Simulation of linear brushless dc motor speed-controlled system based on MATLAB/SIMULINK
ABSTRACT This paper introduces a simulation method using MATLAB/SIMULINK to analyse speed-controlled system of linear permanent magnet brushless DC motor (LPMBDCM). The speed, thrust curves are presented for the starting procedure and sudden load of the LPMBDCM. The results of simulation can be available on the design of practical speed-controlled system.
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ABSTRACT: Severe iron overload usually develops in patients with hereditary hemochromatosis (HHC), but variability in the phenotypic expression of the disease has been reported. This study assessed whether tumor necrosis factor alpha (TNF-alpha) plays a role in phenotypic expression of HHC. Sixty-four patients with HHC and 172 healthy volunteers (controls) were studied. Release of TNF-alpha from stimulated peripheral blood monocytes was measured by enzyme-linked immunosorbent assay, and 308 and 238 TNF-alpha polymorphisms were detected with polymerase chain reaction and restriction fragment-length polymorphism analysis. The relation between TNF-alpha polymorphisms and clinical expression of HHC was evaluated. Patients with HHC released less TNF-alpha than controls, but the difference was significant only in homozygotes for the C282Y mutation. The prevalence of the 308 TNF-alpha polymorphism was similar in patients and controls, whereas the prevalence of the 238 polymorphic allele was significantly lower in patients (3% versus 16%; P =.002). A lower prevalence of cirrhosis was observed in patients with TNF-alpha polymorphism than in those without it (4 of 15 [27%] versus 28 of 49 [57%]), but the difference was not significant (P =.07). In nonhomozygotes for the C282Y mutation, severe liver siderosis was less prevalent in patients with the 308 polymorphism than in those without it (P =.05). Alanine aminotransferase (ALT) values were significantly lower in patients with TNF-alpha polymorphism (P =.006), even when patients with other hepatotoxic factors were excluded. Multivariate analysis showed that TNF-alpha polymorphism was independently associated with ALT values (P =.0008 and P =.045, respectively, in homozygotes and nonhomozygotes for the C282Y mutation) and siderosis in nonhomozygotes (P =.047). Thus, TNF-alpha appears to play a role in HHC by modulating the severity of liver damage. (Blood. 2001;97:3707-3712)Blood 07/2001; 97(12):3707-12. · 9.78 Impact Factor
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ABSTRACT: We designed a pen recorder with a linear dc motor (LDM) which has high speed response. The magnetic field of the LDM was analyzed using the finite element method (FEM). We suggest a design method for thin LDMs (e.g. 13 mm thick) with a long stroke (e.g. 100 mm). With this method, we designed an LDM that has a thrust constant of 2.67 N/A. We evaluated LDM designs in terms of mechanical time constants. We simulated the indicial responses of the LDM that was controlled with a displacement feedback controller. We were able to establish that the mechanical time constant is an appropriate evaluation indexIEEE Transactions on Magnetics 12/1995; · 1.42 Impact Factor
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ABSTRACT: The author develops a position controller for permanent magnet brushless DC motors (PMBDCMs) which systematically determines control laws for operation in both the transient and steady-state with consideration of reluctance force. The controller design is based on a differential geometric approach which assists the motor in overcoming its inherent deficiencies, such as effects of torque ripples and reluctance torque. This is achieved by transforming the nonlinear state equations into an exact linear model. Computer simulations of the resulting closed-loop system were performed to demonstrate the effectiveness of the proposed control laws. Simulation results of the control variables were injected into the actual nonlinear system in an experimental open-loop setup to validate the design procedureIEEE Transactions on Energy Conversion 10/1992; · 2.43 Impact Factor