I. Understanding Wind
From one perspective, wind is a form of solar energy.
1. The causes of wind:
① Earth's rotation
② Temperature difference: Different states of the Earth's surface have different coefficients of heat absorption and release from the sun, resulting in temperature differences between air masses, which in turn leads to the formation of wind. (For example, water absorbs and releases heat more slowly than the Earth's surface).
2. The trajectory of wind movement
When wind encounters an obstacle, it will form turbulence.
II. Wind Turbine
A wind turbine is a power generation device that converts wind energy into electrical energy, realizing the process of converting wind energy into mechanical energy, and then the generator converting mechanical energy into electrical energy.
1. Technical principles of wind turbines
Three-phase uncontrolled bridge rectifier battery
(1) The generator is three-phase (i.e., three wires). The three output phases should be interconnected. The resistance of the two leads is the same. Sparks will occur when any two wires are connected.
(2) After a 12V battery is fully charged, the voltage will rise. Generally, a fully charged battery is considered to be between 13.8V and 14.5V. When charging with wind power, the battery voltage will be higher, with 1.1V to 1.3V being the rated voltage. The operating state selection varies for different types of batteries. 10.2V is switched to the inverter. For generator frequency monitoring, the controller adds monitoring points, and voltage signal selection protection is applied.
Wind energy - Mechanical energy - Electrical energy - Electrical appliances
2. A wind turbine is actually a unit consisting of wind turbine blades, a generator, and a tail rudder.
(1) The most ideal leaf
The larger the swept area of the blades, the more wind energy they can absorb. Different designs of the blade side profile can increase rotational speed and reduce drag.
The theoretical limit value of the blade, CP(max), is 0.593.
P∝SρO3*CP
(Currently, the ideal CP value for large wind turbine blades is 0.48, for small wind turbine blades it is 0.48~0.36, while the CP value of the HY series blades can reach 0.42.)
(2) High-efficiency generator
Generator efficiency:
Large generator 0.95
Small generator 0.6~0.5
HY series generator 0.74
Overall conversion efficiency:
Overall conversion efficiency = aerodynamic efficiency (CP value) * generator efficiency.
The overall conversion efficiency of the HY series generator is 0.42 * 0.74 = 0.28 ~ 0.3, which is much higher than the national standard efficiency value of 0.24.
III. Characteristics of Wind Turbines
Wind is a random energy source; to generate electricity from wind, we must capture its energy. Since wind energy is virtually limitless, without speed limits, even the best wind turbines will be damaged. Currently, wind turbines used for power generation generally operate within an output range of 3 m/s to 60 m/s.
The following types of speed limiting devices are generally used:
(1) Variable pitch (centrifugal variable pitch)
This is a relatively advanced blade control method. When strong winds come, the blades are adjusted to create resistance, causing most of the wind energy to be consumed at the blade tip, thus limiting energy output.
(2) fold tail
(3) Head up (or side up): Push the nose up when the wind is strong to avoid the wind.
All three blade control methods have the disadvantages of poor reliability and easy wear and tear on related components of the fan.
(4) Stall blades
Stall blades were originally used in large wind turbines with constant pitch.
The blades of the HY series wind turbines are made of nylon material manufactured under high temperature and pressure, eliminating the need for traditional speed limiting methods and controlling mechanical power from an aerodynamic perspective.
The blade's unique structure allows it to use the negative force at the blade tip to limit its rotational speed in strong winds. The faster the blade tip speed, the stronger the resulting negative pressure and high-frequency vibrations. This type of flexible blade...
The blades effectively decompose high-frequency vibrations, preventing blade tip damage. Simultaneously, electromagnetic braking provides a faster shutdown speed than mechanical braking, bringing the fan to a complete stop in approximately 3-6 seconds. This reduces the CP value, and...
Current output.
Electromagnetic braking + stall control = strong wind protection
IV. Application of fans.
1. Independent power supply system for small wind turbines.
It includes five main parts:
Wind turbine: generating electricity
Charging controller: Protects the battery status. Once fully charged, it enters a stall state to protect the fan.
Storage batteries: Enable system energy storage
Inverter: Configured according to changes in electrical load, the inverter has a protection system in case of user overload and short circuit, and automatically stops power supply when the battery is undervoltage to protect the battery.
user:
If using a 400W or 600W fan, it is not recommended to use a washing machine or refrigerator (small capacity is acceptable). This is because the starting current is too high, and also because the inverter configuration is relatively...
Increasing the power by 1000W or more will raise the cost.
2. Why is there no direct relationship between wind turbine capacity and power consumption? How is the power generation of a wind turbine measured?
The power generation capacity of wind turbines is directly related to the user's load capacity, and the key factors are electricity consumption and resource conditions.
