Youssef Errami

A MPPT vector control of electric network connected Wind Energy Conversion System employing PM Synchronous Generator

In this paper, a control for variable speed Wind Energy Conversion System (WECS) that incorporates a Permanent Magnet Synchronous Generator (PMSG) is described. The proposed approach is based on a Vector Control theory (VC) for regulate of both grid-side and machine converters of a PMSG wind turbine. Then, an optimal control strategy is developed for integrated control of PMSG power extraction. It combines Space Vector Modulation (SVM) and Maximum Power Point Tracking (MPPT) control strategy to maximize the generated power from Wind Turbine Generator (WTG). A pitch control scheme for variable speed WTG is proposed to limit the output power produced by the turbine. Therefore, WECS can not only capture the maximum wind energy, however also can maintain the frequency and amplitude of the output voltage with unity power factor. Finally, the effectiveness of the novel control strategy is verified by simulation using Matlab/ Simulink environment. Simulation results have shown the effectiveness of the proposed control strategy for WECS based on the PMSG.

VARIABLE STRUCTURE SLIDING MODE CONTROL AND DIRECT TORQUE CONTROL OF WIND POWER GENERATION SYSTEM BASED ON THE PM SYNCHRONOUS GENERATOR

Abstract This paper presents a Variable Structure Sliding Mode Control (VS-SMC) scheme and Direct Torque Control (DTC) for Wind Farm (WF) based on the Permanent Magnet Synchronous Generator (PMSG). The WF consists of a 3 PMSGs which are connected to a common dc bus system with rectifier. The dc-bus is connected to the electrical network using only one inverter system, a grid-side filter as well as the transformer. The efficiency of the WF can be greatly improved using an appropriate control approach. So, the control strategy uses the technique of DTC to regulate the speeds of PMSGs for Maximum Power Point Tracking (MPPT) mode. Besides, by employing VS-SMC the grid-side inverter is controlled to inject the generated power into the electrical network, to regulate DC-link voltage and to achieve Unity Power Factor. The used control strategies provide an optimal control solution for WF systems based on the PMSG.

Maximum Power Point Tracking of a Wind Power system based on The PMSG using Sliding Mode Direct Torque Control

This paper investigates the novel Variable Structure Direct Torque Control (VS-DTC) scheme for Wind Energy Conversion System (WECS) based on the Permanent Magnet Synchronous Generator (PMSG) to maximize the generated power from wind turbine. The system includes a wind turbine, a PMSG, two converters and an intermediate DC link capacitor. The efficiency of the WECS can be greatly improved using an appropriate control strategy. Furthermore, the system has strong nonlinear multivariable with many uncertain factors and disturbances. Accordingly, the control strategy combines the technique of Direct Torque Control (DTC) and Sliding Mode (SM) nonlinear control theory. Considering the variation of wind speed, the grid-side converter injects the generated power into the AC network, regulates DC-link voltage and its used to achieve unity power factor, whereas the PMSG side converter is used to achieve Maximum Power Point Tracking (MPPT). Simulation results, by Matlab/Simulink, have shown the effectiveness of the proposed control strategy for WECS based on the PMSG.

Doubly fed induction generator wind farm fault ride-through capability

Wind farms WF connected to the power network are frequently subjected to grid faults, a large rotor current rising proportion happens during grid voltage sags. These faults may cause damages to rotor windings, converters, DC Link capacitor or induce drive train mechanical stress due to torque fluctuations. This paper develops a crowbar and chopper protection strategy to care for doubly fed induction generator wind farm DFIGWF components. Some limiting circuits are added to the WF model to reduce undesirable fault effects. This control provides WF Fault Ride Through capability FRT to endure grid voltage dips avoiding WF grid-disconnection consigned in grid requirements. A simulation using PSCAD/EMTDC is started to instigate some grid faults and compare WF behavior with and without crowbar and chopper check to make assessment and confirm strategy benefic.

