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In order to assess the performance of an induction generator in standalone wind power application, it is imperative that mathematical models are developed that accurately represent the system and take into account various electromagnetic influences such as skin effect. The purpose of this paper is to utilize mathematical models to study the transient and steady‐state behaviour of the self‐excited induction generator (SEIG), in one case with an aluminum rotor, in another case, with a copper rotor, under various load conditions while taking the above factor into account.

Mathematical models of a SEIG in the d‐q axis frame have been developed based on the generalized machine theory. A relationship between the mutual inductance and the magnetizing current of the machine has been presented. The rotor impedances have been customized to include skin effect. Using these relations, the model has been extended to include the saturation and skin effects. In order to verify the accuracy of the models, numerical and experimental investigations have been carried out on two 7.5 hp aluminum‐rotor and copper‐rotor SEIGs.

It was found that the model that takes into account the saturation and skin effects produces numerical results that closely match experimental values for both the machines.

This paper describes how a model of an SEIG considering saturation and skin effect has been developed and applied to aluminum‐ and copper‐rotor machines of similar power ratings to analyze their performance.

This paper presents a model based on the 2D finite element method (FEM) which can be used to study a self‐excited induction generator in unbalanced modes. In the proposed model, we take into account the magnetic non linearity of the iron by introducing a B(H) curve which is identified experimentally from magnetic materials. On the other hand, effects such as end windings and the short circuit ring are also taken into account using analytical expressions. The coupling between electrical circuit and FE equations is introduced. After validating the model in steady and transient modes, we will discuss the choice of the different capacitances and give simulated results of a specific unbalanced case.

More electric aircraft (MEA) is defined as the extensive usage of electric power in aircraft. The demand for electric power in new generation aircraft rises due to environmental and economic considerations. Hence, efficient and reliable starter/generators (SGs) are trending nowadays. The conventional main engine starting system and power generation system can be replaced with an individual SG. The constraints of the SG should be investigated to handle the aviation requirements. Even though the SG is basically an electric machine, it requires a multidisciplinary study consisting of electromagnetic, thermal and mechanical works to cope with aviation demands. This study aims to review conventional and new-generation aircraft SGs from the perspective of electric drive applications.

First of all, the importance of the MEA concept has been briefly explained. Also, the historical development and the need for higher electrical power in aircraft have been indicated quantitatively. Considering aviation requirements, the candidate electrical machines for aircraft SG have been determined by the method of scoring. Those machines are compared over 14 criteria, and the most predominant of them are specified as efficiency, power density, rotor thermal tolerance, high-speed capability and machine complexity. The features of the most suitable electrical machine are pointed out with data gathered from empirical studies. Finally, the trending technologies related to efficient SG design have been explained with numeric datasets.

The induction motor, switched reluctance motor and permanent magnet synchronous motor (PMSM) are selected as the candidate machines for SGs. It has been seen that the PMSM is the most preferable machine type due to its efficient operation in a wide range of constant power and speed. It is computationally proven that the using amorphous magnetic alloys in SG cores increases the machine efficiency more. Also, the benefits of high voltage direct current (HVDC) use in aircraft have been explained by a comparison of different aircraft power generation standards. It is concluded that the HVDC use in aircraft decreases total cable weight and increases aircraft operation efficiency. The thermal and mechanical tolerance of the SG is also vital. It has been stated that the liquid cooling techniques are suitable for SGs.

The demand for electrical power in new generation aircraft is increasing. The SG can be used effectively and efficiently instead of conventional systems. To define requirements, constraints and suggestions, this study investigates the SGs from the perspective of electric drive applications.

The purpose of this paper is to present an improved approach for estimation of the rotor position and speed of doubly fed induction generator, which can be used in vector control and direct torque control (DTC) schemes.

Some novel equations are developed for calculation of the rotor position and rotor speed. Such equations do not need to the value of stator flux linkage and just, measured values of the stator voltage and currents as well as rotor current are required to be known.

The simulation results verify the satisfactory steady-state and dynamic performance of proposed approach with both the vector control and DTC schemes. The results show that the proposed estimation approach benefits from the starting on the fly, robustness against the variations of the most of the stator and rotor parameters and immunity against the noise.

The proposed estimation approach is novel and the outcome of the research of authors. It is simple and effective and, no approximation is made in the calculations. The simulation results demonstrate that the proposed scheme can be successfully implemented in various control strategies, e.g. DTC and vector control.

Modeling electric machines is one of the powerful approaches for analyzing their performance. A dynamic model and a steady-state model are introduced for each electric machine. Permanent magnet induction machine (PMIM) is a dual-rotor electric machine, which has various advantages such as high-power factor and low magnetizing current. Studying PMIM and its modeling might be valuable. The purpose of this paper is to introduce a simple and accurate method for dynamic and steady-state modeling of PMIM.

