Brushless double feed double stator induction generator

Lindu simply crushes concrete by impact method, which is not only inefficient, but also has high noise and dust. Japan is studying the technique of directly heating the steel bar to cause cracks in the concrete and then crushing the concrete with a hydraulic breaker.

The energized bars will heat up. This heat is transferred to the surrounding concrete. Due to the small heat transfer coefficient of the concrete, a temperature gradient is generated between the steel bar and the surrounding concrete, thereby generating stress on the concrete.

When the stress exceeds the tensile strength of the concrete, the concrete is cracked and the bonding force between the steel and the concrete is also reduced. If a row of steel bars parallel to the free surface of the concrete member is heated, the concrete may be peeled off in pieces to facilitate breakage. According to the test, the crack condition of the concrete is that the spacing between the steel bars is less than 10 times the diameter of the steel bars, and the temperature of the steel bars is raised to about 400 T. The following has been done. The performance of the device is as follows: the maximum output voltage is 50V. For safety, the voltage between the energized terminals should not exceed 30V; the maximum output current is 1330A; the total power of the three channels is about 200kW. According to the experimental data, about 10% of the energy is used for the steel bars. Heating. In order to reduce weight and facilitate movement, the device is divided into several parts. Among them, the heating transformer is made into three single-phase, each capacity is 66kW; the heating transformer and the converter are connected by three-phase to reduce the number of cables, the cross-section of the cable is 325mm2; the current frequency is preferably 400Hz to reduce the equipment. The volume is increased by the skin effect; the connection between the heating transformer and the steel bar is 325 mm2, which consists of a single wire with a diameter of 0.45 mm; the electrode terminal (clip) is made of beryllium bronze.

The technology was originally studied for the crushing of nuclear power plant concrete and has been used in other areas. For example, a large concrete block with a thickness of 10.3m and a volume of 913m3 is pre-buried with 33 layers of 22mm diameter steel bars for heating, with a layer spacing of 30cm; each layer of steel bars is about 42 segments, and the spacing of steel bars is 20cm. The transformer is energized and heated to a layer (area of ​​about 86 m2, thickness 30 cm), which is broken by a crusher during the day. The typical heating data is about 26m3 broken every day. Factory and building construction control circuit brushless double feed double bookmark1 stator induction issued bookmark2 Jiang Baoqi-8) reported that before 1998, Sydney University of Science and Technology and Varispeed Electronic Motor Company of Australia A brushless double stator induction motor was developed; in 1998, the double feed (one stator was fed by a variable frequency output inverter) was started in the form of a double stator, which produced a high efficiency and easy control. Brushless dual feed dual stator induction motor (BDFTSIM) operating in synchronous mode. A recent study X was extended to a generator used to convert mechanical energy, namely a brushless double-fed double stator induction generator (BDFTSIG).

The 20 kW unit and system are being tested. Both the BDFTSIM or BDFTSIG in the experimental equipment include two identical wound rotor induction motors, one constituting the power winding and the other forming the control winding. Since the rotor windings of the two motors are directly connected internally, no brushes and slip rings are required. These components were installed in the experimental unit in order to be able to measure the current of the experimental rotor. If a 42 (474) cage rotor is to be used, it should be specifically designed to obtain the correct phase sequence of the two rotor windings.

The capacity ratio between the two rotors can vary depending on the speed range. In a variable speed generator, the power winding is connected to the grid, and the control winding is fed by a variable frequency PWM converter whose power is significantly less than the output power from the power winding.

If the BDFTSIG is operating in synchronous mode, the current vector control map is used, then the rotor speed frequency, pole logarithm.

The controller is set to operate at the maximum output power based on the specified active and reactive power values.

It has two motor configurations, all of which have the advantages of variable speed æ›° BDFTSIG technology. A motor structure is specially designed to form a double stator induction motor (synchronous operation) with a larger number of magnetic poles. In this way, the speed of the generator is the same as the speed of the fan impeller, and no gear box is required. Another motor construction uses two matched standard forms of induction motors (one for "power" windings and the other for "control" windings), all using a smaller number of poles (typically 4-6 poles). It has a low speed ratio gearbox to convert low speed fan impellers to higher generator speeds.

