Analysis and Reduction of Electromagnetic Force Waves of Permanent Magnet Synchronous Motors Considering Rotor Eccentricity

Xing Zezhi,Wang Xiuhe,Zhao Wenliang 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.6

The accurate calculation and reduction of electromagnetic force waves are important prerequisite for the evaluation and optimization of electromagnetic vibration. In this paper, an accurate calculation method of air gap permeance is proposed, the air gap fl ux density and the resulting electromagnetic force waves of 6p36s surface-mounted permanent magnet synchronous motor considering the rotor eccentricity are analyzed and calculated. Furthermore, the components of air gap fl ux density and electromagnetic force waves under rotor eccentricity with three diff erent windings connection modes at rated load are compared. The results indicate that the components of electromagnetic force waves introduced by rotor eccentricity can be eff ectively weakened by adopting appropriate windings connection modes without aff ecting the basic performance of the motor, and the windings connection mode in which the adjacent coils of each phase constitute parallel branches with equalizing lines has the best weakening eff ect.

Electromagnetic Vibration Reduction of Surface-Mounted Permanent Magnet Synchronous Motors Based on Eccentric Magnetic Poles

Xing Zezhi,Wang Xiuhe,Zhao Wenliang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5

As an important indicator to evaluate the performance of electric vehicles, the electromagnetic vibration of the motor is excited by the electromagnetic force waves acting on the stator core. Considering the influence of complex stator slot structure and inevitable saturation at teeth, the electromagnetic force waves of surface-mounted permanent magnet synchronous motor with eccentric magnetic poles are calculated quickly and accurately by combining the magnetomotive force-permeance method and the improved subdomain method, the amplitudes, orders, and frequencies of electromagnetic force waves are calculated and summarized. Considering the anisotropy of the stator material and the influence of the enclosure and windings, the natural frequencies of the entire stator are analyzed, and the vibration accelerations are calculated by the multiphysics model including electromagnetic, structural, and vibration models. Furthermore, the components of electromagnetic force waves that have a great impact on electromagnetic vibration are summarized, and the optimal parameters of eccentric magnetic poles that can effectively weaken the electromagnetic vibration are obtained by combining the particle swarm optimization algorithm and the subdomain method. For the 6-pole 36-slot motor, the maximum vibration accelerations of the motor are reduced by 45.14% at no load and 42.74% at rated load by optimizing the parameters of eccentric magnetic poles.

Design and Analysis of Basic Model of High-speed Surface-mounted Permanent Magnet Synchronous Motors Based on Subdomain Method

Xing Zezhi,Wang Xiuhe,Zhao Wenliang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5

This paper presents a design method of the basic model of high-speed surface-mounted permanent magnet synchronous motor (SPMSM) comprehensively considering the mechanical and electromagnetic properties based on the subdomain method. In the rotor design stage, the mechanical stresses of the permanent magnet (PM) and retaining sleeve are investigated and calculated by the subdomain method, the interference pre-stress, centrifugal force, thermal stress, and material anisotropy are accurately considered. For the rotors with different retaining sleeves, the rotor parameters such as the thicknesses of the PM and retaining sleeve and the interference between them considering both electromagnetic performance and stress extreme conditions are determined. In the stator design stage, the performances of motors with different stator structures are analyzed and compared based on the subdomain method considering stator saturation, and the optimal stator structure parameters are determined. Finally, the design scheme of the 2-pole 36-slot high-speed SPMSM that meets the requirements of mechanical and electromagnetic properties is determined, and the comprehensive performance of the motor is verified by the finite element method (FEM).

