The optimization of laying the solar PV

Abstract. At present， the biggest problem people are faced with is the issue of the energy and resources， so the use of the renewable energy has become the development-based strategy of the energy around the world. Therefore， the solar photovoltaic system is divided into two： the networking photovoltaic system and the independent photovoltaic system， both of which have a rapid development in recent years， while the independent photovoltaic system is mainly used as the photovoltaic cells. This paper briefly introduces the application of the solar photovoltaic battery system.

Key words： Solar photovoltaic battery； photovoltaic system； photovoltaic building integration； photovoltaic lighting

1. Introduction

Solar photovoltaic power generation system is composed of four basic structures of the panel， the inverter， the controller and the battery. The use of the photoelectric system should analyze first the solar energy structures， and now the photoelectric system is developing rapidly in China， so we need to use the value of the photoelectric system， and do the multi-cost recovery. Secondly， we should briefly analyze the structure of the solar photovoltaic cells. The solar photovoltaic development should start from three aspects of the development cost， the running efficiency， and the reliability， to improve the technical efficiency with specific analysis and discussion. If we want to optimize the solar photovoltaic system we need to further design and analyze this structure， and we need to optimize the representative appliances， and compare both the optimization and the inverter. Finally， we come to the conclusion and summarize the design to propose the topology structure of the main circuit of double boosted by the former stage voltage matching and the post stage full bridge inverter. Since then， through the effective analysis of the efficiency of the solar power system in Tianjin， we also verified the design of power generation efficiency of the solar power generation system. The data show that through the design and optimization this study show， we can effectively improve the power generation efficiency of the solar power generation.

2. The optimal design of the solar photovoltaic system （taking the grid-connected photovoltaic system for example）

At present， the main drawbacks of the solar photovoltaic power generation system are the large investment， high cost and so on. Therefore， we should explore the photoelectric conversion materials and devices of low cost and high performance. Second， we should reduce the loss of the system to improve the efficiency of the power generation and we should pay attention to the optimization according to these two points. The inverse development efficiency of the grid system will affect the choice of the system of the capacity， and will also affect the whole configuration and other self losses. Therefore， in the configuration process of the grid-connected photovoltaic system， the inverter has become the decisive factor which restricts the efficiency of the PV grid-connected photovoltaic power generation， the operation and the safety as well as the reliability. In the inverter interference， we should research and develop the inverter optimization and the structural adjustment.

2-1. Design of the inverter for the photovoltaic grid-connected photovoltaic system

As shown in Figure 1， the component of a- part says that the grid-connected photovoltaic system has three aspects： the photovoltaic array， the controller and the inverter. The first task is the inverter to realize the maximum power point tracking MPPT. The task two is to achieve the sinusoidal current into the grid in the photovoltaic inverter， and the inverter is the important component that is electrically connected to the grid array module in the system.

In the photovoltaic power generation it will have some impact on the public power grid. In order to solve the problems such as the harmonic pollution， we should introduce a smaller distortion sine wave in the inverter， so as to reduce the impact of the harmonics on the grid. Find out the existing problems in the system of the inverter， and the switch efficiency of the inverter is one of the most important factors leading the wave distortion. If we want to control this problem， we should improve the efficiency of the numerical control inverter system， which is a very important process. At present， the theoretical and the practical circles agree that the high speed digital signal processor is an effective way to improve the inverter， and has gotten better effects， and it also plays a role in connecting the power grid. In a device， the master device plays a big role. A capacity device should use the self breaking capacity and the breaking capacity crystal box tube and the system of large capacity should use the insulated gate bipolar transistor （IGBT）， and in a small capacity and mortgage system we should use more the MOSFET， and the resistance will often increase sharply through the voltage.

In order to ensure the secure， reliable and efficient operation of the inverter and the grid， we should try to put the grounding technology and the inverter and the grid effectively isolated. For such three items in the key photovoltaic lighting system， we can model three provisions which are proposed by the International Electro-technical Commission， such as the non grounding （NT）， the transformer neutral grounding and the individual protective earthling （TT） mode. Then we can do link equipment through the shell of the PE lines and the level of the metal properties of chain （TN）.

2-2. Matching problems of the large Internet photovoltaic system and the national grid

Because the power status of the power system in China is the centralized power， and the solar photovoltaic and the wind power are changed with the solar and the wind. Therefore， the large Internet photovoltaic system and the State Grid of China are hard to match because the renewable energy is not stable. At present our country faces three major problems in order to solve the problem of the renewable energy： the power generation， surfing the Internet and the market consumption. The energy department enforces the quota obligations of the "three subjects"， and through the research has made the "measures for the administration of the quota of the renewable energy power".

