• New & Renewable Energy
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• v.10 no.3
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• pp.14-21
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• 2014

As the world supply of fossil fuel sources decreases, the need for efficient energy consevation and develping green energy technologies becomes critical. Because of the high cost of the foundation for large turbines and optional high wind speed (over 12 m/s), it is very difficult to be located at inland city. For the solution above mentioned problem, we have been experimented about that not only using the adaption of wind power system on buildings for improving turbine efficiency, but also applying a wound rotor type induction generator for a small wind turbine.In this research, we try to find out the wind direction and wind speed those were measured every 1 min., during operation period, using the anemometers which consist of horizontally spinning cups on a vertical post. Performance testing for small wind turbine generating system was carried out by using the induction motor and invertor. Finally, we measured the power of 1 kW wind turbine system with the clamp meter and a voltmeter.

• Journal of Electrical Engineering and Technology
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• v.2 no.4
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• pp.478-484
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• 2007

This paper deals with the high efficient vector control for the reduction of copper losses of the doubly fed motor. Firstly, the feedback linearization control based on Lyapunov approach is employed to design the underlying controller achieving the double fluxes orientation. The fluxes# controllers are designed independently of the speed. The speed controller is designed using the Lyapunov method especially employed to the unknown load torques. The global asymptotic stability of the overall system is theoretically proven. Secondly, a new Torque Copper Losses Factor is proposed to deal with the problem of the machine copper losses. Its main function is to optimize the torque in keeping the machine saturation at an acceptable level. This leads to a reduction in machine currents and therefore their accompanied copper losses guaranteeing improved machine efficiency. The simulation and experimental results in comparative presentation confirm largely the effectiveness of the proposed DFIM control with a very interesting energy saving contribution.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1621-1625
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• 2015

Power quality has always been a concern of power engineers. Certainly an argument can be successfully made that most parts of power engineering have the ultimate objective to improve power quality. AC motors were widely used in industrial and domestic applications. Generally, AC motors were of two types: Induction and Synchronous motors. In motor many parameters like different load cycling, switching, working in hot weather and unbalances creates harmonics which creates major reasons for temperature rise of the motors. Due to high peak value of voltage, harmonics can weaken insulation in cables, windings and capacitors and different electronic components. Higher value of harmonics increase the motor current and decrease the power factor which will reduce the life time of the motor and increase the overall rating of all electrical equipments. Harmonics reduction of all the motors in India will save more power. Coating of windings of the motor with nano fillers will reduce the amount of harmonics in the motor. Based on the previous project works, actions were taken to use the enamel filled with various nano fillers for the coating of the windings of the different AC motors. Ball mill method was used to convert the micro particles of Al₂O₃, SiO₂, TiO₂, ZrO₂ and ZnO into nano particles. SEM, TEM and XRD were used to augment the particle size of the powder. The synthesized nano powders were mixed with the enamel by using ultrasonic vibrator. Then the enamel mixed with the nano fillers was coated to the windings of the several AC motors. Harmonics were measured in terms of various indices like THD, VHD, CHD and DIN by using Harmonic analyzer. There are many other measures and indices to describe power quality, but none is applicable in all cases and in many instances, these indices may hide more than they show. Sometimes power quality indices were used as a basis of comparison and standardization. The efficiency of the motors was increased by 5 – 10 %. The thermal withstanding capacity of the motor was increased by 5º to 15º C. The harmonics of the motors were reduced by 10 – 50%.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1838-1844
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• 2011

In this paper, the propulsion control of a high-speed maglev train is studied. Electromagnetic suspension is used to levitate the vehicle, and linear synchronous motors (LSM) are used for propulsion. In general, a low-speed maglev train uses a linear induction motor (LIM) for propulsion that is operated under 300[km/h] due to the power-collecting and end-effect problem of LIM. In case of the high-speed maglev train over 500[km/h], a linear synchronous motor (LSM) is more suitable than LIM because of a high-efficiency and high-output properties. An optical barcode positioning system is used to obtain the absolute position of the vehicle due to its wide working distance and ease of installation. However, because the vehicle is working completely contactless, the position measured on the vehicle has to be transmitted to the ground for propulsion control via wireless communication. For this purpose, Bluetooth is used and communication hardware is designed. A propulsion controller using a digital signal processor (DSP) in the ground receives the delayed position information, calculates the required currents, and controls the stator currents through inverters. The performance of the implemented propulsion control is analyzed with a small maglev train which was manufactured for experiments, and the applicability of the high-speed maglev train will be explored.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.631-632
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• 2006

