Development status and Prospect of the control sys

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Current situation and Prospect of wind turbine control system editor's note: China's wind power industry has developed rapidly in recent years and has become a major wind power country in the world. Under the condition that the main components of the wind turbine have been basically matched domestically, the independent matching ability of the control system is still weak, which is still the weakest link in the wind power equipment manufacturing industry. This paper analyzes the causes of this phenomenon, and puts forward the main technical problems to be solved in the next step of the control system

current situation of China's wind power industry

since 2005, China's wind power installed capacity has developed rapidly at an average annual rate of 100%. By the end of 2008, China's total installed capacity of wind power had reached 12.15 million KW, accounting for about 10% of the world's total installed capacity of wind power, which is a quite amazing growth. At present, in terms of installed capacity, China has become the largest wind power country in Asia and the fourth in the world, with an installed capacity of more than 10 million kilowatts. The top three are the United States, Germany and Spain, with installed capacity of 25.17 million KW, 23.9 million KW and 16.75 million KW respectively

the rapid growth of demand has also driven the rapid development of China's wind power equipment manufacturing industry. In 2004, there were only 6 wind turbine manufacturing enterprises in China. At present, more than 70 enterprises have clearly entered the wind turbine manufacturing industry. In addition, some companies are carrying out preliminary preparations for entering the wind turbine manufacturing industry, showing a mixed pattern of "I will enter the market before you sing, and a hundred wind turbine enterprises will compete for the wind". The good news is that after these years of development, the production scale of domestic and joint ventures has been expanding, their technical capacity has been enhanced, and their market share has risen rapidly. In 2004, domestic (joint) funded enterprises and foreign-funded enterprises accounted for 25% and 75% of the new wind power installed capacity in that year, respectively. By 2008, this proportion was reversed. Domestic (joint) funded enterprises have occupied an absolutely dominant position in the wind power market. As for the number of parts manufacturers driven by these complete machine manufacturers, it is impossible to make accurate statistics. The development and expansion of these wind turbine manufacturing enterprises and parts enterprises have effectively promoted the improvement of the technical level and production scale of China's wind power manufacturing industry. What worries me is the technical level and Production scale "Although WPC technology originated in the United States with uneven service capabilities, only a few companies have truly formed a large scale and are more competitive. Most enterprises do not estimate the huge risks they will face in the future, which is a prominent problem in China's current wind power equipment manufacturing industry.

from the perspective of future development situation, the wind power industry will have a golden development period of at least more than ten years. From a worldwide perspective, In order to solve the problems of energy shortage and environmental pollution, the United States, Germany and other industrialized countries have taken the large-scale development of wind power as the main solution. The same is true in our country. At the end of 2008, the installed capacity of 12.15 million kilowatts of wind power accounted for only 1.5% of the total installed capacity of China's power. It is expected that this proportion will reach about 10% by 2020, that is, the installed capacity of wind power will reach 140million kilowatts by 2020. The detection instruments to be equipped include: quantitative sampling knife, electronic balance, paper thickness gauge, ring pressure gauge (paperboard compression gauge), tension machine, moisture tester, bursting tester, folding tester Surface absorption weight tester, smoothness tester, whiteness tester, stiffness tester, gloss tester and other levels, which is a very considerable number. This shows that from the macro situation, the climax of the great development of the wind power industry has indeed come

development status of wind turbine control system

the control system of wind turbine is an important part of wind turbine. It undertakes the important tasks of wind turbine monitoring, automatic regulation, realizing maximum wind energy capture and ensuring good electrical compatibility. It is mainly composed of monitoring system, main control system, pitch control system and frequency conversion system (frequency converter). The main functions of each part are as follows:

monitoring system (SCADA): the monitoring system realizes the monitoring, start and stop operation of the fan status of the whole wind farm, including large-scale monitoring software and perfect communication network

main control system: the main control system is the main body of the fan control system. It realizes the important control and protection functions such as automatic start, automatic direction adjustment, automatic speed regulation, automatic combination and automatic. At the 6th conference of the parties to the Stockholm Convention held in may2013, hbcdd was listed in the control list, automatic shutdown in case of failure, automatic cable unwinding, and automatic recording and monitoring. Its three main external interface systems are the monitoring system, the pitch control system and the frequency conversion system (frequency converter). It interfaces with the monitoring system to complete the exchange of real-time data and statistical data of the fan, and interfaces with the pitch control system to complete the control of the blades, so as to achieve the maximum wind energy capture and constant speed operation, and interfaces with the frequency conversion system (frequency converter) to realize the automatic adjustment of active power and reactive power

pitch control system: in cooperation with the main control system, through the control of blade pitch angle, the maximum wind energy capture and constant speed operation are realized, which improves the operation flexibility of the wind turbine. At present, there are two ways to drive the blades of the pitch control system: hydraulic and electrical. Among the electrical driving ways, there are two different schemes: AC motor and DC motor. The method to be adopted mainly depends on the technical route and tradition formed by the manufacturer over the years

frequency conversion system (inverter): interface with the main control system, connect with the generator and electricity, and directly play an important role in ensuring the power supply quality, improving the power factor, and meeting the electrical compatibility standard

according to the current situation in China, the independent supporting scale of the above components of the wind turbine control system is quite unsatisfactory. So far, it still relies heavily on foreign brands and is still the weakest link in the wind power equipment manufacturing industry. However, other components of the fan, including blades, gear boxes, generators, bearings and other core components, have been basically localized (although the quality level and operation status are not satisfactory). The main reasons for this are:

