• Journal of IKEEE
• /
• v.18 no.4
• /
• pp.586-592
• /
• 2014

In this paper, high efficiency power management IC(PMIC) with DT-CMOS(Dynamic threshold voltage Complementary MOSFET) switching device is presented. PMIC is controlled PWM control method in order to have high power efficiency at high current level. The DT-CMOS switch with low on-resistance is designed to decrease conduction loss. The control parts in Buck converter, that is, PWM control circuit consist of a saw-tooth generator, a band-gap reference(BGR) circuit, an error amplifier, comparator circuit, compensation circuit, and control block. The saw-tooth generator is made to have 1.2MHz oscillation frequency and full range of output swing from supply voltage(3.3V) to ground. The comparator is designed with two stage OP amplifier. And the error amplifier has 70dB DC gain and $64^{\circ}$ phase margin. DC-DC converter, based on current mode PWM control circuits and low on-resistance switching device, achieved the high efficiency nearly 96% at 100mA output current. And Buck converter is designed along LDO in standby mode which fewer than 1mA for high efficiency. Also, this paper proposes two protection circuit in order to ensure the reliability.

• International Journal of Control, Automation, and Systems
• /
• v.6 no.5
• /
• pp.670-676
• /
• 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
• /
• v.56 no.3
• /
• pp.524-530
• /
• 2007

This paper presents a new and simple method for sensorless operation of matrix converter drives using a constant air-gap flux and the imaginary power flowing to the motor. To improve low-speed sensorless performance, the non-linearities of a matrix converter drive such as commutation delays, turn-on and turn-off times of switching devices, and on-state switching device voltage drop are modelled using PQR transformation and compensated using a reference power control scheme. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system. Experimental results are shown to illustrate the feasibility of the proposed strategy.

• Proceedings of the KIPE Conference
• /
• 2001.12a
• /
• pp.129-132
• /
• 2001

Recently, a ZVT boost converter is embedded in a power factor correction system. The control circuit of the converter assures soft-switching for all the MOSFETs and load regulation. The PFC system contains additional control circuits which assure the input voltage in a sinusoidal form and feed-forward line voltage regulation. In this paper, a soft switching boost converter with zero-voltage transition(ZVT) main switch using zero-current switching(ZCS) auxiliary switch is proposed. Operating intervals of the converter are persented and analyzed. The proposed results show that the main switch maintains UT while auxiliary switch retains ZCS for the complete specified line and load conditions.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.17 no.4
• /
• pp.281-290
• /
• 2012

This paper describes a Cross-regulation characteristics of a multi-output LLC resonant converter widely used in consumer electronics. The output characteristics of the multi-output LLC converter is derived from the assumption that the current and voltage in the resonant network is sinusoidal and the duty loss exists. The simulation and experimental results are provided to verify the theoretic results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.7
• /
• pp.32-39
• /
• 2011

FPS(Filament Power Supply), one of the KSTAR NBI(Neutral Beam Injections) is implemented by full-bridge DC/DC converter. NBI heating device for KSTAR(1.5MW) is developed for heating an ion source of plasma in KSTAR tokmak. The full-bridge DC/DC converter is applied to FPS for isolation with input and output. And FPS is operated with PWM control method which is the most usual method. In this paper, NBI FPS of 4.8kW is simulated by using the PSIM 6.0. And the full-bridge DC/DC converter using IGBTs is fabricated to demonstrate it. The processor DSP 28335 is implemented for digital control.

• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.110-113
• /
• 1993

The MOSFET synchronous rectification in the Active-Clamp Forward converter is presented. The Active-Clamp Forward converter has little dead time during the off time of the main switch and it is suitable for the MOSFET synchronous rectification comparing to the other Forward converter topologics. Using the MOSFET synchronous rectification on the Active-Clamp Forward converter with 3.3[V] output and 500[kHz] switching frequency, the improvement of efficiency is achieved comparing with the conventional Schottky barrier diode rectification.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.914-919
• /
• 1998

A Capacitor Commutated Converter (CCC) has less difficulty of commutation failure in comparison to the conventional line commutated converter. This paper proposes the Ar1R control of the CCC in the inverter operation, which deserves as the Ar1R of the conventional converter. The CCC can be operated in high power factor area by using the proposing Ar1R control. The voltage stability at an AC bus connected the CCC inverter is investigated and estimated its ability of preventing the AC voltage collapse. To estimate the voltage stability, this paper developed the simplified converter mathematical model and led the VSF index. The results shows that the AC voltage stability is guaranteed and enables the interconnection to an weak AC system, when compensation factor of the compensation capacitor is higher than 200%.

• Proceedings of the KIEE Conference
• /
• 1999.11b
• /
• pp.364-368
• /
• 1999

This paper suggests switching regulator technique to overcome the drawback of conventional variable linear power supply. Switching regulator technique can eliminate the extremely lossy operation and reduce the size and weight of variable linear power supply and provide nearly constant output power over the majority of output voltage range. The topology of variable switched mode power supply is employed active clamp forward converter with a current doubler rectifier and by using control of variable-frequency together with control of fixed-frequency, output voltage can be controled. Equivalent circuits pertinent to each operational mode of converter are derived, and an experimental 20V, 50A converter was designed and built. The converter operates from an output voltage of zero to 25 V, under 100 kHz switching frequency.

• Proceedings of the KSR Conference
• /
• 1999.05a
• /
• pp.322-327
• /
• 1999

In most railway vehicle applications, a single phase AC/DC converter is used greatly and is essential equipment for Korea High Speed Train. A diode bridge rectifier and a phase-controlled thyristor bridge rectifier generate harmonics in power system. Nowadays, power factor and harmonics become major issue in electrical equipment for railway vehicle. Many researchers have been trying to improve the power factor and ac-side harmonics. Therefore the PWM converter is used to operate at unity Power factor and to reduce ac-side current harmonics. This paper describes the circuit for AC/DC PWM converter of Korea High Speed Train and proposes control algorithm to realize the sinusolidal input current waveform and the effective unity power factor. The validity of the proposed control method is verified through the experimental result.