Analysis and Design of PV based Energy Storage System with Improved MPPT Algorithm-개선된 MPPT 기법을 적용한 PV 기반 에너지 저장 시스템의 설계와 해석
ABSTRACT
Analysis and Design of PV based Energy Storage System with improved MPPT Algorithm Paeng, Seong Il Department of Electrical Engineering Graduate School of Konkuk University
Research and use of renewable energy is becoming more active due to the demand for reduction of carbon dioxide, which is the main cause of depletion of fossil fuels and global climate change, and regulation of the generation. However, Renewable energy using sunlight or wind power has a problem that it is adversely affecting the system due to irregularity of solar radiation or wind power, or it is difficult to operate efficiently. To overcome this problem, PV ESS (Photovoltaic Energy Storage System), which is used after storing power using a battery, has been actively studied. The operation method and control method of PV ESS linked with solar power generation and ESS are proposed into single phase and three phase in this PhD thesis. In the single phase system, during the daytime, the electric power generated from the photovoltaic power generation is used to supply power to the LED lamp, charge the battery, and transmit power to the grid when surplus power is generated. In the night, the - xii - LED lamp is supplied by the power stored in the battery, and the battery is charged by the grid power in the late night. In the daytime mode, technical improvements in Maximum Power Point Tracking(MPPT) algorithm is proposed for single phase photovoltaic Energy Storage System(PV ESS). The three-phase system performs a power leveling function to improve daytime and nighttime power uneven consumption and a function to level out the irregularities of solar power generation power. Therefore, during the day when the solar power is less than the set power, the battery replenishes the power. In the nighttime, battery power is used to transmit power to the system as much as the set value to be used in the load, and the battery is charged using surplus power of the night time. In case of power failure, three phase PV ESS is used as UPS (Uninterruptable Power Supply) function. This paper will contain two major sections which are briefed below. First, a single phase 3.3kW, 600W PV ESS system is designed and a control algorithm according to operating mode is proposed. And a three phase 15kW PV ESS system is designed and a control algorithm according to operation mode is proposed. Second, the MPPT algorithm is explained and the developed MPPT algorithms is proposed. Second, there are various MPPT algorithms in the paper which are reviewed and new MPPT algorithm based the P&O(Perturb and Observe) method is proposed. The proposed algorithms is carried out in simulation and have been validated in the prototype.
Keyword : Photovoltaic, Energy Storage System, Maximum Power Point Tracking
