Switched Reluctance Generator Research Articles

Exploring The Potentials and Drawbacks of Hysteresis Current Controller For SRM: A Case Study Of Wind Energy Conversion System

Switched Reluctance Machines (SRMs) have drawn interest in renewable energy systems because of their special qualities and applicability. This study examines the idea of hysteresis current regulation in a wind energy conversion system with a Switched Reluctance Generator (SRG). The system is modeled in MATLAB/SIMULINK. The model is simulated and analyzed to ascertain the system’s benefits and shortcomings, focusing on reducing torque ripples in SRG. Considering most classical controllers are complicated to construct, the hysteresis current control is straightforward and effective. However, this controller's two primary shortcomings are that it produces a variable switching frequency and increases current ripples at a steady state, both enhancing acoustic noise in SRM. Lastly, the report suggests that improving controller performance should be the primary emphasis of future research in this field.

Linearization for Output Voltage Control of Switched Reluctance Generator

Linearization for Output Voltage Control of Switched Reluctance Generator

Wind-Driven Position Sensorless Switched Reluctance Generator and Diesel Generator Based Microgrid for Optimal Fuel Consumption and Power Blackout Mitigation

This paper proposes a battery-supported wind power generation system (WPGS) with a mechanical position sensorless switched reluctance generator (SRG) and a diesel generator set (DGS) to enable uninterrupted electricity to remote locations. A sliding mode position observer (SMPO) estimates the SRG speed and position based on the generator voltages and currents. The proposed control approach enhances the consideration of dynamic variations in demand and generation in light of the potential for off-grid operation of small-scale WPGS in regions with a weak or nonexistent grid. Diesel engines perform best at 80%-100% of full capacity. At this mechanical loading, CO and other greenhouse gases are the lowest. The proposed approach keeps the DGS at 80%-100% loading regardless of mechanical load to maximize efficiency. In such a microgrid, the power quality (PQ) concern is dominant due to the use of local nonlinear loads. Hence, a joint logarithmic hyperbolic cosine adaptive filter (JLHCAF) is designed for the microgrid to mitigate the PQ issues emerging due to the nonlinear loads.

Fuzzy Super-Twisting Sliding Mode Controller for Switched Reluctance Wind Power Generator in Low-Voltage DC Microgrid Applications

There is limited research focused on achieving optimal torque control performance of Switched Reluctance Generators (SRGs). The majority of existing studies tend to favor voltage or power control strategies. However, a significant drawback of SRGs is their susceptibility to high torque ripple. In power generation systems, torque ripple implicates fluctuations in the generated power of the generator. Moreover, high torque ripple can lead to mechanical vibrations and noise in the powertrain, impacting the overall system performance. In this paper, a Torque Sharing Function (TSF) with Indirect Instantaneous Torque Control (IITC) for SRG applied to Wind Energy Conversion Systems (WECS) is proposed to minimize torque ripple. The proposed method adjusts the shared reference torque function between the phases based on instantaneous torque, rather than the existing TSF methods formulated with a mathematical expression. Additionally, this paper introduces an innovative speed control scheme for SRG drive using a Fuzzy Super-Twisting Sliding Mode Command (FSTSMC) method. Notably robust against parameter uncertainties and payload disturbances, the proposed scheme ensures finite-time convergence even in the presence of external disturbances, while effectively reducing chattering. To assess the effectiveness of the proposed methods, comprehensive comparisons are made with traditional control techniques, including Proportional–Integral (PI), Integral Sliding Mode Control (ISMC), and Super-Twisting Sliding Mode Control (STSMC). The simulation results, obtained using MATLAB®/SIMULINK® under various speeds and mechanical torque conditions, demonstrate the superior performance and robustness of the proposed approaches. This study presents a thorough experimental analysis of a 250 W four-phase 8/6 SRG. The generator was connected to a DC resistive load, and the analysis focuses on assessing its performance and operational characteristics across different rotational speeds. The primary objective is to validate and confirm the efficacy of the SRG under varying conditions.

An Incorporated Power and Data Synchronous Transmission Method for SRG Integrated Wind Power Generation Systems

Reliable communication places important roles in renewable generation for operating status monitoring, fault alarming, cooperative control and so on. For existing power and data synchronous transmission strategies applied to switched reluctance generator (SRG) systems, the communication rate is limited by very low power switching frequencies. Hence, in this paper, a new PDST strategy is proposed and implemented in an SRG integrated wind generation system by incorporating power and data composite modulation method with signal injection method. For lower signal band, the data is modulated together with power by regulating the lower power switch of each phase in a fixed interval with given frequency, and for the higher signal band, the data in form of voltage ripple is injected into the bus by a coupling circuit. Therefore, specific voltage ripples with different given frequencies can be embedded into the power line for carrying signals, and the frequency band of signal bus can be well exploited. On signal receiver end, the voltage ripples are sampled and analyzed by fast Fourier transform method for demodulating the transmitted data. The feasibility of the proposed incorporated data transmission method is verified by experimental testing.

