PMSG-based Wind Energy Conversion System Research Articles

A hybrid fuzzy logic-based MPPT algorithm for PMSG-based variable speed wind energy conversion system on a smart grid

Recently, wind power has gained popularity as a sustainable energy source. Wind energy conversion systems (WECSs) can accept fixed speed and variable speed (VS) operations. VS-WECSs are preferable to conventional WECSs because of their higher electricity collection capacity. Maximum power point tracking systems (MPPTs) are essential for maximizing the efficiency of wind energy generation in wind turbine installations linked to power grids. This study introduces a hybrid fuzzy logic controller-based MPPT (FLC-MPPT) for wind turbines (WTs) connected to permanent magnet synchronous generators (PMSGs) to accurately determine the maximum power output of WTs. This study employs a three-phase back-to-back converter to link a PMSG to a utility grid. The reference signals for pulse width modulation controllers comprise two-phase system currents. It constructs a converter that can transfer electrical energy in both directions using insulated-gate bipolar transistor technology and is powered by a battery. The machine-side converter uses model predictive control for the present control loop. Given the generator's susceptibility to changes in wind conditions, this factor is of the utmost importance. A WT simulation was conducted using MATLAB/Simulink and an FLC methodology was employed. The model used a PMSG. Measurements of rotor speed, power, induced voltage, and current were taken in relation to variations in wind speed. The simulation results show that the FLC-MPPT can maximize the output power over a wide range of wind speeds with a higher efficiency of 92.6% and performance of 95.7%.

Black-box modeling of PMSG-based wind energy conversion systems based on neural ODEs

Abstract Integrating renewable energy sources like wind power into the power grid enhances the dynamic interactions among renewable energy-producing equipment, leading to new technological issues for the power grid. Modeling and simulation are essential to ensure the stability of the emerging power grid, but they require precise dynamic component modeling, which is often unavailable due to technical confidentiality and other factors. Conventional hardware-in-the-loop (HIL) simulation can accurately simulate the dynamics of a single renewable energy device, but not the complex dynamics of multiple devices. This research introduces a method that combines classical mechanism modeling and differential neural network modeling to create accurate wind turbine models utilizing equipment measurement data or HIL simulation data. A realistic wind turbine electromagnetic transient simulation model of a specific type is developed and validated by connecting it to the IEEE-39 node system, confirming the model’s accuracy.

Augmented Two-Stage Hierarchical Controller for Distributed Power Generation System Powered by Renewable Energy: Development and Performance Analysis

The sustainable development of an area is highly reliant on a reliable electrical energy supply. Microgrids are important in integrating distributed energy resources (DERs) using power electronic converters. However, microgrid control becomes challenging with the increasing number of distributed generators and loads. With the conventional droop control method, power contributions from DER converters cannot be accurately shared due to a mismatch of line impedances. In this paper, an augmented hierarchical control mechanism is proposed to solve the issues mentioned above. This hierarchical control mechanism consists of primary and secondary controllers. The primary stage utilized the droop controller to improve optimal power flow, mainly for the resistive network. The secondary stage is based on an improved methodology to compensate for the voltage and frequency variations during small and large signal disturbances. Moreover, the modelling and analysis for PMSG-based wind energy conversion systems are also presented. The response of the primary controller for active and reactive power sharing is investigated. The analysis emphasizes the demonstration of optimal power-sharing under normal and abnormal conditions for the considered load. Finally, the suggested robust controller’s performance is evaluated in a MATLAB environment, and simulation results show the proposed scheme’s superiority under different operating conditions. The frequency is stable at 50 Hz after a 50 KW load is added.

