• Proceedings of the KIEE Conference
• /
• 2002.04a
• /
• pp.31-33
• /
• 2002

This paper is presents dynamic analysis of slotless PM linear synchronous motor using 3-D analytical method and improvement of controllability using PI control system. In oredr to calculate dynamic characteristic, back-EMF waveform and inductance are caculated by PM's magnetic field and winding's magnetic filed respectively. PMLSM simulated by PI control system.

• Journal of Welding and Joining
• /
• v.31 no.1
• /
• pp.26-32
• /
• 2013

Recently, welding technology of nonferrous metals which were difficult to implement by arc welder has become available through digitalization of arc welding machine. Among them, the welding quality improvement of aluminum welding is very noticeable. These results increase the arc stability by controlling arc current and voltage waveform precisely, and control wire feed speed by synchronizing with arc current which the feed rate of filler wire is controlled by a precise motor control of servomotor and not by a simple constant speed feeding. Not only through the hardware digitalization of arc welding machine but also through advance of software of arc welding, it became possible to implement a certain level of welding quality by a simple operation. These led to CMT welding process implementation which requires low heat input than current arc welding and highly increased the applicability of the aluminum welding.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.10
• /
• pp.50-57
• /
• 1997

A fast tool servo (FTS) for diamond turning improves machining accuracy by quickly compensating relative position errors between the cutter and the workpiece. Therefore, the FTS needs to have large band-width with good tracking performance. Serious hysteresis nonlinearity of PZT actuators used in the FTS, however, deteriorates fast tracking performance. Several types of feedforward hysteresis compensators and feedback controllers are tested to improve tracking performance. Through simulations and experiments, control structure which yields the smallest tracking error is selected. The maximum peak to peak error in tracking a sinusoidal waveform is reduced by one fifth compared to that of a regular PID controller.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.3
• /
• pp.141-146
• /
• 2001

This paper presents a one digital controller two topology PWM DC-DC converter that controls, simultaneously, the separate Buck converter and boost converter with the different specification by using an inexpensive and efficient 8 bit micro-controller. One timer interrupt is used for the detection of output feedback voltage, and other two timer interrupts are used for the generation of PWM waveform for Buck and Boost converter. The control characteristics of one digital controller two topology PWM DC-DC converter is validated by experimental results.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.1 no.3
• /
• pp.360-365
• /
• 2012

Cascaded H-Bridge rectifier (CHBR) is a more attractive solution in traction application for its transformerless structure. Because of the currents of different cells are exactly the same one, it is a challenge job to regulate the voltages of cells with only one current controller. In this paper, a PI-based control scheme is presented to deal with the voltages balance issue in CHBR. To satisfy the demand of rectifier such as unity power factor and regulated output DC voltages, the proposed control scheme consists of two parts. One is for shaping the grid current waveform and regulating the sum of DC-link voltages of all the cells; the other one is for balancing DC-link voltages. The latter is more concerned in this paper and is discussed in detail especially. Simulations and experiments are carried on. The results verified the feasibility and effectiveness of the proposed scheme.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.12
• /
• pp.1807-1812
• /
• 2012

In this paper, the d, q-axis inductance of IPMSM(Interior Permanent Magnet Synchronous Motor) was calculated by the FEA(Finite Element Analysis). And the CVCT(Current Vector Control Test) was performed, and compared with FEA. Therefore the inductance experiment according to the variation of the current phase angle was performed. However, the error was generated in the fundamental wave detection of the voltage and current waveform. So, error has largely effect on the result of computation, it has to note specially. In addition, by using the calculated inductance, the torque calculation was performed and this result was compared through the dynamometer experiment.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.3 no.1
• /
• pp.46-52
• /
• 1998

This paper describes a current-shaping method for the production of constant torque of SRM under the nonlinear magnetic saturation condition. A current detection technique in the inductance increasing region and an approximation technique for modeling of nonlinear inductance profile are adopted. In the proposed system, a single switching angle control and voltage control is used to shape the current waveform for the generation of flat torque at any given load condition. Finally the validity of the proposed method was verified using a constructed 3HP 6/4 SRM.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.1
• /
• pp.263-269
• /
• 2018

In this study, a selective inverter operation between a 2-level voltage source converter (VSC) and a 3-level T-type VSC (3LT VSC) is proposed to improve the efficiency of a 3LT VSC. The 3LT VSC topology, except for its neutral-point switches, has similar operations as that of the 2-level VSC. If an operation mode is changed according to efficiency, the efficiency can be improved because efficiencies of each methods are depending on current and MI (Modulation Index). The proposed method calculates the power losses of the two topologies and operates as the having lower losses. To calculate the losses, the switching and conduction losses based on the operation mode of each topology were analyzed. The controller determined the operation mode of the 2- or 3-level VSC based on the power loss calculated during every cycle. The validity of the proposed control scheme was investigated through simulation and experiments. The waveform and average efficiency of each method were compared.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.48 no.9
• /
• pp.461-466
• /
• 1999

The switched reluctance motor (SRM) would have torque ripple if not operated with an MMF waveform specified for switching angle and phase voltage. This paper describes the robustic control scheme that permits the phase torque to be flat by PLL(Phase Locked Loop) controller. In this control scheme, the locked phase signal of PLL controls the switching dwell angle and it's loop filter signal controls the switching voltage adaptively. Experimental results show that stable dynamic performance is obtained for torque and speed together with low torque ripple on the operation of variable loads.

• Proceedings of the KIPE Conference
• /
• 2007.07a
• /
• pp.293-295
• /
• 2007

This paper proposes a control algorithm for the power supply to maintain the desired output voltage waveform when the instantaneous power failure occurs. The proposed system switches the control mode between the voltage-controlled and the current-controlled modes in the instantaneous power failure. The proposed control method has little steady-state error and good transient response. The validity of the proposed scheme is investigated through simulation and experimental results.