• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.5
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• pp.488-493
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• 2005

This paper presents a method of detecting rotor position for single phase Switched Reluctance Motors(SRMs) using a search coil. In the single phase SRM, mainly Hall effect sensors or photo interrupters have been used to detect the rotor position. But these sensors have many disadvantages. In this paper, low cost and robust characteristics of rotor position detection method are focused in order to compensate for disadvantage of existing sensors. Search coils wound around the stator pole are used for detection of the rotor position in single phase SRM. Rotor position detection is achieved through electromotive force patterns induced by time-varying flux linkage in the search coil. The simulation and experimental results are presented to verify the performance of the proposed method in this paper.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.38-44
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• 2019

This paper proposes fingerprint-based positioning methods which can be used in a magnetic resonant wireless power transfer(WPT) system and verifies their performance. A new receiver coil with small orthogonal auxiliary coils is proposed to measure magnetic field signals in three axial directions. The magnitude and phase characteristics of the three-axis electromotive force can be obtained by using the proposed coil. To predict a position with the measured values, we propose a lookup table-based method and linear discriminant analysis-based method. For verification, the proposed methods are applied to predict 75 positions of the 6.78 MHz WPT system, and the performances such as accuracy and computation time are compared.

• Journal of IKEEE
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• v.24 no.4
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• pp.954-960
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• 2020

This paper proposes a speed variable proportional resonant current control method for a single-phase permanent magnet synchronous motor(PMSM). Due to the electromagnetic characteristics of a single-phase PMSM, negative and zero torques are generated in the part corresponding to the phase difference between the stator current and the back electromotive force. In addition, overcurrent limitation is required because of the low stator resistance and inductance in sensorless operation. When using the vector control for current control of single-phase PMSM under these conditions, processes of coordinate transformation, inverse coordinate transformation, and generation of virtual dq-axis components are required. However, the proposed variable speed proportional resonant current control method does not need the coordinate transformation used for AC motors. In this paper, we have confirmed stable maneuverability by using variable proportional resonant current control algorithm, and proposed sensorless control based on a mathematical model of a single-phase PMSM without a position sensor when reaching a constant speed. The usefulness of the current control method was verified through several experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.10
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• pp.955-962
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• 2016

In this paper, we propose a design method for speed controller, current control of a Brushless Direct Current(: BLDC) motor using disturbance rejection techniques. Disturbance assumes a back electromotive force occurring in the electrical system and the variation of the load acting on the rotary shaft from the outside of the motor. And it assumed to be constant during the time interval and the Luenberger's observer design. So that the error of the observer about the system status can converge to zero show how to set the appropriate gain. Further, to stabilize the whole system, and proposes a method for setting the appropriate PI gain control to improve the tracking performance. By applying the proposed controller to 120W BLDC motors were tested for the ability to follow the velocity and current reference. Since the simulation results of the steady state error is within 0.1%, we were able to show the usefulness of the tracking performance of the proposed controller.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.6
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• pp.572-581
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• 2014

A design and control method of DC/DC converter, which can control variable DC-link voltage to drive a fuel cell electric vehicle (FCEV), is proposed in this study. Given that a fuel cell has low-voltage and high-current characteristics, the required voltage for operating motor must be output through the DC/DC boost converter in the system to drive an FCEV. The proposed converter can choose the output voltage of battery or fuel cell in consideration of the driving mode, as well as control DC-link voltage in accordance with the back electromotive force. The switching lag-time to prevent shortage of pulse-width modulation inverter arms makes distorted current waveform caused by voltage distortion. Through this control method, the proposed converter can reduce the output voltage distortion and current ripple of the inverter, thereby reducing the distorted torque. Simulations and experimental results are presented to verify the reliability of the proposed DC/DC converter.

• Korean Journal of Materials Research
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• v.13 no.2
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• pp.115-119
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• 2003

The thick film type sensor having Pt/Na Super Ionic Conductor(NASICON) solid electrolyte/Pt/$Na_2$$SO_4$/Pt catalyst system for $SO_2$gas was fabricated by screen-print method. The phase of Na Super Ionic Conductor solid electrolyte sintered at different temperature of 1050, 1150,$ 1250^{\circ}C$ and for different time of 1.5, 2.5, 3.5 hr were investigated by XRD. The Electromotive Force variation of the sensor with $SO_2$concentrations and operating temperatures were investigated. The major phase of Na Super Ionic Conductor film sintered at 115$0^{\circ}C$ for 3.5 hr was sodium zirconium silicon phosphate($Na_3$Zr$_2$$Si_2$PO$_{12}$). The Nernst's slope of Na Super Ionic Conductor sensor for $SO_2$gas with the variation of concentration from 10 to 100 ppm was 167.14 ㎷/decade at the operating temperature of $500 ^{\circ}C$. The increase of oxygen partial pressure was not affected to the variation of Nernst's slope.e.