A New Multilevel Converter Configuration for Medium-Voltage Open-Winding PMSG-Based Wind Energy Conversion Systems

A New Multilevel Converter Configuration for Medium-Voltage Open-Winding PMSG-Based Wind Energy Conversion Systems

Fractional-Order Extremum Seeking Based MPPT for Wind Energy Conversion System with PMSG and ANPC Inverter Using Model Predictive Control

In this paper, a real-time optimization-based extremum seeking (ES) approach is applied to a grid-connected PMSG-based wind energy conversion system (WECS) for maximum power point tracking (MPPT). The proposed model-free approach aims harness the output power of the WECS by controlling the system from the DC side, eliminating the need for speed sensor. Moreover, using fractional order calculus in ES improves the convergence speed and robustness compared with the conventional integer-order ES methods. Additionally, an MPC controller for the inner loop is designed to maintains fast transient response through ANPC inverter. Finally, the effectiveness of the proposed method is verified by simulating the WECS in MATLAB/Simulink environment. It was shown that the proposed method is feasible and robust under different weather conditions.

Fuzzy Memory Sampled-Data Controller Design for PMSG-Based WECS With Stochastic Packet Dropouts

The fuzzy memory sampled-data control problem for permanent magnet synchronous generator (PMSG)-based wind energy conversion system (WECS) with stochastic packet dropouts is discussed in this paper. To do this, the PMSG-based WECS dynamics are firstly modelled by a set of fuzzy IF-THEN rules of the Takagi–Sugeno (T–S) fuzzy model because of high nonlinearity. And then, to minimize design conservatism, a suitable augmented looped-type Lyapunov functional along with a novel integral inequality is established by using the sampling mode information with signal transmission delay. Further, a fuzzy memory-based sampled-data controller is designed to obtain the asymptotic stability condition under the circumstances of packet dropouts, and simultaneously, disturbance reduction is confirmed. Thereafter, the associated fuzzy controller gains can be computed by solving a number of linear matrix inequalities (LMIs). Finally, the application of the suggested method to a real-world system is proved using PMSG-based WECS, and the mathematical Rossler's system demonstrates the effectiveness and superiority of the proposed technique over the existing method.

An improved model predictive control of back-to-back three-level NPC converters with virtual space vectors for high power PMSG-based wind energy conversion systems

In this study, an improved virtual space vector (VSV)-based two-stage model predictive control (MPC) scheme is presented for neutral point clamped (NPC) converters in high power-rated permanent magnet synchronous generator (PMSG)-based wind energy conversion system applications. The presented MPC scheme utilizes the VSVs and involves two-stage prediction for effectively reducing computation complexity. In stage-I prediction, a virtual space vector is identified based on the optimum cost function. Then, a set of sub-sector vectors are placed in stage II prediction based on the capacitor voltage levels. From this, the cost function predicts the optimum switching state. At the same time, the conditional selection of small voltage vectors in stage II prediction eliminates the neutral point voltage balancing constraint. Finally, the presented method is verified by the simulation of the back-to-back NPC converter of a high-power-rated PMSG-based wind energy conversion system. Further, the adaptability of the presented scheme for maximum power point tracking, reactive power control, and dc-link voltage control is also verified by simulation.

Application of different MPPT algorithms for PMSG-based grid-connected wind energy conversion system

Renewable energy sources such as wind energy sources have become the most prominent area of research work over the last two decades. Extraction of maximum power and lowering of THD are still the main issues during the integration of wind energy sources to the grid due to the noncontrollable variability of wind energy sources and the application of power electronic devices as interfacing devices. The main objective of this paper is to utilize modern optimization techniques for extracting maximum power points and implementing a Multilevel inverter to obtain minimal THD. This paper has introduced Improved Grey Wolf Optimization with Levy Flight for tracking maximum power from WECS. This Levy flight concept is applied in combination with the improved hunting process of GWO for providing an efficacy solution and a high rate of convergence through global tracking. Distinct MPPT algorithms such as Perturb and Observe (P&O), Grey Wolf Optimization (GWO), and Levy Flight Grey Wolf optimization (LGWO) are presented, simulated, and analyzed using MATLAB/SIMULINK. These algorithms have been compared based on quantitative analysis to examine the stability, figure out performance, and verify the best algorithm among the proposed algorithms. The consequences of the comparison demonstrated the supercilious characteristic of LGWO in the matter of tracking GMPP, rate of convergence, and the time to catch GMPP. The multilevel inverter is utilized as an interfacing unit between wind energy sources and the grid. This power electronic-based multilevel inverter is the main source of harmonic generation. This harmonic has been reduced to 5.5% (THD) due to the application of a 23-level Cascaded H-bridge multilevel Inverter using MATLAB/SIMULINK software.

