Hybrid Excitation Synchronous Generator Research Articles

Investigation of the Robust Fractional Order Control Approach Associated with the Online Analytic Unity Magnitude Shaper: The Case of Wind Energy Systems

This paper investigates the development of a novel analytic approach for computing Unity Magnitude (UM) shapers that deviates from established numerical methodologies. The experimental validation on a test bench confirms the practicality and benefits of the suggested UM shaper technique. The study extends the use of UM shapers to improve the control of wind conversion systems (WCSs), particularly those including hybrid excitation synchronous generators (HESGs), demonstrating their adaptability and versatility. Experimental validation guarantees real-world application, confirming the suggested UM shapers’ trustworthiness. Strict management is still required to assure the system’s efficiency and dependability. In reality, the dynamic equations of a turbine, as well as those of an HESG, are substantially nonlinear; most system parameters are very uncertain; and, finally, a WCS is always impacted by disturbance sources such as load variations, harmonics, and mechanical vibrations. Robust control measures must be used to overcome these issues. A CRONE controller (Robust Fractional Order Control) of the second generation is created. A comparative study performed on the Simulink platform reveals substantial gains brought about by UM shapers in real-world circumstances. The study demonstrates the effectiveness of UM-shaped inputs in mechanical stabilization and Maximum Power Point Tracking (MPPT), emphasizing both theoretical soundness and practical advantages. The analytic equations for UM shapers in undamped and damped systems, offered together with a real-time algorithm, contribute to the optimization of wind conversion systems.

Advanced modeling and control of wind conversion systems based on hybrid generators using fractional order controllers

AbstractThe focus of this study is on modeling and management of a Wind Energy Conversion System (WECS) based on a Hybrid Excitation Synchronous Generator (HESG). Using a wind simulator, two controllers, CRONE and H∞, are evaluated for Maximum Power Point Tracking (MPPT) and optimal rotation speed. The results show the CRONE controller's higher tracking capability, and robustness tests investigate the influence of parametric uncertainty. Space harmonic effects, commutation effects, and turbine shaft flexibility are all addressed in the sophisticated models. The introduction of Fractional Order Proportional‐Integral (FOPI) control for MPPT is a game changer. Although fractional calculus‐based accuracy and robustness are uncommon in WECS, they show promise for emissions reduction and increased energy efficiency. This work validates a dependable control approach inside an isolated HESG‐based WECS's power‐maximizing range. Extensive investigation of the parameters impacting FOPI control efficiency yields useful insights for effective MPPT control. A variable‐speed wind turbine (WT) is linked to a HESG through a multiplier, with a controller controlling generator coil excitation voltages and a rectifier connecting the WECS to a load. A thorough 3 kW HESG electrical model that includes generator space harmonics and converter commutation effects is among the contributions. For HESG‐based WECS stability, frequency analysis finds important resonant and anti‐resonant frequencies. These issues are addressed by a FOPI control technique, which ensures system stability and performance. The necessity of exact frequency analysis in HESG‐based WECS is highlighted by a step‐by‐step controller parameter tuning approach.

DC Voltage Output Control of a Hybrid Synchronous Generator-based Wind Turbine

This article discusses regulating a Wind Turbine (WT) that uses a Hybrid Excitation Synchronous Generator (HESG) to power an isolated load via a diode bridge rectifier. The HESG acts as a DC generator and supplies power to the DC load. The primary objective of the suggested control strategy is to maintain a steady DC voltage output, even when there are changes in rotor speed and/or load. The entire system is simulated and modelled in Matlab/Simulink, and the simulation results prove the effectiveness of the proposed method in delivering power to an isolated location.

A hybrid excitation synchronous generator for a 1.5 MW grid-connected wind conversion system

A hybrid excitation synchronous generator for a 1.5 MW grid-connected wind conversion system

Brushless Excitation Principle and Experimental Verification of Hybrid Excitation Synchronous Generator Based on Harmonic Magnetic Field

It is well known that the air-gap magnetic field of the permanent magnet synchronous generator (PMSG) is difficult to adjust. To overcome this challenge while maintaining the brushless feature of PMSGs, a hybrid excitation synchronous generator (HESG) based on inherent third harmonic field induction is proposed in this paper. The HESG adds a set of third harmonic windings with a pitch of 1/3 of the armature winding in the stator core and a set of harmonic windings with the same pitch as the third harmonic winding in the rotor core. Due to electromagnetic induction, the third harmonic field established by third harmonic windings in the stator induces the harmonic electromotive force (EMF) of six times the frequency in the rotor harmonic winding. This harmonic EMF is directly provided to the rotor excitation winding after rectifying by the diode rotating rectifier. The HESG has armature windings and third harmonic windings in the stator, and excitation windings, harmonic windings and permanent magnets in the rotor. In this article, the mechanism of stator third harmonic winding EMF, rotor harmonic EMF, and the brushless excitation are elaborated. The experimental results of adjustable armature winding voltages with controlling the stator third harmonic winding current have proven the feasibility of the proposed brushless excitation principle based on the third harmonic.

