• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.110-113
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• 2005

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 12/8 SRM is designed and analyzed. In order to get a fast build-up and demagnetization of excitation a current, now 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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.3
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• pp.328-334
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• 1999

A fish pump makes very important roles in an automation system of an aquaculture farm, thus it has been used widely in order to transfer fishes from one place to the other place automatically. In spite of its significant roles, the efforts for developing performance and promoting efficiency of the fish pump are not sufficient yet. In this paper, a method which makes the fish pump automation system is suggested. Automation of the fish pump can be accomplished by using variable voltage and variable frequency inverter system including induction motors. Especially, very simple logic to generate Pulse width Modulation(PWM) wave to control induction motor efficiently and three steps speed control method to regulate liquid quantity of the fish pump simply are suggested. Owing to the simplifies speed control and PWM wave generation technique, a cheaper microprocessor, 80C196KC, than a digital signal Processor(DSP) can be used to operate control algorithm in induction motor systems for real time control Also, a new idea of remote control for the simplifies novel inverter system by Programmable logic Controller(PLC) without special output unit, digital to analog converter(D/A), is suggested in this paper. Consequently the function of reliability, availability and serviceability of the fish pump system are developed. It will be expected to contribute expanding of application of the fish pump in aquaculture farms because the system can reduce energy consumption and some difficulties according to manual operation prominently.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.186-194
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• 1997

In this thesis, a new speed control algorithm based on the load torque observer theory is pro¬posed for the high performance speed control of a voltage source inverter to drive a 3 - phase induction motor. The proposed system becomes robust against disturbances using a feed -- for¬ward control of the load torque estimated at load torque observer. Computer simulation and experimental works using the proposed control confirm that transient response for the varia¬tion ofload torque becomes improved, compared with the conventional PI control method.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.500-503
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• 1997

In this paper, we investigate the control methodology of inverter Airconditioner, using the three dimensional vector scheme. The method of three dimensional vector aims at the determination of optimal switching patterns for PWM to reduce switching loss and to improve the performance supplied voltage. The induction motors are widely used for home Airconditioners. These motors can be classified into two types: on or off control of Airconditioner and the speed control of motor. For speed control of motors, generally PWM methods are used. The PWM method based upon the modulation of triangular wave can not afford to supply line voltage to the motor sufficiently because of the capacity of processing speed of micro processors. Therefore airconditioner can not be operated efficiently. This problem can be solved with the method of three dimensional vector since it can increase the supplied voltage and maximum operating frequency of motor to 173V and 96Hz, respectively. As the result, this method shows 10 - 15% increase of voltage and 10% increase of operating frequency over the modulation of triangular wave. According to a theoretical study, the number of switching in the method of three dimensional vector is smaller than that of the modulation of triangular wave. The power consumption can be reduced and the supplied voltage can be increased. In other words, the efficiency of Airconditioner can be improved. We show that the method of three dimensional vector can supply higher voltage than the modulation of triangular method through the experiments and verify the degree of improvement of efficiency theoretically.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.295-299
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• 2007

This paper presents the photovoltaic(PV) water pumping system with a maximum power point tracking(MPPT). The wale- pumping system uses a variable speed single phase induction motor(SPIM) driven a centrifugal pimp by field oriented control(FOC) inverter. The MPPT using a DC-DC converter controlled the duty cycle to track maximum power from PV under different insolation conditions. The duty cycle directly relate with a flux producing current control($i_{ds}$). The FOC inverter uses a current control voltage source inverter(CC-VSI). The simulation results are shown that the characteristics and performance of drive system, which varies as each conditions of light by expresses in voltage ($V_{dq}$), current($I_{dq}$), speed of motor and torque.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.216-221
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• 2017

In this paper, the converter and traction system of 8200 electric locomotive is modeled using matlab simulation module. And the characteristic was analyzed through simulation of the combined system of converter and inverter for controling 8200 electric locomotive. The validity of the simulation was proved through performing unit power factor control of converter and speed control of inverter.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.3
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• pp.252-255
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• 2014

In the case of long-stator linear drives, unlike rotative drives for which speed or position sensors are a single unit attached to the shaft, these sensors extend along the guideway. The position signal transmitted from maglev vehicle can't meet the need of the real-time propulsion control. In this paper the position estimator for propulsion inverter driving long stator linear synchronous motor (LSLSM) in high speed maglev train is proposed. In order to get the higher resolution of the position information transmitted from vehicle, Full order state observer is proposed for position estimator.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.100-109
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• 2017

This paper proposes performance improvement schemes for sensorless PMSM control drive using a four-switch three-phase inverter (so-called B4 inverter). In the proposed scheme, the back-EMF estimation-based sensorless control algorithm is used to control the brushless PMSM without position sensors. In order to have stable operation, this paper presents a gain adjustment scheme that compensates the reduction of stable sensorless operation range as long as the rotor speed increases. In B4 topology, the center point of dc-link capacitors is connected to 3-phase load, and it is prone to have the load current distortion. Hence, to mitigate this problem, a distortion compensation scheme by modifying voltage commands using measured dc-link potentials is proposed in this paper. The validity of the proposed method is evaluated by simulations and experiments.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.163-167
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• 2014

To prove the vibration and speed error problems caused by the nonlinear friction characteristics and load variation of the hydraulic system, a PID speed controller and a load compensation controller for the hydraulic inverter-fed elevator are proposed. The load compensation controller is composed by the PI controller and the speed controller is composed by the PID controller. The P,I and D gains of the control parameters are obtained by the frequency response of system transfer function. The Effectiveness of the proposed controller are shown by experimental results, which the proposed controller yields robustness with load variations and stable and good speed and acceleration responses with less oscillations.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1264-1273
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• 2015

An inverter output power control based power factor correction (PFC) strategy is being extensively used for permanent magnet synchronous motor (PMSM) drives in appliances because such a strategy can considerably reduce the cost and size of the inverter. In this strategy, PFC circuits are removed and large electrolytic DC-link capacitors are replaced with small film capacitors. In this application, the PMSM d-q axes currents are controlled to produce ripples, the frequency of which is twice that of the AC main voltage, to obtain a high power factor at the AC mains. This process indicates that the PMSM operates under periodic magnetic saturation conditions. This paper proposes a back electromotive-force (back-EMF) estimator for the high-speed sensorless control of PMSM operating under periodic magnetic saturation conditions. The transfer function of the back-EMF estimator is analyzed to examine the effect of the periodic magnetic saturation on the accuracy of the estimated rotor position. A simple compensation method for the estimated position errors caused by the periodic magnetic saturation is also proposed in this paper. The effectiveness of the proposed method is experimentally verified with the use of a PMSM drive for a vacuum cleaner centrifugal fan, wherein the maximum operating speed reaches 30,000 rpm.