China has developed a large-scale wind turbine with AC excitation frequency conversion speed regulation

Text / Harbin Electric Machinery Co., Ltd. Tan Guowei Wind energy is a clean energy source, and it is inexhaustible. Wind power generation in the world is developing rapidly, and China has already leapt to the tenth place in the world. However, power generation equipment mainly relies on imports. Foreign manufacturers agree to export production technology when exporting wind turbines, but do not transfer design ideas and design methods, and do not allow joint design methods to prevent our experts from grasping the connotation, thoroughly understanding the key, in-depth design, and mastering the design and manufacturing methods.

If it is not solved, it will be impossible to fundamentally improve the overall competitiveness of enterprises. Therefore, accelerate the pace of corporate reform of large enterprises, and establish a modern enterprise system with clear property rights, clear responsibilities, separate government and enterprises, and scientific management, and shape large enterprises into real market entities and legal entities with strong competitiveness. The main solutions are: first, establish a standardized corporate governance structure; second, to achieve diversification of investment entities; third, through the reform of the labor system, personnel system, and distribution system, establish an effective incentive and restraint mechanism for senior managers, using mechanisms and The environment attracts talents, cultivates talents, and retains talents. The fourth is to strengthen management innovation, achieve scientific management, timely organize innovation and business process reengineering according to changes in the external environment, and build an innovative and responsive learning organization.

Sixth, further develop the service functions of industry associations to provide a basis for government decision-making and enterprise development.

Development technology.

The Development Fund Committee has allocated 200,000 yuan to support the 380kW AC excitation variable-speed constant-frequency generator test. After six years of scientific research, the Harbin Institute of Electrical Engineering successfully completed this major national research project. The self-developed rotor of the constant frequency large-scale wind turbine with AC excitation variable speed was established, and the related special test rig was established. The supporting hardware and software were developed, which ended the history that China could not design and manufacture large-scale wind turbines.

More effective use of the intermediary services of industry associations is the challenge facing the association itself in the new situation and the new environment, and it is also the concern and expectation of the government and the business community. In the new historical period, the association organization can play the following roles in the further reform of state-owned enterprises: First, it can summarize and promote many good experiences accumulated by mechanical enterprises in reform and development, and analyze their successful environment and the effectiveness of reforms. The second is to study the problems existing in large-scale machinery manufacturing enterprises and the new situations and new problems encountered in the development, and to use the one-factor-one-pronged approach to propose policies and management recommendations to the government and enterprises; It is a good job for all enterprises, and it is beneficial to the society and associations, such as promoting self-discipline in the industry, establishing a learning organization, innovating corporate culture management, shaping corporate integrity, establishing an entrepreneurial system, communicating information services, and conducting policy research. Exchanges and cooperation, etc., are all the work that industry associations should and must do, so that the association truly becomes the principle of public technology and commercial secrecy. This paper briefly introduces that the 300kW rotor developed by the company uses AC excitation and can be frequency-controlled and the stator is The basic principle, main parameters and structural characteristics of large-scale wind turbines that are still generating constant frequency power,

Seventh, reform is the only way for large-scale machinery manufacturing enterprises to get out of the predicament. To develop, one must base itself on the changes that adapt to the trend of the times, and reposition itself in the international context. It is necessary to take the world's peers, that is, competitors, as a control system, soberly to see their own gaps and deficiencies, and fundamentally solve the problems in the development of enterprises. The problems involving state-owned assets and property rights mainly rely on the investment-side government of state-owned enterprises to help enterprises solve problems; the problems involving excessive enterprises are dependent on government policies to support and strengthen social security, and enterprises must create more economic growth. The point is to solve the problem, and the problem of strengthening management, changing concepts, and changing the mechanism is mainly done by the enterprise itself. The government can only make demands from the legislation and the system, and carry out the technology development of bookmark3 and its superiority. At the same time, it also provides relevant support. Hardware and software, including directional control strategy and digital control system for stator total flux linkage, full digital 120RVA AC drive, 380kW AC excitation variable speed constant frequency generator test bench, computer sampling test system, this generator and grid Interplay simulation studies and special electromagnetic field problems. The scientific research results obtained have passed the national appraisal and reached the domestic leading level.

