• International Journal of Control, Automation, and Systems
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• v.6 no.5
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• pp.670-676
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• 2008

While the matrix converter has many advantages that include bi-directional power flow, a size reduction, a long lifetime, and sinusoidal input currents, it is vulnerable to the input voltage disturbances, because it directly exchanges the input voltage to the output voltage. So, in this paper, a critical evaluation of the effect of various abnormal voltage conditions like unbalanced power supply, balanced non-sinusoidal power supply, input voltage sags and short time blackout of power supply on matrix converter fed induction motor drives is presented. The operation under various abnormal conditions has been analyzed. For this, a 230V, 250VA three phase to three phase matrix converter (MC) fed induction motor drive prototype is implemented using DSP based controller and tests have been carried out to evaluate and improve the stability of system under typical abnormal conditions. Digital storage oscilloscope & power quality analyzer are used for experimental observations.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1721-1724
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• 2017

This paper presents a numerical optimization technique to reduce input current and torque ripple of the low voltage BLDC motor using core, coil and switching angle optimization. The optimization technique is employed using the generalized response surface method(RSM) and sampling minimization technique with FEM. A 50W 24V BLDC motor is used to verify the proposed algorithm. As optimizing results, the input current is reduced from 2.46 to 2.11[A], and the input power is reduced from 59 [W] to 51 [W] at the speed of 1000 [rpm]. Also, applied the same optimization algorithm, the torque ripple is reduced about 7.4 %. It is confirmed that the proposed technique is a reasonably useful tool to reduce the consuming current and torque ripple of the low voltage BLDC motor for a compact and efficient design.

• Transactions on Electrical and Electronic Materials
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• v.10 no.5
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• pp.156-160
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• 2009

In an ultrasonic motor, a piezoelectric ceramic material forms the active element which vibrates the stator, thus initiating the rotational motion. In the operation of ultrasonic motors, many factors exist that can affect the resonance characteristics of the piezoelectric ceramic component. For examples, these factors are the bonding conditions with the piezoelectric element, the magnitude of the input voltage, the normal force in the frictional drive and the emission of heat due to vibration and friction etc. Therefore, it is important to research properly the inclination for variation of piezoelectric ceramics in the circumstance where complex elements are involved. In this paper, we focus on the analysis of the resonance characteristics of an ultrasonic motor as a function of the magnitude of the input voltage and the normal force.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.392-396
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• 1994

A method which improves the efficiency of induction motor by controlling the input voltage by the three phase AC voltage controller is studied at the sides of theory and practice. At first, the principle of decreasing the input power and improving the efficiency by adjusting the amplitude of the input voltage according to the load rate is shown. Secondarily, the mathematical model of the three phase AC voltage controller-induction motor system is drived to translate the dynamic characteristics. The validity of the dynamic model is verified by simulation. The new driving method is also proposed, which regulates the rated speed's driving by the speed estimation from the firing angle and the magnitude reverse induced-voltage information. As a result, the digital control system is constructed. Expermintal results show desirable characteristics of proposed system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.305-306
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• 2008

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.4
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• pp.419-424
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• 2012

This paper presents a tubular reciprocating translational motion permanent magnet synchronous motor for percussive drilling applications for offshore oil & gas industry. The motor model and rock model are built up by doing force analysis of the motor and analyzing the physical procesof impact. The optimization of input voltage waveforms to maximize the rate of penetration is done by simulations. The simulation results show that the motor can be utilized in percussive drilling applications and achieve a very large impact force. Simulation results for optimization also show that second harmonic input voltage produces a higher rate of penetration than the sine wave and fourth harmonic input voltages.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.82-93
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• 2006

In this paper, filters are designed to reduce transients overvoltage in inverter fed high-voltage large-capacity induction motor drive system. Design issues for a LCR filter at the inverter output terminals to reduce the dv/dt of the inverter output pulse and a RC filter at the induction motor input terminals to match the characteristic impedance between cable and induction motor are examined in detail. These filters are modeled to be suitable to high-voltage large-capacity induction motor. The performance of the filter is evaluated through simulation using EMTP(ElectroMagnetic Transients Program). We presented filters that used high voltage large-capacity induction Motor on the basis of this. Effect of the filter is analyzed for variation of the cable length. Characteristics of filters are analyzed to reduce harmonic in voltage waveform of induction motor input terminal. The switching surge voltage became the major cause to occur the insulation failure by serious voltage stress in the stator winding of induction motor. Filter for to mitigate transients overvoltage presents a required component in drive system of high-voltage large-capacity induction motor. Also, proposed filters are proved through simulation using EMTP.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.665-673
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• 2017

This paper proposes a field weakening control method for operating an induction motor with a variable DC input voltage condition. In the variable DC voltage condition such as a battery, the field weakening method are required for the maximum output power. The conventional field weakening control methods can be used for operating the induction motor over the rated speed in a constant DC-link voltage condition. However, the conventional methods for operating the motor with the variable DC voltage is not suitable for the maximum output power. To overcome this problem, this paper proposes the optimized field weakening control method to extend the operating range of the induction motor with a rated power in a limited thermal and a wide DC input voltage conditions. The optimized d-axis and q-axis current equations are derived according to the field weakening region I and II to extend the operating region. The experimental results are presented to verify the effectiveness of the proposed method.

• KIEE International Transactions on Power Engineering
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• v.5A no.1
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• pp.22-30
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• 2005

The PWM inverter drive may cause an over voltage at the motor terminal, which imposes severe electric stresses on the inter-turn insulation of motor windings. Unlike low-voltage induction motors, high-voltage induction motors have a stator type of form-wound coil for insulation and are insulated to the slot and the coil. So, this paper presents a PWM 3-level inverter, H-Bridge cascaded 7-level inverter and High-voltage induction motor model. It then analyzes the voltage that generates at the input terminal of the high-voltage induction motor fed by each inverter. Also, in order to examine a factor that influences the switching surge voltage, this paper proposes the system equivalent model and performs the case studies using EMTP.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.2
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• pp.145-150
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• 2010

This paper deals with reduction of torque ripple in a brushless DC motor with input voltage control. The commutation torque ripple can be controlled with varying input voltage, but cogging torque is independent on it. So, in this paper a strategy for minimizing torque ripple is proposed by offsetting the cogging torque with deliberate voltage control. The optimal condition is determined with variable voltage levels and advance angles. As results, it is shown that the method causes 63% decrease of torque ripple.