In this paper, arbitrary dqo reference frame is used to model PMIM. First, three-phase dynamic equations of stator and rotors are introduced. Then, they are transferred to an arbitrary reference frame. The voltage and magnetic flux equations aligned at dqo axes are obtained. These equations give the dynamic model. To investigate the results, PMIM simulation is performed according to obtained dynamic equations. Simulation results verify the analytic calculations.

In this paper, dynamic equations of PMIM are obtained. These equations are used to determine dynamic equivalent circuits of PMIM. Steady-state equations and one phase equivalent circuit of the PMIM using phasor relations are also extracted.

PMIM equations along dqo axes and their dynamic and steady-state equivalent circuits are determined. These equations and the equivalent circuits can be transformed to different reference frames and analyzed easily.

This paper aims to propose a double-sided switched reluctance linxear generator (DSRLG) exclusively for wave power generation. The initial dimensions are given through design experience and principles. To ameliorate comprehensive performance of the DSRLG, the multi-objective optimization design is processed.

The multi-objective optimization design of the DSRLG is processed by adopting a modified entropy technique for order of preference by similarity to ideal solution (TOPSIS) algorithm. First, sensitivity analyzes on geometric parameters of the DSRLG are conducted to determine several pivotal geometric parameters as optimization variables. Then, the multi-objective optimization is conducted on the basis of initial dimensions. After determination of synthetical evaluation value of each structure parameter, the best dimension scheme of the DSRLG is concluded.

After verification by finite element method simulation and dynamic simulation, the final dimension scheme proves to perform better than the initial scheme. Finally, experiments are conducted to verify the accuracy of both the stable finite element DSRLG model and dynamic simulation system model so that the conclusion of this paper proves to be reliable and compelling.

This paper proposes an improved structure of the DSRLG, which is superior for wave power generation. Meanwhile, a novel modified entropy TOPSIS algorithm is applied to the field of electrical machine multi-objective optimal design for the first time.

The purpose of this paper is to track the maximal power of wind energy conversion system (WECS) and enhance the search capability for WECS maximum power point tracking (MPPT).

The hybrid technique is the combination of tunicate swarm algorithm (TSA) and radial basis function neural network.

TSA gets input parameters from the rectifier outputs such as rectifier direct current (DC) voltage, DC current and time. From the input parameters, it enhances the reduced fault power of rectifier and generates training data set based on the MPPT conditions. The training data set is used in radial basis function. During the execution time, it produces the rectifier reference DC side voltage that is converted to control pulses of inverter switches.

Finally, the proposed method is executed in MATLAB/Simulink site, and the performance is compared with different existing methods like particle swarm optimization algorithm and hill climb searching technique. Then the output illustrates the performance of the proposed method and confirms its capability to solve issues.

The purpose of this paper is to propose an efficient current control technique based on model predictive control (MPC) for grid-connected wind conversion system. This nonlinear strategy is applied for the chopper circuit and grid-tied inverter and compared with other two conventional schemes; a traditional proportional-integral (PI) and sliding mode controller (SMC) using the same switching frequency.

Firstly, the MPC scheme uses the mathematical model to predict future behaviors of the controlled converter outputs for possible switching states. After that, the optimal voltage vector is selected by minimizing a cost function, which is defined as a sum of the absolute values of the controlled current errors. Then, the corresponding switching signals are applied to the converter switches in the next sampling period to track correctly the reference current. Thus, the MPC scheme ensures a minimal error between the predicted and reference trajectories of the considered variables.

The MPC-based algorithm presents several benefits in terms of high accuracy control, reduced DC-link voltage ripples during steady-state operation, faster transient response, lower overshoots and disturbance rejection and acceptable total harmonic distortion.

The authors introduce several simulation case studies, using PSIM software package, which prove the reliability and effectiveness of the proposed MPC scheme. Therefore, the MPC performances, during dynamic and steady-state condition, are compared with those obtained by a PI regulator and SMC to highlight the improvements, specifically the transfer of smooth power to the grid.

A METHOD of joining pipes which does not make use of heavy bulky fittings has always been required in the aircraft industry. In addition, as aircraft speeds increase well into the supersonic range, the need for more reliable joints that will withstand even more rigorous working conditions becomes apparent.

This paper describes models of micro‐turbines and fuel cells, which can be used in stability studies.

The plants models derived are based on the main equations. These models are developed in the Laplace domain and transient simulation is done using a software developed based on the MATLAB package.

The micro‐source is capable of providing effective load‐following service in the distribution system. However, the results also show that the micro‐source is not an uninterruptible power supply and does not protect the load from voltage instability while in grid‐connect mode. When a micro‐turbine plant is connected to a point where it gives support to a load in fault conditions, the lower the inertia of micro‐turbine plant, the greater is the destabilizing tendency for faults in the distribution system. On the other hand, transient stability is enhanced with aid of the SOFC inverter.

The effects of these micro‐sources on the network performance are shown and a distribution system embedded with the micro‐sources is used as an example. Finally, transient stability and voltage stability of the system are investigated.