I. Preface ~ There are two main types of generators for wind turbines, namely synchronous motors and asynchronous motors. It is difficult to connect the synchronous generators, and the control lines are complicated, and the speed control devices are expensive. When wind conditions (wind pressure, air volume, wind speed) When the change occurs, the generator affects the stability of the transition process due to the violent fluctuation of the input power. The asynchronous generator is easy to connect to the grid, has good running characteristics, is rarely repaired, is easy to implement automatic control, has low cost, and has good soft characteristics. If it is set to a high slip rate (maximum up to S= 8%) also improves output power stability. Therefore, its application is more.

The new technology of rotor AC excitation is a fundamental breakthrough in the development of large wind turbines. It enables the excitation system to achieve three adjustment parameters, namely frequency, amplitude and phase, so that the active and reactive power can be flexibly adjusted. The power factor expands the operating range of the unit and improves the stability of the power system.

There are unexpected events, and the wind energy situation is more complicated and changeable. How to make the wind turbine generator maintain high efficiency and stable operation under variable operating conditions? This is the main purpose of developing and applying the new technology of rotor AC excitation frequency conversion speed regulation.

Magnetic, with f2=, W2=, the generator rotates at synchronous speed. When the rotor adopts AC excitation, f20, W2, the generator rotates at asynchronous speed, that is, nr=ni-2. It can be seen that as long as the AC current frequency f2 supplied to the rotor is changed, W2n2 can be changed to realize the adjustment motor. The mechanical speed nw allows the unit to adapt to wind conditions and always operate under optimal conditions.

Second, the basic principle ~ When the rotor is AC excitation, the stator's current of the generator forms a rotating magnetic field with the nu angle frequency as wi. When the rotor is excited by the alternating current of frequency f2, the current produces a rotating magnetic field relative to the rotor. The rotational speed is m and the angular frequency is wz. In order to achieve effective energy conversion, the motor's internal rotation and the rotating magnetic field of the rotor must remain relatively static. At this time, the mechanical speed nr and the angular frequency wr of the motor must meet the DC of the alternator rotor. Lisan, the main parameters of the first domestic AC excitation variable speed constant frequency generator successfully developed as follows: rated power (kW) 300 power factor (coscp>0.91 rated voltage (V) 690 rated frequency (Hz) 50 synchronous speed (r/min)1 350~1650 Rotor voltage 364.6 Rotor current (A) 41.2 Rotor excitation power (kW) 30 Motor efficiency 95 IV. Structural characteristics Table AC excitation motor and relay motor comparison transmission motor AC excitation motor motor type Synchronous motor winding plough asynchronous motor stator winding two and. Very phase: rotor winding series concentric two-phase 茈 alternating double staggered rotor omnidirectional salient Hidden pole car, excitation current DC AC rotation speed constant adjustable collector ring 2 4 stator frequency (Hz) 5050 rotor frequency (Hz) 0510 frequency conversion device no cross female inverter production cost (PU) 11.21.65 times motor Efficiency can be increased by 2.5%~4.5%. From the overall structure, the variable-frequency generator with AC excitation is similar to the wound-type asynchronous motor. The stator adopts three-phase double-stack winding, and the rotor has a cylindrical hidden-pole structure. Two-layer windings orthogonal to the two phases, four collector rings are placed on the rotating shaft to supply power to the independent windings of the two phases on the rotor. The excitation AC power of the rotor is the AC frequency converter. AC excitation is compared with the conventional motor. See table (the table lists AC excitation for pumped storage units).

V. Superiority When the rotor adopts the new technology of AC excitation, the frequency, amplitude and phase of the excitation current of the rotor can be adjusted to ensure that the generator is always operating under the optimal conditions, achieving high efficiency and stability even in the case of constant changes in wind energy conditions. It can also enable the unit to track the optimal operating conditions, ensure that the unit will not lose the step, and improve the stability of the power system. If modern vector control is used, the control of the generator can be quickly responded while flexibly adjusting the active and reactive power.

