Analysis of the development and prospects of wind power generation. The wind turbines used in wind power generation are roughly divided into two types. One is a squirrel cage type asynchronous generator, which requires the reactive power of the absorption system to generate the excitation current for power generation, and the rotation speed is basically constant. The other is a doubly-fed generator with a wound rotor. Through the frequency adjustment of the excitation current, the generator can be shifted and operated, and the variable speed constant frequency is realized, which is beneficial to grid connection. In terms of performance, the doubly-fed generator is beneficial to the transient stability of the system after the failure, but the cost is also higher than the squirrel-cage asynchronous generator.
China also has abundant wind resources, such as Daban City in Xinjiang, Inner Mongolia and the eastern coast are ideal wind farm addresses. With the advancement of wind power technology, the capacity of wind farms is further expanded, the cost of wind power is further reduced, and the stability analysis of the system after wind power is connected to the network, wind power will gradually enter the stage of commercial operation.
Exploring the fan model and simulation research after the fan is connected to the system, and discussing the impact of wind power on the stability of the power system, including the low-voltage capacity, the reactive power compensation configuration of the wind farm, and the emergency treatment of the fan after the accident. Stable operation is of great significance.
Hobbing uses a hobbing machine with two skew spindles, one mounted with a blank workpiece and the other with the hob. The angle between the hob's spindle (axis) and the workpiece's spindle varies, depending on the type of product being produced. For example, if a spur gear is being produced, then the hob is angled equal to the lead angle of the hob; if a helical gear is being produced then the angle must be increased by the same amount as the helix angle of the helical gear. The hobbing features for gears are straight, helical, straight bevel, face, crowned, worm, cylkro and chamfering. The two shafts are rotated at a proportional ratio, which determines the number of teeth on the blank; for example, for a single-threaded hob if the gear ratio is 40:1 the hob rotates 40 times to each turn of the blank, which produces 40 teeth in the blank. If the hob has multiple threads the speed ratio must be multiplied by the number of threads on the hob. The hob is then fed up into the workpiece until the correct tooth depth is obtained. Finally the hob is fed through the workpiece parallel to the blank's axis of rotation.
Often, during mass production multiple blanks are stacked using a suitable fixture, then cut in one operation.
For very large gears the blank can be gashed to the rough shape first to make hobbing easier.
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