• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1806-1812
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• 2016

We propose an interior permanent magnet syhchronous motor (IPMSM) with arc-shape ferrite permanent magnets (PMs) as a substitute for the rare-earth permanent magnet, and determine its optimal design through parametric study. First, we use 2D finite element analysis to analyze 4-poles and 6-slots initial model according to performance requirements and design parameters. The current angle of the maximum average torque considered in the analysis is different compared with the current angle of the minimum torque ripple. Thus, the parametric study for optimal rotor design is performed by varying the thickness and the offset radius of the PMs according to current angle. In particular, a narrow bridge is required in conventional IPMSM for reducing flux leakage; however, the increase in cogging torque in the analysis model saturates the narrow bridge (large offset radius). Therefore, we suggest an appropriate shape considering limiting conditions such as DC link voltage, average torque, torque ripple, and cogging torque taking into account performance requirements.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.505-508
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• 1997

In this paper, an auto-tuning method for fuzzy controller based on the neural network is presented. The backpropagated error of neural emulator offers the path which reforms the fuzzy controller's membership functions and fuzzy rule, and used for speed control of induction motor. For the torque control method, an indirect vector control scheme with slip calculation is used because of its stable characteristics regardless of speed. Motor input current is regulated by a current controlled voltage source PWM inverter using space voltage vector technique. Also, the scheme of current control fuzzy controller is synchronous reference frame with decoupling term. DSP(TMS320C31) is used to achieve the high speed calculation of the space voltage vector PWM and to build the self-learning fuzz. control algorithm. An IPM is used to simplify hardware design.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.578-581
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• 1996

A torque trajectory control of the IPM synchronous motor using an adaptive input-output linearization technique is proposed. The input-output linearization is performed using the estimated torque output with the knowledge of machine parameters. The linearized model gives the output torque error under the variation of the flux linkage. To give a good torque tracking in the presence of the flux linkage variation, the flux linkage will be estimated where the adaptation law h derived by the Popov's hyperstability theory and the positivity concept. This estimated value is also used for the generation of the d-axis current command for the maximum torque control. Thus, a good torque tracking and the exact maximum torque-per-current operation will be obtained.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.69-71
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• 2007

Need correct analysis of thrust for control performance improvement of HB-LPM (Hybrid type Linear Pulse Motor). It is difficult to analyze HB-LPM's thrust. In this paper, HB-LPM's thrust is expressed to mathematical expression. And it is proved validity of this numerical formula by thrust measurement system. Two phase driver is composed. It is verified validity of numerical formula that measure waveform of electric current and voltage that is supplied in each phase. In this study, composed two phase drive driver, advantage of this IGBT element 6 by accumulated IPM module 1 Driver composition possible. That is, can economize 1 moule. In other words, Driver composition is available by IGBT or metal oxide semiconductor field effect transistor element 4. This is economical big gain.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.28-30
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• 2007

Need analysis of correct thrust for control performance improvement of HB-LPM (Hybrid type Linear Pulse Motor). It is difficult to analyze HB-LPM's thrust. In this paper, HB-LPM's thrust is expressed to mathematical expression. And it is proved validity of this numerical formula by thrust measurement system. Two phase driver is composed. It is verified validity of numerical formula that measure waveform of electric current and voltage that is supplied in each Phase. In this study, composed two phase drive driver, advantage of this IGBT element 6 by accumulated IPM module 1 Driver composition possible. That is, can economize 1 module. In other words, Driver composition is available by IGBT or metal oxide semiconductor field effect transistor element 4. This is economical big gains.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.25-33
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• 2015

This paper presents the d-q axis equivalent circuit model of an interior permanent magnet (IPM) which includes the iron loss resistance. The model is implemented to be able to run in real-time on the FPGA-based HIL simulator. Power electronic devices are removed from the motor control unit (MCU) and a separated controller is interfaced with the real-time simulated motor drive through a set of proper inputs and outputs. The inputs signals of the HIL simulation are the gate driver signals generated from the controller, and the outputs are the winding currents and resolver signals. This paper especially presents iron loss prediction which is introduced by means of comparing the torque calculated from d-q axis currents and the desired torque; and minimizing the torque difference. This prediction method has stable prediction algorithm to reduce torque difference at specific speed and load. Simulation results demonstrate the feasibility and effectiveness of the proposed methods.