PERFORMANCE ANALYSIS ON PMSG BASED WIND GENERATION SYSTEM INTERFACED MULTILEVEL CONVERTER WITH ARTIFICIAL INTELLIGENCE TECHNIQUE

This paper focuses on the development of ANN based MPPT interfaced Permanent magnet synchronous generator (PMSG) for wind energy conversion system (WECS). There are many drawbacks to conventional energy sources, such as higher fossil fuel prices, damaging to the environment, a shortage of resources, and increased pollution. Due to the unpredictable and arbitrary nature of wind energy, it is crucial to introduce several control strategies in order to maximize its efficiency. In this work, Levenberg algorithms are developed for Artificial Intelligence Technique using MPPT algorithms for PMSG-based wind energy conversion systems. The proposed system consists of 3 kW PMSG integrated WECS, DC to DC boost converter, multilevel inverter and different loads. The DC to DC converter is connected to the multilevel inverter through a DC link capacitor. The inverter power is fed to the grid through a step-down transformer. MPPT controllers are used in the standalone wind energy conversion system. The goal of this research is to develop an MPPT controller using Levenberg-based Artificial Intelligence Technique for wind energy conversion systems. With the proposed Levenberg-based Artificial Intelligence Technique, MPPT uses voltage and current as input variables for DC to DC boost converter duty ratios. The Artificial Intelligence Technique of MPPT controller for standalone wind energy conversion systems with various different input/output conditions is modeled and simulated in MATLAB/ Simulink environment. The performance of the Artificial Intelligence Technique-based MPPT controller versus the conventional incremental conductance MPPT controller. Simulation results show that for a wide range of input wind speed, Artificial Intelligence Technique based MPPT controller shows improved performance than the conventional MPPT at various operating conditions. The response of the developed Levenberg based Artificial Intelligence Technique based MPPT algorithms for PMSG based wind energy conversion system in MATLAB/ Simulink environment to investigate the robustness of the developed control strategy and validate the reliability and stability under different input/output conditions for grid connected wind generation system.

Three-phase AC-DC Converter for Direct-drive PMSG-based Wind Energy Conversion System

In this paper, a wind energy conversion system (WECS) is presented for the electrification of rural areas with wind energy availability. A three-phase AC-DC converter based on a bridgeless Cuk converter is used for power extraction from the permanent magnet synchronous generator (PMSG). The bridgeless topology enables the elimination of the front-end diode bridge rectifier (DBR). Moreover, the converter has fewer components, simple control, and high efficiency, making it suitable for a small-scale WECS. A squirrel cage induction motor (SCIM) is used to emulate a MOD-2 wind turbine to implement the PMSG-based WECS. A direct-drive eight-pole PMSG is used in this study; thus, a low-input-voltage system is designed. The converter is designed to operate in the discontinuous inductor current mode (DICM) for inherent power factor correction (PFC) and the maximum power point tracking (MPPT) is achieved through the tip-speed ratio (TSR) following. The performance of the developed system is analyzed through simulation, and a 500 W hardware prototype is developed and tested in different wind speed conditions.

Simulation of MPPT with a PMSG-based wind energy conversion system considering variable wind speed

The proposed method provides a good tracking performance through detecting the variation in the wind speed rapidly. In addition, the implementation does not require prior information on the wind turbine parameters, air density, or wind speed. By investigating the change directions of the mechanical output power of the wind turbine and the rotor speed of the generator, the proposed MPPT algorithm can determine an optimal speed to achieve the maximum power point (MPP).
 Then, this optimal speed is set to the reference in the speed control loop to force the system to operate at the MPP. The DC-DC boost converter has been used to boost up the low AC voltage generated by the PMSG directly driven by the wind turbine. The mechanical output power of the wind turbine is calculated from the mechanical torque which is measured directly by sensor.
 The proposed scheme is modeled and simulated under SIMULINK/MATLAB. The simulation results are accurate and validate the wind energy conversion system.

