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Droop control is generally used to realize power sharing without communication lines. VSG (Virtual Synchronous Generator) is a control method that mimics both steady-state droop and dynamic characteristic of SG (Synchronous Generator) to enhance inertia of microgrid. In this paper, the comparison of different damping effect forms in VSG control is given firstly to draw conclusions: For the aspect...
This paper investigates spatial and time harmonics of flux density and radial force distributions in the airgap of a hydrogenerator with fractional-slot windings. Hydrogenerator is connected to a neutral-point-clamped (NPC) converter, representing a converter-fed synchronous machine (CFSM) in pumped-storage hydropower plant. Magnetic field in the hydrogenerator is computed using time-stepping finite...
Theoretical researches and simulation results, which based on numerical realization of the finite element method of three-dimensional transient mathematical model of the electrical and magnetic fields in induction motor which displayed the features of the processes of AC energy conversion in the experimental short-circuit mode are obtained. Through the implementation of the dynamic spatial model of...
Generally three phase motors are better than single phase motors but three phase system cannot be used in many applications for house. Especially single phase motors are used in city centers because of structure of the single phase feeder system. In general, small powered single phase motors in the range of 0.18–1.5 kW are used in small workplaces, portable hand looms, homes, fans, kitchen equipment,...
Double Excited (or Hybrid Excited) Synchronous Motors (DESM or HESM) has gained great interest as they have the ability to control the air-gap field, and consequently the electrical drive speed due to the auxiliary excitation winding. To obtain the magnetic field distribution in the air gap many techniques are used. The Schwarz-Christoffel (SC) mapping allows the mapping of the slotted structure of...
Harmonic brushless excitation synchronous machine does not rely on permanent magnetic material, which also can be excited without brush and slip rings. The air-gap magnetic fields are easy to be adjusted. However, the tooth harmonics in 12-slots machine are relatively big. In order to reduce the tooth harmonics content, and improve the excitation performance and efficiency of this kind of machine,...
Engineering often requires magnetic bearings with sufficient capacity and to reduce the volume as much as possible at the same time. In this paper, the design principles of air gap, magnetic pole, rotor, stator, magnetic pole area and coils are given on the basis of practical engineering experience. Radial magnetic bearing structure with different shaft diameters and different magnetic poles number...
The failure rate of rotor bars is high, which causes large area of broken conducting bars, shortening the lifetime of motors. Therefore, the diagnosis of broken rotor fault diagnosis is of great importance. First, the mathematical model of induction motors is presented, and the internal and external magnetic field boundary conditions are defined. Second, frequency domain analysis method is combined...
High-frequency electromagnetic waves suffer considerable attenuation when propagating through media such as soil, rocks, human body, water, etc. However, low-frequency magnetic waves easily penetrate the aforementioned media. Earlier magnetic field communication systems typically employ current-excited coils to generate modulated magnetic fields for communication. These systems require large currents...
Electric motors for traction applications are traditionally designed with internal rotors. However, torque density can be increased with the rotor in the outside. Two permanent magnet synchronous machines (PMSM) with fractional slot concentrated windings (FSCW) and internal and external rotors, designed with same electromagnetic properties and volume restrictions, are compared to prove which one gives...
Since air-gap magnetic fields of brushless doubly-fed machine (BDFM) are produced by two stator windings of different pole pairs, the spatial harmonic contents of the BDFM are higher than conventional induction machines and have a considerable effect on the machine performance. To reduce the contents of main slot harmonics, the harmonic components of airgap magnetic field for the BDFM are analyzed...
This, paper examines how changing the magnetic orientation of permanent magnets in concentrated winding interior permanent magnet synchronous motors (IPMSMs) affects their demagnetization resistance. We evaluated a prototype for demagnetization at 180°C that consists of a 130-degree V-shaped rotor core in which parallelogram magnets with oblique orientation are arranged and confirmed by finite element...
Aiming at the problem of multi-DOF bionic drive, a new type of hybrid driven permanent magnet multi-DOF motor with liquid suspension mode is presented in this paper. The structure and working principle of the motor are introduced in detail. The analytical method and the finite element method are used to analyze the air gap magnetic field, and the results are compared and verified. In addition, the...
Brushless doubly fed machine(BDFM) has been widely used in industrial production. Due to its unique operation mechanism, the harmonic magnetic fields of internal structure are very rich which bring the problem of high temperature rise. Therefore, it is necessary to research the situation of temperature rise distribution. In this paper, aiming at BDFM with hybrid rotor which is proposed newly for enhancing...
Post-assembly magnetization can greatly simplify the manufacturing process and improve the performance of permanent magnet (PM) motors, especially for high speed PM rotor with metallic retaining sleeve. The retaining sleeve has to be heated up during the shrink-fit process and the high temperature will cause irreversible demagnetization of the pre-magnetized magnet. We had developed a post-assembly...
Principle of rotating magnetic field is very difficult to understand to new learners because the field is in high speed and invisible. In this paper a novel dynamic demonstrating device for rotating magnetic field is designed. With the help of synchro transmitter and phase demodulating technologies, a rotating handle is adopted as speed input to drive the magnetic field rotating at a speed of only...
The performance of high-speed motorized spindle will directly affect the overall performance of high-speed machine tools, such as machining precision, processing strength and efficiency, vibration and noise, lifetime and so on. As one of the key R&D items of the motorized spindle design, motor control system is a nonlinear and strong coupling system. Based on the analysis of the control system...
Theoretical researches and simulation results, which based on numerical realization of the finite element method of three-dimensional mathematical model of the induction motor are obtained. The regularities of the distribution of the induction and magnetic field energy in the short-circuit mode and their quantitative relation for active zone and the area of the coil ends of the stator windings of...
An electromagnetic 2D model of axial-flux eddy current brakes with slotted conducting disk rotor is proposed. The 2D model takes into account variations in magnetic field strength and eddy current densities in radial and tangential directions. However, the proposed model neglects nonuniformity of primary field created by an inductor because this can be evaluated from separate consideration of the...
In this paper two constructions of a coaxial magnetic gear (CMG) have been investigated. A 2D time dependent Finite Element Method (FEM) models of the two constructions have been implemented. A harmonic analysis of the gears' magnetic fields and output dynamic torques are performed. The FEM modelling is carried out by ANSYS Maxwell software. The harmonic analysis is made by Fast Fourier Transform...
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