This superiority of the new AC excitation technology has been proven. There are 7 large-scale pumped-storage units in Japan that use AC excitation, and the longest running time is more than 10 years. The survey results show that the efficiency of the 85MVA unit of Yamuze Power Station has increased by 2%~3%, which has greatly reduced the vibration, reduced the damage degree of the cavitation and wear of the runner, and prolonged the service life. The 395MVA unit of Dahei Power Station is running in pumping. The automatic frequency modulation capacity can reach 80% of the soil, and the fluctuation of active power is small, which improves the stability of the power grid. The 140MVA unit of Gaojian Power Station can replace the automatic frequency modulation operation of the ordinary hydropower station and the speed regulation operation of the thermal power station at night, but the output can not be output. Reduce the input power under variable conditions to achieve energy savings. Under normal circumstances, AC excitation can increase the efficiency of the unit by 2.5%~4.5%. However, due to the need to equip the inverter and rotor protection equipment and a large floor space, the cost is relatively high, about 1.2~1.65 times that of the traditional motor.

Sixth, related hardware and software ~ ~ rotor using AC excitation frequency control is the world's advanced technology, it was not until the last 10 years to develop and apply mainly based on the new development of high-power power electronic components. Modern inverters continue to achieve high voltage, high current and large capacity. However, the voltage and current output from the inverter are non-sinusoidal. In order to solve this problem, it is necessary to develop the necessary hardware and software in research, design, and test.

The variable speed constant frequency generator first establishes a dedicated test bench of 380 kW. This is a major research topic issued by the state. The test rig was built using a newly developed all-digital AC excitation generator vector control system with stator total flux linkage orientation, and corresponding software and hardware for generator power and speed regulation.

In addition, the newly developed 120kVA all-digital 6-pulse loopless sinusoidal voltage source is delivered to the inverter, and the corresponding hardware and software for flexible adjustment of the generator excitation current frequency, amplitude and phase. In addition, a newly developed low-power microcomputer measurement system was also adopted. The test bench adjusts the active and reactive power and the rotational speed of the generator by controlling the excitation of the rotor. The speed adjustment range of the constant frequency (the frequency of the output voltage of the specified sub-side generator is 50 Hz) is 5% of the rated speed. The adjustment range of the generator power factor is cos9=0.8 (late phase)~0.9 (phase advance). The test bench will serve the national wind turbine testing, testing and appraisal.

When the generator rotor adopts AC excitation for variable frequency speed regulation, its frequency is very low, only a few Hz. The AC frequency conversion mode is obtained by the power frequency 50Hz chopping to obtain the low frequency voltage, thus containing a large number of higher harmonics. This kind of electric quantity measurement with higher harmonics has not been completed by suitable instruments. Even if some instruments can measure low-frequency electric power, it cannot be used in the whole range of 0~50Hz when measuring such high-order harmonics. The measurement is performed internally, and the error is greater when the frequency is close to zero. The newly developed microcomputer test system can be well applied to the cross-frequency power supply, which is a low-frequency power measurement with a large harmonic. The test system hardware adopts A/0 acquisition, and the counter synchronously triggers sampling, which is analyzed and stored by the PC. The software uses object-oriented technology to realize the visualization of the test, and the integration of data acquisition, graphic display, function selection and print output.

The frequency conversion speed control system is mostly for the stator control, and the frequency conversion, speed regulation and control device with the same capacity of the motor must be installed between the motor and the power system, and the cost is high. When the inverter AC excitation is used for frequency conversion speed regulation, the capacity of the inverter can be reduced, and only 20°/.~30°/. of the motor capacity can be used. This is another great advantage of rotor AC excitation.

The frequency converter is mainly composed of various thyristors, and their output voltage and current waveforms are non-sinusoidal waves. This has become a key issue for the output voltage and current waveform of the stator-side generator.

The commonly used 6-pulse loopless AC-to-AC converter has a large harmonic amplitude of the output voltage, which is more than 20% of the fundamental. In order to ensure the generator ti waveform output from the generator to the grid, 12-pulse inverters are used abroad to reduce the harmonic components of the excitation power supply, but the cost is doubled. For China, where the power electronics industry is still not well developed, the cost of high-power power electronic components is still high, and it is not suitable for consideration. Therefore, it is necessary to improve the distortion of the waveform by studying the law of waveform variation.

