Synchronous Generator Wind Turbine Research Articles

A Parameter-Adaptive Method for Primary Frequency Regulation of Grid-Forming Direct-Drive Wind Turbines

When wind turbines contribute to system frequency support using virtual synchronous generator (VSG) control, conventional VSG methods often fall short of meeting operational demands, particularly in terms of inertia and frequency support. In this study, considering both the frequency regulation and dynamic performance of VSG, a novel parameter design method that enhances frequency modulation capabilities is proposed in this paper. Initially, VSG control is integrated into the grid-side converter of a direct-drive permanent magnet synchronous generator (D-DPMSG) wind turbine. A small-signal model of the D-DPMSG-VSG active power is then formulated to analyze how the moment of inertia and damping coefficient impact system stability. Subsequently, ensuring that system parameter constraints are met, the key parameters of VSG are adaptively designed to dynamically adjust the system’s frequency and output power during transient responses. Finally, simulation results based on D-DPMSG-VSG in MATLAB/Simulink validated the feasibility, effectiveness, and advantages of the proposed parameter-adaptive VSG control strategy for enhancing the frequency modulation (FM) performance of wind turbines.

FEHD model of a synchronous wind turbine generator aimed at frequency transient simulation

Frequency dynamics analysis and simulation of variable frequency systems, e.g., a synchronous wind turbine generator (WTG), require the use of models capable of accurately replicate frequency dynamics and faithfully mirror the actual behavior of their components.A commonly used methodology that models frequency dynamics, in a straightforward manner, is the flexible extended harmonic domain (FEHD). There are several FEHD models available for different types of electrical and electronic systems; however, there is a lack of a suitable FEHD approach designed to handle variable frequency systems. This lack hindered the exploration of this particular aspect in the realm of electrical system modeling.To overcome the abovementioned gap, this paper introduces a novel FEHD approach and a dedicated model approximation for the analysis of variable frequency systems. The proposed FEHD methodology exhibits significant advantages over traditional FEHD and PSCAD simulations when it comes to display, accurately and in a straightforward manner, the frequency evolution of variable frequency systems. This proposed FEHD approach shows an impressive degree of flexibility and adaptability, contributing to a more thorough comprehension of the dynamic behavior.A case study of a wound rotor synchronous WTG is presented to validate the proposed methodology.

Investigation on Overvoltage Distribution in Stator Windings of Permanent Magnet Synchronous Wind Turbines

The PWM voltage pulses output by the inverter reaches the stator winding of the wind turbine generator through the cable. Due to the impedance mismatch between the motor and the cable, the voltage at the motor end rises under the action of the circuit wave process; on the other hand, electromagnetic oscillation occurs within the motor winding. Higher overvoltage is generated under the combined effect of both, which greatly accelerates the aging and breakdown of the insulation layer of the permanent magnet synchronous wind turbine. In this paper, a three-dimensional electromagnetic model of the permanent magnet synchronous wind turbine generator is established. The distribution circuit parameters of the stator winding of the permanent magnet machine are calculated using the finite element method, and its circuit model is based. The voltage distribution of the stator winding under different PWM excitations is investigated by simulation software, and the effects of the time of the rising edge and the pulse width of the PWM pulse on the stator winding voltage to ground and the turn-to-turn voltage distribution are studied. The results show that the effect of the rising edge time is larger when the rising edge time is shorter, the maximum voltage to ground occurs in the first coil, and the amplitude can be up to 1.5 times of the output voltage. When the rising edge time is longer, the maximum voltage to ground occurs in the end coil, and the amplitude is slightly higher than the output voltage. The trend of turn-to-turn voltage variation is similar for different rising edges; only the maximum turn-to-turn voltage amplitude is different. Pulse width has a small effect on overvoltage and only occurs when the pulse width is less than 10 μs. The research results of this paper are of great significance in revealing the aging and breakdown mechanism of the generator stator insulation, as well as the insulation coordination and design.

