• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.4
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• pp.185-192
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• 2001

In SRM drive, the ON·OFF angles of each phase switch should be accurately controlled in order to control the torque and speed stably. The accuracy of the switching angles is dependent upon the resolution of the encoder and the sampling period of the microprocessor, that are used to provide the information of the rotor position and to control the SRM power circuit, respectively. However, as the speed increases, the amount of the switching angle deviation from the preset values is also increased. Therefore, the low cost encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper, As a result, a stable high speed SRM drive can be achieved by the high resolution switching angle control and it is verified from the experiments that the proposed encoder the logic controller can be a powerful candidate for the practical low cost SRM drive.

• Journal of Power Electronics
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• v.6 no.4
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• pp.340-346
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• 2006

A high efficiency drive technique for synchronous reluctance motors (SynRM) using a neural network (NN) is presented in this paper. High efficiency drive condition depends on the mathematical model of SynRM. A NN is employed as an adaptive model of SynRM. The proposed high efficiency drive technique does not require an accurate mathematical model of SynRM. Moreover, the proposed method shows robustness against machine parameter variations because the training algorithm of the NN is executed on-line. The usefulness of the proposed method is confirmed through experimentation.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.76-81
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• 2002

In high power motor drive system, the hard-switching topology produces severs switching losses and EMI noises. Also the inverter switching frequency is thus limited because of excessive loss and thermal handling problem. The primary purpose of the proposed works on the induction motor drive system is to develop an advanced soft-switching inverter topology that is most suitable for high power induction motor drive applications. To make the optimal selection EMI comparison of the switching losses presented. To verify the proposed design procedure, detailed simulation analysis with theoretical and experimental approaches have been done using laboratory prototype.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.148-154
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• 2014

This paper describes problems of the sensorless starting of horizontal axis washing machines with direct drive and suggests solution, which was experimentally verified. Horizontal axis washing machines have very difficult conditions for the drive starting, especially at full load. Inertia of the tub and water, torque from the laundry make load torque at starting higher than rated one and sometimes even higher than the maximum torque of the motor, which makes sensorless starting extremely challenging task. This paper suggests modified open-loop starting, where control system is closed shortly after beginning at low speed and rotates the drum until laundry restructuring. To ensure proper work of the sensorless algorithm at low speed additional measures for increasing of the estimation algorithm performance have been taken. These measures include special algorithm for the drive parameters estimation, which has been developed and verified by the experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.5
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• pp.418-426
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• 2016

This paper analyzes the effect of resistance error to the performance of sensorless drive system of surface-mounted permanent magnet synchronous machine (SMPMSM) based on the back-EMF observer. The analysis shows that the bandwidth of the entire sensorless drive system decreased in the low-speed region when using smaller resistance value than the actual one in the back-EMF observer. Even if the back-EMF observer invokes estimation error, the entire sensorless drive system does not make any steady-state position error. These characteristics may have positive effects such as extension of the low speed limit that goes further down in the sensorless drive. The validity of the analysis is verified by the experimental setup comprising the MG set.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.231-233
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• 1991

This paper discribes a study on the switching character of MOS-GTO and the design of gate drive circuit. Chopping power supply converter, synchronious and asyncronious motor speed adjustment, inverter, etc., needs low drive energy "high frequency" switches. To fulfill these need, switches must have rapid switching time and insulated gate control. MOS-GTO structure is well suited to these constraints. The power switch is serial installation of a GTO thyrister and a MOS Transistor. The gate of the GTO is linked to positive pole of the cascode structure via a MOS high voltage transistor and ground via a transient absorber diode. This high performance MOS-GTO assembly considerably increases the strength which facilitate the drive of GTO thyristers.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.57-61
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• 2006

In the single-phase switched reluctance motor (SRM) drive, the required DC source is generally supplied by the circuit consisting of bridge rectifier and large filter capacitor connected with DC line terminal. Due to the large capacity of the capacitor, the charged time of capacitor is very short from the AC source. Lead to the bridge rectifiers draws pulsating current from the AC source side, which results in reduction of power factor and low system efficiency. Therefore a novel single-phase SRM drive system is presented in this paper, which includes drive circuit realizing reduction of torque ripple and improvement of power factor with a novel switching topology. The proposed drive circuit consists of one switching part and diode, which can separate the output of AC/DC rectifier from the large capacitor and supply power to SRM alternately, in order to realize the torque ripple reduction and power factor improvement through the switching scheme. In addition, the validity of the proposed method is tested by some simulations and experiments.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.741-743
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• 2004

In this paper, we describe a Control Element Drive Mechanism(CEDM) operation test using a Power Controller. By testing, we can catch the mechanical and electrical characteristics of CEDM and obtain the information about the improvement of CEDM and the design of CEDM power cabinet. The power controller for CEDM introduced in this paper can input firing angles directly into gate drive circuits of thyristors so that this method can be used to derive the maximum and minimum values of firing angles within available limits for a 3-phase half-wave rectifier. Angle inputs help us understand each coil's response characteristics. Since this power controller generates a serial sequence for CEDM insertion and withdrawal operations, we may judge whether CEDM works correctly as expected or not in each phase of a step movement.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.481-484
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• 2003

A strategy for a torque ripple reduction drive of single-phase SRM with high power factor is proposed. The drive for switched reluctance motor (SRM) is presented to achieve sinusoidal, near unity power factor input current with low torque ripple. The proposed SRM drive has no additional active switch. And a single-stage approach, which combines a DC link capacitor used as dc source and a drive used for driving the motor into one power stage, has a simple structure and low cost. The characteristics and validity of the proposed circuit is discussed in depth through the experimental results.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.48-58
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• 2011

In this paper, an attempt has been made to design the current and speed proportional and integral (PI) regulators of self-commutating current source inverter-fed induction motor drive having capacitors at the machine end and to investigate the transient performance of the same for step changes in reference speed. The mathematical model of the complete drive system is developed in closed loop, and the characteristic equations of the systems are derived using perturbation about steady-state operating point in order to develop the characteristic equations. The D-partition technique is used for finding the stable region in the parametric plane. Frequency scanning technique is used to confirm the stability region. Final selection of the regulator parameters is done by comparing the transient response of the current and speed loops for step variations in reference. The performance of the drive is observed analytically through MATLAB simulation.