Magnet Synchronous Generator-based Wind Energy Research Articles

Application of optimal fuzzy and PI hybrid controllers for permanent magnet synchronous generator–based wind energy conversion systems

Permanent magnet synchronous generator (PMSG)–based wind turbines (WTs) are preferred over doubly fed induction generators (DFIGs) due to some appealing features. The control techniques used in this paper are fuzzy-based pitch angle controller, optimal torque-controlled maximum power point tracking, and optimal fuzzy and proportional integral (PI) hybrid controller under MATLAB-Simulink software. A grey wolf optimization technique is used to optimize the input scaling factor of the fuzzy logic controller (FLC) and gains of the PI controller. The results indicate that optimal FLC-PI performs better in DC-link voltage control than an optimal PI controller in terms of peak overshoot (0.82%), undershoot (2.51%), and settling time (0.18 s). However, the peak overshoot (1.87%), undershoot (10.6%), and settling time (0.22 s) are recorded for DC-link voltage response while utilizing the optimal PI controller. The generator’s efficiency reaches up to 97.35% for the optimal FLC-PI controller while 96.01% is obtained with the optimal PI controller at rated wind speed.

Adaptive event-triggered stochastic estimator-based sampled-data fuzzy control for fractional-order permanent magnet synchronous generator-based wind energy systems

This study aims to develop an adaptive event-triggered estimation sampled-data control method for a fractional-order permanent magnet synchronous generator (PMSG)-based wind energy system (WES) using the Takagi–Sugeno (T–S) fuzzy approach. Unlike existing PMSG-based WES control schemes, we propose an aperiodic event-triggered communication scheme with an adaptive mechanism to reduce data transmission. To address the challenge of limited communication resources, we introduce an adaptive event-triggered (AET) estimation method with aperiodic sampling, significantly reducing communication overhead while maintaining stable WES performance. This method employs transmission techniques based on absolute errors, resulting in high data transmission efficiency. First, the fractional-order model for the PMSG-based WES is represented using linear sub-models through the T–S fuzzy approach. Next, a fuzzy aperiodic AET mechanism is proposed for the PMSG model with augmented estimation error systems. Then, the fractional Lyapunov function theory is employed to derive linear matrix inequalities (LMIs), ensuring bounded mean-square stability for the PMSG-based WES with the augmented estimation error systems. Additionally, the desired estimator control gains are determined through solvable LMIs. Finally, simulation studies are presented to demonstrate the superiority and feasibility of the proposed control scheme.

Certainty equivalence-based robust sliding mode control strategy and its application to uncertain PMSG-WECS.

This work focuses on maximum power extraction via certainty equivalence-based robust sliding mode control protocols for an uncertain Permanent Magnet Synchronous Generator-based Wind Energy Conversion System (PMSG-WECS). The considered system is subjected to both structured and unstructured disturbances, which may occur through the input channel. Initially, the PMSG-WECS system is transformed into a Bronwsky form, i.e., controllable canonical form, which is composed of both internal and visible dynamics. The internal dynamics are proved stable, i.e., the system is in the minimum phase. However, the control of visible dynamics, to track the desired trajectory, is the main concern. To carry out this task, the certainty equivalence-based control strategies, i.e., conventional sliding mode control, terminal sliding mode control and integral sliding mode control are designed. Consequently, a chattering phenomenon is suppressed by the employment of equivalent estimated disturbances, which also enhance the robustness of the proposed control strategies. Eventually, a comprehensive stability analysis of the proposed control techniques is presented. All the theoretical claims are verified via computer simulations, which are performed in MATLAB/Simulink.

A new predictive control strategy for improving operating performance of a permanent magnet synchronous generator-based wind energy and superconducting magnetic energy storage hybrid system integrated with grid