Design of 20 MW direct‐drive permanent magnet synchronous generators for wind turbines based on constrained many‐objective optimization

AbstractThis study introduces a constrained many‐objective optimization approach for the optimal design of 20 MW direct drive (DD) permanent magnet synchronous generators (PMSGs). Designing a high‐performance, competitive DD‐PMSG requires considering the generator's performance as well as its weight and material cost. Therefore, we focus on four main characteristics as our design objectives: (1) specific power (power per weight), (2) power‐per‐cost, (3) efficiency, and (4) power factor. To achieve this, we apply an advanced constrained nondominated sorting genetic algorithm III (NSGA‐III), a many‐objective optimization method utilizing evolutionary computation, capable of optimizing four or more objectives with constraints. Additionally, the electromagnetic finite element method is employed to evaluate the generator's characteristics. Through our proposed design process, we optimize three distinct 20 MW DD‐PMSG configurations: a 320‐pole/300‐slot, a 350‐pole/300‐slot, and a 350‐pole/336‐slot topology. Following this optimization, we perform additional multiphysics simulations (covering electromagnetic, structural, overload, and thermal aspects) and control response simulations on four selected models from the Pareto‐optimal solutions to validate their effectiveness as preliminary DD‐PMSG designs. Finally, we conduct a comprehensive analysis of all simulation results.

Grid Forming Fast Frequency Response for PMSG-Based Wind Turbines

Electric power systems are undergoing a rapid transition from fuel-based generation using synchronous generators to renewable generation interfaced by power electronics. In this context, a key challenge is using renewable generation with limited controllability to contribute to power system stability. In this work, we investigate grid-forming control of permanent magnet synchronous generator (PMSG) wind turbines. The proposed control and curtailment strategy supports the entire spectrum of standard functions of grid-following (e.g. maximum power point tracking (MPPT) and grid-forming control (e.g., primary frequency control) without explicit mode switching. A detailed case study is used to compare the performance of the proposed control at operating points corresponding to MPPT and frequency control with standard grid-forming and grid-following controls. The results demonstrate that (i) the proposed energy balancing grid forming control is self-synchronizing in MPPT mode, (ii) the (limited) energy storage and controllability of wind turbines can be adequately utilized to provide grid support, and (ii) the proposed control exhibits good performance under variable wind speeds and does not result in a significant increase of wind turbine fatigue loads.

Direct-Driven PMSG Wind Turbines: Adaptive Super Twisting Algorithm Control Approach

This paper deals with the development of a robust nonlinear control strategy for direct-driven Permanent Magnet Synchronous Generator (PMSG) wind turbines. First-Order Sliding Mode Controllers (FOSMC) are commonly used in such systems to regulate generator rotational speed and optimize power extraction; however, they encounter significant drawbacks, notably the undesirable chattering effect and the necessity for measuring additional system states, leading to increased complexity and implementation costs. In addressing these issues, an effective control technique based on an Adaptive Super-Twisting Algorithm (ASTA) has been proposed. This algorithm not only mitigates the chattering effect but also offers a more cost-effective implementation by incorporating online gains adaptation to accommodate the unpredictable nature of wind speeds. The proposed control technique has been evaluated in MATLAB/Simulink through model-in-the-loop simulations; demonstrating superior performance compared to classical FOSMC and STA controllers under various scenarios.

Sustainability of the Permanent Magnet Synchronous Generator Wind Turbine Control Strategy in On-Grid Operating Modes

Today, there are a variety of technologies for wind-generating systems, characterized by component complexity and control. Controllers are essential for the sustainability of the output voltage and the optimal speed of the generator. To overcome the problems, the system must use controllers that determine the controllers’ ability relative to each other and ultimately the controller that behaves better. This paper investigates the simulation of a PMSG wind turbine with PI, PID, neutral-point-clamped (NPC) and fuzzy controllers to study performance at different wind speeds as input. The wind energy is converted by the wind turbine and given to the PMSG generator. The PMSG output power is transferred to the power network; in this case, we have modeled the power network with a three-phase load. In order to confirm the performance of the proposed method, a PMSG wind turbine is simulated using MATLAB R2017. The simulation results show that the controllers can adjust the DC link voltage, the active power produced by the wind system.

