Jung-Hwan Chang

Finite-element analysis of an electromechanical field of a BLDC motor considering speed control and mechanical flexibility

This research presents a finite-element analysis of the electromechanical field of a BLDC motor considering speed control and mechanical flexibility. The magnetic field is analyzed by the nonlinear time-stepping finite-element method considering the switching action of the pulse width modulation (PWM) inverter. Magnetic force and torque are calculated by the Maxwell stress tensor. Mechanical motion of a rotor is determined by a time-stepping finite-element method considering the flexibility of shaft, rotor, and bearing. Both magnetic and mechanical finite-element equations are combined in the closed loop to control the speed using PWM. Simulation results are verified by the experiments, and they are in good agreement with the experimental results.

Optimum Design of TFLM With Constraints for Weight Reduction Using Characteristic Function

This paper presents optimum design of transverse flux linear motor (TFLM) to reduce the weight of the machine with the constraints of thrust and detent force. Employing penalty functions, each constraint is included in the characteristic function, and the response value is determined by three dimensional magnetic field analyses. Finally, the contribution and effect of the each design variable on the characteristic function is evaluated by the analysis of means (ANOM), and optimum design set is determined. With this procedure, the weight of initially designed TFLM can be reduced 10% with small variation of thrust and detent force

Determination of Parameters Considering Magnetic Nonlinearity in Solid Core Transverse Flux Linear Motor for Dynamic Simulation

This paper presents methods to calculate motor parameters considering magnetic nonlinearity in solid core transverse flux linear motors (TFLM) for dynamic simulation. The magnetic field characteristics of the machine are analyzed by using 3-D equivalent magnetic circuit network (3-D EMCN) method, and parameters for dynamic simulation such as linkage flux, thrust, attraction force, and core loss are calculated by using the magnetic field analysis results. The calculated parameters are used as a form of lookup table in the dynamic simulation model. The accuracy of the method is examined by the comparison of input currents which are calculated by using the dynamic simulation model and measured for an example TFLM.

Transverse Flux Linear Machine with High Thrust for Direct Drive Applications

This paper describes the development of a novel transverse flux linear motor (TFLM) excited by permanent magnets (PMs). It combines the advantage of two different TFLMs and produces high thrust with reduced normal force. The magnetic field is analyzed by combining the three-dimensional (3D) equivalent magnetic circuit network (EMCN) method with 2D finite element analysis. The experimental findings of the prototype motors are in good agreements with the analysis results, and demonstrate the potential of the proposed motor as a direct drive requiring relatively long displacement of a mover.

Dynamic Characteristic Analysis Considering Core Losses in Transverse Flux Linear Machine With Solid Cores

This paper deals with a method for dynamic characteristic analysis considering core losses in transverse flux linear machines (TFLMs) with solid cores. This paper focuses on how to calculate the core losses of solid cores and how to apply the core losses to the dynamic simulation. The magnetic field characteristics, which are used for the core loss calculation and dynamic simulation, are calculated by using a 3-D equivalent magnetic circuit network analysis method. The accuracy of the proposed core loss calculation and dynamic simulation methods are examined by comparing the input currents of the dynamic simulation model with the measured input current of two TFLM prototypes.

Development of Rotating Type Transverse Flux Machine

This paper describes the design and development of rotating type transverse flux motors (TFM) excited by permanent magnets. In-plane phase construction and axial phase arrangement are compared each other and many variants of them are introduced by combining soft magnetic composite (SMC) core and laminated steel core. Magnetic field is analyzed by three-dimensional equivalent magnetic circuit network (EMCN) method with the help of two-dimensional finite element analysis. The experimental results of prototyped motor compared with the analysis ones, and show the possibility of the suggested motor as a direct drive application requiring relatively low speed and high torque.

A Study on Sensorless Control of Transverse Flux Rotating Motor Based on MRAS with Parameter Estimation

This paper presents a sensorless control and parameter estimation strategies for a Transverse Flux Rotating Motor (TFRM). The proposed sensorless control method is based on a Model Reference Adaptive System (MRAS) to estimate the stator flux. Parameter estimation theory is also applied into the sensorless control method to estimate motor parameters, such as inductances. The effectiveness of the proposed methods is verified by some simulations and experiments.

Variation of Phase Difference Between the Peak Value of Applied Current and the Maximum Displacement of Mover in Linear Actuator

This paper is associated with the manufacture of a transverse flux linear motor (TFLM) and the characteristic of the thrust force and the maximum displacement of the mover in linear motor. The thrust force of this calculation is in good agreement with experiments. We utilized a new design for household electric applications that the volume of a linear motor reduced by 3/4. In this paper, we examine the initial displacement of piston for linear actuator and the reaction force of sustained body for a constant spring coefficient and damping coefficient under several current rates in linear motor. Thus, we calculate with FN3D and ANSYS and experiment the thrust force of the linear actuator with applied current, 0, 500, 1000, and 2000 [ampere turns, AT]. We used the experiment with several types of alternating current and the phase difference between the peak value of applied current and the maximum displacement of the mover of the linear actuator is changed with applied current frequency

On-line Compensation Method for Magnetic Position Sensor using Recursive Least Square Method

This paper presents the error correction method of magnetic position sensor using recursive least square method (RLSM) with forgetting factor. Magnetic position sensor is proposed for linear position detection of the linear motor which has tooth shape stator, consists of permanent magnet, iron core and linear hall sensor, and generates sine and cosine waveforms according to the movement of the mover of the linear motor. From the output of magnetic position sensor, the position of the linear motor can be detected using arc-tan function. But the variation of the air gap between magnetic position sensor and the stator and the error in manufacturing process can cause the variation in offset, phase and amplitude of the generated waveforms when the linear motor moves. These variations in sine and cosine waveforms are changed according to the current linear motor position, and it is very difficult to compensate the errors using constant value. In this paper, the generated sine and cosine waveforms from the magnetic position sensor are compensated on-line using the RLSM with forgetting factor. And the speed observer is introduced to reduce the effect of uncompensated harmonic component. The approaches are verified by some simulations and experiments.