Rotor Stress Analysis of High-Speed Surface-Mounted Permanent Magnet Motors with Segmented Poles Considering Fillings

Xing Zezhi,Wang Xiuhe,Zhao Wenliang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

This paper presents an analytical method for calculating rotor stresses of high-speed surface-mounted permanent magnet synchronous motors (SPMSMs) with segmented permanent magnets (PMs), the pole-arc coefficient, fillings between poles, and material anisotropy are accurately considered. Afterward, the rotor stresses with different retaining sleeves and fillings are compared, the variation laws of rotor stresses with the materials of the retaining sleeve and filling are summarized, and the optimal filling material is determined. The maximum tangential stresses of the PMs and retaining sleeves of high-speed SPMSMs with segmented PMs can be effectively reduced by filling PPS between the segmented PMs or designing the rotor as a surface-inserted structure. The stress extreme conditions of the PMs and the retaining sleeves with different materials are different. Compared with the Inconel718 retaining sleeve, the thickness of the carbon fiber retaining sleeve is smaller.

Olanzapine May Inhibit Colonic Motility Associated with the 5-HT Receptor and Myosin Light Chain Kinase

Jiarui Zhang,Ying Qiao,Jingjing Le,Daliang Sun,Yangtai Guan,Zezhi Li 대한신경정신의학회 2016 PSYCHIATRY INVESTIGATION Vol.13 No.2

ObjectiveaaTo study whether the effects of olanzapine on gastrointestinal motility is related to the serotonin antagonism and myosin light chain kinase. MethodsaaMale Sprague-Dawley rats were randomly divided into four groups. Olanzapine gavage was performed for each treatment group during the course of 30 continuous days, while the same volume of saline was given to the rats in the control group. Defecation of the rats was observed on days 7 and 30 after olanzapine gavage. The effects of olanzapine on contraction of colonic smooth muscles were observed in ex vivo experiments. A Western blot was used to evaluate expression levels of the serotonin transporter (SERT) and MLCK in colon segments of the rats. ResultsaaCompared to the control group, 5–160 μM of olanzapine could inhibit dose-dependently the contraction of colonic smooth muscle ex vivo experiments. The maximum smooth muscle contraction effects of 5-HT and acetylcholine significantly decreased after treatment with 40–160 μM of olanzapine. Constipation was found in the olanzapine-treated rats on day 7 and have sustained day 30 after gavage. Expression of MLCK in olanzapine-treated rats was significantly decreased, whereas the expression of SERT significantly increased on the day 7, then significantly decreased on the day 30 after olanzapine gavage. ConclusionaaSERT and MLCK may involve in the inhibition of colonic contraction induced by olanzapine.

Association Between Metabolic Risk Factors and Cognitive Impairment in Schizophrenia Based on Sex

Hongna Huang,Lizhao Du,Zhengping Pu,Yuan Shi,Zifan Xiao,Xi Chen,Shun Yao,Lijun Wang,Zezhi Li,Ting Xue,Donghong Cui 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.10

Objective Sex differences have been observed in many aspects of schizophrenia, including cognitive deficits. Despite extensive research into the relationship between metabolic factors and cognitive deficits in schizophrenia, few studies have explored the potential sex difference in their association. Methods We recruited 358 schizophrenia patients and 231 healthy controls. The participants underwent measurements of body mass index (BMI), waist circumference, blood pressure, triglycerides, high-density lipoprotein cholesterol, and fasting blood glucose. Metabolic risk factors included abdominal obesity, hypertension, hyperglycemia, and dyslipidemia. A collection of these metabolic risk factors has been defined as metabolic syndrome. These diagnoses were based on the criteria of the National Cholesterol Education Program’s Adult Treatment Panel III. Cognitive performance was measured using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). A descriptive analysis, difference analysis, and linear regression model were used to identify the metabolic risk factors for cognitive function in schizophrenia. Results Our findings revealed sex differences in the rate of abdominal obesity and hypertension in schizophrenic patients. Additionally, we observed sex differences in the association between metabolic risk factors and cognitive impairment in schizophrenia. Specifically, hyperglycemia was associated with the immediate memory index score of RBANS in male patients, while dyslipidemia was associated with language, attention, delayed memory index scores, and RBANS total score in female patients. Conclusion Our results suggest that sex should be considered when evaluating the impact of metabolic disorders on the cognitive function of schizophrenic patients. Moreover, our study identifies hyperglycemia and dyslipidemia as potential targets for precise treatment by sex stratification, which could benefit the improvement of cognitive impairment in schizophrenic patients.