phase Permanent Magnet Synchronous Machine (5P-PMSM). Design procedure of the control scheme is discussed. The non-sinusoidal waveform of the EMF is considered as an external disturbance. Then, the proposed controller rejects its impact on the electromagnetic torque ripples and offers good transient performances. Simulation results show the effectiveness of our design, and demonstrate an excellent torque ripples reduction.

Singular perturbation modelling and control of embarked electrical network

In an embarked electrical network, it is necessary to maintain constant voltage and frequency using regulators. This paper deals with an approach of embarked network modelling in view of control. The system model is decomposed to two lower order systems according to the singular perturbation theory and RST regulators are designed for each subsystem. Regulators performances are tested using a software benchmark representing embarked network behaviour in both steady and transient states

Power quality improvement using a Three Dimensional Space Vector Modulation with SRF theory for three level neutral point clamped four leg shunt active power filter controlling in dq0 axes

In this paper, a Three level NPC four leg inverter is used as a shunt active power filter (SAPF), and the Three level Three Dimensional Space Vector Modulation technique in the aßo axes (3-level 3D SVM) for generate the switching signals of this SAPF for power quality improvements under balanced and unbalanced loads are proposed. In order to, improved the output voltage forms, lower switching losses, fix switching frequency, minimizing the harmonics of source currents, reducing the magnitude of neutral current, eliminating the zero-sequence current, and to compensating the reactive power in the four-wire distribution network, and for a good dynamic the synchronous reference frame (SRF) theory in the dq0-axes for generate and extract the reference currents which should be injected by Three level NPC four leg inverter is presented. Simulation results of three level Shunt Active Power Filter performances are presented to validate the proposed three level 3D-SVM with SRF theory for switching signals and reference signals generating.

Fuzzy logic and selectivity controllers for the paralleling of four-leg shunt active power filters based on three dimensional space vector modulation

A new structure of paralleling four leg shunt active power filters is presented in order to compensate the four-wire electrical network supplying the high power of non-linear singlephase loads. An effective selectivity of control with fuzzy logic and Three Dimensional Space Vector Modulation (3D-SVM) introduced in this configuration of SAPFs to maintain the same amplitude and frequency of output current of each inverter, this is necessary to determine the numbers of inverters in service and their frequency of commutation according to the power of nonlinear single-phase loads, to make operating or stopping the inverters without disturbing the performance of paralleling SAPFs. The fuzzy logic controller (FLC) and Three Dimensional Space Vector Modulation (3D-SVM) is necessary to robustness, minimizing the harmonics of source currents, reducing the magnitude of neutral current, eliminating the zero-sequence current, compensating reactive power in the four-wire distribution network, stabilizing the DC bus voltage, switching losses, and to fixe switching frequency in inverters. Also, a instantaneous real, imaginary and zero-sequence powers pq0 theory in the αβο-axes is presented to generate the reference currents which should be injected by the paralleled four leg SAPFs.

Torque control strategy of non-sinusoidal Brushless DC Motor based on fractional regulator

This paper deals with Torque Control Strategy of non-sinusoidal Brushless DC Motor based on fractional regulator. In this case, the dq components of the EMF are not constants. Then, the optimisation of the torque and the reduction of copper losses and torque ripples need to synthesize and to impose an optimal current waveform in dq frame. Also, the current regulators must ensure reference tracking without affecting the signal magnitudes or introducing phase shift. So we propose to investigate the fractional order regulator to control the dq currents in the park frame.

Low THD voltage source involving two sliding mode controllers

This paper deals with a converter using two legs of inverters which operate in parallel and act as current and voltage sources. This is done in order to increase the output power and to get a low output voltage harmonic distortion. One of the legs implements IGBTs and acts as the slave current source, when the other leg implements MOSFETs and acts as the master voltage one. The slave output current and master output voltage modules are under control of two sliding mode controllers. Then, the current source feeds the low frequency current to the load when the voltage source is in charge of compensating the high frequency current ripple of the slave source and also controls the output voltage of the converter. Thus the current source feeds the power to the load and the output voltage THD is low.