Information supply of the power control system of the synchronous generator of the autonomous wind unit

This paper deals with information supply of automatic maximum power control system of synchronous hybrid excited genera-tor for the autonomous wind unit. The power supply system based on an autonomous wind turbine consists of an electric generator, a battery charging controller, a battery pack and an inverter, which provides the required frequency and valueof the consumer's supply voltage.Three phase permanent magnet synchronous generator that have high technical and economic indicators are most widely used as electric generator of autonomous wind turbines.The main disadvantage of these generators is the lack of effective methods of magnetic flux control, limiting the optimization of the energy balance of the wind turbine.The paper discusses the application of synchronous generator with hybrid excitation system that consists of permanent magnets and additional field excitation winding lo-cated on the stator. Mathematical model of a hybrid excited synchronous generator is presented. Also,an output maximum power control system in a case of wind speed change by varying field excitation current is developed. Control system is developed based on concept of reverse task of dynamics in combination with minimization of local functionals of instantaneous values of energies.In the basics of the control method is put an idea of the reversibility of the Lyapunov direct method for the stability analysis.Obtained con-trol law provides thesystem stability inwhole, which allows solving control tasks of interrelated objects via mathematical models of local loops. Control law also provides low sensitiveness to parametric disturbances and gives dynamic decomposition of interrelated non linear system that ensures its practical implementation. The study of the proposed power control system based on parameters of hybrid excited synchronous generatorexperimental sample has been carried out. The graphs of transient process of armature power, voltage and current in a case of wind speed change from 3 to 8 m/s were obtained, as well as in a case of active resistance load change. The results of study showed high efficiency of power control of a wind turbine with hybrid excited synchronous generator.

Robust control of a HESG for a wind energy application

Lately, robust control strategies have been of much interest in the domain of Wind Conversion System (WCS). The purpose of this paper is to validate a robust control scheme for a stand-alone WCS, based on a Hybrid Excitation Synchronous Generator (HESG), in its maximum power point tracking (MPPT) zone. This research is motivated by the use of a HESG in a WCS. Previous works involving HESG deal mostly with the structural features of this innovative generator. Here, the focus is mainly on the development of an efficient and reliable control strategy for the hybrid generator in the wind energy field. The control is synthesized using a PI controller for the excitation current loop and an H∞ controller for the velocity loop. A step-by-step procedure for designing the velocity controller is presented.In the proposed approach, an accurate equivalent model of a WCS is implemented under Matlab-Simulink software. A two-mass mechanical model of a wind turbine is proposed in order to properly analyze the dynamics of the flexible shaft and thereby avoid any possible instability of the drive train. The effects of the generator’s space harmonics and converters’ commutations on the control are taken into account. Robustness tests are performed. Despite the generator complexity, good simulation results are obtained. An experimental implementation on a test bench is realized in order to further validate the efficiency of the proposed control strategy and thereby prove the applicability of a HESG in the wind energy field.

Robust control of a wind conversion system based on a hybrid excitation synchronous generator: A comparison between [formula omitted] and CRONE controllers

This paper deals with a Wind Conversion System (WCS) based on a Hybrid Excitation Synchronous Generator (HESG) connected to an isolated load. The set is modeled under Matlab–Simulink. To ensure an efficient and reliable use of the system, a tight control remains vital. In fact, the dynamic equations of a turbine are strongly nonlinear as are the ones of a HESG; most of the system parameters are highly uncertain, and, at last, a WCS is always affected by disturbance sources such as load variances, harmonics, mechanical vibrations…To address these problems, robust control methods must be adopted. In this paper, two strategies for the control of variable speed wind turbine are investigated. First, an H∞ controller is implemented. Then, a second-generation CRONE controller is designed. The performance of the two regulators is compared with respect to the tracking of the optimal rotation speed, the attenuation of the mechanical vibration and the robustness to the uncertainty of the parameters, using time-domain simulations. It has been found that the CRONE controller is more robust to parameters uncertainty and minimizes the fluctuations of the torsional torque and the generator’s angular velocity. Finally, an experimental validation of the velocity controllers is presented to complete the simulation results and fully validate the chosen approach.