Comparative Analysis of the 6/4 and 8/6 Switched Reluctance Generator in Different Operating Conditions

This paper presents a comparative study between two Switched Reluctance Generators 6/4 and 8/6 both of 60kW. The main features of the two machines and the mathematical modeling that considers the magnetic saturation effect are established. A computational simulation was performed in Matlab/Simulink environment and has allowed the machine behavior under various operating conditions to be verified. This work made it possible to evaluate: ripple voltage, phase voltage and current, speed, torque, flux, power, losses and efficiency. The comparative results between the two generators are presented and discussed.

Analysis and Implementation of a Switched Reluctance Generator in Connection with the Three-Phase Power Grid and Proposal of an Anti-Islanding Strategy

This paper presents a dynamics study of the Switched Reluctance Generator (SRG) dynamics when connected to a three-phase AC power grid. A mathematical model that includes magnetic saturation is used to represent the SRG, which is driven by an asymmetric half bridge converter. Output generated voltage is smoothed with a shunt capacitor leading to a DC link voltage. This voltage is regulated using a PI compensator that controls the magnetizing angle of the generator phases. It is shown that putting a freewheeling stage between the magnetizing and the demagnetizing states per phase, allows the best use for a better usage of the mechanical power in electromechanical conversion process. Injection of active power in the grid is performed by two PI compensators that determine the modulation indexes to each sinusoidal PWM modulators that drive the three phases of the converter. This work also proposes the implementation of an islanding detection method for distributed generation (DG) systems. This method is based on voltage and frequency parameters detection. It proved to be robust and useful to detect the islanding under different load conditions and the output of the power grid.

Output DC Voltage Control Strategy for Switched Reluctance Generator

This paper presents a proposed generated voltage control for a Switched Reluctance Generator (SRG). The strategy developed uses a PI controller to vary the magnetization angle of the machine phases, acting in the top switches opening angle (θoff) of the converter. The strategy is used together with the freewheel intermediate step, between the steps of magnetization and demagnetization of the phases. The main vantage is decrease the input power of the excitation source and to get the better use of mecanic energy to increase the phase current of the generator, maximizing the electric energy production. Is used the classic half-bridge converter without the need to alteration in your project, changing only the switching strategy. A nonlinear model of the SRG and the control strategy were implemented in MatLab/Simulink. The experimental platform was developed to validate the proposal presented.

A switched reluctance generator behavior under variable speed and variable excitation

The subject of this paper is the wind powered Switched Reluctance Generator - SRG and its behavior. Simulations and experimental results are presented. It was analyzed the efficiency of SRG under different conditions. Many operational test were conduced to state clearly the behavior of a prototype drove by a half-bridge (HB) converter. Variable excitation voltage and angular speed relationship is clearly established. It shows that the suitable excitation control for a wind powered SRG must adjust the operation parameters to match the desired point on certain surfaces.

About phases dependence in switched reluctance generator

This paper analyses and discusses the phase’s dependence of the switched reluctance generator - SRG. A 6x4 SRG prototype was assembling for tests. Each one of this SRG phases can be connected and disconnected when needed. A reduced switches count converter that was use to drive the SRG. Experimental results showed changes in the characteristics wave forms of two operational phases when the third phase is disconnected. At a first sight, it was an unexpected result [1], [2]. Although many tests were conduced confirming the first result. Therefore, it should be say that for the prototype tested under the conduced testing conditions each phase behavior depends in the other phases behave. Remarkable changes in the waveforms those are present here. They show that there is not independence between the phases but a truly strong dependence among them.

Performance comparison of an alternative converter for wind powered switched reluctance generators

The subject of this paper is a comparison of the performances of two converter topologies for Switched Reluctance Generators – SRG. It deals with this special electrical generator excited through a rectified DC link. The prime mover is a wind turbine. Mathematical model and simulation results are presented. Both the power converters topologies implemented work well but the alternative one is cheaper and more efficient than the conventional half-bridge one. Furthermore, only the alternative converter allows to feed the load from the grid even when the SRG is not running. This is good for complementary wind power. Experimental results are presented. It was shown that the SRG worked as expected and that the alternative topology reached expectations.

