An efficient variable-step P&O maximum power point tracking technique for grid-connected wind energy conversion system

Abstract

This paper proposes an efficient modular sector variable-step perturb and observe (VSPO) maximum power point tracking algorithm. The proposed algorithm enhances the speed tracking and minimizes oscillations level problems associated with traditional P&O methods. The routine of generating the variable step sizes depends on splitting the (P-ω) characteristic curve of wind turbines into modular sectors, in which the perturbation step size for each sector is selected by comparing a suggested ratio with another specified ratio designed according to the required accuracy. By continuously observing the distance between the actual rotor speed and the optimal rotor speed, the VSPO technique applies variable perturbation step sizes according to the current operating sector. Moreover, a wind speed estimation technique is used as a replacement of distributed anemometers for tracking the optimal rotor speed at different wind speeds. The studied system configuration includes three-phase back-to-back converter which is used to connect a 1.5 MW permanent magnet synchronous generator into the utility grid. Furthermore, the model predictive control is used for current control loop in the machine-side converter. To demonstrate the performance of the proposed algorithm, its simulation results are compared with the simulation results of conventional P&O technique under step and random wind variations. In addition, the algorithm performance is studied with real wind data (Hokkaido Island, Japan) using MATLAB/SIMULINK environment. Simulation results show that the VSPO ensures the high tracking speed of maximum power point, while the steady-state oscillation is significantly reduced. The proposed algorithm enhances the system efficiency by 3.5% over the conventional one.

An MPPT Strategy for Wind Turbines Combining Feedback Linearization and Model Predictive Control

“…Figures 5 and 6 demonstrate that the combination of feedback linearization and MPC can achieve faster and more accurate maximum power point tracking, resulting in a higher power generation. As mentioned in [36], the efficiency of the wind energy conversion system was used as a performance metric, which is defined as the ratio of actual output power to theoretical power. This can be expressed as shown in (34).…”

Wind energy conversion technologies and engineering approaches to enhancing wind power generation: A review

“…More importantly, to realize maximum-energy harvesting and supply the electricity to the grid, the control strategies listed below should be implemented particularly in large scale-power WECSs: MPPT for each wind-speed range [ 143 ]. Net DC-bus voltage regulation to meet acceptable operation standards for the GSC [ 144 ].…”

Development of a Novel Efficient Maximum Power Extraction Technique for Grid-Tied VSWT System

“…Besides, the number of operating zones is limited and associated SS must be carefully tuned. Therefore, the development of a new MPPT algorithm that is not reliant on dividing the P − ω, hence picking a certain perturbing SS or measuring wind speed is still required [54].…”