This research work proposes an unscented Kalman filter (UKF) as an observer for predictive current control (PCC) of a permanent magnetic synchronous generator (PMSG)-based wind energy conversion system (WECS) connected with a superconducting magnetic energy storage (SMES) system and the main power grid. The proposed UKF observer estimates the rotor angle, rotor angular speed, stator currents, and electromagnetic torque of PMSG connected in the proposed hybrid WECS-SMES configuration. The PCCs designed for both the rotor- and grid- side converters of the proposed hybrid configuration use estimated parameters instead of the measured quantities. Furthermore, due to the intermittent nature of wind energy, control of an energy storage device (which is SMES in this research) is necessary to mitigate the fluctuations in the DC-link voltage and output power being sent to the main power grid. Therefore, a novel control configuration based on fractional order-PI (FOPI) controllers has also been proposed for the SMES system to control the output power and the DC-link voltage. An artificial bee colony optimization algorithm has been used to tune the gains and integration operators of two FOPI controllers. For UKF estimation performance comparison, three popular observers i.e., Luenberger, sliding mode, and extended Kalman filter, have also been designed and implemented in MATLAB. Mean absolute percentage error and root mean squared error performance metrics are used to measure the estimation performance. The simulated results have demonstrated the superior performance of proposed the UKF observer for PCC and FOPI controllers for SMES under different realistic wind speed conditions and noisy measurements. The proposed UKF observer has improved estimation by up to 99.9 %. Lyapunov stability criteria are used to prove the stability of the proposed UKF based PCC control of hybrid WECS-SMES configuration.

Coordinated Control of Grid-Connected PMSG Based Wind Energy System With STATCOM and Supercapacitor Energy Storage

In this paper, two coordinated control schemes have been designed for a grid-connected permanent magnet synchronous generator-based wind energy conversion system with static synchronous compensator (STATCOM) and supercapacitor energy storage (SCES) under various operating conditions. The coordinated control scheme-I (CCS-I) integrated a SCES into the DC-link through a bidirectional DC/DC converter to stabilize the DC-link voltage under varying wind speed and grid disturbances. The coordinated control scheme-II (CCS-II) implemented a STATCOM at the point of common coupling (PCC) to enhance the grid voltage stability during the grid voltage sag or swell. In CCS-II the SCES balances the active power while reactive power support is extracted from the grid side converter (GSC). The STATCOM is only activated when the reactive power requirement by the PCC exceeds the support capacity of the GSC. The proposed coordinated control schemes have been experimentally implemented with a dSpace MicroLabBox. Results show that CCS-I and II ensured the uninterrupted operation of the wind energy system and satisfied grid code requirements under various operating conditions and grid disturbances.

Reinforcement Learning-Based Adaptive Optimal Fuzzy MPPT Control for Variable Speed Wind Turbine

A reinforcement learning-based adaptive optimal fuzzy controller is proposed for maximum power point tracking (MPPT) control of a variable-speed permanent magnet synchronous generator-based wind energy generation system. The algorithm consists of a critic, an adaptive optimal fuzzy controller, and an adaptive optimal fuzzy estimator. The critic is built based on an adaptive neuro-fuzzy inference system (ANFIS) network instead of the neural network as normal to reduce the computation. The error between the system output and the estimator output is used as the input of the critic. In addition, the critic is used to calculate the update law for the parameters of the adaptive optimal fuzzy controller and adaptive optimal fuzzy estimator based on minimizing the input error function. Moreover, the proposed control scheme is output feedback instead of state feedback, which does not require a system model as well as system parameters, so the system is robust to uncertainties and external disturbances. Besides, the stabilization proof is accomplished by using the Lyapunov stability theorem for the closed-loop system and the convergence of the update law. Finally, the effectiveness of the proposed reinforcement learning-based adaptive optimal fuzzy control scheme is verified through simulation with various scenarios such as step wind speed, random wind speed, and system parameter variations. Also, the comparisons with other control schemes in the state-of-art (neural network reinforcement learning based adaptive optimal fuzzy controller, PI controller) are executed to demonstrate the advantages of the proposed control scheme.

Performance Enhancement of PMSG Based Wind Energy Conversion System: Experimental Analysis

Wind energy is a hopeful renewable energy which is used to generate electricity. The kinetic energy present in the wind is converted into electrical energy by the principle of Wind Energy Conversion System. This effort approaches the performance enhancement by re-design, re-fabrication, and re-implementation of Permanent Magnet Synchronous Generator-based wind energy conversion system and data logging system. PMSG connected to the wind turbine converts wind power into electricity. The proposed hardware design of PMSG aims to achieve the overall improved efficiency of the wind turbine by 7-10% of the existing hardware design. In the proposed design of PMSG overall efficiency was improved by increasing the magnet grade, reducing the air gap, and changing the winding type. A web dependent supervising system has been recognized. A data logging system was used for collection of data on wind speed, generating power, and other related data. Besides, the stored data can be observed through the website depend on data showed by the Global System for Mobile Communications. So, the user can monitor related data through the website. The Load Management System was used to balance the supply of electricity

