• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2000년도 전력전자학술대회 논문집
• /
• pp.472-475
• /
• 2000

An balanced tapped inductors using RPPT (Regulated Peak Power Tracking) system is proposed. In the series/parallel PPT system battery charger and discharger are operating complementary. So they both can be combined into a single hardware block. Battery charger and dis-charger share same magnetic cores thus can be reduced core weights.

• Journal of Astronomy and Space Sciences
• /
• 제27권3호
• /
• pp.253-262
• /
• 2010

The electrical power system (EPS) of Korean satellites in low-earth-orbit is designed to achieve energy balance based on a one-orbit mission scenario. This means that the battery has to be fully charged at the end of a one-orbit mission. To provide the maximum solar array (SA) power generation, the peak power tracking (PPT) method has been developed for a spacecraft power system. The PPT is operated by a software algorithm, which tracks the peak power of the SA and ensures the battery is fully charged in one orbit. The EPS should be designed to avoid the stress of electronics in order to handle the main bus power from the SA power. This paper summarizes the results of energy balance to achieve optimal power sizing and the actual trend analysis of EPS performance in orbit. It describes the results of required power for the satellite operation in the worst power conditions at the end-of-life, the methods and input data used in the energy balance, and the case study of energy balance analyses for the normal operation in orbit. Both 10:35 AM and 10:50 AM crossing times are considered, so the power performance in each case is analyzed with the satellite roll maneuver according to the payload operation concept. In addition, the data transmission to the Korea Ground Station during eclipse is investigated at the local-time-ascending-node of 11:00 AM to assess the greatest battery depth-of-discharge in normal operation.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.982-986
• /
• 1998

The peak-power-tracking solar array regulator sensing the inductor current is proposed. Since it uses the inductor current as the solar array output power information, the PPT control scheme can be greatly simplified. The charge controlled two-loop scheme is presented to improve the dynamics due to the inductor current sensing. The comparison between the single-voltage loop controlled system and the two-loop controlled system employing the charge control is presented. This paper also contains the simulation results of that comparison.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
• /
• pp.299-303
• /
• 2011

This paper proposes a novel sensorless maximum power point tracking (11PPT) algorithm for PV systems. The method is based on dividing the operating time into several intervals in which the PV terminals are short circuited in one interval and the calculated short-current of the PV is obtained and used to determine the optimum operating point where the maximum output power can be obtained. The proposed MPPT algorithm has been introduced into a current-controlled boost converter whose duty ratio is controlled to the maintain MPP condition. The same sequence is then repeated regularly capturing the PV maximum power. The main advantage of this method is eliminating the current sensor. Meanwhile, this MPPT algorithm reduces the power oscillations around the peak power point which occurs with perturbation and observation algorithms. In addition, the total cost will decrease by removing the current sensor from the PV side. Finally, simulation results confirm the accuracy of the proposed method.

• Journal of Power Electronics
• /
• 제11권6호
• /
• pp.870-879
• /
• 2011

Regulated peak power tracking (RPPT) systems such as the series structure and the series-parallel structures are commonly used in satellite space power systems. However, these structures process the solar array power or the battery power to the load through two cascaded regulators during one orbit cycle, which reduces the energy transfer efficiency. Also the battery charging time is increased due to placement of converter between the battery and the solar array. In this paper a parallel structure has been proposed which can improve the energy transfer efficiency and the battery charging time for satellite space power RPPT systems. An analogue controller is used to control all of the required functions, such as load voltage regulation and solar array stabilization with maximum power point tracking (MPPT). In order to compare the system efficiency and the battery charging efficiency of the proposed structure with those of a series (conventional) structure and a simplified series-parallel structure, simulations are performed and the results are analyzed using a loss analysis model. The proposed structure charges the battery more quickly when compared to the other two structures. Also the efficiency of the proposed structure has been improved under different modes of solar array operation when compared with the other two structures. To verify the system, experiments are carried out under different modes of solar array operation, including PPT charge, battery discharge, and eclipse and trickle charge.

• 전자공학회논문지B
• /
• 제32B권6호
• /
• pp.932-942
• /
• 1995

A spacecraft power system can be divided into two types : DET system(Direct Energy Transfer system) and PPT system(Peak Power Tracking system). In a DET system employing the regulated bus voltage control method, the battery charger and discharger are widely used for the bus voltage regulation. The battery charger has two different modes of operation. One is the bus voltage regulation mode and the other is the charge current regulation mode. The battery discharger is employed to provide the power when the spacecraft is in the earth's shadow or the sun is eclipsed. The operating mode, charging or discharging, is selected by a power control circuit. In this paper, small-signal dynamic characteristics of battery charging and discharging system are analyzed to facilitate design of control loop for optimum performance. Control loop designs in various operating modes are discussed. Anaylses are verified through experiments.

• Journal of Astronomy and Space Sciences
• /
• 제24권2호
• /
• pp.179-194
• /
• 2007

인공위성 전력계의 설계 및 분석은 위성 전체의 무게, 크기 및 성능을 결정하는 중요 변수로 작용한다. 위성체의 모든 타 부분체들은 전력계 설계의 영향을 받으며 특히 발사체 선정, 열 제어계 설계 및 구조계 설계의 경우 전력계의 성능 및 제한 조건 등 전력계 설계 결과에 매우 큰 영향을 받는다. 이 논문에서는 현재 국내에서 지속적으로 개발되고 있는 저궤도 위성의 전력계 설계를 위한 새로운 프로그램을 소개하고 타 위성의 설계 자료를 이용한 개발된 프로그램의 성능 실험 결과를 기술하였다. 실험 결과 제안된 전력계 설계 프로그램은 전력계 사이징 뿐 아니라 궤도상에서의 전력계 성능을 예측하는데도 사용할 수 있음을 보였다.

• 항공우주기술
• /
• 제1권1호
• /
• pp.72-83
• /
• 2002

본 논문은 다목적실용위성 전력시스템의 초기 설계과정으로, 2000년 11월 ASTRIUM과 KARI에서 진행한 다목적실용위성 2호기 전력시스템의 용량설계와 태양전지 어레이의 설계를 기술하였다. ASTRIUM은 다목적실용위성 2호기 전력시스템의 기본설계를 위하여, ASTRIUM의 기존 위성 프로그램인 CHAMP 위성과 GlobalStar 위성에 적용한 전력설계 개념을 고려하였다. 그러나 전력시스템의 설계는 전력운용 개념, 각 전장품 및 전력원의 특성에 따라 설계가 다르다. 그리고 ASTRIUM사의 전력시스템 운용개념은 다목적실용위성 1호기와 다르며, 전력시스템에 사용한 전력원과 각 전장품의 상이한 특성으로 전력시스템의 설계에 근본적인 차이가 있음을 미리 밝혀둔다. 따라서 본 논문은 2호기의 제안서에 기술된 내용을 중심으로 ASTRIUM과 KARI에서 수행한 2호기 전력시스템의 기본설계를 요약하였다.