• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.2
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• pp.216-223
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• 1996

The active power factor control AC/DC converter needs a current loop compensator to obtain better dynamic characteristics and power factor performance, but the optimal design of a current loop compensator is difficult because the AC/DC converter is a nonlinear system having periodically varying poles and zeros. The predictive current control scheme generates a control input using the dynamic equations of the AC/DC converter so that the dynamic of the AC/DC converter is included in the controller and the necessary bandwidth and the gain characteristics of the current control loop are satisfied. And as a result, a compensator becomes unnecessary and the current loop shows the improved current loop characteristics. In this paper, a power factor controller without current loop compensator by adopting a predictive current control scheme is designed and the designed power factor controller is modelled by using a small signal perturbation modelling technique, and simulated to investigate its small signal characteristics. A 200 W power factor control AC/DC converter is built to verify the effectiveness of the proposed power factor controller.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.749-753
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• 2003

This paper presents an output voltage regulation system using PWM Buck-Boost AC-AC converter for power qualify improvement of custom power. This paper proposes dynamic modeling of the system for control object and in addition, a controller design example. Therefore, system state equation is derived whereby the transfer function could be obtained. The paper shows a regulation controller for tracking the output voltage to the reference under specific operating point. Finally, this paper shows validity and practical applicability of the proposed modelling and system design by experimental results.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1634-1641
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• 2018

This study focuses on a high-performance direct active and reactive power controller design that is successfully applicable to three-phase pulse width modulation (PWM) AC/DC converters used in renewable distributed energy generation systems. The proposed controller can overcome the sluggish transient dynamic response of conventional controllers to rapid power command changes. Desired active and reactive powers can be thoroughly obtained at the end of each PWM period through a deadbeat solution. The proposed controller achieves an exact nonlinear cross-coupling decoupling of system power without using a predefined switching table or bang/bang hysteresis control. A graphical and analytical analysis that naturally leads to a control voltage vector selection is provided to confirm the finding. The proposed control strategy is evaluated on a 3 kW PWM AC/DC converter in the simulation and experiment.

• Journal of Power Electronics
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• v.10 no.3
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• pp.306-312
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• 2010

In this paper, the design of an optimum single input Fuzzy controller for application in dc to ac converters is presented. Contrary to conventional Fuzzy controllers, the proposed controller has a smaller number of rules and tuning parameters but is capable of performing identically to a conventional controller. These benefits lead to a simpler controller design. The controller is designed as a PI controller for small-signal disturbances. However, for optimum large-signal performance, heuristic tuning is used. The tuning is less complicated and hence optimum large-signal performance is achievable. The system is simulated and a hardware prototype was developed for comparison purposes.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.311-314
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• 1999

This paper presents the design method of a repetitive controller to educe the harmonics in the output voltage waveform of the AC power supply systems. Output voltage error under the nonlinear load like a rectifier is cyclic with the same period to fundamental wave, therefore one can design the repetitive controller calculating cycle by cycle. The controller is verified mathematically and by simulations.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.61-62
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• 2016

It is the general trend that AC/DC power system topologies with various sources and loads. To control the AC/DC power system, different kind of control system are needed. This paper discusses the parallel operation of single-phase AC/DC converters using a proportional integral (PI) controller and a proportional resonant (PR) controller. The performance of PI and PR controller have been evaluated by simulation.

• Journal of Power Electronics
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• v.9 no.1
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• pp.124-131
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• 2009

This paper presents a PWM dc-ac converter regulation using a Single Input Fuzzy PI Controller (SIFPIC). The SIFPIC is derived from the signed distanced method, which is a simplification of a conventional fuzzy controller. The simplification results in a one-dimensional rule table, that allows its control surface to be approximated by a piecewise linear relationship. The controller multi-loop structure is comprised of an outer voltage and an inner current feedback loop. To verify the performance of the SIFPIC, a low power PWM dc-ac converter prototype is constructed and the proposed control algorithm is implemented. The experimental results show that the SIFPIC performance is comparable to a conventional Fuzzy PI controller, but with a much reduced computation time.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.177-181
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• 2004

In this paper design of speed controller for AC servo system by rapid design system(RG-01D) using DSP of Realgain company is introduced. 'AC Servo-Designer' system, including CEMTool/SIMTool S/W, RG-DSPIO board, AC servo driver and AUTOTool program, is used in this research. Because 'AC Servo-Designer' system can use SIMTool blocks to design and implement various controller in short time, speed controller for AC servo system is easily designed and implemented according to control objectives.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.4
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• pp.177-182
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• 2003

We have proposed the dimming controller using the AC chopper technique. The AC chopper changes the amplitude of the input source voltage with the same frequency. The conventional dimming controller is operated by controlling voltage phase with the triac. It has bad characteristics of the input current THD and the input power factor But the dimming controller using the ac chopper technique has a low current THD and a good power factor. The developed dimming controller is consist of the IGBT and the low pass filter. The system is operated by the variation circuit of the input source voltage and the microprocessor.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.4
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• pp.177-177
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• 2003

We have proposed the dimming controller using the AC chopper technique. The AC chopper changes the amplitude of the input source voltage with the same frequency. The conventional dimming controller is operated by controlling voltage phase with the triac. It has bad characteristics of the input current THD and the input power factor But the dimming controller using the ac chopper technique has a low current THD and a good power factor. The developed dimming controller is consist of the IGBT and the low pass filter. The system is operated by the variation circuit of the input source voltage and the microprocessor.