Byung-Yeol Bae

Line-Interactive Single-Phase Dynamic Voltage Restorer With Novel Sag Detection Algorithm

This paper describes the development of a line-interactive single-phase dynamic voltage restorer (DVR) with a novel sag detection algorithm. The developed detection algorithm has a hybrid structure composed of an instantaneous detection part and the root-mean-square (rms) variation detection part. The source voltage passes through the instantaneous sag detection part. If instantaneous sag is detected, the rms variation detector-1 is selected to calculate the rms variation. The rms variation detector-2 is selected when the instantaneous sag occurs under the operation of the rms variation detector-1. The feasibility of proposed algorithm was verified through computer simulations and experimental works with a 3-kVA-rating prototype of line-interactive DVR. The line-interactive DVR with the proposed algorithm can compensate the input voltage sag or interruption within 2.0-ms delay. The developed DVR can be effectively utilized for the sensitive loads, such as a computer, communication device, and automation device.

Novel Sag Detection Method for Line-Interactive Dynamic Voltage Restorer

This letter proposes a novel sag detection method for the line-interactive dynamic voltage restorer (DVR). The DVR with proposed detection method can compensate the voltage sag or interruption within 2-ms delay, which is faster than the existing delay time of 4 ms. The feasibility of proposed method was verified through computer simulations. The DVR with proposed detection method can effectively compensate the voltage sag or interruption for sensitive loads.

Islanding Detection Method for Inverter-based Distributed Generation Systems using a Signal Cross-correlation Scheme

This paper describes the development of a new islanding detection method for inverter-based distributed generation systems, which uses a signal cross-correlation scheme between the injected reactive current and the power frequency deviation. The proposed method injects 1% of the reactive current to the rated current which brings about a negligible degradation of the power quality. It discriminates the islanding state, when the calculated cross-correlation index is larger than 0.5. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software and experimental research with a hardware prototype. The proposed method can detect the islanding state without degrading the power quality at the point of common connection. Further study is required to overcome the cancellation of the injected reactive current from multiple distributed generation units interconnected with the utility grid.

New Reference Generation for a Single-Phase Active Power Filter to Improve Steady State Performance

This paper proposes a new algorithm to generate a reference signal for an active power filter using a sliding-window FFT operation to improve the steady-state performance of the active power filter. In the proposed algorithm the sliding-window FFT operation is applied to the load current to generate the reference value for the compensating current. The magnitude and phaseangle for each order of harmonics are respectively averaged for 14 periods. Furthermore, the phase-angle delay for each order of harmonics passing through the controller is corrected in advance to improve the compensation performance. The steady-state and transient performance of the proposed algorithm was verified through computer simulations and experimental work with a hardware prototype. A single-phase active power filter with the proposed algorithm can offer a reduction in THD from 75% to 4% when it is applied to a non-linear load composed of a diode bridge and a RC circuit. The active power filter with the proposed reference generation method shows accurate harmonic compensation performance compared with previously developed methods, in which the THD of source current is higher than 5%.

Novel 3-phase phase-locked loop composed of adaptive linear combiner

This paper proposes a novel structure of 3-phase phase-locked loop that is composed of adaptive linear combiner and proportional integral control. The operational principle was investigated through theoretical approach. The performance was verified through computer simulations with MATLAB and experimental works with TMS320vc33 digital signal processor board. The 3-phase Phase-Locked Loop shows accurate performance under the voltage disturbances such as sag, harmonics, and phase-angle jump.

Development of high-performance single-phase line-interactive dynamic voltage restorer

This paper describes the development of a high-performance single-phase line-interactive Dynamic voltage Restorer, which is composed of a full-bridge inverter and super- capacitors. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental works with 3 kVA prototype. The developed system can compensate the input voltage sag and interruption within 2 ms, in which the maximum allowable duration of voltage interruption is 2 seconds. It can be effectively used to compensate the voltage interruption in the sensitive load, such as computer, communication equipment, automation equipment, and medical equipment.

Load Simulator with Power Recovery Capability Based on Voltage Source Converter-Inverter Set

This paper proposes a load simulator with power-recovery capability. 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 feeds the energy back to the power source with harmonic compensation. The operation of proposed system was analyzed through simulations with PSCAD/EMTDC, and the feasibility of hardware implementation was confirmed through experimental works with a 20 kVA prototype. The load simulator can save the electric energy that should be consumed to test performance of the power quality compensator and power equipment.

Algorithm for rapid detection of voltage disturbance in dynamic voltage restorer

This paper proposes a high-performance line-interactive DVR which can compensate the voltage interruption within 2 ms. The operational feasibility was verified through computer simulations and experimental works with a 3 kVA prototype. The developed system can compensate the input voltage sag and interruption within 2 ms, in which the maximum allowable duration of voltage interruption is 2 seconds. It can be effectively used to compensate the voltage interruption to the sensitive load, such as computer, communication equipment, automation equipment, and medical equipment.

Novel Structure of 3-Phase Phase-Locked Loop with Stiffness against Disturbances

These instructions provide basic guidelines for preparing papers for the PESC 2006 using desktop publishing software. PLL is a key item of power converter for power quality compensation and power flow control. This paper proposes a novel 3-phase PLL that is composed of ALC and PI controller. The operational principle was investigated through theoretical approach, and the performance was verified through computer simulations with MATLAB and experimental works with TMS320VC33 DSP board. The proposed 3-phase PLL shows accurate performance under the voltage disturbances such as sag, harmonics, and phase-angle jump.