• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.198-206
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• 2017

This paper presents a novel scheme to estimate the rotor position of a single-phase hybrid switched reluctance motor (HSRM). The back-EMF generated by the permanent magnet (PM) field whose performance is motor parameter independent is adopted as an index to achieve the sensorless control. The differential value of back-EMF is calculated by hardware and processed by DSP to capture a fixed rotor position four times for every mechanical cycle. In addition, to accomplish the normal starting of HSRM, the determination method of the turn-off time position at the first electrical cycle is also proposed. In this way, a sensorless operation scheme with adjustable turn on/off angle can be achieved without substantial computation. The experimental verification using a prototype drive system is provided to demonstrate the viability of the proposed position estimation scheme.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.413-417
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• 1998

In order to obtain better performance for a SRM(switched reluctance motor) drive, the commutation from one phase to another must be as fast as possible. In this paper a novel converter for SRM drive is proposed, which can accelerate the turn-off and turn-on time by using two capacitors to form a resonant circuit with the motor inductance. Two capacitors recover rapidly stored energy in the off going phase and establish rapidly the current rising in the on going phase. As a result, the current tail can be shortened and the dwell angle in the positive torque region can be extended. And comparing with the asymmetric converter, this converter has higher energy availability in energy conversion process and less number of switches.

• Journal of Power Electronics
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• v.11 no.3
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• pp.285-293
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• 2011

This paper proposes two SRM driving systems using a variable dc-link voltage controlled by a single-phase inverter. Two SRM converter topologies of a half bridge type and a full bridge type are proposed according to the power circuits of an inverter. The phase current can be controlled by means of a PWM controller at the inverter, and the turn-on/off angle at the phase switches can be controlled by a position sensor at the converter in the drive system. The inverter acts as a peak-current limiter if the transient current exceeds its maximum value. SRMs using the proposed topologies maintain high efficiency due to energy regeneration after the turn-off of power switches. The operational modes of the proposed topologies are verified by simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.654-656
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• 2002

The pole shape. turn-on angle. and turn-off angle are important design factors that largely influence Switched Reluctance Motor' s performance when designing a switched reluctance motor. These design factors must be considered simultaneously because an independent factor restricts the improvement of the switched reluctance motor' s performance. After performing the analysis using nonlinear same characteristic finite element method that contains a operating circuit, the influence upon the torque characteristics was analyzed by the pole shape and the angles. This paper presents the most suitable design value according to input conditions and various speeds. Especially.the most suitable angles were derived from the voltage equation. and an effective design range is showed from the angles.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.87-90
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• 2006

The direct instantaneous torque control (DITC) method is presented in this paper, which enables torque to be generated during all region and instantaneous torque control to be possible. The hysteresis control mode with the compared value between given torque and instantaneous output torque as input is applied in respect region. The output torque function, that is instantaneous output torque with the variation of current and position of rotor, is achieved by experiment. In this control mode the torque subsection function and current control are not needed. The turn on angle with variation of load torque and speed is only selected and turn off angle can be neglected. The validity of method is tested by simulation and experiment.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.99-101
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• 2005

This paper deals with drive characteristics of LSRM according to position detection angle. Position of LSRM detected approximation sensor. Position choose mover of LSRM and inductance. When approved current in each phase by decided position, we made sure current and voltage according to turn-on, turn-off.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.280-283
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• 2004

This paper discribes the design concept, fabrication process and measuring result of 2.5kV Gate Commutated Thyristor devices. Integrated gate commutated thyristors(IGCTs) is the new power semiconductor device used for high power inverter, converter, static var compensator(SVC) etc. Most of the ordinary GTOs(gate turn-off thyristors) are designed as non-punch-through(NPT) concept; i.e. the electric field is reduced to zero within the N-base region. In this paper, we propose transparent anode structure for fast turn-off characteristics. And also, to reach high breakdown voltage, we used 2-stage bevel structure. Bevel angle is very important for high power devices, such as thyristor structure devices. For cathode topology, we designed 430 cathode fingers. Each finger has designed $200{\mu}m$ width and $2600{\mu}m$ length. The breakdown voltage between cathode and anode contact of this fabricated GCT device is 2,715V.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.1
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• pp.11-17
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• 2023

In this study, the correlation analysis between total system error and environmental factor variables was performed to confirm the effect on the performance of the integrated navigation system by various environmental factors. To collect flight data of hybrid vertical take-off and landing UAVs, scenarios including various turning sections and straight sections such as left turn, right turn, turning rate, and path change angle were selected, and environmental data of wind direction, wind speed, temperature, air pressure, and humidity were collected in real time through weather station. As a result of the correlation analysis between the collected flight data and environmental data, it was concluded that the performance of the integrated navigation system by environmental factors within the collected data was not significant affected and was robust.

• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.52-57
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• 2006

In this paper, a new 'impedance sensing' method is described. This method overcomes the shortcomings of the impedance sensing method. According to the new method, sensing voltage pulse is applied to the idle phase in the minimum inductance region and the beginning of the increasing inductance region to detect rotor position. The negative torque produced by the sensing voltage pulse can be neglected in the minimum inductance region and the efficiency of SRM is improved. In the minimum inductance region the back electromotive force (EMF) can be neglected. And in the increasing inductance region the EMF opposes the rise of current in the phase, so the position estimation scheme is reliable. Therefore the new 'impedance sensing' method is sufficiently precise even under the high back EMF effect. The adjustment of turn-on angle and turn-off angle is also easy to be realized. The technique is very useful in applications where cost or size is primary concerns, such as electric bicycle drives. Experimental results are presented to verify the proposed method.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.95-98
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• 2006

This paper proposes high speed SRM drive system for blower with a new 4-level inverter and precise excitation position generator. For the high speed blower, a proper inverter and control method are proposed and the output characteristics are analyzed. In order to get a fast build-up and demagnetization of excitation a current, 4-level inverter system is proposed. The proposed 4-level inverter has additional charge capacitor, power switch and diode in the conventional asymmetric converter. The charged high voltage is supplied to the phase winding for fast current build-up, and demagnetization current is charged to additional capacitor of 4-level inverter. In addition, a precise excitation position generator can reduce turn-on and turn-off angle error according to sampling period of digital control system. The proposed high speed SRM drive system is verified by computer simulation and experimental result.