Design of a versatile Half-Bridge Converter Able to Drive 6x6, 6x4, 8x6, 12x8 Switched Reluctance Generators and Motors Using Arduino

This paper presents the studies required for the design and construction of a versatile Half-Bridge converter. This converter can drive a wide variety of machines - from one to four phases. The converter was designed mainly to drive Variable Reluctance Machines in 6x4, 6x6, 8x6 and 12x8 topologies, working as both motor and generator. The versatility of the proposed converter is its main advantage, as in both academic and industrial applications, this feature can generate financial and production time savings. An analysis was carried out among the main converter topologies to justify the choice of the Half-Bridge topology followed by a project detailing of the chosen converter. For the design and construction of this converter, only commercially available devices were considered. To control the triggering keys, the Arduino platform was used due to its easy access and low cost. After the converter power circuit definition, the circuit for communication between the sensor (encoder), the controller (Arduino), and the switches (IGBT) is presented, and the project assembly is shown at the end.

Advanced Control Strategy of Switched Reluctance Generator-Based Wind Energy Conversion Systems Using Backstepping and Extremum Seeking Techniques

Switched reluctance generators (SRG) become increasingly competitive with other electrical machines due to their design, which includes only a stator winding. The SRG are known for their reliability and capacity to operate over a wide speed range, these generators find significant use in variable wind power plants. The main limitations of these machines are torque fluctuation and relatively low efficiency. In this respect, the aim of this work is to mitigate these drawbacks. Presently, an extremum seeking online method has been developed, and a backstepping controller is designed for SRG-based wind energy conversion system (WESC) connected to the grid via a VSC converter. One of the main objectives of the proposed controller is to achieve the optimum rotation speed of the turbine and to regulate the SRG for tracking the maximum power point (MPPT) while minimizing torque ripple via Direct Instantaneous Torque Control (DITC). To show the efficiency and performance of the proposed controllers, simulation examples of the proposed controllers are established using MATLAB/SIMULINK tools. The simulation results show that the efficiency and performance of the system using the proposed controller are significantly improved.

Predictive Control of Output-Current in a Single-Pulse-Operated Switched Reluctance Generator

Predictive Control of Output-Current in a Single-Pulse-Operated Switched Reluctance Generator

Enhancement of the Performance of Switched Reluctance Generators in Low Wind Speed Conditions Using Advanced Tracking Techniques

Enhancement of the Performance of Switched Reluctance Generators in Low Wind Speed Conditions Using Advanced Tracking Techniques

A Voltage-controllable Switched Reluctance Generator System with a ring winding structure

A Voltage-controllable Switched Reluctance Generator System with a ring winding structure

A Review “The Research Status of Switched Reluctance Generator"

Switched Reluctance Generators (SRGs) have become quite popular lately because they offer some big advantages compared to regular generator technologies. This comprehensive review paper is dedicated to illuminating the latest developments in the realm of SRGs, offering a deep dive into their operational intricacies, diverse types, design principles, control strategies, versatile applications, and the formidable challenges that lay ahead. The paper begins by explaining in simple terms how Switched Reluctance Generators (SRGs) work and uncovering the main ideas that make them special and different from other generators. It then proceeds to categorize SRGs into various types, providing an insight into the diverse design features that distinguish them. This foundational understanding sets the stage for a more profound exploration of SRGs. The review focuses significantly on studying the complex control methods that manage SRGs, exploring the advanced techniques used to make them work better and more efficiently. As SRGs continue to evolve, their applicability spans a broad spectrum, ranging from clean energy generation to enhancing transportation systems and powering industrial machinery. This review carefully explains how SRGs can help change many different industries for the better. It shows how they have a lot of potential to make big improvements. Nevertheless, SRGs do not come without their share of challenges, encompassing issues related to efficiency, reliability, and the complexities inherent in control strategies. This review serves as an informative exploration of SRGs, highlighting their potential across various industries. It acknowledges their development and urges them to keep exploring their promising abilities. As switched reluctance generators become more popular, this discussion provides a detailed guide for those interested in understanding how they work and navigating their complex features.

Novel proposal of PTO direct-drive linear generator, an Azimuthal Multi-translator Switched Reluctance Machine (AMSRM): mechanical, characterization and performance tests.