Improvement of PMSG-Based Wind Energy Conversion System Using Developed Sliding Mode Control

In recent years, regulating a wind energy conversion system (WECS) under fluctuating wind speed and enhancing the quality of the electricity provided to the grid has become a hard challenge for many academics. The current research provides a better control strategy to decrease the occurrence of chattering phenomena. Combined with the Maximum Power Point Tracking (MPPT) strategy and a pitch angle control, the control is possible to increase the performance and the efficiency of the Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System. This study attempts initially to regulate the generator and the grid side converter to track the wind speed reference established by the MPPT algorithm. And secondly, to relieve the chattering problem associated with the conventional sliding mode control (CSMC), the proposed sliding mode control (PSMC) is based on a novel smooth continuous switching control. Besides, the suggested sliding mode control stability is confirmed using Lyapunov’s stability function. The complete system was evaluated in the MATLAB/Simulink (MathWorks, Natick, MA, USA) environment using a 2 MW PMSG’s power, under random fluctuations in the wind speed to show the suggested approach’s efficiency and robustness, which was then compared to the CSMC and other common approaches available in the literature. The simulation results reveal that the recommended sliding mode control approach delivers good speed, accuracy, stability, and output current’s ripple.

Adaptive super-twisting sliding mode control for maximum power point tracking of PMSG-based wind energy conversion systems

This paper proposes a super-twisting adaptive sliding mode control law for maximum power point tracking of wind energy conversion systems based on permanent magnet synchronous generators (PMSGs). The employed sliding mode control algorithm can be considered an effective solution, as it retains the robustness properties of classical sliding mode control methods in the presence of disturbances and parameter uncertainties; at the same time, it provides chattering reduction via gain adaptation and generation of second-order sliding modes. In our work, a nonlinear multi-input multi-output tracking control problem is solved to maximize the captured power. Simulation results are presented using real wind speed data, and discussed for the proposed controller and four other sliding mode control solutions for the same problem, in the presence of variations of stator resistance, stator inductance and magnetic flux linkage. The proposed controller achieves the best trade-off between tracking performance and chattering reduction among the five considered solutions: compared to a standard sliding mode control algorithm, it reduces the amount of chattering from two to five orders of magnitude, and the steady-state error on PMSG rotor velocity of one order of magnitude. Also, it reduces the above-mentioned steady-state error of four orders of magnitude with respect to a previously-proposed linear quadratic regulator based integral sliding mode control law for the same system.

Coordinated LVRT Support for a PMSG-Based Wind Energy Conversion System Integrated into a Weak AC-Grid

In a grid, the choice of the point of common coupling (PCC) does not solely rely on the voltage level alone but also conjointly depends on the grid strength for many explicit purposes. Nowadays, the affinity of low SCR grid connections has become a crucial thought once it involves the integration of wind generation plants (WPPs). Since the quality of wind resources is a critical issue, these plants are usually placed in remote areas with a sophisticated potential of wind flow. These remote areas are typically less inhabited, where the grid does not perpetually always have to be sturdy. Moreover, the exceeded power demand loading and higher wind penetration affect the generation, transmission, and distribution utilities by permitting the flow of unbalanced voltages and currents in the power system. Therefore, the quality of transmitted power is becoming a crucial facet of distributed energy generation units. In this paper, a permanent-magnet synchronous generator (PMSG) based wind energy conversion system (WECS) is presented. It discusses a solution, which provides the low voltage ride through (LVRT) provision by the suppression of DC link overvoltage and active power limitation during an asymmetrical grid fault. With improved back-to-back converter control, the machine side converter (MSC) is employed to control the DC-link voltage. Furthermore, the grid side converter (GSC) is used to implement the active/reactive current injection according to the outlined limits. The need for external hardware is eventually avoided, which is typically required to dissipate the additional energy generated during a grid fault. Hence, it is proven to be an affordable solution.

