• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.2
• /
• pp.317-324
• /
• 2007

Most conventional hybrid systems using renewable energy sources have been applied for stand-alone operation, but Utility-interface may be an useful and viable option for hybrid systems. Grid-connected operation may have benefits such as reduced losses in power system distribution, utility support in demand side management, and peak load shaving. This paper addresses power control and dynamic performance of a grid-connected PV/wind/BESS hybrid system. At all times the PV way and the wind turbine are individually controlled to generate the maximum energy from given weather conditions. The battery energy storage system (BESS) charges or discharges the battery depending on energy gap between grid invertger generation and production from the PV and wind system. The BESS should be also controlled without too frequently repeated shifts in operation mode, charging or discharging. The grid inverter regulates the generated power injection into the grid. Different control schemes of the grid inverter are presented for different operation modes, which include normal operation, power dispatching, and power smoothing. Simulation results demonstrate that the effectiveness of the proposed power control schemes for the grid-interactive hybrid system.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1102_1103
• /
• 2009

본 논문은 에너지 고갈로 인해 신재생에너지가 대두되는 가운데 독립형 태양광 발전시스템의 PV_Array 선정에 대한 논문이다. 독립형 태양광 발전 시스템만을 이용한 PV_Array 출력을 조정해서 부하에 안정적으로 공급하게 설계하였다. 본 논문에서는 PV_Array 내부 모듈의 개수와 인버터 변환 효율을 조정하였다.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.1
• /
• pp.27-34
• /
• 2023

This study conducted a study on a small-capacity PCS using lithium-ion batteries used in personal mobility. Most of the batteries in Personal Mobility only charge with external chargers and are used only as mobile energy sources. However, this paper aims to charge the battery of PM using PV and system power or to use the charged power as a stand-alone power supply. The developed PCS can be operated as a two-channel battery charger/discharger, a battery charger using solar power, and a stand-alone solar inverter depending on the operation method. The validity of the manufactured small-capacity PCS was verified through experiments.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.23 no.2
• /
• pp.77-85
• /
• 2018

Renewable energy has been increasingly used and widely acclaimed as one of the solutions to rampant environmental problems. Among numerous kinds of renewable sources, the penetration rate of the PV system is relatively higher than that of others due to ease of installation. However, one disadvantage of the PV system is its dependence on weather condition. The PV system is especially critical when it is used for standalone systems because it cannot operate when the power generated from a PV module is not enough. Therefore, PV systems are often used with an energy storage system, such as batteries, to store backup energy when the weather condition is insufficient to supply power to the system. Blackout time can be reduced by increasing the size of the energy storage system, but it is a trade-off with system cost. In this work, optimal sizing of a standalone PV system is proposed to supply power to the system without blackout. The sizing of PV modules and batteries is performed by a simulation based on actual irradiation data collected during the past five years. The Life cycle costing of each system is evaluated to determine an optimal set of PV modules and batteries among several different combinations. The standalone PV system designed by the proposed method can supply power to the system with no interruption as long as the weather condition is similar to those of the past five years.

• Advances in Energy Research
• /
• v.7 no.1
• /
• pp.67-84
• /
• 2020

Given the recent surge of interest towards utilization of renewable distributed energy resources (DER), in particular in remote areas, this paper aims at designing an optimal hybrid system in order to supply loads of a village located in Esfarayen, North Khorasan, Iran. This paper illustrates the optimal design procedure of a standalone hybrid system which consists of Wind Turbine Generator (WTG), Photo Voltaic (PV), Diesel-generator, and Battery denoting as the Energy Storage System (ESS). The WTGs and PVs are considered as the main producers since the site's ambient conditions are suitable for such producers. Moreover, batteries are employed to smooth out the variable outputs of these renewable resources. To this end, whenever the available power generation is higher than the demanded amount, the excess energy will be stored in ESS to be injected into the system in the time of insufficient power generation. Since the standalone system is assumed to have no connection to the upstream network, it must be able to supply the loads without any load curtailment. In this regard, a Diesel-Generator can also be integrated to achieve zero loss of load. The optimal hybrid system design problem is a discrete optimization problem that is solved, here, by means of a recently-introduced meta-heuristic optimization algorithm known as Lightning Attachment Procedure Optimization (LAPO). The results are compared to those of some other methods and discussed in detail. The results also show that the total cost of the designed stand-alone system in 25 years is around 92M€ which is much less than the grid-connected system with the total cost of 205M€. In summary, the obtained simulation results demonstrate the effectiveness of the utilized optimization algorithm in finding the best results, and the designed hybrid system in serving the remote loads.

