• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1065-1067
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• 2000

This paper describes performance analysis of ARCP Inverter, which can offer zero voltage switching at nominal voltage stress. The system consists of a voltage-source inverter with sort-switching module. Each main switch is connected in parallel with resonant capacitor and two auxiliary switches are placed in series with a resonant reactor for soft-switching capability. The described ARCP inverter could be effectively applied for active power filter reactive power compensator, and UPS.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.127-132
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• 2000

This paper describes a 3-phase Line-Interactive APF system and analyzes its operating characteristics considering LC Filter output characteristics. Topology of APF is similar to that of Off-Line UPS in the point of parallelly operating inverter system. So it is possible to be multi-functioned active compensating system according to power condition. Likewise this actively operating system from APF to UPS and vice versa is often to be called Line-Interactive system. And more than that Line-Interactive system needs precise design of LC filter on converter output side to make this system fully operate in both APF and UPS modes. The problem in this point is how to design LC Filter to be contented with two different system characteristics so this paper analyzes this problem and proposes its design procedures. Then suggested filter design is verified to be contented by the simulations and experimental results

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.965-968
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• 2003

This paper describes the PWM-VSI controller of three-phase UPS system using stationary reference frame. This controller meets the specification the UPS inverter output voltage even under the unbalanced or nonlinear load. This controller is also constructed with duble control loop of the outer voltage control loop and the inner current control loop. For the fast response of the output voltage control, yhr inner current control loop of the capacitor current os used. To get the good property against overshoot, the If controller us used. The outer voltage controller is designed with P controller and the high gain transfer function is used for the zero steady state error. All control gains of both controller is designed base on the CDM method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.69-77
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• 1998

The uninterruptible power supply (UPS) has become an integral part of modern computer and communication system to assure a continued and stable operation by providing an uninterruptible power to vital equipments. Various control methods have come to the fore in recent times with the advent of high frequency switching technologies. This paper describes the DSP control method for three phase UPS inverter which guarantees the sinusoidal output voltage under nonlinear load conditions. The proposed control scheme is verified by simulation and experiment.riment.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.3
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• pp.240-246
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• 2013

An Uninterruptible Power Supply(UPS) is a system designed to deliver energy during accidents that the AC mains is out of its acceptable limits, without interruption of power flow through the load. Battery Discharger is the device to supply high quality power to the Inverter, when accidents occur, such as Power Failure. The Battery Discharger should have a fast response characteristics. The LLC resonant converter for UPS battery discharger is proposed. The proposed Battery Discharger offers substantial improvements in efficiency, size and cost. The proposed Battery Discharger of UPS approach is a good solution for high power applications above KW. To verify the validity of proposed Battery Discharger, simulations and experiments are carried out.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.163-169
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• 2014

Using the classical cascade voltage control strategy, this paper proposes an analytical solution to an MPC (Model Predictive Control) problem with a hexagonal input constraint set for the inner-loop to regulate the output voltage of the UPS (Uninterruptible Power Supply). Focus is placed on how to deal with the hexagonal input constraint set without any approximation. Following the conventional cascade voltage control strategy, the PI (Proportional-Integral) controller is used in the outer-loop in order to regulate the output voltage. The simulation results illustrate that the capacitor voltage rapidly goes to its reference in a satisfactory manner while keeping other state variables bounded under an unexpected load changes.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.3
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• pp.106-113
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• 1997

In uninterruptible power supply(UPS), a high speed phase control is usually required to compensate transients in the output voltage at the instant of transfer from the ac line to the inverter when the ac line fails or backs to the ac line in case of the inverter fails. To overcome this problem, this paper pre¬sents the closed digital phase-locked loop(DPLL) techniques designed by full software with TMS320C31 digital signal processor and describes the functional operation of the proposed DPLL. Fi¬nally, the performance of the proposed DPLL is shown and discussed through simulation and experiment.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.2 no.2
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• pp.59-63
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• 1988

In a fixed AC power source the PWM techniques were used to vary the voltage and the fundamental frequency. The conventional PWM techniques due to the problem of commutation number and filter size have been studied the PWM output waveforms which applied the motor drive. However in this paper, the carrier frequency with sinusoidal PWM waveform is modulated from 10(KHz) to 45(KHz) using termination devices with high - speed switching capacity and applying LPF(Low Pass Filter) with small capacity to output of inverter and the PAM(Pulse Amplitude Modulation)is obtained. Considering the property of the speed and the control, the sinusoidal PWM control circuit was composed of the microprocessor and analog circuit. In experment result, the system properties are study on the sinusoidal voltage waveform with modulation index changing from 0.6 to 1.0.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.606-608
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• 1996

In this paper, a new control scheme based on deadbeat control with disturbance observer for voltage controlled Inverter system is proposed. The inverter system is modelled as the 4th-order system treating R load current variation caused by disturbance. So the disturbance observer exists in the state observer. By using the pole placement strategy, the observer estimates the state and disturbance variable of the next sampling instant. Simulation results so show that The proposed scheme has robust feature against disturbance.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.151-154
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• 2001

In this paper, a two-level switching algorithm of the deadbeat to control PWM inverter is proposed. A modified algorithm of the deadbeat is suitable for the UPS system. Two levels in the pulse pattern are used. This scheme allows the use of higher switching frequency for a given computation time delay, which results in lower total harmonic distortion at the output. The proposed control scheme is implemented using TMS320F240 DSP chip for controlling on inverter.