• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.3
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• pp.204-210
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• 2009

This paper proposes a novel current-sensorless maximum torque per ampere control for a surface mounted permanent magnet synchronous motor with low-resolution position sensor. A direct axis current is estimated from the mathematical model of the permanent magnet synchronous motor and the phase angle between direct and quadrature axis voltage commands is controlled to adjust the estimated direct axis current to zero, thus a maximum torque per ampere control can be achieved. The proposed method is suitable for low cost applications with slow dynamic response characteristics.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1263-1271
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• 2014

A novel hysteresis PWM control strategy for synchronous buck converter is proposed. The proposed control strategy is based on ampere-second balance of the modulate capacitor, which not only offers faster transient response to meet the challenges of the power supply requirements of fast dynamic load changes, but also provides better stability and solves the compensation problem of error amplifier in the conversional voltage PWM control. Finally, the steady-state and dynamic operation of the control method is analyzed and verified by simulation and experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1474-1477
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• 2005

This paper is proposed maximum torque per ampere of induction motor using fuzzy-neural networks controller. Operation of maximum torque per ampere is achieved when, at a given torque and speed, the slip frequency is adjusted to that so that the stator current amplitude is minimized. This paper introduces a induction motor drive system with fuzzy-neural networks controller. A neural network-based architecture is described for fuzzy logic control. The characteristic rule and their membership function of fuzzy system are represented as the processing nodes in the neural network structure. This paper is proposed the analysis as well as the simulation results to verify the effectiveness of the new method.

• 전기의세계
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• v.31 no.2
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• pp.132-140
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• 1982

Designing the capacitor-run motor for balanced operation is accompanied with the excessive capacitor value and low capacitor terminal voltage of condenser. As a solution for this problems, It was reported the design by equal volt-ampere method. The running characteristics of capacitor-run motor by this method due to the balancing point selection, however, has a room to be studied further. This paper deals with the determination of the winding ratio and capacitor value of a permarient-split capacitor motor by balanced operation and equal volt-ampere method at the different load points. The analysis of the running characteristics of a motor and its designing method also presented for both cases. It concluded that the running characteristics due to the equal volt-ampere operation are very close to the balanced operation.

• Journal of Magnetics
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• v.16 no.1
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• pp.46-50
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• 2011

This paper presents size reduction of primary iron core for tubular linear induction motor by improved winding configuration. Using one-ampere conductor method, magnetic field analysis of tubular linear induction motor for size reduction is conducted. Size reduction and improvement of air gap flux distribution is achieved by improved winding configuration, and analysis results are verified by finite element analysis (FEA) and experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.2
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• pp.142-149
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• 2010

Interior Permanent Magnet Synchronous Motor(IPMSM) have gained an increasing popularity in recent years for a variety of industrial applications, because of their high power density, high efficiency and possibility of flux weakening operation. Because the efficiency of IPMSM is one of the important performance characteristic, the Maximum Torque Per Ampere(MTPA) operating method has been indispensible. In theory, MTPA operating point can be calculated using the exact values of the machine parameters. However, the values of the IPMSM parameters are known to vary widely according to the operating condition. Therefore, to operate the IPMSM in the MTPA operating point, the machine parameters should be estimated in real-time. In this paper, the new MTPA operating method based on the signal injection is presented. By injecting the high frequency current signal, the MTPA operating criteria can be calculated by measuring the input power to IPMSM. The proposed method can find the MTPA operating point with simple signal processing regardless of the parameter variation.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.2
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• pp.19-28
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• 1997

A simple AC complex circuit analysis for LCL type series resonant converter with phase shift control is proposed. Based on these analyses, a set of characteristic curves which allows a optimal design procedure for this converter is shown, without increasing the volt-ampere rating of tank circuit. Especially, inverter output peak current can be minimized in both full load and partial load conditions. The presented design considerations can make the load range wide from full loads to light loads achieving turn-on with zero voltage switching (ZVS) operation. The simulation and experimental results show the effectiveness of the proposed design algorithms.

• Proceedings of the KWS Conference
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• 1994.10a
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• pp.89-92
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• 1994

According to the industrial development welding technology is necessitated to develop in the direction of full automation, high efficiency, energy saving, and full safety. In this study, thus, a simple holder ampere controller for welding systems is developed and applied to arc welders and its capability is examined and tested. The results are as follows: 1. It has a simple structure, since the primary AC power for the welder can be directly control led using a triac. 2. It can control the electric power strength in several steps as well as on and off easily, since a small-sized variable resistance is installed in the small controller on the welding holder. 3. In real field applications a welding system with this controller increases the working efficiency greatly compare to the conventional arc welders without the system, because the controller can control the ampere onsite far from the main power supply. 4. It can reduce the probability of the electrical mishap due to electrical leakage, since the electricity is disconnected as soon as the switch is off or welding person's hand is taken off from the welder after the work or for rest. 5. It can control the welding depth in the beginning and do the crater treatment well in the ending of welding, since it always supplies the relevent amount of electrical current. Therefore, it can improve the mechanical properties of the welding zone.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.1
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• pp.76-87
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• 1998

The concentration of welding fume was measured by 221 welders themselves in chassis frame workplace of the manufactory from February, 1, 1996 to May, 31, 1997. Welding parameters were the welding current and the distance between helmet and arc. Those two optimum conditions were proposed by excess probability analysis using logistic regression, so the best position in the workplace was proposed considering two factors to control the welding fume. The results are as followings; 1) The excess proability of welding fume TLV was over 99% in above 260 Amperes of welding current and also in below 30cm of distanced between helmet and arc. 2) The equation from logistic regression analysis using SPSS/PC+5.02 had the welding current as a independent variable and the excess of welding fume TLV as a dependent variable (p<0.05). Logit(welding fume TLV) = 0.1296 ${\times}$ wlding currnet - 28.8750 3) The equation from logistic regression analysis using SPSS/PC+5.02 had the distance between helmet and arc as a independent variable and the excess of welding fume threshold limit value a, a dependent variable (p<0.05). Logit (welding fume TLV) = -0.6809 ${\times}$ distance between helmet and arc +25.1665 4) Considering both cases or 2) and 3). the result equation is following. (p<0.05). Logit (welding fume TLV) = 0.1346 ${\times}$ welding current -0.3859 ${\times}$ distance between helmet and arc -15.7382 5) The excess probability of welding fume threshold limit value was 100% in above 240 Ampere of welding current. Thus, below 220 Ampere can be suggested to reduce the 40% number of welders who have a excess welding fume threshold limit value. 6) The excess probability of welding fume TLV was 100% in below 34cm of distance between helmet and arc. Thus, over 38cm can be suggested to reduce the 33% number of welders who have a excess welding fume TLV. 7) Considering both 5) and 6) cases, first of all, the best welding current can be 200 Ampere to have a below 15% of welding fume excess probability for the welders who works in distance of 34-37cm. Secondly, to have a below 30% excess probability of welding fume TLV, the working distance must be over 38cm in 220 Ampere and 32cm in 200 Ampere. 8) To reduce the average exposure concentration of welding fume ($8.21{\pm}5.83mg/m^3$), the movable local exhaust system equipped with flexible hoods can be used.

• Journal of the Korean Professional Engineers Association
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• v.29 no.3
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• pp.71-82
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• 1996