• Journal of the Korean Society for Railway
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• v.2 no.4
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• pp.32-39
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• 1999

A flywheel system which can compensate electric power is presented. The designed system has a capability of providing real and imaginary power instantaneously as well as storing energy. In this paper, a control algorithm is designed. The designed algorithm is to control the secondary side current of the wound rotor induction motor using voltage-based PWM inverter. The flywheel system has advantages in converter size and power quality improvement comparing to the conventional system.

• Journal of Power Electronics
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• v.9 no.3
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• pp.410-417
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• 2009

This paper represents a design and implementation of a digital controller for a multi-phase synchronous buck converter (SBC) using a digital signal processor (DSP). The multi-phase SBC has generally been used for a voltage regulation module (VRM) of a microprocessor because of its high current handling capability at a low output voltage. The VRM requires high control performance of tight output regulation, high slew rate, and load sharing capability of multiple converters. In order to achieve these requirements, the design and implementation of a digital control system for a multi-phase SBC are presented in this paper. The digital PWM generation, current sensing, and voltage and current controller using a DSP TMS320F2812 are considered. The experimental results are provided to show the validity of the implemented digital control system.

• Proceedings of the KIPE Conference
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• 2004.11a
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• pp.76-80
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• 2004

This paper describes a load simulator with power-recovery capability, which is based on the voltage source converter-inverter set. The load simulator described in this paper can save the electric energy that should be consumed to test the operation and performance of the distributed generation system and the power quality compensator. The load simulator consists of a converter-inverter set with a DSP controller for system control and PWM pulse generation. The converter operates as a universal load to model the linear load and the non-linear load, while the inverter feed the energy back to the power source with harmonic compensation. The load simulator can be widely used in the lab to test the performance of the distributed generation system and the power quality compensator.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.572-578
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• 2008

As the railway transportation is getting faster and its operation speed has increased rapidly, its signal control has been complicated. For real time signal processing it is very important to prohibit any critical error from causing the system to malfunction. Therefore, handling complicated signals effectively while maintaining fault-tolerance capability is highly expected in modern railway transportation industry. In this paper, we suggest an SoC (Sytem-on-Chip) design method to integrate these complicated signal controlling mechanism with fault tolerant capability in a single chip. We propose an SoC solution which contains a high performance 32-bit embedded processor, digital filters and a PWM unit inside a single chip to implement ATO's, ATC's, ATP's and ATS's digital signal-processing units. We achieve an enhanced reliability against the calculation error by adding fault tolerance features to ensure the stability of each module.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.4
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• pp.181-187
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• 2005

This paper describes a load simulator with power-recovery capability, which is based on the voltage source converter-inverter set. The load simulator described in this paper can save the electric energy that should be consumed to test the operation and performance of the distributed generation system and the power quality compensator. The load simulator consists of a converter-inverter set with a DSP controller for system control and PWM pulse generation. The converter operates as a universal load to model the linear load and the non-linear load, while the inverter feed the energy back to the power source with harmonic compensation. The load simulator can be widely used in the lab to test the performance of the distributed generation system and the power quality compensator.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.274-282
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• 2013

In this paper, a linear motor stroke controller using a phase lag filter and a single phase PWM inverter with a current controller has been implemented. In order to control the cooling capability of a refrigerator or an air conditioner in which linear compressors are applied, the piston speed should be controlled. The piston speed control can be obtained by adjusting the frequency or the stroke of linear motors. Generally, the frequency is fixed, for example, as 60Hz and the stroke is adjusted. The dynamic performance of linear compressors depends on how accurately the stroke or the piston position is controlled by the current applied. A linear motor piston position controller with a current control loop is proposed and verified via some simulation studies.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.1
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• pp.75-85
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• 2010

In this paper, a Z-source hybrid active power filter is proposed to compensate the harmonics and reactive power in power distribution system. The proposed system is composed of a 7th harmonics-tuned passive filter and an active power filter with a Z-source inverter topology, while voltage source PWM inverter or current source PWM inverter are applied as the power converter topology of conventional active power filters. The Z-source impedance network along with shoot through capability would ensure a constant DC voltage across the DC link. A polymer electrolyte membrane fuel cell is employed as an compensation DC energy source of the proposed system and its equivalent R-L-C circuit is modeled for simulation. As the compensation and control algorithm of the proposed system, the current synchronous detection algorithm is applied. The simulation analysis by PSIM is performed under the three-phase 220V/60Hz voltage source and 25A nonlinear diode loads. The effectiveness of the proposed the system is verified in the steady and transient states.

• Journal of IKEEE
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• v.14 no.2
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• pp.82-89
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• 2010

In this paper, a buck-boost converter using three DTMOS(Dynamic Threshold Voltage MOSFET) switching devices is presented. The efficiency of the proposed converter is higher than that of conventional buck-boost converter. DTMOS with low on-resistance is designed to decrease conduction loss. The threshold voltage of DTMOS drops as the gate voltage increases, resulting in a much higher current handling capability than standard MOSFET. In order to improve the power efficiency at the high current level, the proposed converter is controlled with PWM(pulse width modulation) method. The converter has maximum output current 300mA, input voltage 3.3V, output voltage from 700mV to 12V, 1.2MHz oscillation frequency, and maximum efficiency 90%. Moreover, the LDO(low drop-out) is designed to increase the converting efficiency at the standby mode below 1mA.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1654-1663
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• 2015

Compared to LC resonance, LCL resonance has distinct advantages such as a large resonant capability, low voltage and current stresses of the power device, constant voltage or current output characteristics, and fault-tolerance capability. Thus, LCL resonant compensation is employed for a movable Inductive Contactless Power Transfer (ICPT) system with a multi-load in this paper, which achieves constant current output characteristics. Peculiarly, the primary side adopts a much larger compensation inductor than the primary leakage inductor to lower the reactive power, reduce the input current ripple, generate a large current in the primary side, and realize soft-switching. Furthermore, this paper proposes an approximate resonant point for large inductor-ratio LCL resonant compensation through fundamental wave analysis. In addition, the PWM control strategy is used for this system to achieve constant current output characteristics. Finally, an experimental platform is built, whose secondary E-Type coils can ride and move on a primary rail. Simulations and experiments are conducted to verify the effectiveness and accuracy of both the theory and the design method.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.860-865
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• 2003

Recently, SRMs are used in automobiles for power assistant steering, accessory motion control and traction drives. Especially in the motion control and traction drives, safety and efficiency are of paramount important. The paper describes the essential elements, faced in designing and constructing drive circuits for a switched reluctance motor for automobiles. These converters will be referred to as energy efficient C-dump converter and modified C-dump converter Energy efficient C-dump converter topology eliminate all the disadvantages of the C-dump converter without sacrificing its attractive features, and also provide some additional advantages that have lower number of power devices, full regenerative capability, free-wheeling in chopping or PWM mode, simple control strategy, and faster demagnetization during commutation. The experiments are peformed to verify the capability of proposed control method on 6/4 salient type SRM.