• Journal of Power Electronics
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• v.6 no.4
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• pp.315-321
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• 2006

Switched Reluctance Motors (SRM) have emerged as viable alternatives to other adjustable speed drives such as vector controlled induction motors (VCIM) and permanent magnet brush-less (PMBL) motors due to their simple construction, ease of control, low inertia and higher operating speeds. However, the indispensability of the rotor position sensor in an SRM for its successful operation increases its cost, apart from causing other problems like decreasing its reliability and inability to operate in adverse environmental conditions. In this paper, a new sensorless control scheme for the SRM is advocated. The required fundamental data is obtained by analyzing the SRM using the Finite Elements (FE) package MAXWELL. The drive is studied in both 'with sensor' and 'sensorless' modes and a comparison of the performances, in both cases, is presented for various operating conditions.

• Proceedings of the KIEE Conference
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• summer
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• pp.857-859
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• 2004

This paper presents design of speed control system for slot less air-cored PM linear synchronous motor using space vector PWM. The vector control requires information about rotor position. And we can need to the Hall sensor for sampling current. In order to agree with this purpose, Digital Signal Processor(TMS320F2406A) developed for implementation of a speed Field Oriented Control.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.369-373
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• 2001

Multilevel inverter has attracted great interest in high-voltage high-power field because of its less distorted output. In this paper, a direct torque control (DTC) technique based on a three-level neutral-point-clamped (NPC) inverter is presented. In order to solve the intrinsic neutral-point voltage-balancing problem and to obtain a high performance DTC, a special vector selection method is introduced and the concept of virtual vector is developed. By using the proposed PWM strategy, a MRAS speed sensor-less DTC drive can be achieved without sensing the neutral-point voltage, The strategy can be verified by simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.92-94
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• 2004

This paper presents modeling of dynamic system for slot less air-cored PM linear synchronous motor using space vector PWM. The vector control requires Information about rotor position. And we can need to the Hall sensor for sampling current. In order to agree with this purpose, Digital Signal Processor(TMS320F2406A) developed for implementation of a speed Field Oriented Control.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1273-1275
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• 2005

This paper presents design of speed control system for slot less iron-cored PM linear synchronous motor using space vector PWM. the design must be considered by the useable limits of the DC link voltage and dynamic operating rage as well as the characteristics of design parameters in a point of system. Therefore, in this paper, the permissible operating range of manufactured motor by determination of rate speed and rate thrust according to switching scheme of DC link voltage are offered. The vector control requires information about rotor position. And we can need to the Hall sensor for sampling current. In order to agree with this purpose, Digital Signal Processor(TMS320F240x) developed for implementation of a speed Field Oriented Control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1064-1071
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• 2006

In electric motor coaches, the rolling stocks move by the adhesive effort between rail and driving wheel. Generally, the adhesive effort is defined by the function of both the weight of electric motor coach and the adhesive effort between rails and driving wheel. The characteristics of adhesive effort is strongly affected by the conditions between rails and driving wheel. When the adhesive effort decreases suddenly, the electric motor coach has slip phenomena. This paper proposes a re-adhesion control based on disturbance observer and sensor-less vector control. The numerical simulation and experimental results point out that the proposed readhesion control system has the desired driving wheel torque response for the tested bogie system of electric coach. Based on this estimated adhesive effort, the re-adhesion control is performed to obtain the maximum transfer of the tractive effort.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.91-102
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• 1999

The paper describes a robust adaptive control algorithm for induction motor drive without speed sensor at low speed range. The control algorithm use only current sensors in a space vector pulse width modulation within loop control with rotor speed estimation and voltage source inverter. On-line rotor speed estimation is based on utilizing parallel model reference adaptive control system. MRAC of the modified flux model for flux and rotor speed estimator uses dual-adaptation mechanism, ${\omega}_r$ and ${\omega}_e$ scheme. The estimated flux components in the model can be compensated from the effects of offset errors on pure integrals. It can be compensated to the parameter variations and torque fluctuation with speed estimation in less then 10 rad/sec. In a simulation, the proposed induction motor control algorithm without speed sensor at very low speed range are shown to operate very well in spite of variable rotor time constant and fluctuating load without change the controller parameters. The suggested control strategy and estimation method have been validated by simulation study, and it proposed the designed system for the implementation using TI320C31 DSP/ASIC controller.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.673-676
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• 1993

The field-oriented control of induction motor without speed sensor has been widely studied. This paper proposes the new design method of adaptive sliding observer for induction motor, which include the rotor speed identification together with the rotor flux estimation. The proposed adaptive observer has advantage of their global stability which is developed on some assumption. It is easy to analyse because the identifier is seperated from the controller. Finally, the chattering which is caused by switching is reduced by new control scheme, and the validaity of the adaptive algorithm is verified by simulation.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.358-365
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• 2005

In induction machine drive without a speed sensor, the estimation of the motor flux and speed often becomes deteriorated at low speeds with low back EMF. Our analysis shows that, in addition to the state resistance variation, the estimated value of field orientation angle is often corrupted by accumulative errors from the integration of voltage variables at motor terminals that have low signal/noise ratio at low frequencies. A repetitive loop path of integration in the feedback can amplify this type of error, thus speeding up the degradation process. The control system runs into information starvation due to the loss of correct field orientation. The machine's spiral vectors are controlled only in a reduced dimension in this situation. A novel control scheme is developed to improve the control performance of motor's current, torque and speed at low frequencies. The scheme gains a full-dimensional vector control and is less sensitive to the combined effect of the error sources at the low frequencies. Experimental tests demonstrate promising performances are achievable even below 0.5 Hz.

• Journal of Biosystems Engineering
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• v.33 no.1
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• pp.58-62
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• 2008

The need for position information in agriculture is gradually increasing for precise control farm vehicle and effective manage farm land. Though geomagnetic sensor has a lot of merits in estimating heading angle of vehicle because of low costs and sensing ability of magnetic north, it is easy that sensor outputs are distorted in electro magnetic field environment. This study was conducted to develop geomagnetic compass which could be available in measuring relative position from reference point correcting output distorted by external electro magnetic field in a small scale field. Magnetic inducing sensor (PNI's Vector2X) which wound enamel coated copper coil on ferrite core in order to measure and correct earth magnetic field. Magnetic azimuth was corrected using the algorithm which estimated amount of magnetic distortion from the difference between each outputs of magnetic sensors that located on the cross shaped base. Developed auto-tuning magnetic sensor was showed less then 5% as bearing accuracy in the strong magnetic field.