• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.764-766
• /
• 1993

A new static var compensator(SVC) system using three-level inverter is proposed for high voltage and high power applications. A general and simple model for the overall system is obtained using circuit DQ-transform and DC and AC analyses are achieved to characterize the open-loop system. Using the proposed model, a new control method which controls both the phase angle and modulation index of switching pattern simultaneously is suggested to provide fast response of SVC system without using independent voltage source. Finally, predicted results are verified by computer simulation.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1537-1539
• /
• 2005

This paper proposes 210[kVA] rated SIV(Static Inverter) system for the TTX(Tilting Train eXpress). The SIV provides power of a fluorescent light in the car, Air-conditioner, and other equipments. To control output voltage it is used voltage control loop for constant voltage control and simultaneously used current control loop for instantaneous control at load changing. The performance of SIV system will be verified by simulation and experimental results.

• Proceedings of the KIEE Conference
• /
• 2000.07e
• /
• pp.136-141
• /
• 2000

This paper proposes the novel control of a static synchronous compensator (STATCOM). This STATCOM system consists of cascade multilevel inverter which employs H-bridge inverter(HBI) The STATCOM system is modeled in the d-q transform matrix. This model is used to design a controller. The selective harmonic elimination method(SHEM) allows to keep the total harmonic distortion (THD) low in the output voltage. The switching method produces the staircase type waveform in cascade multilevel inverter. To balance the DC voltages in HBIs capacitor, the rotated switching scheme is newly proposed in this paper. The proposed control scheme is verified in the simulated results.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.6 no.1
• /
• pp.107-113
• /
• 2001

This paper describes dynamic performance analysis of a STATCOM based on 3-level inverter. Major attention is focused on the controller design for 3-level inverter, including regulator design for voltage sharing across the dc link capacitors. A detailed simulation model was developed with Matlab and a scaled hardware model was built and tested to verify the proposed approach. Both simulation and experimental results confirm that the developed controller can regulate the reactive power. The developed controller could be effectively applied to the actual hardware system for STATCOM.

• Proceedings of the KIEE Conference
• /
• 2002.06a
• /
• pp.9-11
• /
• 2002

These days, electromagnetic radiation noise and switching losses of static converter become harmful. Many resonant inverters with radiation techniques solve their such problems. Auxiliary Resonant Commutated Pole Inverter (ARCP) was proposed. but it has two demerits. In circuit configuration. It isn't constructed by 2 in 1 IGBT modules, Besides, control is complicated because of neutral point voltage control and boost. current control. This paper proposes a new auxiliary resonant inverter which solved two demerits. In addition, it deals efficiency which compared with hard switching inverter and result of separation of power loss

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.6 no.6
• /
• pp.49-57
• /
• 1992

This paper proposes a Intel 8097 single-chip microprocessor based instantaneous voltage control scheme of inverter for UPS(Uninterruptible Power Supply). There microprocessors are used to control the output voltage and frequency of the inverter, the synchronization with by-pass, and the switching of the static switch. And the status and operating conditions of UPS systems is monitored by micro processor. The inverter output voltage is controlled instantaneously with a double regulation loop so that it has very good dynamic response for the varying loads or nonlinear loads as a rectifier. And also, the software and hardware of control system is described. From simulation and experimental results, it is shown that the proposed scheme has very good performance.

• Proceedings of the KIEE Conference
• /
• 2000.11a
• /
• pp.214-216
• /
• 2000

This paper presents an comparative study on the effect of STATCOM and UPFC to the power system static analysis. The effect of STATCOM can be analyzed with PSS/E program which is generally used in power system analysis, while UPFC model for static analysis is not provided yet. Thus, UPFC is equivalently represented as a synchronous condenser and load, while the active and reactive power of the specific transmission line and the voltage of the bus is controlled appropriately. This procedure is implemented by IPLAN which is an external macro program of PSS/E. The simulation results show that UPFC is more effective to control the bus voltage than STATCOM, because UPFC can control not only the bus voltage where the parallel inverter is installed but also the active and reactive power flow in the transmission line where the series inverter is installed.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.909-913
• /
• 1998

Transient and static characteristics of HVDC inverter can be analyzed with various simulation tools. For the optimal filter design, various performance criteria are proposed. In this paper, performance index is calculated based on proposed per phase equivalent circuit. Voltage and harmonic and filter power loss are selected as criteria. Optimization procedure is performed to find optimal passive filter parameters. Dynamic characteristics is also analyzed with proposed equivalent circuit.

• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.767-769
• /
• 1993

A multilevel PWM voltage source inverter, especially five-level one, is introduced to obtain a static var compensator(SVC) as a large scale power, source. In this paper, the three phase SVC is modeled using circuit DQ transformation and completely analyzed. Finally, through the experimental results from 5-kVA SVC, the validity of the analyses and the feasibility of the SVC system are shown for high power applications.

• Proceedings of the KIEE Conference
• /
• 2006.04a
• /
• pp.288-290
• /
• 2006

An efficiency improving method for Uninterruptible Power Supply System(UPS) was developed by using OP-AMP based application circuits such as voltage detection device, current detection device and static switch control device. The efficiency improving algorithm was made by mixing the operating concepts of On-Line type UPS with the operating concepts of Off-Line type UPS. The UPS' inverter does not work if the UPS' output load current is not higher than the low load operating current which is about 0-30(%) of the UPS' output load capacity. The low load operating current is adjustable within the half of the UPS' output load capacity. If the UPS' output load current is rising over than the low load operating current, the UPS' inverter starts working and the inverter output power feeds to the loads of UPS. If UPS' input power breaks out while UPS' inverter does not operate because the load current is low, the inverter starts working within 4(ms) with excessive output voltage which is ${\pm}$8(%) of normal UPS' output voltage. Like these. UPS can continuously feeds power to it's load device and reduce power consumptions.