2-3. The storage problems of the photovoltaic system energy

At present， the lead-acid battery is the storage battery that the independent photovoltaic power generation system uses the most， because it has five basic requirements that the solar power generation system has for the storage battery. The first is the long service life； the second is the low cost； the third is that the temperature range is wide at work； the fourth is no maintenance or less maintenance； the fifth is that it has the low discharge rate and the higher charging rate with stronger deep discharge capacity. And it also has the mature technology and lowest price. But the shortage is that the capacity has certain limitations， and the life of it only has five to eight years. The cost of the battery is twenty-five percent of the dehumidification equipment of the photovoltaic power station. If the charging and discharging control of the battery is too simple， it will cause early failure of the battery. And the energy control of the system can solve the problem， and the method is to reasonably design the control circuit， and improve the energy utilization. In addition， there is also a serious consequence that too much use of the lead-acid battery will cause the lead pollution. So in order to solve this problem， a novel energy storage device is being developed， and the following two are the main：

（1） Figure 2 shows a written paper capacitor super-capacitor with two electric layers. Through the floating two inert porous electrode plates in the capacitance， the negative plate is transmitted to the cations of the capacitor quality， and on the contrary the cations are transmitted to the anion of the capacitor quality， and thus there will be two storage layers. The cation and the anion are attached around the positive and the negative panels of the capacitor quality. In the process of the stored energy it can be recycled， so we can charge and discharge hundreds of thousands of times. Now the market has been in the circulation of the super capacitor， and the effect is good. It has the following advantages compared with the general capacitor of other memory. The storage capacity is big， and the storage time is short. We don't worry about the charge and discharge time， and the fracture also need not worry， and we can weld etc. China has many well-known enterprises which all produce the super capacitors such as the Shanghai EVEVCAR. But there still exist the reasons that the current cost is high and the technology of the producers is not in place and so on. The market must belong to the world of the small PV systems.

（2） Full liquid vanadium equipment Figure 3 shows the full vanadium redox flow energy storage battery of the energy storage and conversion devices of the new generation. The principle of the devices is that the liquid of the vanadium ions of different valences is divided into 8U to be used as the materials of the positive and negative reactions， and is hidden respectively in the capacitor quality solution by an external pump reservoir in the battery， so as to flow with the current direction of the closed loop. The battery is hampered by the ion exchange membrane instead， and when the capacitor quality flows through the direction of the current with the electrode electrochemical reaction， accumulate and circulate the current by the positive and the negative poles， so the reservoir can become the electricity in the chemistry of vanadium ion solution， and has the following advantages： Don't worry about the problems of the cost， life， and danger， and produced power is large， and the capacity is large， so as to be used in the large memory capacity of the power companies. The full liquid vanadium flow energy storage battery the Chinese Academy developed can successfully charge and discharge ten thousand times， and is applied in the party and the solar power equipment.

From the point of view of the solar photovoltaic television production and productivity， China is in the leading position， but in the quality and cost of products there are great differences between China and the countries around the world. The photovoltaic products must have at least 20 to 50 years of life， while the product technical standards will be very complete and perfect. The current photovoltaic TVs produced in China are sold abroad， so the products must meet the international requirements in quality， and at the same time， China also needs to establish the highest quality standard system of its own， which would enhance China's competitiveness in the world， enhance our international right to speak in the industry， and also can strengthen the competition of China’s PV products in the world. At present， there also exist dramatic differences of the standardization of the PV products of our country with the standard of the international industry， and there also exists a great gap with the huge market demand. To make a long story short， our development level of the photovoltaic products is still far from the international advanced level， so in many ways， we also need to continue to work hard， and we still need a lot of work especially in the technology.

3. Conclusion

So， let us continue to work hard， strive for the cooperation between the industry and the school， speed up the transformation of the scientific and technological achievements， improve our quality of the PV products， expand the scale of the industry， reduce the costs， and constantly expand the application market of the product， so that China's solar energy industry will ascend into the international market. At the same time， save the resources， reduce the carbon emissions， improve China's environmental situation， and early realize the development goal of the low carbon content in China， and create a harmonious society.

References：

[1] Pei Yu. Research on the development strategy of China's renewable energy [D]， Liaoning： Liaoning Normal University， 2004， 5

[2] Wang Changgui. The present status of the new energy and the renewable energy and the prospects and development of the solar energy photovoltaic industry [C]， 2003， 9， 4-9

[3] Zhao Yuwen. On the development strategy of the PV industry in China in the 2lst century [C]， Lecture at HeFei University of Technology， 2002