Optimum 7 MW HTS direct-drive wind turbine synchronous generator designs with different rotor and stator iron topologies

Partially superconducting direct-drive wind turbine generators with high-temperature superconducting excitation winding enable an increase of the rated unit power, higher efficiency, and a high, adjustable power factor. The high excitation ampere-turns allow for iron topologies that differ from conventional permanent magnet-excited generators. This study compares four different iron topologies for 7,mathrm{MW} rated power and 8.33 rpm with a slotted stator or stator air gap winding regarding technical key characteristics and economic aspects. The generator designs are numerically optimized based on 2D finite element simulations. Maximum efficiency and the most lightweight designs are obtained with the stator air gap winding, whereas all-iron topologies prove advantageous regarding the trade-off between small active mass and high-temperature superconductor material consumption. The costs of the cryogenic cooling system and of the full converter are both found to be less than 15% for a wide range of generator designs.

Finite-time fault detection and reconstruction of permanent magnet synchronous generation wind turbine via sliding mode observer

In this study, a method for fault detection of a permanent magnet synchronous generator (PMSG) wind turbine is proposed. The dynamic model of the wind energy conversion system is simulated and the system’s fault is diagnosed using a proposed terminal sliding mode observer (TSMO). The nonlinear state-space equations of the closed-loop wind turbine are derived, which include a robust adaptive controller that is implemented for maximum power capture and a PI controller that is designed for pitch angle control. Then, utilising a new approach, a TSMO is designed for estimating the states and faults in a finite time. The stability and convergence of the states and fault estimation error are investigated via the Lyapunov stability theory. A PMSG wind turbine is simulated and using TSMO the states are estimated and a blade imbalance fault (BIF) fault is detected. The state and fault estimation errors converge to zero in a finite time.

Comparative Performance of DFIG and PMSG Wind Turbines during Transient State in Weak and Strong Grid Conditions Considering Series Dynamic Braking Resistor

The recently stipulated grid codes require wind generators to re-initiate normal power production after grid voltage sag. This paper presents a comparative performance of two commonly employed variable speed wind turbines in today’s electricity market, the doubly fed induction generator (DFIG) and the permanent magnet synchronous generator (PMSG) wind turbines. The evaluation of both wind turbines was performed for weak, normal and strong grids, considering the same machine ratings of the wind turbines. Because of the critical situations of the wind turbines during faulty conditions in the weak grids, an analysis was done considering the use of effective series dynamic braking resistor (SDBR) for both wind turbines. The grid voltage variable was employed as the signal for switching the SDBR in both wind turbines during transient state. Additionally, an overvoltage protection system was considered for both wind turbines using the DC chopper in the DC-link excitation circuitry of both wind turbines. Furthermore, a combination of the SDBR over-voltage protection scheme (OVPS) was employed in both wind turbines at weak grid condition in order to improve the performance of the variable speed wind turbines and keep the operation of the power converters within their permissible limits. Furthermore, the performance of the DFIG and PMSG wind turbines in weak grids were further investigated, considering the combination of 75% and 50% effectively sized SDBR and OVPS. It was observed that, even with a 50% reduction in SDBR or OVPS, the performance of both wind turbines is still satisfactory with faulty conditions. Therefore, it is recommended to use a combination of the SDBR and OVPS with DFIG- or PMSG-based variable speed wind turbines to achieve a superior fault ride through performance, especially in weak grids. The system performance was evaluated using the power system computer design and electromagnetic transient including DC (PSCAD/EMTDC) platform.

Investigation of LVRT capability of wind driven dual excited synchronous generator

This paper proposes an effective control technique for low voltage ride through (LVRT) capability in dual excited synchronous generator (DESG) wind turbines. The proposed control technique is dependent on controlling the field circuit parameters. Where the active power is controlled by the field-current space phasor magnitude and the reactive power is controlled by the field-voltage space phasor phase. With the proposed control strategy, the DESG can generate additional reactive power to support grid voltage recovery under grid faults. The DC-link voltage is kept within an acceptable limit since the excess power, due to the power mismatch between the mechanical and armature power is stored in the generator inertia. Using the proposed control strategy, the DESG can enhance the LVRT capability efficiently without using extra protection circuits or any additional control techniques during fault conditions. To test the proposed control method, simulation, and experimental results for a 1.1 kW DESG wind turbine system were obtained.