This paper is written by research for the transient characteristics of the Single-phase Line-start permanent Magnet. The Single-phase Line-start permanent Magnet is most likely to substitute for Single-phase Induction Motor which is used about many appliance currently, because that has good points. For example, It has a Line-start of ability and a High-efficiency. And it need not power convergence device. The rotor of The Single-phase Line-start permanent Magnet has cage-bar with permanent magnet. This motor is started by cage-bar. When it entered synchronous condition, the rotor is rotated by the permanent magnet. But the design of the permanent magnet is very important, because the breaking torque of the permanent magnet interrupt to start a rotor. Finally, if Flux Barrier is not concerned, we do not get result of our object. Therefore this thesis is concerned about Flux Barrier.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1047-1048
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• 2006

The DITC of SRM for smooth hoist driving is presented in this paper. In the hoist system, the switched reluctance motor (SRM) is applied instead of induction motor because of high efficiency and good traction characteristic. In order to improve start-up and stop performance of hoist system, the smoothing operation sequence of SRM using DITC is proposed. According to the switching sequence and hysteric band, the instantaneous torque is controlled. Since, the proposed method uses only the turn-on angle depending on variation of load and speed, a simple DITC can be implemented. The validity is proved by simulation and experiment.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.8
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• pp.373-380
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• 2003

This paper consists of a study in post-assembly magnetization of LSPM (Line Start Permanent Magnet Motor). Recently, LSPM is noted as an alternative to the induction motor because it offers a very high efficiency and unity power factor, And it is necessary for permanent magnets to be magnetized by means of post-assembly magnetization in LSPMS because of the manufacturing cost involved. The manufacturing process is also simpler in post-assembly magnetization than in pre-assembly magnetization. Generally, permanent magnet motors are magnetized by their own stator coil or by magnetizing fixtures. However, the permanent magnet in a LSPM is scarcely magnetized by using them because of the eddy current of the rotor bar. Hence, it is necessary to design a magnetizing fixture that overcomes this problem. In this paper, the author analyses the post-assembly magnetization of a LSPM and proposes a method for designing the magnetizing fixture. The method that the author proposes is to make the number of coil turns greater in order to reduce the effect of the eddy current of the rotor bars.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1043-1044
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• 2007

The line-start permanent magnet synchronous motor has a high efficiency and an advantage in constant speed operation regardless of the effect of load variation. However it is difficult to predict the performance of characteristics accurately, because of the unbalanced starting torque with the initial starting position of the rotor and the generation of a break torque. In this paper the dynamic characteristics of the line-start permanent magnet synchronous motor are described and compared with those of the squirrel-cage induction motor through the simulation to find the characteristics of the permanent magnets and the rotor bars in the line-start permanent magnet synchronous motor. Finally this paper gives the comparison between the simulation results and the experiment results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1700-1707
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• 2011

Interior permanent magnet synchronous motor(IPMSM) adjustable speed drives offer significant advantages over induction motor drives in a wide variety of industrial applications such as high power density, high efficiency, improved dynamic performance and reliability. Since the fuzzy neural network(FNN) is recognized general approximate method to control non-linearities and uncertainties, the development of FNN control systems have also grown rapidly. The FNN controller is compounded of fuzzy and neural network. It has an advantage that is the robustness of fuzzy control and the ability to adapt of neural network. However, the FNN has static problem due to their feed-forward network structure. This paper proposes high performance speed control of IPMSM drive using the recurrent FNN(RFNN) which improved conventional FNN controller. The RFNN has excellent dynamic response characteristics because of it has internally feed-back structure. Also, this paper proposes speed estimation of IPMSM drive using ANN. The proposed method is analyzed and compared to conventional FNN controller in various operating condition such as parameter variation, steady and transient states etc.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.756-760
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• 2001

Two different designs of permanent magnet motors as direct wheel-set drive for the German high speed train ICE 3 are designed, one with surface mounted magnets (SM) and one with buried rotor magnets (BM). The surface magnet motor has $17\%$ less mass and a slightly higher efficiency and was therefore chosen for further investigations. Compared with the conventional drive system of the ICE 3, consisting of geared inverter fed induction machines, the gearless permanent magnet direct drive yields about $16\%$ lower losses. This calculation is based on the route parameters of the high speed track between Frankfurt/Main and Cologne in Germany, which is currently under construction.