Design of a novel hybrid control for permanent magnet synchronous generator–based wind energy conversion system

With the ever-increasing permeation of wind energy into electrical grids, the low operating efficiency and poor stability seem to become major challenges for the power industry because of the stochastic characteristic of wind speeds. Aiming at these problems, this article designs a novel hybrid control method for a permanent magnet synchronous generator–based wind energy conversion system. A port-controlled Hamiltonian with dissipation model is proposed to apply in the models of the machine and grid-side converters of the permanent magnet synchronous generator–based wind energy conversion system. Then, this port-controlled Hamiltonian with dissipation model is used to the energy shaping method of interconnection and damping assignment. The hybrid control strategy, containing the outer-loop proportional–integral control and inner-loop passivity-based control, is finally designed in this article. To achieve the analysis, a Simulink model of the 1.5 MW permanent magnet synchronous generator–based wind energy conversion system is established under various types of wind speeds. A comparative analysis between the proposed hybrid control strategy and conventional proportional–integral vector control is conducted through the electrical behaviors and the harmonic distortion rates. The simulation results verify that the hybrid control strategy has better regulation performance than that of conventional proportional–integral control strategy in terms of maintaining at optimal state and improving system stability. It is also demonstrated that the proposed control strategy optimizes the quality of supplied power, which is of significance to reduce the harmonic pollution of wind energy.

Maximum power extraction framework using robust fractional-order feedback linearization control and GM-CPSO for PMSG-based WECS

The most important issue in the use of wind energy conversion systems is to ensure maximum power extraction in terms of efficiency. Therefore, maximum power point tracking algorithms are as important as the maximum power point tracking controller. In this study, maximum power extraction frameworks operating the state-of-the-art optimization methods are presented for permanent magnet synchronous generator–based wind energy conversion system. These frameworks consist of a Gauss map–based chaotic particle swarm optimization and a hybrid maximum power point tracking approach that combines feedback linearization technique with fractional-order calculus. The feedback linearization control strategy can fully decouple and linearize the original state variables of the nonlinear system and thus provide an optimal controller crossing wide-range operating conditions. The objective is to maintain the tip speed ratio at its optimal value, which implies the use of a rotational speed loop. The method is based on the feedback linearization technique and the fractional control theory. Gauss map–based chaotic particle swarm optimization, which is a remarkable and recent optimization technique, is utilized to achieve optimum coefficients to efficiently ensure the maximum power point tracking operation in here. A simulation study is carried out on a 3-kW wind energy conversion system to show the effectiveness of the proposed control scheme.

Comparative Assessment of Control Strategies Used in a Hybrid AC-DC Micro-Grid Consisting of Composite Energy Sources

In the present paper, comparative assessment of two important available intelligent control strategies namely the Mamdani fuzzy logic controller and the T–S fuzzy controller used for DC-link voltage control in DC micro-grid is carried out, first. Then, a new inverter control technique is proposed to maintain the inverter voltage as well as the DC-link voltage in a hybrid AC-DC micro-grid. The DC micro-grid under study comprises of photovoltaic system, permanent magnet synchronous generator-based wind energy system, battery energy storage system, fuel cell, electrolyzer and DC loads. The complete DC Micro-grid along with its correlated control algorithms are examined and accessed through MATLAB/Simulink environment.

Overall Adaptive Controller Design of PMSG Under Whole Wind Speed Range: A Perturbation Compensation Based Approach

This paper proposes an adaptive overall control strategy of the permanent magnet synchronous generator-based wind energy conversion system (WECS) in the whole wind speed range. For the machine side, the maximum power point tracking (MPPT) operation is realized by stator current and mechanical rotation speed control under below-rated wind speeds. Under above-rated wind speeds, the extracted wind power is limited via pitch control. For the grid side, the reactive and active power injected into grid is regulated by DC-Link voltage and grid current control loop. In addition, under grid voltage dips, the pitch control is employed for limiting grid current and maintaining the DC-Link voltage around its rated value. The fault ride-through capability (FRTC) can be enhanced. The overall control strategy is based on perturbation estimation technique. A designed observer is used for estimating the perturbation term including all system nonlinearities, uncertainties and disturbances, so as to compensate the real perturbation. Then, an adaptive control for the original nonlinear system can be realized. The effectiveness of the proposed overall control strategy is verified by applying the strategy to a 2-MW WECS in MATLAB/Simulink. The results show that, compared with the feedback linearizing control (FLC) strategy and conventional vector control (VC) strategy, the proposed perturbation observer based adaptive control (PO-AC) strategy realizes the control objectives without knowing full state information and accurate system model, and improves the robustness of the WECS parameter uncertainties and FRTC.