• Journal of Aerospace System Engineering
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• v.12 no.3
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• pp.1-8
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• 2018

The fuel pump, which is used for an aircraft, was first developed in Korea through the Civil-Military Dual Components Development Program. The BLDC motor type, which is superior to the DC brush motor when considering efficiency, endurance, and explosive environmental characteristics, was applied to the fuel pump given its capacity and operating condition. The magnetic flux of the permanent magnet was analyzed based on the magnet flux density equation, using the Maxwell equation and the environmental condition. The motor performance, according to the load, was analyzed using the finite element method in order to design validation. The motor assembly was developed by designing the motor drive and the EMI filters. The performance test results of the motor assembly for the fuel boost pump were consistent with the analysis.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.7
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• pp.339-345
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• 2000

This paper deals with the displacement estimation of magnetically suspended simple 1 DOF(degree of freedom) system without the displacement sensor. Inherently electro-magnet for control has two natural feedback loops. One is the transfer function which represents the dependance of the amount of the magnetic flux on the gap displace-ments. The other is the transfer function expressing the properties that the back electromotive force is derived from the time derivative of the magnetic flux. Through these two feedback loops, information about the gap length can be represented by the magnetic flux and the coil current. This means that the gap length can be detected from these two states variables of the electromagnet without a displacements sensor(self-sensing). The displacement can be estimated with the magnetic flux subtracted by the coil current. In this paper we use a balance beam in order to deal with the displacement sensorless estimation of the magnetic bearing system. For the stable estimation of the gap displacements by using the method of self-sensing simple PD controller is used. We first show the mathematical model of the balance beam, and then we show the effectiveness of the current and flux feedback for making stable estimation of the gap displacements for the balance beam. Simulation results show the effectiveness of the current and flux feedback for good estimation of the displacement without using displacement sensor.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.219-225
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• 2014

The purpose of this paper is to control of the low-speed, high-precision PMSM 2-axes pitch/turning. In this paper, apply the PAM-PWM inverter for it. However, The PAM-PWM inverter, control algorithms and hardware is complex. But it is possible to improve the performance in the low-speed operation can reduce the effect of the PWM ripple and Dead Time of inverter by applying suitable DC-bus voltage control. The direct driver PMSM(Permanent Magnet Synchronous Motor) configured to vector control part, PAM control part and the other controller. The vector control part includes PI current, speed control, additional space vector modulation. PAM control part has to have PI voltage controller and P current controller for DC-bus voltage control. Besides, the motor position estimator, the speed estimator and the counter electromotive force and Dead Time Compensation are added. With this arrangement, PMSM was driven with a low pole pitch/turning by performing the current control to the current command or torque command is the paper. As a result, it was possible to minimize the disturbance component that appears in the drive in proportion to the DC voltage magnitude. The use of a hydraulic drive method for a two-axis bubble column is a typical tank. When using the PWM PAM inverter driver is in the turret can be driven by high-precision, low vibration, low noise compared to the hydraulic drive may contribute to the computerization of the turret.

• Journal of Power Electronics
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• v.11 no.3
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• pp.294-303
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• 2011

In this paper an effective five-phase induction motor (IM) and its drive methods are proposed. Due to the additional degrees of freedom, the five-phase IM drive presents unique characteristics for enhancing the torque producing capability of the motor. Also the five-phase motor drives possess many other advantages when compared to traditional three-phase motor drives. Some of these advantages include, reducing the amplitude and increasing the frequency of the torque pulsation, reducing the amplitude of the current without increasing the voltage per phase and increasing the reliability. In order to maximize the torque per ampere, the proposed motor has concentrated winding, the produced back electromotive force (EMF) is almost trapezoidal, and the motor is supplied with the combined sinusoidal plus the third harmonic of the currents. For demonstrating the superior performance of the proposed five-phase IM, the motors are also analyzed on the synchronously rotating reference frame. To supply trapezoidal current waveform and to exclude the effect of the $3^{rd}$ harmonic current, a new control stratagem is proposed. The proposed control method is based on direct torque control (DTC) and rotor flux oriented control (RFOC) of the five-phase IM drives. It is able to reduce the acoustical noise, the torque, the flux, the current, and the speed pulsations during the steady state. The DTC transient merits are preserved, while a better quality steady-state performance is produced in the five phase motor drive for a wide speed range. Experimental results clearly demonstrated a more dynamic steady state performance with the proposed control system.