Optimal Output-Feedback Power Control for the Hybrid Excitation Synchronous Aero-Generator in High Wind Speed Operation

This paper deals with the problem of controlling wind energy conversion systems operating at a high speed. We seek both the achievement of constant power operation and the minimization of Joule power losses in the aero-generator, which presently, is a hybrid excitation synchronous generator (HESG). Furthermore, the system safety over a wide range variation of the wind speed is taken into consideration in the control problem formulation. These energetic optimization and turbine safety requirements are achieved by using an output-feedback controller that is developed by nonlinear design techniques including a backstepping control, a high-gain observer and others. The controller consists of: (i) a sensorless online reference-speed optimizer designed to limit the extracted aerodynamic power in over speed mode; (ii) a power-limiter regulator based on the flux-weakening; (iii) an electromagnetic torque regulator ensuring power loss reduction in the HESG stator. The real-time implementation of the above objectives necessitates online measurements of the rotor flux, the rotor speed, the aerodynamic torque and the wind speed. The point is that the electromagnetic and the mechanical sensors are costly and entail reliability issues. Therefore, a state observer is designed to provide online estimates of all the required variables that are inaccessible to measurements. The output-feedback controller thus developed is formally analyzed using Lyapunov stability tools. The established theoretical performances are confirmed by a set of numerical simulations.

Optimum design and research on novel vehicle hybrid excitation synchronous generator

Hybrid excitation is an organic combination of permanent magnet excitation and electric excitation. Hybrid excitation synchronous generator (HESG) both has the advantages of light quality, less losses and high efficiency like permanent magnet generator and the advantages of good magnetic field adjusting performance like electric excitation generator, so it is very suitable for the vehicle application. This paper presented a novel vehicle HESG which has skew stator core, permanent magnet rotor and both armature winding and field winding in the stator. Using ANSYS software, simulating the electric excitation field and the magnetic field, and finally the main parameters of HESG were designed. The simulation and the test results both show that the novel vehicle PMSG has the advantages of small cogging torque, high efficiency, small harmonic component output voltage and low waveform aberration, so as to meet the design requirements fully.

Magnetic Field Distribution and Operating Characteristics of a Hybrid Excitation Generator Based on Integrated Brushless Excitation

In general, the brushless wound rotor hybrid excitation synchronous generator (HESG) needs a separate exciter. In this paper, a novel integrated brushless excitation HESG (IBE HESG) is developed by integrating the excitation section into the iron core of wound rotor HESG. Compared with the conventional brushless excitation method, the axial length of the IBE HESG is shorter and the original topology of the wound rotor generator is not changed. The excitation section has two sets of windings: stator excitation windings and rotor armature windings. The stator excitation windings are installed in the stator slots evenly. The static excitation field is established by the dc excitation current of the stator excitation windings. The rotor armature windings are buried in the rotor armature slots around the rotor. The static excitation field induces a voltage in the three-phase rotor armature windings and supplies the dc current to the rotor excitation windings through a rotating rectifier on the rotor. The magnetic field distribution is analyzed by the frozen permeability method to decouple the multimagnetic circuits. Also, the influencing factors of excitation efficiency are studied and the parameters of the IBE HESG are obtained to achieve a reasonable excitation characteristic. Finally, the theoretical analysis is confirmed by the experiments on a 1.5 kVA/50 Hz prototype generator. The results show that the output power can be regulated over a wide range.

Theoretical and experimental analyses of a hybrid excitation synchronous generator with integrated brushless excitation

This paper proposes a novel integrated brushless excitation method (IBEM) for a rotor-excited generator. IBEM is applied to a rotor-excited hybrid excitation synchronous generator (HESG) to realise brushless excitation while the key features of the rotor-excited generator are maintained. The new generator is referred as IBE HESG here. The stator excitation windings are buried in the stator slots. The static excitation field is established in the air gap when there is dc excitation current in the stator excitation windings. The three-phase armature coils of the rotor induce the static excitation field and provide the dc excitation current for the rotor excitation windings via a rotating rectifier. The operating principles are discussed theoretically. The magnetic field distribution and the operating characteristics are studied by finite-element analysis. The no-load, external, regulation and excitation characteristics are analysed. Compared with the brush excitation HESG, the rotor excitation current is able to meet the requirement and the output voltage is conveniently regulated by the stator excitation current. Finally, a 1.5 kVA prototype is fabricated to test the operating characteristics of IBE HESG. It demonstrates that the brushless excitation is realised and the output voltage is regulated by the stator excitation current.

Analysis and calculation of electromagnetic and temperature field in a hybrid excitation synchronous generator

Analysis and calculation of electromagnetic and temperature field in a hybrid excitation synchronous generator

Robust control of hybrid excitation synchronous generator for wind applications

The purpose of this paper is to develop a robust control law for a hybrid excitation synchronous generator (HESG) for wind power applications. In a HESG, the excitation flux is created by both permanent magnets and excitation coils, so the output voltage can be controlled by the DC excitation field. For isolated loads, it is then possible to use a very simple and reliable wind generator architecture composed only by a HESG, a rectifier and a DC/DC converter to control the excitation flux. However, the control of such a structure is not easy, especially if the system parameters are not well known. In this paper, the wind generator architecture is presented, modeled and simulated. The control is performed using a cascade control scheme: PI controller for the excitation current inner loop and H∞ controller for the speed outer loop. The obtained results prove that robust control can be used for this architecture and can provide good dynamic responses despite large uncertainties on the electrical parameters.