Direct driven wind energy conversion system connected to load using variable frequency transformer

This paper proposes a variable frequency transformer for wind energy conversion systems using permanent magnet synchronous generator. It is a doubled-fed wound round induction machine which transfers the power between asynchronous networks. Typical permanent magnet synchronous generator-based wind energy conversion systems with back-to-back converters produces harmonics which creates power quality problems.The above problem can be overcome using the variable frequency transformer between permanent magnet synchronous generator and load. This design does not employ any power electronic converter for wind energy conversion system and harmonics can be diminished using the variable frequency transformer. In this paper, the PMSG is connected through variable frequency transformer for different wind speeds. The results are endorsed using MATLAB/SIMULINK.

Robust nonlinear control via feedback linearization and Lyapunov theory for permanent magnet synchronous generator- based wind energy conversion system

In this paper, the method for the nonlinear control design of a permanent magnet synchronous generator based-wind energy conversion system (WECS) is proposed in order to obtain robustness against disturbances and harvest a maximum power from a typical stochastic wind environment. The technique overcomes both the problem of nonlinearity and the uncertainty of the parameter compared to such classical control designs based on traditional control techniques. The method is based on the differential geometric feedback linearization technique (DGT) and the Lyapunov theory. The results obtained show the effectiveness and performance of the proposed approach.

A Robust Control Strategy Research on PMSG-Based WECS Considering the Uncertainties

This paper proposes a robust control strategy for the uncertainties of permanent magnet synchronous generator-based wind energy conversion system, based on state feedback. Meanwhile, the detailed design and analysis process of this robust controller also have been presented. Compared with the conventional control, the new method with a better robustness can not only make the whole closed-loop system stable but also reduce the major harmonics and total harmonic distortion of currents and ripples of torque. And then, we set up a detailed 2 MW simulation test platform based on MATLAB/SIMULINK/SimPowerSysterms. The simulation results verify the effectiveness and correctness of the algorithm.

Maximum power point tracking for the permanent magnet synchronous generator‐based WECS by using the discrete‐time integral sliding mode controller with a chattering‐free reaching law

In this study, a single sensor-based maximum power point tracking (MPPT) algorithm is presented for permanent magnet synchronous generator-based wind energy conversion system (WECS). The MPPT method used in this study uses only the wind speed sensor to generate the reference point required for the maximum power. A discrete-time controller is proposed to bring the system to the reference point determined by the MPPT algorithm. The designed MPPT controller consisting of a new discrete-time reaching-law approach and a discrete-time integral sliding mode control (SMC). The designed discrete-time SMC-based controller is implemented by using an Acorn RISC Machine (ARM)-based LM4F120 microcontroller, and its performance is examined on a WECS emulator prepared in the laboratory. The results got from the real-time studies prove that the proposed controller has the satisfactory performance to bring the system to the MPP. The performance of the proposed controller is also compared with the conventional sliding mode controller and perturb and observe method. The obtained results proved that the proposed controller has a better performance than the other controllers in terms of the settling time and output voltage's ripple.

Robust Sliding Mode Control of Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems

The subject of this paper pertains to sliding mode control and its application in nonlinear electrical power systems as seen in wind energy conversion systems. Due to the robustness in dealing with unmodeled system dynamics, sliding mode control has been widely used in electrical power system applications. This paper presents first and high order sliding mode control schemes for permanent magnet synchronous generator-based wind energy conversion systems. The application of these methods for control using dynamic models of the d-axis and q-axis currents, as well as those of the high speed shaft rotational speed show a high level of efficiency in power extraction from a varying wind resource. Computer simulation results have shown the efficacy of the proposed sliding mode control approaches.

