Assessment of massive integration of photovoltaic system considering rechargeable battery in Japan with high time-resolution optimal power generation mix model

Maximizing renewables in the country's power system has been a key political agenda in Japan after the Fukushima nuclear disaster. This paper investigates the potential of PV resource, which could be systematically integrated into the Japanese power system, using a high time-resolution optimal power generation mix model. The model allows us to explicitly consider actual PV and wind output variability in 10-min time resolution for 365 days. Simulation results show that, as PV expands, the growth of PV integration into the grid slows down when the installed PV capacity is more than the scale of the peak demand, although Japan has immense potential of installable PV capacity – equivalent to 40 times of the peak. Secondly, the results imply that a large-scale PV integration potentially decreases the usage ratio of LNG combined cycle (LNGCC) in specific seasons, which is a challenge for utility companies to ensure that LNGCC is used as a profitable compensating generator for PV variability. Finally, a sensitivity analysis on rechargeable battery cost suggests that the reason for suppressing the PV output instead of storing its surplus output by the battery can be attributed to the high battery cost; hence, the improvement of its economic performance is significant to integrate the massive PV energy.     

Peak-power reduction with 100 kW PV and battery combined system at Shonan Institute of Technology

The grid connected 100 kW PV and 345 kWh battery combined system introduced in 1998 at Shonan Institute of Technology has been investigated. The system, equipped with PV and large battery, has a peak cut function against the big surge in electric power consumption in summer as well as working as an emergency electric power source. The daily peak of power consumption during summer occurs at 2:00 p.m. This time does not coincide with the time of peak power generation. The use of the PV/battery combined peak cut function effectively cuts consumption by 7% during the peak consumption period.     

具有APF功能的光伏并网发电系统的研究

探讨了一种具有有源滤波器功能的光伏并网发电系统。该系统白天可有效地进行光伏并网发电,还可补偿或抑制本地非线性负载产生的无功和谐波,夜晚系统仍可作为APF继续工作。相对于单独的光伏并网系统,它不但提高了设备利用率,也改善了电网的供电质量。文章分析了系统的结构组成,还采用了具有较好鲁棒性和动态响应速度的、基于瞬时无功理论的闭环无功和谐波电流检测的方法,分析了并网电流的合成及其跟踪控制。最后,利用Matlab/Simulink对系统进行了仿真,验证了系统的可行性。     

A multi-function grid-connected PV system with reactive power compensation for the grid

According to the theory of instantaneous reactive power, the active and reactive currents of inverter can be regulated by changing the amplitude and the phase of the output voltage of the inverter. Based on this theory, the active power output and the reactive power compensation (RPC) of the system are realized simultaneously at daylight. When the insolation is weak or the PV modules are inoperative at night, the RPC feature of PV system can still be used to improve the utilization factor of the system. The MATLAB simulation results validate the feasibility of the method.     

Investigation on abundant photovoltaic power generated by 40 kW PV system in Wakayama National College of Technology

We investigated the output characteristics of 40 kW photovoltaic (PV) power system installed at Wakayama National College of Technology. The total amount of PV power measured from our 40 kW PV system was 53 431.5 kW h/year. This abundant PV power was attributable to the greater amount of solar radiation and low temperature of the PV module.     

光伏系统蓄电池组不均衡性的故障分析及排除

蓄电池组是光伏系统的重要设备,其故障往往导致光伏系统不能正常运行。光伏系统蓄电池组的故障多数因其不均衡所致。文章分析了蓄电池组因不均衡性导致的故障,提出了故障预防措施和故障排除方法。     

A photovoltaic powered electrolysis converter system with maximum power point tracking control

One of the main problems for renewable and other innovative energy sources is the storage of energy for sustainability. This study focuses on two different scenarios to benefit from solar energy more efficiently. Photovoltaic (PV) energy is converted to the desired voltage level using a buck converter for generating hydrogen with electrolysis process. A maximum power point tracking (MPPT) algorithm is used to benefit from the photovoltaic sources more efficiently. The basic electrolysis load for hydrogen production needs low voltage and high current and controlled sensitively to supply these conditions. The photovoltaic powered buck converter for electrolysis load was simulated in MATLAB/Simulink software using a perturb and observe (P and O) MPPT algorithm and PI controller. The simulation results show that in normal, short circuit and open circuit working conditions the PV and load voltages are stabilized. The efficiency of the proposed system is reached more than 90% for high irradiance levels.     

