Estimation of stator and rotor forms distortions influence on operating parameters of a hydrogenerator

The field calculation was carried out using finite element method of the Ansys Maxwell software package and verification in the Matlab Simulink software. It should be noted that there are several regulatory documents that describe criteria for permissible distortion of the rotor shape, where the air gap between the stator and the rotor at diametrically opposite points should not differ from each other by more than ± 20% from the average value equal to their halfsum. In this work, a calculation was carried out covering this interval of diameter change; an analysis was carried out considering change in range of ± 35% of the air gap’s width’s value. Results of the research showed that a change in a value of the air gap up to 10% would make a significant contribution to magnitude of magnetic field induction, which increases the value of main losses in a core of magnetic circuit of the generator. Also, there is a significant decrease in voltage (from 25 to 50%) of a nominal voltage in nominal power mode, which requires increase in current in field magnetizing coil, leading to ohmic losses’ increase in rotor’s windings.

Experimental Verification and Analytical Approach for Electromagnetic Characteristics of a High-Speed Permanent Magnet Motor with Two Different Rotors and Winding Patterns

In general, high-speed machines should be designed with high efficiency electromagnetic and mechanical characteristics. It is important to analyze the electromagnetic loss for a design with high efficiency. In this study, the effects of the magneto–motive force and time harmonics of the stator current according to the winding distribution of a high-speed permanent magnet motor on the electromagnetic characteristics were comparatively analyzed using analytical methods and FEM. In addition, the final model was proposed by analyzing the relationship between the magnet usage according to the rotor shape and the electromagnetic and mechanical properties according to the winding patterns. Finally, the optimal model was manufactured and the validity was experimentally verified.

A Study on the Shape of the Rotor to Improve the Performance of the Spoke-Type Permanent Magnet Synchronous Motor

This paper describes a study on the improvement of the dehydration performance of the conventional washing machine model. Recently, as interest in improving the dehydration performance of washing machines has increased, the need for a study on a high-speed electric motor has emerged. However, this conventional spoke-type PMSM has difficulty in speeding up due to the following problems. First, field weakening control is indispensable for high-speed operation of an electric motor. This control method is a big problem in causing torque drop and irreversible demagnetization of the motor. Moreover, the centrifugal force increases during high-speed operation, which adversely affects the stiffness of the motor. Therefore, in this paper, a new rotor shape of spoke-type PMSM was proposed to solve the above problem.

Induced EMF THD Reduction Design of Permanent Magnet Synchronous Generators for Diesel Engine Generators

This paper deals with design of permanent magnet synchronous generators (PMSG) for diesel engine generators. The PMSG is required to reduce the total harmonic distortion (THD) reduction of the induced electromotive force (EMF) for the enhancement of power quality. In this paper, a design method is proposed to reduce the THD of the induced EMF for power quality enhancement in the PMSG. First, the selection process for the number of poles and slots is described. Second, the rotor shape design is proposed using an eccentric curve and slit shape. Based on the results of the first process, the optimal rotor shape is selected to achieve the additional THD reduction of the induced EMF. Finally, the performance for the optimal rotor shape is verified through a 2-dimensional finite element analysis (2D FEA) and prototype.

Optimal Gyrodine Rotor Shape in the Class of Conical Bodies

The problem is to find the optimal shape of the gyrodine rotor and its angular rotation speed that maximizes the angular momentum relative to the axis of rotation at a fixed radius, mass and material of the rotor, taking into account the final strength of the material. The gyrodine rotor is a body of revolution, the thickness of which depends only on the distance r to the axis of rotation, r ∈ [0,R], where R is the radius of the rotor. The rotor surface is defined by rotating the curves z = ±z(r) around the axis. When the rotor is spinning, it undergoes deformation due to centrifugal forces. Normal stress fields appear: radial and annular. Assuming the rotor to be thin, deformations can be described by the functions of the radial displacement of the rotor points u(r). Stress fields can be expressed in terms of this function. The functions u(r) and z(r) are related by the equation of the elastically deformed state. This equation is supplied with the boundary conditions for the absence of radial stresses at r = R and the condition for the absence of displacement on the axis of rotation u(0) = 0. Using the numerical solution of the equation, the problem is solved for the class of conical rotors z(r) = a + br with two parameters a and b. The numerical method is used due to the fact that even in this relatively simple case the problem cannot be solved analytically. Several integrable cases are used to analyze the calculation error in the numerical solution of the problem. The dependence of the problem on the Poisson ratio μ ∈ (−1.1) is investigated, with the remaining parameters fixed. The gain in the angular momentum relative to a rotor of constant thickness is compared. The optimal steel conical rotor (μ = 0.3) is 2.068 times thicker at the center than at the edge. Its advantage in the angular momentum over the rotor of constant thickness is 3.2 %.

Performance enhancement of Savonius wind turbine by blade shape and twisted angle modifications

Three-dimensional CFD simulations are carried out to study the increase of power generated from Savonius vertical axis wind turbines by modifying the blade shape and blade angel of twist. Twisting angle of the classical blade are varied and several proposed novel blade shapes are introduced to enhance the performance of the wind turbine. CFD simulations have been performed using sliding mesh technique of ANSYS software. Four turbulence models; realizable k -[Formula: see text], standard k - [Formula: see text], SST transition and SST k -[Formula: see text] are utilized in the simulations. The blade twisting angle has been modified for the proposed dimensions and wind speed. The introduced novel blade increased the power generated compared to the classical shapes. The two proposed novel blades achieved better power coefficients. One of the proposed models achieved an increase of 31% and the other one achieved 32.2% when compared to the classical rotor shape. The optimum twist angel for the two proposed models achieved 5.66% and 5.69% when compared with zero angle of twist.