Electricity consumption = Power consumption * Usage time
Wind utilization efficiency: 0.12~0.26
Wind turbine utilization rate: 0.8 (overall utilization rate of the wind turbine)
If a 400W wind-solar hybrid street light is used in Guangzhou, then the daily power generation should be: 400W wind turbine * 24 hours * 0.12 * 0.8 = 0.92 kWh.
The amount of electricity generated is 1.3 to 1.5 times the amount of electricity consumed.
3. Why use wind-solar hybrid power generation?
(1) Considering the deficiencies of resources
Wind power generation is highly unpredictable and beyond human control, so it's less able to meet customer needs anytime, anywhere. However, wind-solar hybrid power generation can effectively improve resource utilization.
With the same geographical and material conditions, we can meet customer requirements to a greater extent.
Wind and solar complementarity: Resources are balanced and combined, energy is stored every day, the sun can be used during the day and the wind at night. The sun is strong in summer and the wind is strong in winter, which can effectively make greater use of resources.
(2) Technical
Solar power generates 17V, while batteries operate at 12V. Therefore, solar charging is relatively slow and stable because the battery's charge level depends on the flow of positive and negative ions. If the flow of positive and negative ions is uneven...
Under normal circumstances, the plates are prone to sulfation, which is detrimental to the battery's lifespan. However, wind power is different. Wind energy is a high-current charging method, which can frequently activate the plates and extend the battery's lifespan.
(3) Economic efficiency
Compared to solar generators, wind-solar hybrid generators cost only 1/3 to 1/4 of the price. In terms of power generation, a 300W solar panel for a street light cannot guarantee the user's daily power consumption. In the same geographical location and environment, wind-solar hybrid generators can effectively increase the service life of street lights, improve utilization and reliability, making the application of wind-solar hybrid street lights in cities possible.
4. Target audience
When Hu Yaobang inspected remote areas in 1981, he requested relevant national departments to solve the electricity problem in these areas. After investigation, it was determined that small-scale wind power generation was the most feasible solution. Therefore, for nearly 20 years, wind turbines were primarily intended for use in remote areas. However, the current situation in these remote areas...
The previous drawback was that there were groups with demand but lacking purchasing power. Now, under the advocacy of creating an energy-saving society, various new energy sources are being actively utilized both nationally and globally. Following the Two Sessions in my country, the goal is to pursue a path of economical and sustainable development, and energy conservation has become a performance indicator for government officials. (Municipal Project)
Current situation: 1. Developed countries' legislation requires the use of new energy sources;
2. China's Two Sessions have emphasized a path of conservation and sustainable development, linking government performance evaluations to energy conservation, with a focus on municipal projects.
3. In the real estate sector, this is being used as a new selling point. For example, in Hong Kong's Park Lane, the cost of wind-solar hybrid generators can be included in the construction cost, eliminating the need for annual street light usage fees. Furthermore, some people use windmills as a symbol of good fortune. Based on the above, wind-solar hybrid systems can gradually be applied to urban municipal projects and small-scale residential power supply projects.
V. Problems
1. Customers are not very familiar with the usage and scope of wind-solar hybrid generators. When making application suggestions to customers, we should have a detailed understanding of the load and resource situation they are using.
2. Some customers are very concerned about the wind turbine's start-up speed in a light breeze. Comparing it to other companies' wind turbines in this aspect, taking a wind intake area of 1.5m² (400W) as an example, the energy generated at a wind speed of 3m/sr is too small to be meaningful. Therefore, power generation at wind speeds below 3m is not worthwhile and also changes the cost (by increasing blade length).
3. Why isn't the 600W version made to meet the 12V standard?
The battery needs to be 30V, and the wires also need to be thicker, which increases the cost.
4. Is the vibration of the HY series fan very strong?
We designed the resonant frequency to be at a very low rotational speed, and components such as the HY (hydraulic alloy) are die-cast or injection molded, while other fans are generally handmade. In comparison, the blades operate much more smoothly. Therefore, our streetlights do not use steel wires and generate no vibration.
5. Which is more efficient, wind turbines or solar power?
Wind turbines have high conversion efficiency, but are greatly affected by the environment. The power ratio of wind power generation to solar power generation in wind-solar hybrid systems is 3:1.
6. Information on the solar panels we are using.
The difference between polycrystalline silicon and monocrystalline silicon solar display panels: We use polycrystalline silicon, the raw materials of which are imported from Sharp of Japan, and the manufacturer is Shanghai Solar Energy Co., Ltd.
7. What type of generator does the wind turbine use?
The generators we use are permanent magnet generators (neodymium iron boron permanent magnet generators). There is also an excitation generator, which is generally used in large wind turbines.
8. Inverter
Because inverter voltages and systems vary from place to place, it is generally recommended that guest rooms purchase them locally. For example, the UK uses 230V, Japan uses 110V, and China uses 220V square wave output (which is less efficient and more susceptible to electromagnetic interference).