分布式光伏发电系统最大功率点跟踪技术比较研究

基于当前光伏阵列最大功率点跟踪技术的研究现状,介绍了适用于分布式光伏发电系统最大功率点跟踪的各种常用控制方法,阐述了每一种控制方法的技术原理,分析和比较了这些常用控制方法的特点,总结了各自的优点和缺点,最后对分布式光伏发电系统最大功率点跟踪方法的选择问题进行了探讨,并指出了具体选择方法时应综合考虑的各种因素。     

光伏发电日时段划分增效控制系统

论述了传统光伏控制器的缺点,提出了一种新型光伏控制系统的设计.文章阐述了光伏发电日时段划分增效控制系统的设计思路及实现功能,分析了该系统的硬件设计和工作过程,指出了该增效控制系统的广阔发展前景.     

光伏系统最大功率点跟踪方法

最大功率点跟踪是光伏发电系统中重要的问题.在对太阳电池特性曲线分析的基础之上,阐述了几种常用的光伏系统最大功率点的追踪方法.文章总结并分析了各种方案的优缺点.     

Dynamic model and impact on power quality of large hydro‐photovoltaic power complementary plant

In recent years, with the rapid growth of photovoltaic (PV) power development and utilization, part of the PV power could not be transmitted to the power grid owing to the impact of PV power fluctuation on power quality, leading to a serious PV power rejection in some areas in China. A high‐order model of a hydro‐PV power plant is developed in this paper not only to predict hydropower compensation for PV power fluctuation but also to consider the impact of complementary regulation on power quality. Compared with the existing complementary models, the presented model accurately reveals the effect of water hammer on power quality, low‐frequency power oscillation, and power antiregulation phenomenon during the complementary regulation. Although the complementary control of the hydro‐PV power plant helps to suppress power fluctuation, when the PV power and objective power are negative covariation, the hydropower needs more regulation, which will cause an increase in frequency fluctuation. Moreover, with the increase of the ratio of hydro‐PV power in the power grid, the frequency fluctuation amplitude increases accordingly. Especially, when PV power exceeds the regulation ability of the hydropower, the system frequency deviation will increase rapidly. These problems are worth the attention to the future development of PV power.     

Sizing optimization of grid-independent hybrid photovoltaic/wind power generation system

To allow a real penetration of the huge dispersed naturally renewable resources (wind, sun, etc.) intermittent and more or less easily predictable, optimal sizing of hybrid renewable power generation systems prove to be essential. This paper recommends an optimal sizing model based on iterative technique, to optimize the capacity sizes of different components of hybrid photovoltaic/wind power generation system using a battery bank. The recommended model takes into account the submodels of the hybrid system, the Deficiency of Power Supply Probability (DPSP) and the Levelised Unit Electricity Cost (LUEC). The flow chart of the hybrid optimal sizing model is also illustrated. With this incorporated model, the sizing optimization of grid-independent hybrid PV/wind power generation system can be accomplished technically and economically according to the system reliability requirements. A case study is conducted to analyze one hybrid project, which is designed to supply residential household located in the area of the CDER (Center for Renewable Energy Development) situated in Bouzaréah, Algeria (36^° 48′N, 3^° 1′E, 345 m).     

Effect of high irradiation on photovoltaic power and energy

Solar photovoltaics (PV) is a promising solution to combat against energy crisis and environmental pollution. However, the high manufacturing cost of solar cells along with the huge area required for well‐sized PV power plants are the two major issues for the sustainable expansion of this technology. Concentrator technology is one of the solutions of the abovementioned problem. As concentrating the solar radiation over a single cell is now a proven technology, so attempt has been made in this article to extend this concept over PV module. High irradiation intensity from 1000 to 3000 W/m² has been investigated to measure the power and energy of PV cell. The numerical simulation has been conducted using finite element technique. At 3000 W/m² irradiation, the electrical power increases by about 190 W compared with 63 W at irradiation level of 1000 W/m². At the same time, at 3000 W/m² irradiation, the thermal energy increases by about 996 W compared with 362 W at 1000 W/m² irradiation. Electrical power and thermal energy are enhanced by about 6.4 and 31.3 W, respectively, for each 100‐W/m² increase of solar radiation. The overall energy is increased by about 179.06% with increasing irradiation level from 1000 to 3000 W/m². It is concluded that the effect of high solar radiation using concentrator can significantly improve the overall output of the PV module.     

