• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.971-982
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• 2015

In order to improve the quality of the billet continuous casting, a two-phase orthogonal power supply (TPOPS) for electromagnetic stirrer is researched, which is composed of three-phase PWM rectifier and three-leg inverter. According to the power analysis of system, the ripple of dc-link voltage is analyzed and its analytical expression is derived. In order to improve the performance of electromagnetic stirring, an integrated control method with feedforward control is proposed for PWM rectifier to suppress the fluctuations of dc-link voltage and provide a stable dc source for inverter. According to the simplified equivalent model, a composite current control method is proposed for inverter. This proposed method can combine the merits of feedforward control with feedback control to effectively improve the dynamic output performance of TPOPS. Finally, a 300kVA prototype of TPOPS is developed, and the results have verified the analysis and control method.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.1
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• pp.77-84
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• 2007

In this paper, Takagi-Sugeno (TS) fuzzy integral control is investigated to regulate the output voltage of an asymmetric half-bridge (AHB) DC/DC converter; First, we model the dynamic characteristics of the AHB DC/DC converter with state-space averaging method and small perturbation at an operating point. After introducing an additional integral state of the output regulation error, we obtain the $5^{th}$-order TS fuzzy model of the AHB DC/DC converter. Second, the concept of the parallel distributed compensation is applied to design the fuzzy integral controller, in which the state feedback gains are obtained by solving the linear matrix inequalities (LMIs). Finally, simulation results are presented to show the performance of the considered design method as the output voltage regulator and compared to the results for which the conventional loop gain method is used.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.1
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• pp.55-62
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• 2008

This paper proposes a feedback linearization control scheme of AC/DC PWM converters with LCL input filters using no damping resisters. This feedback linearization scheme can eliminate the non-linearity of the system. So, the controller of the system can be designed by using linear control theory, which gives a good transient response. The cascade structure of the controller makes the converter current be controlled within a certain limit. To reduce the number of sensors, the source voltage and current is estimated. The validity of the proposed control algorithm is verified by simulation and experimental results.

• Journal of Power Electronics
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• v.10 no.3
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• pp.228-234
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• 2010

This paper investigates the conducted-noise characteristics of a digitally-controlled randomly-switched dc-dc converter. In order to investigate the effect of the suggested digital controller on the conducted-noise characteristics of a dc-dc converter, three factors have been studied: the field-programmable gate array (FPGA) clock speed, the randomization ratio percentage, and the effect of using a closed loop feedback controller. A field-programmable gate array is much more flexible than analog control circuits, has a lower cost, and can be used for power supply applications. A novel FPGA-based implementation has been suggested for obtaining the experimental validations and realizing the studied concepts. Furthermore, the experimental results have been discussed and design guidelines have been included.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.85-87
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• 2009

This paper presents a new PID controller for a DC/DC boost converter model that has a parasitic inductor resistance. In order to maintain the robust output regulation property under load variations the proposed controller is designed by using an additional state variable developed via a parallel-damped passivity-based control approach. Simulation results using Matlab/Simulink SimPowerSystems compare the performances of the proposed controller with a conventional PI controller for reference step changes and load uncertainties.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.3
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• pp.141-146
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• 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 the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.338-343
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• 2006

In this paper, design of current and speed controller for DC motor drive system using dSPACE 1104 system is introduced. Current and speed controller is designed and implemented using MATLAB/SIMULINK program simply and easily, and speed control response of DC motor can be advanced. Current and speed control of DC motor is carried in DSP control board using dSPACE system. Speed feedback is processed through QEP using pulse encorder as speed sensor, and current feedback is processed through A/D converter using hall sensor as current sensor. Controller is designed to PI current controler and PI speed controller. Current and speed response is verified through simulations and experiments.

• Journal of Power Electronics
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• v.11 no.5
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• pp.743-750
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• 2011

This article deals with the sensor-less control of a DC Motor via a SEPIC Converter-Full Bridge combination powered through solar panels. We simultaneously regulate, both, the output voltage of the SEPIC-converter to a value larger than the solar panel output voltage, and the shaft angular velocity, in any of the turning senses, so that it tracks a pre-specified constant reference. The main result of our proposed control scheme is an efficient linear controller obtained via Lyapunov. This controller is based on measurements of the converter currents and voltages, and the DC motor armature current. The control law is derived using an exact stabilization error dynamics model, from which a static linear passive feedback control law is derived. All values of the constant references are parameterized in terms of the equilibrium point of the multivariable system: the SEPIC converter desired output voltage, the solar panel output voltage at its Maximun Power Point (MPP), and the DC motor desired constant angular velocity. The switched control realization of the designed average continuous feedback control law is accomplished by means of a, discrete-valued, Pulse Width Modulation (PWM). Experimental results are presented demonstrating the viability of our proposal.

• 전자공학회논문지 IE
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• v.47 no.3
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• pp.14-18
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• 2010

In this paper, we describe a CMOS DC-DC converter with a variable output voltage(5-7V @100mA) for a portable battery-operated system applications. The proposed DC-DC converter is used along with a Pulse-Frequency Modulation (PFM) method and consists of reference circuit, a feedback resistor, a controller, and an internal oscillator. The integrated DC-DC converter with two external passive components(L,C) has been designed and fabricated on a 0.5um 2-poly 3-metal CMOS process and could be applied to the Personal Digital Assistants(PDA), cellular Phone, Laptop Computer, etc.

• Journal of Advanced Engineering and Technology
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• v.5 no.4
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• pp.349-353
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• 2012

Recently, Mobile multimedia equipments as smart phone and tablet pc requirement is increasing and this market is also being expanded. These mobile equipments require large multi-media function, so more power consumption is required. For these reasons, the needs of power management IC as switching type dc-dc converter and linear regulator have increased. DC-DC buck converter become more important in power management IC because the operating voltage of VLSI system is very low comparing to lithium-ion battery voltage. There are many people to be concerned about digital DC-DC converter without using external passive device recently. Digital controlled DC-DC converter is essential in mobile application to various external circumstance. This paper proposes the DC-DC Buck Converter using the AVR RISC 8-bit micro-processor control. The designed converter receives the input DC 18-30 [V] and the output voltage of DC-DC Converter changes by the feedback circuit using the A/D conversion function. Duty ratio is adjusted to maintain a constant output voltage 12 [V]. Proposed converter using the micro-processor control was compared to a typical boost converter. As a result, the current loss in the proposed converter was reduced about 10.7%. Input voltage and output voltage can be displayed on the LCD display to see the status of the operation.