Investigating Permanent Magnet Synchronous Generator Wind Turbine Performance During Low Voltage Using Series and Bridge Type Fault Current Limiters

Investigating Permanent Magnet Synchronous Generator Wind Turbine Performance During Low Voltage Using Series and Bridge Type Fault Current Limiters

L/HVRT scheme of offshore permanent magnet synchronous wind turbine

A low/high voltage fault ride through technology scheme of offshore permanent magnet synchronous wind turbine generator (PMSG) is proposed. When the offshore PMSG operates during low/high voltage faults, the reason for the unbalanced power generation between the generator side and the grid side is analyzed, and the jump mechanism of the DC bus voltage is explored. The chopper circuit is connected in parallel with the DC bus capacitor to dissipate the unbalanced power through the unloading resistance, stabilize the DC capacitor voltage and reduce its fluctuation. According to the low/high voltage ride-through technical standards of China, the inverter station control scheme for offshore PMSG is designed, and the reactive power compensation strategy is proposed. the feasibility and effectiveness of the proposed scheme is verified by simulation.

Augmentation of DFIG and PMSG Wind Turbines Transient Performance Using Different Fault Current Limiters

The technology of variable speed wind turbines is very promising in renewable power generation. It is imperative for wind turbines to gain control after grid disturbances and contribute to the stability of power grids as part of the requirements of grid codes set by grid operators in operating wind farms. Fault current limiters (FCLs) are capable of augmenting the performance of wind turbines during grid disturbances. In this article, the augmentation of the Doubly Fed Induction Generator (DFIG) and the Permanent Magnet Synchronous Generator (PMSG) wind turbines, which are the two most popular variable speed wind turbines, is presented. The evaluation of both wind turbines was performed considering the Series Dynamic Braking Resistor (SDBR), Bridge Fault Current Limiter (BFCL) and the Capacitive Bridge Fault Current Limiter (CBFCL). The modeling of the FCLs in the wind turbines was derived for steady state and grid disturbances so that their dynamic behavior could be understood. The grid voltage variable was employed as the signal for switching the FCLs in both wind turbines during grid disturbances. Moreover, a scenario with no control using the FCLs was also carried out for both wind turbines. The performance of the FCLs in both wind turbines was analyzed and compared using a severe three-phase to ground fault at their terminals. For effective comparison, the same conditions of operation were used in investigating the performance of the FCLs control strategies in both wind turbines during grid disturbances. The study was conducted using Power System Computer-Aided Design and Electromagnetic Transient including DC (PSCAD/EMTDC) environment.

PMSG Wind Turbine Based Current Fed Three Phase Inverter with Model Predictive Control

Design of an improved Permanent Magnet Synchronous Generator (PMSG) wind turbine power based Current Fed Inverter (CFI) using Model Predictive Controller (MPC) is proposed in this paper. Optimum torque control is proposed in wind energy conversion system, MPC is used to adjust the dynamic response time based on the application need. This model deals with torque control strategy of PMSG in the machine side controller. Impact of normal mode of operation by the copper losses and torque ripples are minimized by maximizing the average torque. Synthetization of adequate stator phase current are obtained naturally. Uncertainty of the steady state errors of the plant and parameter error are rectified in the system model. The designed CFI with MPC was implemented using medium range wind turbine in MATLAB /Simulink. The simulation output shows the better efficiency in over modulation region by the proposed CFI with controller. Constant switching frequency is maintained and efficient required dynamic response (DR) value is attained.

