Yu-wu Zhu

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.

Thrust Ripples Suppression of Permanent Magnet Linear Synchronous Motor

The thrust ripples in permanent magnet linear synchronous motor (PMLSM) are mainly generated by the distortion of the stator flux linkage distribution, reluctance force due to the relative position between the mover and stator, cogging force caused by the interaction between the permanent magnet (PM) and the iron core, and the end effects. This is the significant drawback which will deteriorate the performance of the drive system in high-precision applications. Comparing the complexity of the motor structure design to eliminate the thrust ripples, an optimal control method is more desirable. This paper focuses on thrust ripples reduction based on the predictive control algorithm. To minimize the thrust ripples and realize the high-precision control, the components of thrust ripples are extracted by finite element method (FEM) first and then compensated by injecting the instantaneous current to counteract the thrust ripples using the field-oriented control (FOC) method. The effectiveness of this proposed method is verified by the simulation using Simulink/Matlab according to the comparison between the compensation and noncompensation cases

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.

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.

Simulation of the Reduction of Force Ripples of the Permanent Magnet Linear Synchronous Motor

The significant drawback of the permanent magnet linear synchronous motor (PMLSM) is force ripples, which are generated by the distortion of the stator flux linkage distributions, cogging forces caused by the interaction of the permanent magnet and the iron core and the end effects. This will deteriorate the performance of the drive system in high precision applications. The PMLSM and its parasitic effects are analyzed and modeled using the complex state-variable approach. To minimize the force ripple and realize the high precision control, the components of force ripples are extracted first and then compensated by injecting the instantaneous current to counteract the force ripples. And this method of the PMLSM system is realized by the field oriented control method. In order to verify the validity of this proposed method, the system simulations are carried out and the results are analyzed. The effectiveness of the proposed force ripples reduction method can be seen according to the comparison between the compensation and non-compensation cases.

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.

Electromagnetic Normal Force Characteristics of a Permanent Magnet Linear Synchronous Motor with Double Primary Side

The large normal force of the permanent magnet linear synchronous motor (PMLSM) is caused by the PM group shifting. This is the significant drawback which will deteriorate the performance of the drive system in high-precision applications. In the optimization design process, when the PM group shifting length is not zero the normal force will be changed into a pulsation curve with large amplitude. To solve this problem, this paper proposes that the PMLSM is divided into two symmetrical PMLSMs. The effectiveness of this proposed structure is verified by the simulation and experiment according to the comparison of the electromagnetic force characteristics between the conventional and proposed structures.

Optimal design of slotted iron core type permanent magnet linear synchronous motor for ropeless elevator system

This paper investigates an optimal design of a double-sided slotted iron core type permanent magnet linear synchronous motor (PMLSM) using for ropeless elevator system. To obtain the optimal structure, the combination of response surface methodology (RSM) and two dimensional (2D) finite element analysis (FEA), which can solve the problem effectively without much time consuming, is utilized to investigate the PMLSM characteristics. Moreover, the detent force is more detailed analyzed with the manufacturing consideration. In final some numerical calculation results are reported to validate the applicability of this double-sided slotted iron core type PMLSM in ropeless elevator system.

The Reduction of Force Ripples of PMLSM Using Field Oriented Control Method

The significant drawback of the permanent magnet linear synchronous motor (PMLSM) is force ripples, which are generated by the distortion of the stator flux linkage distributions, cogging forces caused by the interaction of the permanent magnet and the iron core and the end effects. This will deteriorate the performance of the drive system in high precision applications. The PMLSM and its parasitic effects are analyzed and modeled using the complex state-variable approach. To minimize the force ripple and realize the high precision control, the components of force ripples are extracted first and then compensated by injecting the instantaneous current to counteract the force ripples. And this method of the PMLSM system is realized by field oriented control method. In order to verify the validity of this proposed method, the system simulations are carried out and the results are analyzed. It can be seen the effective of the proposed force ripples reduction method according to the comparison between the compensation and non-compensation cases

Topology structure selection of permanent magnet linear synchronous motor for ropeless elevator system

To make the ropeless elevator system become practical, one of the most important requirements is the high force density. The slotted iron core type permanent magnet linear synchronous motor (PMLSM) seems to be the best choice except the large detent force. Therefore, in this paper we will investigate the characteristics of detent force, normal force, and thrust of PMLSM under different motor topology structures. Finally, the long stator double-sided slotted iron core type PMLSM with fractional slot winding is selected for the best performance.