Robust control scheme for the braking chopper of PMSG-based wind turbines–A comparative assessment

Despite the grid-integration of permanent magnet synchronous generator (PMSG) wind energy conversion systems (WECS), utilities are facing challenges that are hindering wind penetration growth. Grid-side voltage sags at the point of common coupling (PCC) are considered as one of such uncontested issues. Due to imbalance in back-to-back (BTB) converter’s dc-link input-output powers, its capacitor and power electronics are highly susceptible to PCC voltage sags. Hence, provision of wind farm grid-codes (GC) for supporting grid operations is imperative and development of strategies for realizing low-voltage ride-through capability in WECSs have emerged as an integral GC requirement. One strategy is to install a braking chopper (BC) across the dc-link. This study presents (a) an overview of conventional BC control methods, (b) design of a robust BC controller for PMSG-based WECSs, and (c) comparative performance assessment of (b) with (a) for PMSG-based WECS operations during normal and grid fault conditions. The robust BC controller takes advantage of the sliding mode method to control BC and to determine the grid-side converter active power reference set-point. This nonlinear control scheme ensures proper execution of GCs and offers reliable protection to the dc-link. Chattering phenomenon and reaching-time is reduced significantly, by further adoption of exponential reaching law. In addition to its robustness, a prominent feature of this BC controller is its applicability to present BTB control structures. The simulation results reflect on effectuality and robustness of the proposed BC controller in comparison to conventional BC control strategies.

A Complete Impedance Model of a PMSG-Based Wind Energy Conversion System and Its Effect On the Stability Analysis of MMC-HVDC Connected Offshore Wind Farms

Impedance modeling of a permanent magnet synchronous generator (PMSG)-based wind energy conversion system (WECS) usually ignores the machine-side dynamics, instead, the machine-side system is simplified as a constant power source, while merely keeping the detailed grid-side converter model. This simplification is mainly based upon the intuition that the dc-bus capacitor is large enough so that the machine- and grid-side dynamics can be decoupled. However, the simplification probably does not hold in practice since there is always a tendency to minimize the capacitor size to achieve a smaller package for installation. Therefore, the machine-side system should not be ignored, otherwise maybe leading to error for stability analysis. To address this issue, this paper developed a complete ac-side impedance model of the PMSG-based WECS. Then, impact factors about the coupling characteristics between machine- and grid-side systems of the PMSG-based WECS are discussed. Finally, a case study of sub/super synchronous oscillation is carried out on a practical offshore wind farm integrated with a modular multilevel converter based high-voltage dc (MMC-HVDC) transmission system in China. The results show that ignoring the machine-side system would lead to an optimistic stability judgement, which confirms the necessity of the complete model of PMSG-based WECS. Furthermore, the system can be stabilized by either changing the couplings between machine- and grid-side systems of PMSG-based WECS or implementing active damping in the wind farm side MMC.

Efficiency improvement and reliability evaluation of small-scale PMSG-based wind energy conversion system using back-to-back T-type converter

Utilization of small-scale wind energy conversion systems (WECS) has been grown in recent years. Permanent magnet synchronous generator due to lack of slip rings is a suitable alternative for induction generators to be used in these systems. However, these generators use full power converters which means higher power losses. In this paper, an ultra-efficient three-level converter, called T-type converter, is used in a back-to-back configuration as power electronic interface for PMSG-based small-scale WECS. Then, simulations are carried out to evaluate the efficiency of the system and compare it to conventional two- and three-level back-to-back configurations. Meanwhile, thermal analysis is carried out to investigate the thermal loading of different switching components of the converter. Data given by this analysis can be further used to evaluate system reliability. Therefore, system reliability is calculated and compared to conventional two- and three-level converter systems.