Thermal Modeling of a Hybrid Excitation Synchronous Generator with Alternated Current Linkages for Stand-Alone Power Supply

This paper presents the thermal modelling and analysis of a hybrid excitation synchronous generator with alternated current linkages (HESG-ACL) for stand-alone power supply. The HESG-ACL belongs to a class of hybrid excitation synchronous machines (HESMs), which combine the merits of electrically excited synchronous machines (EESMs) and permanent magnet synchronous machines (PMSMs). To confirm the performance and thermal behaviour of the HESG-ACL, an experimental prototype (69 kVA apparent power) equipped with thermal sensors was built and tested. A description of the HESG-ACL is given. The thermal analysis of the HESG-ACL is carried out based on the thermal resistance network model. The results obtained from the thermal model are verified by the experimental results.

Design and finite element analysis of a hybrid excitation synchronous machine

The paper presents a hybrid excited synchronous generator (HESG) with field windings and permanent magnets. This paper focuses on the analysis in the operating principle, rotor shape optimization, and inductance characteristic, based on finite element method. The measured voltage waveforms suggest that the rotor shape optimization in the study is a feasible solution to improve the quality of output voltage. Both the simulation and the tested results on generator performance verify further that the electric excitation can efficiently adjust the air-gap flux. Compared to conventional electric excited synchronous generator, the load capacity is improved due to relatively low armature inductance of the HESG.

A Two-Stage Brushless Excitation Method for Hybrid Excitation Synchronous Generator

A two-stage brushless excitation method for hybrid excitation synchronous generators (HESGs) is proposed in this paper. Comparing with the traditional three-stage brushless excitation method, the auxiliary exciter is eliminated. The complete self-excitation is realized. As the main generator of two-stage brushless generation system, a tangential/radial HESG (T/R-HESG) is studied. The exciter is designed for T/R-HESG. The design steps are given. The operation modes of rotating rectifier are analyzed. A 1.5 kVA prototype of a two-stage brushless excitation generation system is made to verify the theoretical design. The measured results agree well with the theoretical design and finite element analysis. It shows that the design of exciter is correct and the two-stage brushless excitation method is feasible.

A Comparison of Two Controller Designs for a Hybrid Excitation Synchronous Generator for Wind Applications

A Comparison of Two Controller Designs for a Hybrid Excitation Synchronous Generator for Wind Applications

Implementation of DSP Based on Vector Control Model of AC Excitation Control System for a New Hybrid Excitation Synchronous Generator

Permanent magnet generator has the advantages of simple structure, reliable operation and low loss, but it is not easy to adjust voltage, which restricts its wide application. This paper presents a new type of hybrid excitation synchronous generator (HESG) and establishes the mathematical model and simulation of vector control based on its AC excitation system to control the output voltage as the expectation. In application, DSP, as the control system, is traditionally programmed and debugged off-line, which requires heavy workload. Whereas, the design based on model greatly shortens the development cycle. By connecting MATLAB simulation environment to the CCS development environment, the simulation model can be translated into code and downloaded to the targeted DSP through an emulator. This implementation will have specific and indispensable significance for the hardware development and software debugging of motor control system.

Output Feedback control of wind energy conversion system with hybrid excitation synchronous generator

This paper deals with the problem of wind energy conversion systems control. The considered aero-generator involves a hybrid excitation synchronous generator (HESG). To extract the maximum power from wind energy system, it is recommended to operate at variable speed. However, this control requires the measure of wind speed, rotor speed and aerodynamics torque, which are both difficult in practice and not very reliable. This paper presents a design of sensorless maximum power point tracking (MPPT) speed controller for achievement of the above energetic goal without resorting to mechanicals sensors (wind velocity, HESG rotor speed and aerodynamic torque). To this end, the control observation strategy is developed, based on the nonlinear model of the whole controlled system and only using electrical variables measurements. The control strategy involves: (i) online reference-speed optimizer designed using the turbine power characteristic to meet the maximum power point tracking requirement. (ii) an interconnected state observer providing online estimates of stator resistance, rotor permanent flux, rotor speed, aerodynamic torque and wind speed. (iii) a nonlinear MPPT speed regulator designed (using the backstepping technique) for the case where the wind speed remains lower than a maximum level (denoted wb). (iv) an optimization of the electromagnetic torque provided (by controlling the machine timing angle ()) to improvement the HESG efficiency. The performances of the proposed regulator are analyzed using tools from the Lyapunov stability. These theoretical results are validated by a series of simulations to show the contribution of hybrid excitation with a wide variation of the wind speed.