• Proceedings of the KIEE Conference
• /
• 2008.04c
• /
• pp.199-201
• /
• 2008

This paper persents charge/discharge system for small PV using micro-processor. Charge/discharge system designs a Buck converter and using constant voltage charge system because regular voltage is rather high a condenser. Besides, we did compensate for charge voltage of condenser through a temperature compensation circuit. We consists of a 170W stand-alone PV system to observe charge/discharge system character. In the result of search about output character we know that charge and discharge are smoothly running.

• Proceedings of the KIEE Conference
• /
• 2002.11d
• /
• pp.304-308
• /
• 2002

This paper studies stand-alone photovoltaic array for solar lighting lamp. The solar lighting lamp has PV modules, batteries. and charge & discharge system. The charge efficiency is improved for the control of each battery which is divided the charge from the discharge to change the structure of existing solar lighting lamp charge & discharge system. so, the charge and discharge times are reduced of 50%. and the depth of discharge control can be controlled in the discharge cut off voltage. This can be effective of battery use. If a battery is out of order, this system can be executed for a regular period. so we saved the repair cost and developed of system's stabilization. It is possible economical effect to apply for solar lighting lamp used photovoltaic array.

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.10
• /
• pp.1103-1109
• /
• 2013

This paper presents an optimal capacity design of a Hybrid generation system based on economical evaluation for various loads. Optimal sizes of a standalone and grid connection wind- PV hybrid systems were designed for normal, residential and industrial loads using HOMER (Hybrid Optimization Model for Electronic Renewable). Their economical evaluation were performed and compared with a diesel generation system that covers the same loads. The results showed that the stand alone hybrid generation system can be more economical than a diesel generation system for long term operation.

• Journal of Power Electronics
• /
• v.15 no.5
• /
• pp.1318-1328
• /
• 2015

The photovoltaic (PV) power conditioning system for small-scale applications has gained significant interest in the past few decades. However, the standalone mode of operation has been rarely approached. This paper presents a two-stage multi-level micro-inverter topology that considers the different operation modes. A multi-output flyback converter provides both the DC-Link voltage balancing for the multi-level inverter side and maximum power point tracking control in grid connection mode in the PV stage. A modified H-bridge multi-level inverter topology is included for the AC output stage. The multi-level inverter lowers the total harmonic distortion and overall ratings of the power semiconductor switches. The proposed micro-inverter topology can help to decrease the size and cost of the PV system. Transient analysis and controller design of this micro-inverter have been proposed for stand-alone and grid-connected modes. Finally, the system performance was verified using a 120 W hardware prototype.

• Proceedings of the KIPE Conference
• /
• 2017.07a
• /
• pp.68-69
• /
• 2017

본 논문에서는 독립형 태양광 시스템의 설계에서 배터리 용량 선정 방식에 관련하여 부하손실확률(LLP: Loss of Load Probability)이 0 인 기준을 토대로 시스템 무정전 전력공급을 위한 시행 착오법을 제안하였으며 시스템의 수명주기비용(LCC: Life Cycle Cost)을 분석하여 기존 시스템에 비해 경제성을 높이고자 한다. 제안한 방식의 검증을 위하여 시뮬레이션을 수행하였다.