• The Korean Journal of Pain
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• v.24 no.4
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• pp.205-215
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• 2011

Background: Interventional pain management (IPM) is a branch of medical science that deals with management of painful medical conditions using specially equipped X-ray machines and anatomical landmarks. Interventional physiatry is a branch of physical medicine and rehabilitation that treats painful conditions through intervention in peripheral joints, the spine, and soft tissues. Methods: A cross-sectional study was conducted using three years of hospital records (2006 to 2008) from the Physical Medicine and Rehabilitation Department at Chittagong Medical College Hospital in Bangladesh, with a view toward highlighting current interventional pain practice in a tertiary medical college hospital. Result: The maximum amount of intervention was done in degenerative peripheral joint disorders (600, 46.0%), followed by inflammatory joint diseases (300, 23.0%), soft tissue rheumatism (300, 23.0%), and radicular or referred lower back conditions (100, 8.0%). Of the peripheral joints, the knee was the most common site of intervention. Motor stimulation-guided intralesional injection of methylprednisolone into the piriformis muscle was given in 10 cases of piriformis syndrome refractory to both oral medications and therapeutic exercises. Soft tissue rheumatism of unknown etiology was most common in the form of adhesive capsulitis (90, 64.3%), and is discussed separately. Epidural steroid injection was practiced for various causes of lumbar radiculopathy, with the exception of infective discitis. Conclusion: All procedures were performed using anatomical landmarks, as there were no facilities for the C-arm/diagnostic ultrasound required for accurate and safe intervention. A dedicated IPM setup should be a requirement in all PMR departments, to provide better pain management and to reduce the burden on other specialties.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.1
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• pp.9-18
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• 2007

This paper proposes the modeling of sensorless drive system using 120 degree conduction method for IPM (Interior Permanent Magnet) BLDC motors and analyzes characteristics of the terminal voltage that is used to detect the rotor position. This paper shows that the ZCP (Zero-Crossing Point) of the measured terminal voltage used In sensorless control is ahead of that of the back EMF of IPM motors because they have a saliency. This research also analyzes that the amount of position detection error is related to saliency, rotor speed, and load condition. In addition, this paper shows that motors have bigger advance angles than we have expected because the ZCP of terminal voltage precedes the actual ZCP, and under operation conditions such as heavy load and high speed it may generate abnormal currents that flow toward opposite direction after phase current becomes zero.

• Journal of Korean Neurosurgical Society
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• v.55 no.4
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• pp.195-199
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• 2014

Objective : Age is a strong predictor of mortality in traumatic brain injuries. A surgical decision making is difficult especially for the elderly patients with severe head injuries. We studied so-called 'withholding a life-saving surgery' over a two year period at a university hospital. Methods : We collected data from 227 elderly patients. In 35 patients with Glasgow Coma Score 3--8, 28 patients had lesions that required operation. A life-saving surgery was withheld in 15 patients either by doctors and/or the families (Group A). Surgery was performed in 13 patients (Group B). We retrospectively examined the medical records and radiological findings of these 28 patients. We calculated the predicted probability of 6 month mortality (IPM) and 6 month unfavorable outcome (IPU) to compare the result of decision by the International Mission for Prognosis and Analysis of Clinical Trials in TBI (IMPACT) calculator. Results : Types of the mass lesion did not affect on the surgical decision making. None of the motor score 1 underwent surgery, while all patients with reactive pupils underwent surgery. Causes of injury or episodes of hypoxia/hypotension might have affected on the decision making, however, their role was not distinct. All patients in the group A died. In the group B, the outcome was unfavorable in 11 of 13 patients. Patients with high IPM or IPU were more common in group A than group B. Wrong decisions brought futile cares. Conclusion : Ethical training and developing decision-making skills are necessary including shared decision making.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.383-388
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• 2014

In This paper, the output characteristics and vibrations were compared and analyzed according to operation method in 100W class. The voltage source is applied only two phase in BLDC drive system therefore commutation torque ripple and imbalance of RMF occurred. Due to this efficiency was significantly degraded because mechanical loss is increased, besides the vibration and noise were greatly generated. The vibration and output characteristics were compared and analyzed according to three phase and BLDC drive system.