A comprehensive simulator for assessing the reliability of a photovoltaic panel peak power tracking system

When designing a maximum power point tracking (MPPT) algorithm, it is often difficult to correctly predict, before field testing, the behavior of this MPPT under varying solar irradiation on photovoltaic (PV) panels. A solution to this problem is to design a maximum power point trackers simulator of a PV system used to test MPPT algorithms. This simulator must have the same role as the MPPT card of the PV panel and thus will fully emulate the response of a real MPPT card of the PV panel. Therefore, it is a good substitute to help to test the peak power trackers of the PV system in the laboratory. This paper describes a simple peak power trackers simulator of the PV system which has a short response time thus, can be used to test MPPT algorithms under very rapid variation condition. The obtained results and the theoretical operation confirm the reliability and the superior performance of the proposed model.     

Energy storage-based power buffering control for photovoltaic power generation system

光伏发电系统输出的最大功率随外界环境变化而波动,无法满足负荷的供电需求,针对该问题,建立了基于储能系统的光伏发电系统结构,介绍了光伏发电系统运行原理,分析了系统功率与直流母线电压的关系,设计了无源式储能系统和有源式储能系统对功率进行缓冲以满足控制目标.仿真结果表明,有源式储能系统较无源式储能系统有更好的功率调节作用,通过双向DC-DC变换器的储放能量自动切换控制,使得光伏发电系统输出的功率与负荷需求功率良好匹配,直流电压稳定.     

Analysis of MPPT characteristics in photovoltaic power system

This paper describes characteristics evaluation of the power conditioner which has the function of Maximum Power Point Tracking (MPPT) by “mountain climbing method” through computer simulations. The generated power on the constant voltage control is compared to the one on MPPT with the load matching correction factor (Kpm). In this simulation, the following parameters are chosen, the rate of the voltage ΔV on changing the operating point and of the voltage ΔV_c on checking the maximum point.As a result, the influence of these parameters on Kpm is showed and it is made clear that we should decide the MPPT parameters with care.     

A comparison of hydrogen storage technologies for solar-powered stand-alone power supplies: A photovoltaic system sizing approach

This paper compares the performance of three different solar based technologies for a stand-alone power supply (SAPS) using different methods to address the seasonal variability of solar insolation—(i) photovoltaic (PV) panels with battery storage; (ii) PV panels with electrolyser and hydrogen (_H2)$({\mathrm{H}}_2)$ storage; and (iii) photoelectrolytic (PE) dissociation of water for _H2${\mathrm{H}}_2$ generation and storage. The system size is determined at three different Australian locations with greatly varying latitudes—Darwin (12^°S${12}^{°}\mathrm{S}$), Melbourne (38^°S${38}^{°}\mathrm{S}$) and Macquarie Island (55^°S${55}^{°}\mathrm{S}$). While the PV/electrolyser system requires fewer PV panels compared to the PV/battery scenario due to the seasonal storage ability of _H2${\mathrm{H}}_2$, the final number of PV modules is only marginally less at the highest latitude due to the lower energy recovery efficiency of _H2${\mathrm{H}}_2$ compared to batteries. For the PE technology, an upper limit on the cost of such a system is obtained if it is to be competitive with the existing PV/battery technology.     

并网光伏发电项目的LCOE分析

围绕并网光伏发电系统的度电成本/平准化电力成本(LCOE)水平进行了分析讨论。针对LCOE的评估依据和测算方法,提出一种适用于我国光伏发电项目的 LCOE评估模型。利用该模型对影响LCOE的几个典型因素进行了敏感性分析;测算了我国光伏发电项目的 LCOE水平;预测了光伏发电项目的 LCOE发展。     

A fast and low cost analog maximum power point tracking method for low power photovoltaic systems

Low power photovoltaic (PV) systems are commonly used in stand-alone applications. For these systems, a simple and cost-effective maximum power point tracking (MPPT) solution is essential. In this paper, a fast and low cost analog MPPT method for low power PV systems is proposed. By using two voltage approximation lines (VALs) to approximate the maximum power point (MPP) locus, a low-complexity analog MPPT circuit can be developed. Theoretical derivation and detailed design procedure will be provided in this paper. The proposed method boasts the advantages such as simple structure, low cost, fast tracking speed and high tracking efficiency. To validate the correctness of the proposed method, simulation and experimental results of an 87 W PV system will also be provided to demonstrate the effectiveness of the proposed technique.     

一种用于光伏系统的具有自均压能力的多电平升压型逆变器

文章提出了一种基于单直流电源的新型九电平SC(Switched Capacitor)逆变器,其开关与电容布置巧妙,避免了外平衡电路的使用,并在负载处于高电感期间提供续流回路。通过与其他类似拓扑比较,证明了所提逆变器的优越性。此外,通过仿真与实验验证了各种动态测试情况下,所提逆变器的合理性和可行性。