The former solution is technically a better choice because it does not require a gearbox. However, the development cycle of the latter solution will be short because all the components required are already available. In both cases, the variable speed wind power system is very technically and economically advantageous over the past systems. This variable-speed power generation system can be used in high-power wind power installations, either inland or by the sea, and can save considerable initial investment and future operating costs.

This power generation system is undergoing experimental verification. The 20kW unit is being tested and evaluated and can be demonstrated, and the results obtained so far are encouraging.

BDFTSIG's new technology uses a synchronous mode and uses a small-capacity PWM to provide advantages in terms of high performance and low operating costs. In the BDFTSIG, both the wound rotor structure and the cage structure eliminate the need for frequently maintained brushes and slip rings. The generator can operate over a wide range of power factors with high efficiency.

Generator Asynchronous Motor Inverter Collector Tower Solar Power Plant>1 Enlia's Envi'roMissi Company is developing an A' collector tower solar power unit, which is expected to start operation within three years.

Surrounded by a circular greenhouse with a diameter of 7km. The circular greenhouse is open and the air can enter. The roof of the greenhouse is open to the central collecting tower. The sun heats the air in the greenhouse, and the hot air rises to the roof of the greenhouse and flows to the bottom of the collecting tower, while driving more air in the circular greenhouse. The air at the bottom of the collector will drive the turbine to generate electricity at a speed of 55 km/h. Since the air temperature at the top of the collector tower is always lower than the air temperature at the bottom, the power generating device can continue to operate for a long time. In order to ensure that the current collector of the current collector can work at night, a black tube filled with water is placed under the glass cover of the circular greenhouse. The heat stored in the black pipe during the day is released at night.

Envl "Missio claims that Australia is suitable for the construction of a collector tower solar power plant because of Australia's stable and abundant sunshine and low land costs. The project was built in Tapi, near Ml1du "a." Jiang Baoqi) 22kW high-efficiency synchronous motor Bentoyo Motor Manufacturing Co., Ltd. has newly developed a rate synchronous motor. It is said to have a efficiency of up to 94%, so it is called UE). The motor has no rotor impedance loss, generates less heat, plus the casing and base. They are all made of aluminum, so the heat dissipation effect is similar to that of a motor with a self-cooling fan.) There is no self-cooling fan, which reduces wind consumption and reduces noise.

A permanent magnet is mounted in the cage rotor. When starting, it relies on the cage rotor to start in an asynchronous manner; after the synchronization is turned on, the permanent magnet is used to provide the magnetic field.

Since the permanent magnet motor is difficult to apply the inverter, it is only suitable for continuous operation of the mains power supply without shifting.

-C4210 standard, can directly replace the same type of asynchronous motor. Since there is no self-cooling fan, its overall length is shorter than that of an asynchronous motor.

(Golden water) 工业 Industrial computer with configuration application software, "Wo" Safu View industrial computer from the company I Automation, which can better select industrial computers and monitors and pre-configure software systems. These computers can be pre-configured. Configure application software such as display, control information, and maintenance. If you add other Rockwell software, you can further expand the capabilities of these computers. For example, by adding RSViewEnterprise software to the display section of the computer, you can build the model of the entire device; RSBIz Ware software has been added to the information section to easily upload data to the processing device and to download data from the processing device. The VersaView industrial computer will be configured for 12, 15 or 17.5 inches (1 inch = 25.4 mm). The display, with 128MB and 512MB of memory, can be expanded to 1GB. (Jiang Baoqi) Researchers at the Massachusetts Institute of Technology, a cheap battery for electric vehicles, turned the lithium-iron phosphate into a highly conductive cathode material. So that the next generation of electric vehicles is cheaper and safer. The trace metal is added to the original material and processed under special conditions. The new process increases the electronic conductivity to 17. This advantage makes it completely possible to replace the expensive and easily overheated lithium currently used. Cobalt and oxygen composite battery. (Du Zong) (Editor Zhong Qing of this column)


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