Research and development on power take-off (PTO) in wave energy has been gaining relevance in recent years, appearing as a priority in various forums (JCR reports [1], SRIA in wave energy development [2], specific research funding program in WES, etc.).
 The new proposal of a linear electric generator to act as a PTO in wave energy extraction applications has been developed in the European project SEATITAN [3].
 The linear generator is based on a switched reluctance machine type topology in which the magnetic flux is azimuthal. This allows eliminating the yoke, reducing the amount of magnetized material needed and increasing the force density, besides having a cylindrical shape that allows adapting perfectly to the spar of point absorber type WECs.
 The Azimuthal Multi-translator Switched Reluctance Machine (AMSRM) has been developed, designed and a prototype has been manufactured in the project. The prototype is composed of two modules of 35 kN of force and 3 m/s of peak velocity.
 The complete manuscript will detail the testing facility, as well as the tests performed for the static characterization of the force, electrical losses, and air gap achieved during manufacturing, as well as the dynamic characterization of frictional losses and a preliminary setting of force control parameters.
 The dry test facility (figure 1) consists of the necessary electronic converters to conveniently operate the generator and impose a reference force controlling current per generator coil. In addition, an end-stopper is provided to ensure the safety of the tests (this equipment is essential for dynamic tests). For static tests, a load cell for force measurement as well as precision electrical power meters are used.
 
 A test protocol has been defined for each test, as well as an analysis procedure to obtain the required results: for example, for the evaluation of friction, dynamic tests based on a back-and-forth motion with drifting sections are proposed to evaluate the braking force with the generator off at various speeds.
 The description of the test protocol, the raw data obtained, the data analysis carried out, and de results obtained will be presented and detailed in the manuscript, as well as the description of the test-based parameterization of a simplified AMSRM model to be used in the dynamic modeling of WECs. The simplified model has been previously developed and presented in EWTEC 2021.
 [1] D. Magagna, R. Monfardini, and A. Uihlein, “JRC Ocean Energy Status Report 2016 Edition,” 2016
 [2] J. L. Villate et al., “Strategic Research and Innovation Agenda for Ocean Energy,” Etipocean, no. 826033, p. 64, 2020.
 [3] WEDGE GLOBAL, “SeaTitan,” 2018. [Online]. Available: https://seatitan.eu/. [Accessed: 29-Nov-2021].
 [4] Marcos Blanco, Miguel Santos‐Herran, Gustavo Navarro, Jorge Jesus Torres, Jorge Najera, and Luis García-Tabarés, “Simplified model of a novel direct-drive PTO based on an azimuthal linear switched reluctance generator,” 2021.

Improving Efficiency and Power Output of Switched Reluctance Generators through Optimum Operating Parameters

The optimization of energy production in renewable energy systems is crucial to improve energy efficiency. In this context, the aim of this study focuses on maximizing the efficiency of a switched reluctance generator. This paper presents a novel approach to enhance the electrical power and efficiency of a switched reluctance generator by determining the optimal operating parameters based on the mechanical input power of the system. The proposed strategy consists of the following steps: First, an algorithm was developed that provides machine data for different power modes based on control parameters, including electrical and mechanical powers such as speed, torque, and turn-on and turn-off angles. In the next step, the obtained data were analyzed to identify the optimum points corresponding to the states with maximum power and efficiency for various scenarios. An algorithm for maximum power point tracking was also developed to determine the optimal parameters as a function of mechanical energy. Finally, the data and algorithms were integrated into the switched reluctance generator control system. Simulations were conducted to compare the proposed MPPT technique with other techniques. This comparison is essential to validate the effectiveness of the proposed strategy in achieving enhanced electrical power generation efficiency.

Improvement of Fault Ride-Through Capability of Grid Connected Wind Turbine Based on a Switched Reluctance Generator Using a Dynamic Voltage Restorer

This paper presents an improvement to the fault ride-through (FRT) capabilities for a wind turbine that employs a switched reluctance generator (SRG) using a dynamic voltage restorer (DVR). The wind turbine may be disconnected from the grid by voltage sag, swell, and faulty line voltage in the grid. To improve the stator voltage of an SRG during grid failures, the DVR is applied to inject voltage at the point of common coupling (PCC) into the grid voltage. A control strategy for the DVR based on fuzzy logic controller (FLC) is proposed in this study to improve the FRT capability and meet the grid codes while avoiding the disconnection of the turbine from the grid. MATLAB/SIMULINK simulation validated the effectiveness and performance of this approach under three test cases: balanced sag, unbalanced sag, and a single line-to-ground fault. In addition, the total harmonic distortions utilizing different controllers were compared in sag mode. Furthermore, the simulation results exhibited significant improvement in transient and steady-state response, thus verifying the effectiveness of the control strategy compared to traditional methods.