• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.26-34
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• 1999

According to increase of nonlinear power electronics equipment, active power filters have been researched and developed for many years to compensate harmonic disturbances and reactive power. However the commercial of active power filter is being proceeded slowly, because the cost of active power filter compared to the passive filter for harmonic and reactive power compensation is expensive. Especially, the use of DSP (Digital Signal Processing) chip, which is frequently used to control 3-phase active power filter, is a factor of increasing the cost of active power filters. On the other hand, the use of only analog controller makes the controller's circuits much more complicate and depreciates the flexibilities of controller. In this paper, a controller with low cost for 5[kVA] 3-phase active power filter system is designed. To reduce the expense of active filter system, the presented controller is composed of digital control part using Intel 80C196KC $\mu$P and analog control part using hysteresis controller for current control. Characteristic analysis of designed controller for active filter system is performed by computer simulation and compensating characteristics of the designed controller are verified by experiment.tegy can apply to the vector control, leading to better output torque capability in the ac motor drive system. This strategy is that in the overmodulation range, the d-axis output current is given a priority to regulate the flux well, instead the q-axis output curent is sacrificed. Therefore, the vector control even in the overmodulation PWM operation can be achieved well. For this purpose, the d-axis output voltage of a current controller to control the flux is conserved. the q-axis output voltage to control the torque is controlled to place the reference voltage vector on the hexagon boundary in case of the overmodulation. The validity of the proposed overall scheme is confirmed by simulation and experiments for a 22[kW] induction motor drive system.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.569-577
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• 2005

In this paper, a new control scheme to use 6-switch IGBI module for 3-phase switched reluctance motors(SRM) is proposed. Compared with the conventional asymmetric bridge converter topology, it can minimize the entire system size and cost. Therefore, it may have a new topology lot SRM to compare the other ac motors, such as induction motors, brushless dc motors, and so on. The validity of the proposed method is verified by simulation, and experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.5
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• pp.384-398
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• 1990

This paper compares and shows the characteristics of various PWM strategies used to generate pulse signals of voltage source inverter. We designed the inverter using PTR and constituted the variable speed drive (VSD) system. For each PWM strategy, acoustic noise level, line-to-line voltage and current waveform, and current harmonic spectrum are measured with respect to the VSD of induction motor. The Suboptimal PWM strategy showed the similar harmonic effects to those of the Optimal PWM strategy. In addition, the microprocessor application was available to the former. The TP PWM strategy was excellent in that it could reduce the CPU load and increase the output voltage since the strategy could control only two phase of the three.