Mohamed Maaroufi

Control strategy for PMSG wind farm based on MPPT and direct power control

A wind farm with variable speed wind turbines usually consists of a large number of wind turbine generators (WTGs) connected and operating simultaneously. The study of a wind farm with permanent magnet synchronous generators (PMSG) is presented. The 10 MW wind farm consists of 5 PMSGs based 2MW generators connected to a common DC-bus. Each PMSG of the wind farm is connected to the DC-bus through a rectifier, but the DC-bus is connected to the grid through only one DC/AC inverter. The proposed control strategy combines pulse width modulation (PWM) and maximum power point tracking (MPPT) control method. The PMSG side converters are used to achieve MPPT. The grid-side converter regulates dc-link voltage and injects the generated power into the AC network. Direct power control of three phases PWM inverter is adopted. Grid-side reactive and active power decoupling method is applied in order to track maximum wind power and regulate the grid-side power factor. Simulation results show that the proposed strategy has excellent performance.

Nonlinear control of MPPT and grid connected for wind power generation systems based on the PMSG

In this paper, nonlinear control of permanent magnet synchronous generators (PMSG) for wind energy conversion system (WECS) is investigated in order to maximize the generated power from wind turbine. The control strategy combines the technique of maximum power point tracking (MPPT) method and sliding mode (SM) nonlinear control. A speed and pitch control scheme for variable speed wind turbines are proposed. The block diagram of the WECS with PMSG and a back-to-back PWM converter structure is established with the dq frame of axes. Both converters used the sliding mode control scheme considering the variation of wind speed. A speed controller is designed to maximize the extracted energy from the wind, below the rated power area, while the objectives of grid-side converter are to deliver the energy from the PMSG side to the utility grid, to regulate the DC-link voltage and to achieve unity power factor and low distortion currents. The employed control strategy can regulate both the reactive and active power independently by quadrature and direct current components, respectively. With fluctuating wind, the controller is capable to maximize wind-energy capturing. Under varying load condition and at constant load, the controller can maintain the load voltage and frequency quite well. The system is built using Matlab/Simulink environment. Simulation results show the effectiveness of the proposed control scheme.

Doubly fed induction generator wind turbine control for a maximum power extraction

Wind turbine WT occupies gradually a large part in world energy market, Doubly fed induction generator DFIG is mostly used in WT, it allow highly flexible active and reactive power generation control. These machines are driven by power collaborating converters: voltage source converter VSC and rotor-side converter RSC protected using crowbar protection against transient over current. This paper develops a DFIG dynamic model, driven by wind turbine model using PSCAD/EMTDC a powerful tool allowing power system analysis to investigate simulations. A control strategy is also established using PI regulator to control stator-grid power flow according to maximum power point tracking MPPT strategy.

Control scheme and power maximisation of permanent magnet synchronous generator wind farm connected to the electric network

In this paper, control of maximum power point tracking MPPT and electric network connected for wind farm WF system based on the permanent magnet synchronous generator PMSG is investigated in order to maximise the generated power with unity power factor UPF. Six PMSGs based 2 MW generators connected to a common DC-bus are used. Each generator is connected to the DC-bus with a rectifier whereas the DC-bus is connected to the grid through one DC/AC converter. The proposed control law combines MPPT control strategy and space vector modulation SVM. Moreover, active and reactive power can be controlled by direct and quadrature current components, respectively. Therefore, the WF system with the PMSG cannot only capture the maximum wind power and adjusts the amount of the reactive and active powers delivered to the grid, but also can maintain the amplitude and frequency of the output voltage with UPF. Simulation results confirm that the proposed control strategy has excellent performance.

Sliding Mode Control Scheme of Variable Speed Wind Energy Conversion System Based on the PMSG for Utility Network Connection

The study of a Variable Speed Wind Energy Conversion System (VS-WECS) based on Permanent Magnet Synchronous Generator (PMSG) and interconnected to the electric network is presented. The system includes a wind turbine, a PMSG, two converters and an intermediate DC link capacitor. The effectiveness of the WECS can be greatly improved by using an appropriate control. Furthermore, the system has strong nonlinear multivariable with many uncertain factors and disturbances. Accordingly, the proposed control law combines Sliding Mode Variable Structure Control (SM-VSC) and Maximum Power Point Tracking (MPPT) control strategy to maximize the generated power from Wind Turbine Generator (WTG). Considering the variation of wind speed, the grid-side converter injects the generated power into the AC network, regulates DC-link voltage and it is used to achieve unity power factor, whereas the PMSG side converter is used to achieve Maximum Power Point Tracking (MPPT). Both converters used the sliding mode control scheme considering the variation of wind speed. The employed control strategy can regulate both the reactive and active power independently by quadrature and direct current components, respectively. With fluctuating wind, the controller is capable to maximize wind energy capturing. This work explores a sliding mode control approach to achieve power efficiency maximization of a WECS and to enhance system robustness to parameter variations. The performance of the system has been demonstrated under varying wind conditions. A comparison of simulation results based on SMC and PI controller is provided. The system is built using Matlab/Simulink environment. Simulation results show the effectiveness of the proposed control scheme.

Distributed energy management by MAS in a stationary hybrid system

The energy debate is at the heart of any political or economic strategy, also the real risk of depletion of non-renewable energy sources in the long term make us look more and more renewable energy sources. This brings us inevitably to the question of scientific research and technological innovation, which today enables to find solutions to the socio-economic and socio-cultural context. Rural electrification or isolated sites may be the subject of these studies, and this paper presents one of the economic solutions of the electrification of remote sites. The system studied is a stationary hybrid system; the objective is to meet the limitations of centralized energy management of these systems through the decentralized management by using multi-agent systems.

Power network control and management

Throughout this paper we present MapManagement, an application that we conceived to include power electric network technics and methods applied to Rabat and regions network (12 bus system) to illustrate its capabilities. Monitoring, load flow, power lines transfer, maneuver orders logs and simulations are the principal analysis and control procedures of this software. A real and dynamic map with reduced scales is used by MapManagement to show states of different power network parts, an adjustable refresh period permits updating from network database. Users can show or hide power network surrounding items using MapManagement interface, and automatic zoom in on fault map zones when alarms start. MapManagement allows secure multiuser management according to many hierarchic levels