Research and Application of Small-Scale Wind-Solar Hybrid Power Generation System

Over the past 200 years, an energy system based on fossil fuels such as coal, oil and natural gas has greatly promoted the development of human society. However, human beings have brought serious environmental pollution and ecological system destruction while using fossil fuels. In recent years, countries around the world have gradually realized the importance of energy to human beings and the damage to the environment and ecosystem caused by conventional energy utilization. According to their national conditions, countries have begun to manage and alleviate the deteriorated environment, and regard the development and utilization of renewable and pollution-free new energy as an important part of sustainable development. Wind-solar hybrid power generation system is a new type of energy power generation system with high cost performance, which makes use of the complementarity of wind and solar energy resources, and has a good application prospect. 

1. Working Principle of Small Wind-Solar Hybrid Power Generation System 

Small wind-solar hybrid power generation system, which is composed of wind turbine, solar photovoltaic array, controller, storage battery, inverter and so on.

When the wind reaches a certain wind speed, the wind turbine will convert the wind energy into AC form of electricity, but because the AC voltage generated is not very stable, so it must be rectified by the rectifier, to charge the battery. 

Photovoltaic array is composed of a number of solar panels in series and parallel, its role is to convert solar energy directly into DC form of electric energy, and charge the battery, the battery plays the role of storage and regulation of electric energy, when sufficient sunshine or wind caused by excess energy, the battery will be the excess energy storage; When the system power output is insufficient or the load power consumption increases, the battery supplies power to the load and keeps the power supply voltage stable. Therefore, the need to design a special control device, the device can be based on the strength of sunshine, the size of the wind and load changes, constantly switch and adjust the working state of the battery, so that it in charge, discharge or floating charging and other conditions of alternating operation, in order to ensure the continuity and stability of wind, photovoltaic and hybrid power generation system. For DC load or AC load, the conversion between the two can also be realized.

 

2. Rationality of Small Wind-Solar Hybrid Power Generation System 

The rationality of resource utilization 

Solar and wind power are the most common natural resources found in nature, as well as inexhaustible sources of renewable energy. Solar energy is the energy generated by the continuous nuclear fusion reaction process in the sun, while wind energy is a form of solar energy on the earth surface. Because the different forms of the earth surface have different absorption capacity of the sun, the temperature difference is formed on the earth surface, thus forming air convection and generating wind energy. 

Solar and wind power are highly hybrid in time distribution. During the day, the sun is strongest and the wind is weak; at night, the sun is weak and the wind is stronger; In summer, the sun is strong and the wind is weak, and in winter, the sun is weak and the wind is strong. The complementarity of solar energy and wind energy in time makes the wind-solar hybrid power generation system have a good match in resource utilization. 

The wind-solar hybrid power generation system is a combined power supply system composed of wind power system and photoelectric system. The wind-solar hybrid power generation system consists of solar photovoltaic panels, small wind turbines, system controllers, storage batteries and inverters, etc. The reasonable allocation of the capacity of each part of the power generation system is very important to ensure the reliability of the power generation system.

 

Generally speaking, the following factors should be considered in system configuration: 

(1) The resource status of solar energy and wind energy, as well as the resource status of solar energy and wind energy in the place where the project is implemented, is another basis for the selection of photovoltaic panel and fan capacity of the system. Generally, the capacity coefficient of the photoelectric panel and the fan is determined according to the resource situation, and then the capacity coefficient is considered under the premise of determining the capacity according to the user's daily electricity consumption, and finally the capacity of the photoelectric panel and the fan. 

(2) The characteristics of electricity load. The power generation system is designed to meet the requirements of users. To provide users with reliable electricity, it is necessary to carefully analyze the characteristics of users' electricity load. It is mainly to understand the maximum power load and average daily power consumption of users. The maximum power load is the basis for selecting the capacity of the system inverter, while the average daily power generation is the basis for selecting the capacity of the fan, the photovoltaic panel and the battery bank. In short, the wind-solar hybrid power generation system is the most reasonable independent power system. This rationality is reflected in the most reasonable resource allocation, the most reasonable technical scheme, the most reasonable performance price.

 

3. Optimization Design Idea Of Small Wind-Solar Hybrid System 

The main index to measure the advantages and disadvantages of the wind-solar hybrid power generation system is its reliability and economy, so it must be scientifically analyzed to make the system not only meet the load needs of users for a long time, but also make the system configuration capacity minimum, with the best economy. 

For the fixed photovoltaic array with average annual load, the fixed value should not be taken as the optimal inclination Angle of the solar cell array in the design, but should be determined by referring to the annual distribution of local solar resources and wind resources as well as the actual annual distribution of load power supply requirements. According to different dip Angle, battery maintenance days, user load, minimum investment and other parameters, through the compiled computer software for cycle calculation, the optimal configuration of the system, so that the initial total investment of equipment to the minimum. 

 

The total initial investment of equipment is mainly the total cost of wind turbine, solar cell, storage battery and some other equipment, which can be expressed as: 

 

The unit price of a solar cell module;

The number of solar cell modules;

The number of a battery;

The unit price of a wind turbine;

A number of wind turbines;

Other accessories, such as control inverter, display, industrial computer, mechanical structure, connecting cable, etc.

  

4. Application of Small Wind-Solar Hybrid Power Generation System 

It is mainly used in rural life and production electricity, semiconductor outdoor lighting, navigation beacon, road monitoring camera power supply, communication base and so on. 

(1) Electricity for life and production in rural areas without electricity

About 5 per cent of China's 900m people, who live in rural areas, do not have access to electricity. However, in China, villages without electricity are often located in areas rich in wind and solar energy reserves, so there is a great potential to solve the electricity problem by using wind-solar hybrid power generation system. In addition, the development of abundant renewable energy resources through wind-solar hybrid systems can provide the most suitable and cheapest electricity services to the rural population in the vast remote areas, thus contributing to the sustainable development of poor areas.

 

(2) The application of semiconductor outdoor lighting

In the world at present, the electricity consumption of outdoor lighting project accounts for about 12% of the global electricity generation, and in the global increasingly tight energy and environmental protection background, its energy conservation work has increasingly attracted the attention of the world. Outdoor road lighting projects mainly include: vehicle road lighting projects, residential road lighting projects, etc.

 

(3) Application of communication base station

At present our country many islands, mountain places far from power grid, but because the local fishery, tourism, navigation and other industries have communication needs, need to build communication base station. These base stations are not very large load, if the use of mains power supply, the pole laying line cost is very big; If diesel engine is used for power supply, there are some problems such as high cost of diesel storage and transportation, low reliability and difficult system maintenance. While solar energy and wind energy are highly hybrid in time and region, island wind-solar hybrid power generation system is an independent power system with good reliability and economy, which is suitable for the power supply of communication base stations.

 

(4) Application of monitoring camera power supply

The application of wind-solar hybrid power generation system to provide power for road surveillance cameras not only saves energy, but also reduces the possibility of cable theft without laying cables. At the same time, the transmission line theft event can be effectively prevented, so that the operation cost of the highway business unit can be greatly reduced.

 

5. Summary of Experience 

At present, with the continuous improvement of technologies in various aspects of our PV PV power generation system, and the continuous improvement of related product quality and efficiency, the market competitiveness of PV PV power generation system will also be enhanced. It will gradually transition from remote areas to cities and develop from hybrid energy to alternative energy. By the middle of the 21st century, this form of distributed power generation will occupy a large share in the energy consumption structure and has a very broad development prospect.