Design of Decentralized Hybrid Microgrid Integrating Multiple Renewable Energy Sources with Power Quality Improvement

Due to the energy crisis and exhaustion in the amount of fossil fuels left, there is an urge to increase the penetration of renewables in the grid. This paper deals with the design and control of a hybrid microgrid (HMG) in the presence of variable renewable energy sources. The DC sub-grid consists of a permanent magnet synchronous generator (PMSG) wind turbine, solar PV array with a perturb-and-observe (P&O) MPPT algorithm, boost converter, and battery energy storage system (BESS) with DC loads. The AC sub-grid consists of a PMSG wind turbine and a fuel cell with an inverter circuit synchronized to the grid to meet its load demand. A bidirectional interlinking converter (IC) connects the AC sub-grid and DC sub-grid, which facilitates power exchange between them. The decentralized control of converters allows all the renewables to operate in coordination independently without communication between them. The proposed control algorithm of the IC enables it to act as an active power filter in addition to the power exchange operation. The active power filtering feature of the IC helps to retain the power quality of the microgrid as per IEEE 519 standards by providing reactive power support and reducing the harmonic levels to less than 5%. The HMG with the proposed algorithm can operate in both grid-connected and islanded modes. While operating in grid-connected mode, power exchange between DC and AC sub-grids takes place and all the load demands are met. If it is in islanded mode, a diesel generator supports the AC sub-grid to meet the critical load demands and the BESS supports the DC microgrid. The proposed model is designed and simulated using MATLAB-SIMULINK and its results are analyzed. The efficacy of the proposed control is highlighted by comparing it with the existing controls and testing the HMG for load variations.

Investigation of chaotic behavior and adaptive type-2 fuzzy controller approach for Permanent Magnet Synchronous Generator (PMSG) wind turbine system

<abstract> <p>This article begins with a dynamical analysis of the Permanent Magnet Synchronous Generator (PMSG) in a wind turbine system with quadratic nonlinearities. The dynamical behaviors of the PMSG are analyzed and examined using Poincare map, bifurcation model, and Lyapunov spectrum. Finally, an adaptive type-2 fuzzy controller is designed for different flow configurations of the PMSG. An analysis of the performance for the proposed approach is evaluated for effectiveness by simulating the PMSG. In addition, the proposed controller uses advantages of adaptive type-2 fuzzy controller in handling dynamic uncertainties to approximate unknown non-linear actions.</p> </abstract>

Wind Turbine Emulator for Wind Power Generation System

This paper proposes the wind turbine emulator for wind power generation systems. The focus is on simulation of the operation of wind turbines at different wind speeds to test the capacity and efficiency of generating three-phase electricity. The wind turbine emulator consists of a simulation program and a mechanical part. To simulate the power generation system of wind turbines, researchers use a 400-watt permanent magnet synchronous generator wind turbine connected to a 400-watt servo motor with a built-in absolute encoder and controlled by a servo driver. The motor's torque is controlled by data from mathematical equations in the MATLAB model.

A 3-Ф grid connected wind system with a technique of DC link control using fewer sensors with fuzzy controller

PurposeThis paper aims to provide a permanent magnet synchronous generator (PMSG) wind turbine, which feeds electric power (AC) to the power grid. The converter, located on the machine side, is used to produce the full amount of wind power. Research on wind energy conversion system (WECS) is carried out in this study using a direct wind turbine in MATLAB with constant and variable speeds.Design/methodology/approachThis paper is about WECS using PMSG and is connected to a grid of two serial converters with common DC connections.FindingsThis paper aims to provide the value of DC connection voltage at its base, regardless of the wind speed alterations, the inverter's output ac voltage can be kept constant.Originality/valueThis paper aims to provide a Hill Climb Search maximum power point tracking (MPPT) algorithm is an effective control system for extracting maximum energy, also called voltage control, pitch control, phase-locked loop (PLL) controls, from a wind turbine. Using the Fuzzy controller, the grid side converter is controlled.

Combined RBFN based MPPT and d-axis stator current control for permanent magnet synchronous generators

This paper proposes a new radial basis function neural network maximum power point tracking controller based on a differential evolution algorithm for machine side converter of permanent magnet synchronous generator wind turbine under variable wind speed. Direct axis stator current control methods of permanent magnet synchronous machine are reviewed shortly. A combined radial basis function neural network-based network maximum power point tracking method and d axis stator current control techniques including zero d axis stator current, unity power factor, and constant stator flux-linkage have been implemented to control the machine side converter of permanent magnet synchronous generator wind turbine. The dynamic performance of the proposed approach is assessed under different operating conditions through a simulation model based on MATLAB. It has been seen that the radial basis function neural network controller can not only track well the maximum power point but also can be reduced costly.