Nengqiang Jin

Research on characteristics of single-sided linear induction motors for urban transit

As a direct electromagnetic driving device without adhesion, the urban transit with single-sided linear induction motor (SLIM) propulsion and wheel on rail support and guidance has many advantages, and has been a part of new type transit. In this paper, a SLIM for urban transit was designed and its characteristics were calculated with improving T-type equivalent circuit model. The specific structure problems of a SLIM such as end effects, half-filled slots for the end windings, skin effect have been taken into account in the design. The prototype has been tested, and the accuracy of the calculation is verified by experimental results.

Levitation control scheme for the hybrid Maglev system based on neuron-PID control

The Maglev train can reach the speed of 500 km per hour, and it is one of the most promising conveyance tools, which has the advantages of high speed, low noise, high security and so on. The levitation control scheme is the key problem of the Maglev system, and the propulsion system has to be designed on the base of stable levitation. To lower the suspension power, permanent magnets are added into the levitation system to assistant the magnetic coil. Its air gap is enlarged and the energy consumed by the levitation subsystem is significantly reduced due to the permanent magnets. Novel scheme combined neuron control and the conventional PID control is proposed, which has good online learning ability. The adaptive neuron is used to regulate the parameters of the PID controller by self-learning and associative searching method according to the dynamic characteristics of the control plant. The suggested strategy is verified by experiments, which is model-free, and can realize fast, precise and flexible suspension. Its performance is better than that of state controller.

Analysis of longitudinal end effect of singled-side linear induction motor

Single-sided linear induction motor (SLIM) has many advantages, such as simple structure, easy maintenance, less environmental pollution and direct drive without the translation mechanisms etc. However, longitudinal end effect deteriorates the performance because of the discontinuous magnetic circuit in SLIM. In this paper, the interpolating linear moving boundary method (ILMBM) in finite element method (FEM) to compute transient electromagnetic field of SLIM is developed and the longitudinal end effect of SLIM is analysed taking into account eddy currents. The paper focuses on the analysis of the eddy current in secondary plate, flux density and electromagnetic force according to current supply and speed variations. Furthermore, the result has been compared with other methods used before. It is clarified that the validity of the FEM with ILMBM by comparison of the results.

Dynamic characteristics study of single-sided linear induction motor with finite element method

Single-sided linear induction motor (SLIM) is widely used in transportation and other field in need of linear drive for their simple, firm structure and linear motion feature without the translation mechanism. But end effect in SLIM deteriorate the performance for the discontinuous magnetic circuit. This paper analyzes 2-D transient electromagnetic field of SLIM by finite element method (FEM). The electromagnetic field-motion coupling problem was handled by the interpolation linear movement interface method. The torque was calculated by nodal force method. The variation and correlation of eddy current and electromagnetic force with respective frequency is studied in detail as well as flux density. The changing trend of longitudinal end effect in SLIM whole operation process and the influence to dynamic characteristics of SLIM is presented. The conclusions presented in this paper can give good theoretical guidance to the control and design of linear induction motor.

Characteristics Analysis of a New Electromagnetic Coupling Energy-Storage Motor

Conventional electromagnetic speed-adjustable motor (ESAM) has wide application in speed adjustment. However, it is difficult to meet the high torque density and transient response requirement in occasion of transient output of high power. A new structure of dual-rotor electromagnetic coupling energy-storage motor (ECESM) is presented to output transient high power under low excitation power. Its mechanical structure and working principle based on eddy effect are explained and the transient equivalent circuit is derived. Finite element analysis (FEA) with Maxwell 2D is used to calculate electromagnetic performance and output characteristics (with terminal leakage considered). The results verify that the new ECESM has high performances in transient response and torque density, providing reference to the motor design and manufacturing.

Research on magnetic force characteristics of the controlled-PM Maglev linear synchronous motor with finite element method

A controlled-PM Maglev system with permanent magnets and electromagnets excitation together can improve the lift/weight ratios, and reduce electromagnetic power consumption at the same air gap compared with a conventional electromagnetic attractive levitation system. It has been proved to be a very effective approach with great potential for application in magnetic levitation system. This paper analyses the magnetic force characteristics of linear synchron ous motor in a controlled-PM maglev model vehicle system in our lab with fi nite element method (FEM), presents the relationship between the magnetic forces and air gap at different current excitat ion, thrust-angle performance, and experiment results. Compared with an electromagnet, a permanent magnet has higher energy density. At present, high energy level of NdFeB can meet the need of most motor performances. If permanent magnets (PM) and electromagnets are combined to form hybrid magnets, the lift force could be increased effectively with the same air-gap length, and the vehicle weight could be decreased. In this hybrid maglev system, PM may provide the base support force required for levitation, while electromagnets produce adjustable support force to stabilize the levitation system. Thus there leads to an extensive reduction of the energy consumption by the vehicle. The rated power of the supply batteries and choppers for exciting current is reduced to a great extent. Since the lift force of the hybrid maglev