Maximum power point tracking method using a modified perturb and observe algorithm for grid connected wind energy conversion systems

This paper analyses the performance of maximum power point tracking in a grid connected permanent magnet synchronous generator-based wind energy conversion system using a linear relationship between optimum speed and wind velocity to increase the speed of the controller response. Furthermore, the proposed large step forward and the small step reverse initial tracking improves the accuracy of the existing large step perturb and observe algorithm and is also capable of tracking maximum power for rapidly varying wind conditions. The system consists of back-to-back sinusoidal pulse-width modulation converters. The generator side converter is used to track the maximum wind power using the proposed method through field oriented control. The role of the grid side inverter is to transfer the generated wind power from DC-link to the grid and regulate the DC-link voltage. Moreover, this paper examines the performance of the grid side inverter in grid synchronisation with a non-linear inductive load. Moreover, it analyses the concept of the proposed method using the theoretical aspects. A model for the complete system is developed in MATLAB/SIMULINK and the performance of the proposed control scheme is validated through simulations.

Smoothing of Wind Power Fluctuations for Permanent Magnet Synchronous Generator-Based Wind Energy Conversion System and Fault Ride-through Consideration

Due to the increment of penetration level of wind power generation, output power fluctuation is one of the most important issue's that can destabilize the power system operation. This article mainly deals with the smoothing of the output power fluctuations of a wind energy conversion system based permanent magnet synchronous generator and fault ride-through enhancement during a grid fault. The concerned wind energy conversion system based permanent magnet synchronous generator adopts an AC-DC-AC converter system. The proposed control method limits the wind energy conversion system output power by adjusting the pitch angle of the wind turbine blades when wind speed is above the rated wind speed. In the grid-side converter, a fuzzy logic controller is used to determine the torque reference for which the kinetic energy stored by the inertia of wind turbine can smooth the output power fluctuations of the permanent magnet synchronous generator. Also, the DC-link voltage, controlled by the grid-side inverter, is adjusted in accordance with the output power fluctuations of the permanent magnet synchronous generator using a voltage smoothing index. Moreover, in this aticle, the proposed method ensures that the wind turbine stays operational during grid faults and provides fast restoration once the fault is cleared. To show the effectiveness of the proposed method, simulations under different conditions have been performed by using MATLAB/Simulink® (The Math Works, Natick, MA, USA).

Predictive Control of a Three-Level Boost Converter and an NPC Inverter for High-Power PMSG-Based Medium Voltage Wind Energy Conversion Systems

In this paper, a new medium voltage power converter topology using a diode rectifier, three-level boost (TLB) converter, and neutral-point-clamped (NPC) inverter is proposed for a high-power permanent magnet synchronous generator-based wind energy conversion system. The generator-side TLB converter performs the maximum power point tracking and balancing of dc-link capacitor voltages, while the grid-side NPC inverter regulates the net dc-bus voltage and reactive power to the grid. A significant improvement in the grid power quality is accomplished as the NPC inverter no longer controls the dc-link neutral point voltage. A model predictive strategy is proposed to control the complete system where the discrete-time models of the proposed power electronic converters are used to predict the future behavior of control variables. These predictions are evaluated using two independent cost functions, and the switching states which minimize these cost functions are selected and applied to the generator- and grid-side converters directly. In order to comply with the high-power application, the switching frequencies of the TLB converter and NPC inverter are minimized and maintained below 1.5 and 1 kHz, respectively. The proposed topology and control strategy are verified through MATLAB simulations on a 3-MW/3000-V/577-A system and dSPACE DS1103-based experiments on 3.6-kW/208-V/10-A prototype.

Unified Power Control for PMSG-Based WECS Operating Under Different Grid Conditions

A unified power control strategy is proposed for the permanent magnet synchronous generator-based wind energy conversion system (WECS) operating under different grid conditions. In the strategy, the generator-side converter is used to control the dc-link voltage and the grid-side converter is responsible for the control of power flow injected into the grid. The generator-side controller has inherent damping capability of the torsional oscillations caused by drive-train characteristics. The grid-side control is utilized to satisfy the active and reactive current (power) requirements defined in the grid codes, and at the same time mitigates the current distortions even with unsymmetrical grid fault. During grid faults, the generator-side converter automatically reduces the generator current to maintain the dc voltage and the resultant generator acceleration is counteracted by pitch regulation. Compared with the conventional strategy, the dc chopper, which is intended to assist the fault ride through of the WECS, can be eliminated if the proposed scheme is employed. Compared with the variable-structured control scheme, the proposed strategy has quicker and more precise power responses, which is beneficial to the grid recovery. The simulation results verify the effectiveness of the proposed strategy.