• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.215-219
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• 2005

In this paper, a novel motor control method is proposed to improve the performance of sensorless drive of BLDC motors. The unknown input (back-EMF) is modelled as the additional state of system in this paper. Taking into account the disturbance adopted by the back-EMF, the observer can be obtained by the augmented system equation. An algorithm to detect the back-EMF of the BLDC motor using the state observer is constructed. As a result, the novel sensorless drive of BLDC motors that can strictly estimate rotor position and speed is proposed.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.4
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• pp.188-194
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• 2003

The SRM (Switched Reluctance Motor) has a more inherent simple mechanical structure, greater ruggedness and higher efficiency than a conventional AC motor. It is for these reasons that SRM is widely applied in an extensive range of industrial applications. In this paper, SRM is designed and analyzed for EPS (Electrical Power Steering) application. Electrical power steering in a vehicle plays the role of reducing a driver's handling control power. For proper design, a FEM analysis is implemented according to the rotor structure. Using both a FEM and a magnetic circuit analysis, a designed motor is simulated and tested. The effectiveness of the suggested SRM drive for EPS application is verified by the prototype motor drive tests.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.63-68
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• 2004

Since rotor position information is necessary to drive the SRM, absolute-encoder, resolver and incremental-encoder is used to detect a poor position. But, it is not desirable to use a high priced encoder and high efficient microprocessor under the condition of the simple driving system when precision control is not demanded. In this paper, Only using the reflective type 2 photosensors replace the conventional opto interrupter and slotted disk, which not only remove a slotted disk section but drive 3-phase 6/4 SRM bidirectionally. Moreover, as control circuit only is composed of common analog device economy is maximized.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1144-1145
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• 2007

This paper is investigated the sensorless drive for BLDC motor using microprocessor. Since the BLDC motor should be commutated according to a rotor position, the sensors are required to detect the position. But the sensors increase cost and volume, complicate the motor configuration, and do not operate properly in some operating environments such as high temperature conditions, so that the necessity of sensorless commutation algorithm is getting increased. This paper is proposed the method to drive BLDC motor without position-detecting sensor using Back EMF. Back EMF commutation method was implemented the sensorless drive system which could control the rotational speed and monitor the behavior of a motor.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.192-194
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• 2005

This paper is investigated the drive for sensorless BLDC motor using back EMF with ATMEGA-128. Since the BLDC motor should be commutated according to a rotor position. But the sensors increase cost and volume, complicate the motor configuration, and do not operate properly in some operating environments such as high temperature conditions, so that the necessity of sensorless commutation algorithm is getting increased. This paper is proposed the methode to drive BLDC motor without position sensor using Back EMF.

• Journal of Wind Energy
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• v.2 no.2
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• pp.54-60
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• 2011

A PMSG in variable speed wind turbine needs to know the position of rotor for vector control. Since the position sensor has the disadvantage in terms of cost, complexity of the system, a sensorless algorithm is needed. The sensorless strategy using the back EMF estimation is used for PMSG Wind Turbine. This algorithm is comparatively easy to implement than other strategies. This paper introduces the application of stable sensorless control for 2MW direct drive PMSG. In order to confirm the sensorless algorithm, the implementation is proceeded using 2MW direct drive PMSG from no-load condition to full-load condition. To drive 2MW PMSG artificially, 2MW PMSG connected PMSG through the mechanical coupling.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.4
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• pp.319-326
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• 2002

In switched reluctance motor(SRM) drive, it is important to synchronize the stator phase excitation with the rotor position; therefore, the information about rotor position is essential. Generally, optical encoders or resolvers are used to provide the information. However, these sensors are expensive and are not suitable for high-speed operation. The accuracy of the switching angles is dependent upon the resolution of the encoder and the sampling period of the microprocessor. In the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost linear encoder suitable far the practical and stable SRM drive is proposed and also the control algorithm to generate the switching signals using a simple digital logic is presented. The validity of the proposed linear encoder with a proper logic controller is verified through the experiments.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.57-64
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• 2006

This paper is proposed for a artificial neural network(ANN) sensorless control based on the vector controlled induction motor drive, or proposes a adaptive fuzzy teaming control(AFLC). The fuzzy logic principle is first utilized for the control rotor speed. AFLC scheme is then proposed in which the adaptation mechanism is executed using fuzzy logic. Also, this paper is proposed for a method of the estimation of speed of induction motor using ANN Controller. The back propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The error between the desired state variable and the actual one is back-propagated to adjust the rotor speed, so that the actual state variable coincide with the desired one. The back propagation mechanism is easy to derive and the estimated speed tracks precisely the actual motor speed. This paper is proposed the analysis results to verify the effectiveness of the new method.

• Journal of the Korean Solar Energy Society
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• v.32 no.5
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• pp.31-40
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• 2012

This paper introduces a methodology for NREL 5MW wind turbine, which is the variable speed and variable pitch(VSVP) control system. This control strategy maximizes the power extraction capability from the wind in the low wind speed region and regulates the wind turbine power as the rated one for the high wind speed region. Also, pitch control efficiency is raised by using pitch scheduling.Torque schedule is made of torque table depending on the rotor speed. Torque control is used for vertical region in a torque-rotor speed chart. In addition to these, mechanical loads reduction using a drive train damper and exclusion zone on a torque schedule is tried. The NREL 5MW wind turbine control strategy is comprised by the generator torque and blade pitch control. Finally, proposed control system is verified through GH Bladed simulation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.476-483
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• 1999

In this paper, electromagnetic forces acting on the rotor surface of a BLDC motor for hard disk drive are calculated by the finite element field analysis. The frequency characteristics of torque ripple, local force and unbalanced magnetic force as a source of mechanical vibration area analyzed. Ring-type permanent magnets for the brushless DC motor are apt to have different magnetization levels at each pole because of the unbalanced air gap between the magnet surface and the magnetizer fixture during the multi-poles magnetizing process. This paper discusses the effect of the unsymmetric magnetization distribution in the permanent magnet on the brushless DC motor performances. As a result, the unbalanced magnetic force acting on the rotor surface and the torque ripple are examined for the motor with an unsymmetric magnetization distribution, and compared with those of an ideally symmetric motor.