Recently developed the largest domestic all-digital AC frequency conversion device adopts 4 pieces of quasi 16-bit single-chip microcomputer, and connects 4 MCUs with STD industrial control bus to form a large system with 4CPU running in parallel, which can be completed only by microcomputer above 486. Real-time computing and real-time control, while also greatly improving the reliability of the system. In terms of software, special programming techniques are used to replace the sinusoid with multiple lines, which improves the calculation speed of the cosine intersection. The t-loop uses a loopless mode and a fast photodetection circuit, and uses a thyristor as a power electronic power component.

In order to study the influence of higher harmonics, a new concept of harmonic transfer impedance and its frequency characteristics was theoretically established t times, and the corresponding electromagnetic calculation program was developed. The experimental results show that the damper winding has stronger suppression of higher harmonics and less influence on the fundamental wave. At the same time, a waveform digital simulation model including the transmission of the inverter and the motor and its program were established, and the validity was verified on the real machine.

The test results show that the influence on the stator no-load potential waveform comes from two parts, namely the rotor power supply voltage harmonic and the harmonic of the motor body. The former has less influence, while the latter (especially the tooth harmonic) has more prominent effects. In order to improve the potential waveform, fractional slot windings can be used to effectively suppress the tooth harmonics. Based on the research results, an electromagnetic field calculation program for an AC excitation generator with a damper winding was developed. The design problem of installing the damper winding is studied, and the following conclusion is obtained: it is feasible to install the damper winding when the slip rate S is small (S<0.085).

The design of such a motor is very difficult, especially in the case of high voltage and high current, the fixing and protection of the rotor winding, and the structure of the collector ring. However, these problems have been solved. After taking effective measures, it has been proved that the harmonic component of the stator voltage is not prominent, its harmonic rate is <1°/., and there is no oscillation during the speed regulation process, and the stability of the speed regulation response is also very impressive. satisfaction.

~~1, the recently developed 300kW AC excitation variable speed constant frequency generator developed by Harbin Institute of Electrical Machinery is the first AC excitation large-scale wind turbine developed by China. It indicates that China has designed and produced AC excitation large wind turbines. Ability.

Major scientific research results such as test benches, test systems, AC frequency converters, and electromagnetic calculation programs will be tested for wind turbines nationwide. Provide services such as testing and identification.

On the other hand, Harbin Power Generation Equipment National Engineering Research Center will further develop this capacity of this wind turbine.裘Oriental Electric used information technology to change cable equipment text / Dongfang Electric Machinery Co., Ltd. Chen Peiyu Wu Shukang Yin Guocheng After three years of reorganization of traditional machinery industry with high-tech information industry, Dingren Technology Deyang Dongfang Electric Machinery Co., Ltd., in summary 38 years line On the basis of the experience in the design and manufacture of cable special equipment, we strive to find the combination of information technology and traditional iron and steel special equipment, and establish the strategic goal of “guide the market with technological innovation and build the first cable equipment production base in the east”. The company's electrical machinery design and technology center, according to the existing level of nearly 200 varieties of 13 series of wire drawing (wire), stranded wire, Chengyu I extrusion, casting rod, etc., which are urgently needed to be updated by the wire and electric industry, adopts new design, New materials, new technologies, new processes, new structures, etc., have continuously developed special equipment for wire and cable with high technology. Now the new product items are introduced as follows: (1) Drawing, wire drawing machine series, wire drawing machine series are It consists of various types of micro-drawing machine, fine drawing machine, small wire drawing machine, medium wire drawing machine and large wire drawing machine, and is also divided into copper wire drawing machine, copper wire drawing machine and aluminum wire drawing machine according to the raw material of the drawn wire.

First introduce the following five kinds of copper wire production equipment: (starting from small pull, then pull, pull) LHT-120/20 copper wire drawing machine, a total of three varieties: /20 (SS) type double double frequency conversion / 20 (DS) type single layer double frequency conversion

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