• Journal of the Korean Society for Railway
• /
• v.15 no.2
• /
• pp.116-121
• /
• 2012

DC/DC switching power converters produce DC output voltages from different DC input sources. The converter is used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The DC/DC converter is composed of a PWM-IC (pulse width modulation integrated circuit) controller, a MOSFET (metal-oxide semi-conductor field-effect transistor), an inductor, capacitors, and resistors, etc. PWM is applied to control and regulate the total output voltage. In this paper, radiation shows the main influence on the changes in the electrical characteristics of comparator, operational amplifier, etc. in PWM-IC. In the PWM-IC operation, the missing pulses, the changes in pulse width, and the changes of the output waveform are studied by the simulation program with integrated circuit emphasis (SPICE) and compared with experiments.

• Journal of Institute of Control, Robotics and Systems
• /
• v.18 no.4
• /
• pp.371-374
• /
• 2012

DC/DC switching power converters produce DC output voltages from different stable DC input sources regulated by a bi-polar transistor. The converters can be used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The voltage mode DC/DC converter is composed of a PWM (Pulse Width Modulation) controller, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an inductor, and capacitors, etc. PWM is applied to control and regulate the total output voltage. It is shown that the output of DC/DC converter depends on the variation of threshold voltage at MOSFET and the variation of pulse width. In the PWM operation, the missing pulses, the changes in pulse width, and a change in the period of the output waveform are studied by SPICE (Simulation Program with Integrated Circuit Emphasis) and experiments.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.28 no.1
• /
• pp.8-14
• /
• 2023

This paper proposes a PFC converter with a double step-up function using an asymmetrical PWM scheme. For the conventional PWM scheme, the input voltage range, which maintains a double step-up function, is limited because the proposed converter has different voltage gains and characteristics when the duty ratio(D) is less than 0.5. The proposed converter has a constant voltage gain regardless of the magnitude of the input voltage and can achieve output voltage balancing by using the asymmetrical PWM scheme. A 1.6-kW prototype of the proposed converter was built and tested to verify the performance.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.288-291
• /
• 2007

Since the residential load is an AC load and the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feedforward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• Proceedings of the KIEE Conference
• /
• 2003.04a
• /
• pp.166-169
• /
• 2003

In this paper, a PWM Buck-Boost AC-AC converter for improvement of power quality of custom power is presented. The PWM Buck-Boost AC-AC converter is modelled by using circuit DQ transformation whereby the design guideline is obtained. Based on the analysis, the converter system is implemented with the design criteria and the experimental results show the validity of modelling and analysis.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.97-100
• /
• 1999

AC to DC single phase PWM converter for traction application requires rated high power and voltage. Therefor, series or parallel operation converters are necessary with considering the limitation of the power device specification. This paper compares the characteristic between two parallel operation of conventional PWM converter and Single phase three level converter about comparison of power circuit, cooling system control method and harmonic current by computer simulation.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.358-361
• /
• 1999

In auxiliary block of high speed train power factor correction and harmonics reduction is very important issue for efficient energy transport. The GTO-equipped PWM converter is used for traction untill resently. But the rising power capability of IGBTs resently allows to build IGBT-equipped PWM converter with a considerably increased switching frequency. This paper presents switching pattern, control method, operation mode and tuned filter to reduce dc link voltage ripple for paralleled converter.

• Proceedings of the KIPE Conference
• /
• 2002.11a
• /
• pp.129-132
• /
• 2002

In this paper, a PWM Buck-Boost AC-AC converter for improvement of power quality of custom power is presented. The PWM Buck-Boost AC-AC converter is modelled by using circuit DQ transformation whereby the both static and dynamic characteristics are analyzed completely. Finally, the converter system is implemented with the design criteria and the experimental results show the validity of modelling and analysis.

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.1015-1019
• /
• 2001

This paper presents a novel three-phase current-fed Pulse Width Modulation converter with switched capacitor type resonant DC link commutation circuit operating PWM pattern strategy under a design consideration of low-pass filter, which can operate on the basis of the principle of zero current soft switching commutation. In the first place, the steady state operating principle of this converter with a new resonant DC link snubber circuit is described in connection with the equivalent operation circuit, together with the practical design procedure of the switched-capacitor type resonant DC link circuit is discussed from a theoretical viewpoint on the basis of a design example for high-power applications. The actively delayed time correction method to compensate distorted currents due to a relatively long resonant commutation time is newly implemented in the open loop control scheme so as to acquire the new optimum PWM pattern. Finally, the experiment of set-up in laboratory system of this converter is concretely demonstrated herein to confirm a zero current soft-switching commutation of this converter. The comparative evaluations between current-fed hard switching PWM and soft-switching PWM converters are carried out from a viewpoint of their PWM converter characteristics.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.404-407
• /
• 2011

This paper presents a design of current mode PWM/PFM DC-DC Boost converter. This DC-DC Boost Converter operates with PWM mode at the heavy loads and with PFM mode at light loads. The DC-DC boost converter is designed with CMOS 0.35${\mu}m$ technology. It operates at 500KHz and can drive a load current up to 600mA. It has a maximum power efficiency of 92.1%. The total chip area is $1300{\mu}m{\times}1070{\mu}m$ including pads. The DC-DC boost converter operates in a wide range of load currents while occupying a small chip area.