• KEPCO Journal on Electric Power and Energy
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• 제7권1호
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• pp.107-114
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• 2021

High penetration of renewable energy generators causes unnecessary investment for power system facilities. Especially with Korean government policies such as Renewable Energy 3020 and Inter-connection support Responsibility of KEPCO for 1 MW DERs, the applications of DER interconnection in distribution system have been increasing. To save the investment, smart control functions for DERs are required and the test bed for the inverters which have not been prepared are necessary to insure DER inter-connection stability. For this, test bed for advanced functions of a smart inverter has been constructed and the tests for necessary functions have been implemented. In this paper, the test bed and environment as well as specifications are introduced and the test results for the validation of the functions are analyzed.

• 전기학회논문지
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• 제56권10호
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• pp.1744-1750
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• 2007

This paper addresses grid interconnection tests of a 3kW transformer-less photovoltaic (PV) inverter to verify the effectiveness of the PV inverter and promote its wide use. The 3kW transformer-less PV inverter, which was equipped with intelligent protection and control system, was manufactured. A hardware test bed was constructed for performance tests of the PV inverter. Control performance and grid protection tests were carried out using the test bed. Test results verify the performance of the power control and grid protection functions of the developed transformer-less PV inverter.

• 전력전자학회논문지
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• 제12권5호
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• pp.424-431
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• 2007

본 논문은 발전소의 이차공기송풍기를 가변 회전수 제어하여 소내 소비 전력을 절감하고 전동기의 직입기동에 의한 스트레스를 줄이기 위하여 실증 적용된 200MW 석탄화력 발전소 순환 유동층 보일러 이차 공기 송풍기 구동용 H-브릿지 멀티레벨 인버터에 관한 것이다. H-브릿지 멀티레벨 인버터는 독립적으로 절연된 직류 부를 갖는 저전압의 단상 인버터(셀 인버터)를 다수 직렬 접속하여 고전압 3상 전압을 출력하는 Cascaded H-브릿지 전압형 인버터이다. 전력연구원은 6.6kV, 1MVA급 인버터 개발, 발전소에 설치, 보일러 점화 전/후 시험 및 계통 병입 후 부하 시험 등을 국내 최초로 성공적으로 완료하였다. 현재 200MW 석탄화력 발전소 이차 공기 송풍기 구동용 인버터는 상업 운전 중에 있다. 본 논문에서는 개발된 H-브릿지 멀티레벨 인버터, 기존 발전 설비와 신규 인버터 시스템의 인터페이스 부분에 해당하는 보일러 DCS(Distributed Control System : 분산 제어 시스템) 로직, 계통 병입 후 시운전 결과에 대하여 상세히 기술하였다.

• KEPCO Journal on Electric Power and Energy
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• 제7권1호
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• pp.101-105
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• 2021

Encouragement of DER from Korean government with several policies boosts DER installation in power system. When the penetration of DER in the grid is getting high, loss of generation with break-away of DER by abnormal grid conditions should be considered, because loss of high generation causes abnormal low frequency and additional operations of protection system. Therefore, KEPCO where is Korean power utility is preparing improvement in regulations for DERs connected to the grid to support abnormal grid conditions such as low and high frequencies or voltages. This is called 'Ride Through' because the requirement is for DER to maintain grid connection during required periods when abnormal grid conditions occur. However, it is not easy to have a test for ride through capability in reality because emulation of abnormal grid conditions is not possible in real power system in operation. Also, it is not easy to have a study on grid effect when ride through capability fails with the same reason. PHILs (Power Hardware In the Loop System) makes it possible to analyze power system and hardware performance at once. Therefore, this paper introduces PHILs test methods and presents verification of ride through capability especially for low voltage grid conditions.

• Journal of Power Electronics
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• 제15권3호
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• pp.830-840
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• 2015

The H-bridge inverter is the fundamental power cell of the cascaded distribution static synchronous compensator (DSTATCOM). Thus, cell reliability is important to the compensation performance and stability of the overall system. The concept of the power electronics building block (PEBB) is an ideal solution for the power cell design. In this paper, an H-bridge inverter-based “plug and play” HPEBB is introduced into the main circuit and the controller to improve the compensation performance and reliability of the device. The section that discusses the main circuit primarily emphasizes the design of electrical parameters, physical structure, and thermal dissipation. The section that presents the controller part focuses on the principle of complex programmable logic device -based universal controller This section also analyzes typical reliability and anti-interference issues. The function and reliability of HPEBB are verified by experiments that are conducted on an HPEBB test-bed and on a 10 kV/± 10 Mvar DSTATCOM industrial prototype.

• 전력전자학회논문지
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• 제17권2호
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• pp.158-165
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• 2012

In this paper, the test bed using three-phase PWM converter connected with single phase inverter in series is set up to configure an active AC electric load. Since the two topologies, three-phase PWM converter and single-phase inverter, can be operated bidirectionally, the system not only re-generates surplus power to grid but also prevents power dissipation. However, the construction of system has a drawback. That is, ripple components two times of inverter operation frequency occur at DC-Link due to cascade connection, it can be cause of three phase unbalance Since the operational characteristic of the active AC electric load, the power frequency entered into the electric load can be varied, and the ripple of DC-Link is changed as well. In this paper, the three-phase PWM converter using a variable notch filter is proposed, and the reduction of three-phase current unbalance is presented. the validity of the proposed PWM converter using a variable notch filter is verified by the simulation and experimental results.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.168-180
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• 2018

In order to achieve the high quality output voltage of single-phase voltage source inverters, in this paper an Adaptive Complementary Sliding Mode Control (ACSMC) is proposed. Firstly, the dynamics model of the single-phase inverter with lumped uncertainty including parameter variations and external disturbances is derived. Then, the conventional Sliding Mode Control (SMC) and Complementary Sliding Mode Control (CSMC) are introduced separately. However, when system parameters vary or external disturbance occurs, the controlling performance such as tracking error, response speed et al. always could not satisfy the requirements based on the SMC and CSMC methods. Consequently, an ACSMC is developed. The ACSMC is composed of a CSMC term, a compensating control term and a filter parameters estimator. The compensating control term is applied to compensate for the system uncertainties, the filter parameters estimator is used for on-line LC parameter estimation by the proposed adaptive law. The adaptive law is derived using the Lyapunov theorem to guarantee the closed-loop stability. In order to decrease the control system cost, an inductor current estimator is developed. Finally, the effectiveness of the proposed controller is validated through Matlab/Simulink and experiments on a prototype single-phase inverter test bed with a TMS320LF28335 DSP. The simulation and experimental results show that compared to the conventional SMC and CSMC, the proposed ACSMC control strategy achieves more excellent performance such as fast transient response, small steady-state error, and low total harmonic distortion no matter under load step change, nonlinear load with inductor parameter variation or external disturbance.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.653-656
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• 2002

This paper presents the development of 15G(Integrate Starter Generator). The ISG is the crank shaft mount type and it is installed at tile flywheel. The wide operating range of ISG requires large constant power speed ratio, good overload performance and high efficiency. High saliency ratio permanent magnet motor is developed for the ISG applications and 500A MOSFET inverter is designed to derive the ISG. The characteristic of developed ISG is investigated using the special test-bed for the 42V PowerNet and the detailed results is presented