Passive filter for harmonics mitigation in standalone PV system for non linear load

Several studies have been presented regarding the harmonics mitigation by using different types of filters. Passive filter is one of them and is employed due to his simplicity, economical cost and high reliability in power system. This paper presents an analysis and study of three types of passive filters to minimize harmonics distortion caused by non linear loads in standalone PV system. In order to achieve the certain filtering effect, it is necessary to combine different filter topologies; generally these topologies can be divided into two categories: series AC reactor and shunt passive filter such as tuned filters and high pass filters. This paper presents firstly the basic design and components of PV system, secondly describes the causes of harmonics and their effects and presents the means to improve power quality and to protect the equipment in our power system. The proposed system is verified by the simulation using Matlab/Simulink environment.

Nonlinear control of DC-bus voltage and power for Voltage Source Inverter

This paper presents a nonlinear control of dc-bus voltage, active and reactive powers for wind power grid connected Voltage Source Inverter (VSI). The controller exploits the backstepping scheme to calculate the required inverters control to eliminate the instantaneous errors of dc-link voltage, active and reactive powers. The nonlinear control can increase the system effectiveness and realize voltage source control frequency. The proposed control laws are derived from the Lyapunov approach which is well suited for this nonlinear circuit. Control analysis and simulations results are obtained using Matlab/Simulink. These results show how the backstepping control laws provides an efficient control design in comparison with conventional linear control for tracking references and regulations in order to improve dc-link voltage stability. The active power and reactive power are regulated independently, and good unity power factor correction (PFC) is achieved.

New control strategy for inductin generator-wind turbine connected grid

This paper presents a nonlinear control of 900-kW wind power, to track the maximum power point (MPPT,) and control Power Factor Correction (PFC) of wind farm using three Squirrel Cage Induction Generator (SCIG) driven by 300-kW wind turbines. The wind turbine delivers an active and reactive power to grid via common DC-bus and Voltage Source Converter (VSC), the proposed control strategy provides perfect tracking performances of the DC-bus voltage and the active and reactive powers to their references trajectories. The proposed control laws are derived from the Lyapunov approach using backstepping controllers. Finally, the simulation results verify the stability and effectiveness of the control strategy.

Variable structure control approach for grid connected PMSG Wind Farm

The study of a Wind Farm (WF) based on Permanent Magnet Synchronous Generator (PMSG) and interconnected to the electric network is presented. The 8 MW wind farm consists of 4 PMSGs based 2 MW generators connected to a common DC bus. Each generator is connected to the DC-bus with a rectifier while the DC-bus is connected to the grid through one DC/AC converter. 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 Generators (WTGs). Moreover, considering the variation of wind speed, both converters used the SM-VSC scheme. The PMSGs side converters are used to achieve MPPT, while the grid-side converter regulates DC-link voltage and injects the generated power into the AC network. Accordingly, WF system not only can capture the maximum wind energy, but also can maintain the frequency and amplitude of the output voltage with unity power factor. The effectiveness of the control strategy is verified by simulation analyses using Matlab/ Simulink.

Design of variable structure control for wind energy system-based permanent magnet synchronous generator and operating under different grid conditions

This paper proposes a nonlinear control approach for an electrical network connected variable speed wind energy system VS-WES based on a permanent magnet synchronous generator PMSG. The proposed configuration consists of a wind turbine WT, a direct driven PMSG, a rectifier and an inverter which is connected to the power grid through a filter. Under the variation of wind velocity, the generator side rectifier is used to control the speed of the PMSG with maximum power point tracking MPPT. The grid-side converter is employed to inject the extracted power into the electrical network, to regulate dc-link voltage and to attain unity power factor UPF. This work explores a variable structure sliding mode control VSSMC considering the variation of wind speed. Lyapunov stability theory is used to find the conditions for the existence of the sliding mode. So, the performance of the VS-WES has been demonstrated under varying wind conditions and under a grid fault. The simulation results through MATLAB/Simulink show the effectiveness of the proposed VSSMC approach.

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.