Modeling, Parameter Measurement, and Control of PMSG-based Grid-connected Wind Energy Conversion System

The design of reliable controllers for wind energy conversion systems (WECSs) requires a dynamic model and accurate parameters of the wind generator. In this paper, a dynamic model and the parameter measurement and control of a direct-drive variable-speed WECS with a permanent magnet synchronous generator (PMSG) are presented. An experimental method is developed for measuring the key parameters of the PMSG. The measured parameters are used in the design of the controllers. The generator-side converter is controlled using a vector control scheme that maximizes the power extraction under varying wind speeds. A model predictive controller (MPC) is designed for the grid-side voltage source converter (VSC) to regulate the active and reactive power flows to the power grid by controlling the $d$ - and $q$ -axis currents in the synchronous reference frame. The MPC predicts the future values of the control variables and takes control actions based on the minimum value of the cost functions. To comply with the grid code requirement, a modified design approach for an LCL filter is presented and incorporated into the system. The design process is simple and incorporates significant filter parameters while avoiding iterative calculations. The comparative analysis of the designed filter with conventional L, LC, and iterative LCL filters demonstrates the effectiveness of the modified design approach. The proposed wind energy system with MPC and LCL filter is simulated in MATLAB/Simulink and experimentally implemented in the laboratory using the dSpace digital signal processor (DSP) system. The simulation and experimental results validate the efficacy of the designed controllers using the measured parameters and show dynamic and steady-state performance under varying wind speeds.

Decentralized Unintentional Islanding Identification for Converter-Interfaced Multiple DGs

The unrelieved developments in the field of power electronics have cemented a strong base to distributed generation, exploiting various renewable and nonrenewable energy resources. However, such a power generation is denied permission to supply during accidental isolation owing to copious whys and wherefores. It is vital to perceive such isolation and eventually shut down the distributed generators under such circumstances. To do so, an active islanding detection based on disturbance injection through q-axis current controller is adopted, and an analyzing method is proposed in this article for converter-interfaced multiple DGs (including solar, PMSG-based wind energy conversion system and battery) to distinguish between the islanded and nonislanded situations. The proposed method is competent to detect the island formation, within 160 ms, in a decentralized manner, with zero nondetection zone for the load quality factor ≤ 2.5 and also distinguishes the nonislanding conditions from the islanding conditions accurately. The proposed analyzing methodology is corroborated for several operating conditions by simulation using MATLAB 2017b/Simulink platform.

Mechanical Stress Comparison of PMSG Wind Turbine LVRT Methods

The grid code for renewable energy is increasingly strict to circumvent issues with grid stability and reliability. One grid code standard that is enforced for most modern variable speed wind turbines (WTs) is the low-voltage ride-through (LVRT) criteria, where WTs are to be grid-connected during voltage dips. Traditionally, for permanent magnet synchronous generator (PMSG) WTs, LVRT is achieved by using a DC crowbar or DC chopper to dissipate the power difference between the grid and the generator. Alternatively, a popular LVRT strategy proposed by the research community for PMSG-based wind energy conversion system (WECS) is the stored energy in rotor inertia (SEIRI) strategy, which is done by altering the control of the machine-side converter (MSC) with potential cost savings. However, there are some concerns regarding additional mechanical stress to the drivetrain that may pertain to this method. A hybrid LVRT method has been suggested to combine the crowbar and the SEIRI methods to incorporate the benefits from both methods. In this article, we are studying and comparing the electrical and mechanical performance of PMSG WTs operating with the traditional crowbar, the SEIRI, and the hybrid LVRT method. To do so, the electrical and mechanical dynamics of these strategies are simulated using a two-mass drive train model, which is necessary for analyzing WTs under mechanical transient. Finally, the performance of wind farms with power reserves while using an inertia based LVRT method will be investigated to show the impact of the power reserve on the WT's LVRT mechanical dynamics.