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Sequential multiobjective optimization method based on radial basis function model is presented in this work to deal with the multiobjective design and optimization problems of engineering electromagnetic devices. Firstly, the initial sample set can be generated by using the sequential optimization method (SOM). SOM can greatly reduce the sample size by integrating the advantages of optimization algorithms...
Magnetic encoder based on giant magnetoresistance effect, also known as GMR-based magnetic encoder, has several distinct advantages over the traditional Hall-effect magnetic encoder such as its simpler structure, higher resolution and sensitivity as well as a better tolerance toward extreme working environment. This paper gives a detail design scheme of a GMR-based magnetic encoder. Finite element...
To develop a new standard design of gas-insulated bus(GIB), an electromagnetic-structural finite element analysis has been conducted considering the electromagnetic force generated in GIB with a large current. The GIB are electrical bus-bar parts of a gas-insulated switchgear(GIS) installed as a protective device in power plants and substations. Since the electromagnetic forces generated by a large...
Transformer short-circuit force insufficient has been a hot research issue. There is some residual stress on the conductor section when winds the wounding, which produces adversely affect on winding short-circuit strength. This paper deduces the calculation model of the circular winding considering the residual stress. Taking the test transformer as an example, winding internal radiation short-circuit...
Based on the model of surface mounted permanent magnet synchronous motor, an improved algorithm for off-line parameter identification of motor is presented. In this paper, the single-phase sinusoidal AC signal is injected into the motor which can simulate the single-phase locked-rotor test and the DC signal is injected into the motor in order to simulate the DC test, then filtering the input signal...
An external rotor transverse flux motor has been proposed in our previous research, which has the advantages of low manufacturing cost and high torque density. In this paper, a novel transverse flux is introduced based on the foregoing motor's structure. At first, the detail motor structures and working principle are introduced. Then, the three-dimensional model of proposed motor is built by finite...
The Power density of ECRIS magnet coil is larger than 3000kW/m3, and evaporative cooling technology is an ideal method to achieve the cooling requirement. The two phase flow of evaporative cooling system affects the cooling efficiency of coil. This paper introduces the self-driven evaporative cooling system of magnet, and analyses the pie structure of magnet coil and two phase flow channel in the...
Five-phase tubular linear PM (TLPM) motors have high thrust force density, zero net radial force and volumetrically efficient. Conventional direct thrust control (DTC) improves the dynamic performance of TLPM motor, but exhibits significant ripple in thrust force and flux. To solve the problem, a new DTC strategy based on third-harmonic current suppression is proposed. The effect of inverter voltage...
A FEM platform is developed to support high precision electric field computing and data analysis. For the precise computing of 550kV SF6 arc quenching chamber, a solve regions division project is presented to improve meshes quality and computation efficiency. At the same time, approach regular triangle algorithm is realized by combing the uniform and gradient disperse for boundary, constraint condition...
Compared to permanent magnet motors using rare-earth metals, a wound field synchronous motors tends to generate more heat due to increased windings, so it is required to consider cooling measures in design. In this study, a 3D computational fluid dynamics simulation and experimental verification of an 80kW Wound Field Synchronous Motor was performed to investigate the cooling performance of dual cooling...
Although a number of 800kV UHVDC (Ultra High Voltage Direct Current) transmission lines have been built, there is lack of general UHVDC electroscope equipment and relevant standards. Therefore, a non-contact electroscope based on MEMS (Micro-Electro-Mechanical System) is proposed in this paper. The reasonable measuring position of the electroscope is selected. The distribution of electric field of...
Nowadays, many studies on LVDC (Low Voltage Direct Current) distribution system are underway as the future solution for reliable power system network. This new concept in power distribution is expected to improve power system efficiency, reliability and uninterrupted power supply capability when it is implemented. This paper is based on Bipolar LVDC distribution system and it focuses on analysis of...
This paper presents a novel axial doubly salient electro-magnetic machine with a new double sets of stator structure based on the traditional permanent magnet brushless DC motor and the switched reluctance motor. A new external control circuit is designed according to the special structure and working mechanism of the motor. And according to the electromagnetic characteristics in different conditions...
Single-phase two-stage inverters generally use an intermediate capacitor to buffer the power imbalance between DC input and AC output. However, the resultant low-frequency voltage ripple on this intermediate capacitor may produce low-frequency ripple at the source side, especially when the front-end dc/dc converter operates in continuous conduction mode (CCM). Some common solutions to reducing this...
Core losses of nanocrystalline alloy high frequency transformer (HFT) are calculated by adopting the finite element method with magnetic hysteresis effects considered. A normal Preisach model is used to represent the magnetic hysteresis during the numerical simulation. The normal Preisach model features with simple formulations and easy parameters identification. A dynamic circuit model of laminated...
This paper is concerned with the process of current commutation and overvoltage protection in matrix converters. The mechanisms involved in the commutation process and clamp circuit are described and simulation waveforms are presented. A four-step semi-soft commutation strategy is described that this technique relies on knowledge of the output current direction and the ability to control the direction...
Power transformers are an important factor for power transmission and cause fatal losses if faults occur. Various diagnostic methods have been applied to predict the failure and to identify the cause of the failure. Typical diagnostic methods include the IEC diagnostic method, the Duval diagnostic method, the Rogers diagnostic method, and the Doernenburg diagnostic method using the ratio of the main...
Rated power of a specific motor is highly dependent on cooling capacity for its own protection system. This paper addresses an effect of counter rotating vortices generated inside a weather-protected housing mounted over a IP23W motor, deteriorating thermal-flow characteristics. Generative process of the vortices was initially investigated with computational fluid dynamics and passive control device...
Recently the multi-objective optimization of Interior Permanent Magnet Synchronous Motor (IPMSM) used for Electrical Vehicles (EVs) has attracted widely attention. However, it not only suffers from its lower optimization efficiency, but also is difficult to achieve the optimal solution. Therefore, an effective multi-objective optimization design scheme is presented which innovatively integrates Taguchi...
Islanded DC microgrid is equipped with energy storage unit to balance the power between renewable energy power generation and load. Battery becomes one of the optimum choices for energy storage unit with many advantages. To avoid battery deep charging and discharging and prolong its service life, a multi-source coordinated control strategy for islanded DC microgrid is proposed based on battery's state...
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