Yun-Hyun Cho

Investigation of Auxiliary Poles Design Criteria on Reduction of End Effect of Detent Force for PMLSM

The detent force in permanent magnet linear synchronous motor (PMLSM) is caused by the attraction between the permanent magnet (PM) and the iron core without input current. It can be divided into two components: the slot effect and the end effect. This paper proposes a novel technique to reduce the end effect of detent force using auxiliary poles. To investigate the auxiliary poles design criteria, we analyze the characteristics of the detent force according to the height, length, and position of the auxiliary poles by using the 2-D finite-element method (FEM). The numerical calculations and the experimental results prove that this proposed technique has a good effect on the reduction of the end effect of detent force.

Comparison of 12/8 and 6/4 Switched Reluctance Motor: Noise and Vibration Aspects

This paper compares and investigates the vibration and noise characteristics through simulations and experiments of 12/8 and 6/4 switched reluctance motors (SRMs). The radial force which is the main source of vibration is computed from two-dimensional (2D) transient magnetic finite-element analysis (FEA) and compared in both time and frequency domains. At the same output power, the radial force of 6/4 SRM is found to be more than two times as that of 12/8 SRM. Three-dimensional structural finite-element analysis (3D FEA) is used to study the mechanical characteristics. It can be concluded from static structural analysis that the maximum total deformation could be reduced to 1/26 if the motor is designed with 12/8 structure instead of 6/4. The dominant vibration modes are verified by modal analysis and stationary test. It is also found that the vibration and noise are dramatically reduced for 12/8 SRM during experiments.

Detent Force Minimization of Permanent Magnet Linear Synchronous Motor by Means of Two Different Methods

The thrust ripple in a permanent magnet linear synchronous motor (PMLSM) is mainly generated by the detent force that is caused by the interaction between the permanent magnet (PM) and the iron core without input current in armature winding. This paper proposes two different techniques to minimize the detent force in a PMLSM. One is to choose an optimal constructive design; the other is to employ a current compensator. In this paper, we investigate the performance of detent force minimization using both of them. The effectiveness is verified by both numerical and experimental results.

A Study on the Maximum Power Control Method of Switched Reluctance Generator for Wind Turbine

This paper deals with modeling and power control methods of a switched reluctance generator (SRG) driven from the wind power generation system. To consider electromagnetic nonlinear characteristics of SRG, the flux linkage and torque of the designed generator computed by a finite element method (FEM) are applied to the SRG model. And the SRG model is controlled with a required output curve depending on the speed of the generator using optimized switching angle which has been analyzed in advance to maximize its efficiency. The power control algorithm is applied to a manufactured 3 kW prototype SRG. The simulation results are compared with the experimental ones for validation.

Optimal Structure Design for Minimizing Detent Force of PMLSM for a Ropeless Elevator

This paper presents the optimal structure design and magnetic force analysis of a ropeless elevator model that employs permanent magnet linear synchronous motors (PMLSMs) with the structure of a double-sided long-stator. To obtain the optimal structure, the combination of response surface methodology and 2-D finite element analysis, which can solve the problem effectively without consuming much time, is utilized to estimate the design parameters of PMLSM. The numerical calculations and the experimental results are reported to validate the applicability of this double-sided long-stator type PMLSM for a ropeless elevator system.

Design and Analysis of Axial Flux Permanent Magnet Synchronous Machine

In this article, a special kind of axial flux permanent magnet machine has proved to be suitable for high torque and low speed applications. An innovative design of the machine has been proposed in order to make the machine suitable for traction applications by means of field-weakening. The aim of this paper is to analyze, in general terms, the basic equations that describe the operating conditions of such machines. Optimal sizes for design can be obtained by calculating the power density and the air-gap flux density, etc.

Control-Based Reduction of Detent Force for Permanent Magnet Linear Synchronous Motor

The detent force of the permanent magnet linear synchronous motor (PMLSM) is caused by the interaction between the permanent magnet and the iron core of the mover without input current. It is a function of the mover position relative to the stator. This paper proposes a control based method to reduce the detent force for the PMLSM. This detent force that can be predicted by finite element method (FEM) is compensated by injecting the instantaneous current using the field oriented control (FOC) method. Both the simulated and experimental results are reported to validate the effectiveness of this proposed method.

Cogging torque reduction in a novel axial flux PM motor

This article shows the reduction of cogging torque in a novel axial flux permanent magnet (AFPM) motor through the various design schemes. 3D finite element method is used for the exact magnetic field analysis. The effects of slot shapes and skewing of slot on the cogging torque and average torque have been investigated in detail. The validity of the analysis results is also clarified by comparison between calculated results and measured ones

Optimal design of auxiliary poles to minimize detent force of permanent magnet linear synchronous motor

sThe problem in improving the high positioning precision of permanent magnet linear synchronous motor (PMLSM) is the large detent force that is caused by the attraction bet ween the permanent magnet (PM) and the iron core without input current. This detent force can be divided into two components: the slot effect and the end effect. In this paper we propose a novel method to reduce the detent force by employing the optimal designed auxiliary poles. To investigate the characteristics of the detent force of PMLSM with auxiliary poles, the width, position, and height of auxiliary poles are chosen as the opt imal factors and the two dimensional (2-D) finite element method ( FEM) is used to predict to the values of detent force with different combinations of these three factors. And then the structure of auxiliary poles is optimized by the response surface method (RSM) through the fractional factorial design (FFD). Finally, the effectiveness of our proposed technique is verified b y both the numerical calculations and experimental results.

Hall effect sensor based space vector PWM control of permanent magnet synchronous machine

This paper proposes a space vector control of permanent magnet synchronous machine (PMSM) based on Hall effect sensor, which is very useful in practical applications due to the exactly same hardware structures between PMSM and brushless DC (BLDC) machine. This proposed method can be considered as an intermediate stage of development between the general incremental encoder based and sensorless based PMSM control methods. Because the Hall effect sensor is an absolute position sensor with 60-degree resolution, the position initialization process is not needed and the reversal rotation risk can be avoided. To improve resolution the interpolation method implemented by software is employed. Finally the high performance of this proposed method is validated by some experimental results.