(1) China started late in this technical field, especially the research on variable speed constant frequency control technology for megawatt and above high-power units in recent years, This is 20 years behind the advanced countries in fan technology. As mentioned above, China's wind power manufacturing industry has developed rapidly in the last four years since 2005. In order to quickly seize the market, major domestic wind turbine manufacturers are committed to expanding production scale and are unable to independently develop products with high technical content such as control systems. Therefore, they mostly purchase products or introduce technology directly from foreign companies such as Mita and windtec

(2) in terms of the requirements of the fan control system itself, it does have its particularity and complexity. In terms of hardware, the fan control system is installed with the fan in a near natural environment, and works under complex conditions such as large vibration, large-scale temperature change and strong electromagnetic interference. Therefore, the hardware requirements are much higher than those of general systems. In terms of software, in order to realize complete automatic control of fan, there must be a set of perfect control software corresponding to it. The main control system, pitch system and frequency converter need to work together to achieve the maximum wind energy capture under low wind speed, constant speed under medium wind speed and constant frequency and constant power operation under large wind speed, which requires a set of advanced and complex control algorithms in these major components. It really takes some time for domestic enterprises to take full ownership

(3) the wind turbine control system is a system highly integrated with the characteristics of the wind turbine. The control software, including the main control, pitch and frequency converter, not only has complex algorithms, but also the setting of its parameters is closely related to the wind turbine itself. The task of the wind turbine control system is not only to achieve highly automatic monitoring of the wind turbine and power supply, but also to maximize the wind energy capture and minimize the load through appropriate control, Even if a general automation enterprise can develop a prototype, it is difficult to verify it, so it is more difficult to promote it. The fan manufacturers with small and medium-sized sizes but many customers' reaction that the fixture is a perishable part mold are unable to carry out such development

even so, through the efforts in recent years, domestic enterprises have made positive progress in the development of the main components of the control system, and have basically formed their own technology development ability. What they lack is mainly the large-scale operation performance of products and the accumulation of technology and experience. For example, as the main control system and frequency converter with the highest technical content in the fan control system, domestic enterprises have made important progress in independent development. After years of efforts, Dongfang automatic control has successfully developed the dws5000 fan control system, completed various tests and fan operation verification, realized large-scale production and basically formed its independent development capability. Kono Weiye has also developed the control system for megawatt units. In terms of frequency converters, a number of enterprises such as Dongfang automatic control, Hefei sunshine, qingneng Huafu and Kono Weiye have also sprung up and developed high-power doubly fed and direct drive frequency converters. Small quantities of products have been put into operation in wind farms, presenting a gratifying development momentum

with the increasing capacity of fans developed by domestic enterprises, the fan control technology must be continuously developed to meet this requirement. For example, the drive and control technology of blades, such as the development of larger capacity frequency converters, are new topics that must be continuously solved, which will not be described in detail here. At present, due to the increasing proportion of wind turbines in China's electricity, the problem of poor electrical compatibility of wind power generation is gradually exposed. At the same time, users have higher and higher requirements for the connection between different wind farms and different types of wind turbines, which also puts forward new tasks for the wind turbine control system

(1) adopt unified and open protocols to realize convenient interconnection between fans of different wind farms, manufacturers and models. At present, the wind turbine investment users and power dispatching center have increasingly urgent requirements for the connection between wind farms widely distributed in different regions. Although various wind turbine manufacturers have provided certain means to realize the interconnection of wind turbines, due to the different schemes adopted, there are still many problems in the interconnection of wind turbines from different manufacturers, which is difficult to implement. Therefore, it is an important issue to realize the convenient interconnection between different fans

(2) LVRT needs to be further improved. Wind turbines, especially doubly fed wind turbines, have poor resistance to voltage sags. In case of electric voltage drop, the previous practice was to cut off the fan from the electricity. When the proportion of wind turbine in electricity is small, the impact of this practice on electricity can be ignored. However, with the increasing number of wind turbines in operation, especially in areas where wind power generation is concentrated, such as the 60 million kilowatt wind power base planned by the state, this practice will have a serious impact on power and may even further expand the accident. Many European countries, such as Germany, Spain, Denmark and other countries, have long issued relevant standards, requiring the wind turbine to keep running to support electricity under such circumstances. This capability of the wind turbine is called low voltage ride through capability (LVRT), and some countries even require that it can operate when the electric voltage drops to zero

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