Differently, the dual-drive wind turbine is composed of a three-phase asynchronous winding motor and a permanent magnet synchronous motor coaxially connected, and there are two wind wheels: a main wind wheel and an auxiliary wind wheel, hence the name Dual-drive motor, also called dual-wind wheel motor. Among them, the main wind wheel directly drives the asynchronous motor rotor and the permanent magnet motor stator to rotate together, and the auxiliary wind wheel directly drives the permanent magnet motor rotor to rotate in the opposite direction. There is no gearbox in the middle. It is a direct drive structure. The permanent magnet motor stator winding It is connected with the rotor winding of the asynchronous motor in reverse phase sequence. Its main function is to excite the asynchronous motor. The entire generator outputs electric energy from the stator side of the asynchronous motor.
The so-called double-fed can be understood as the stator and rotor can emit electrical energy at the same time. The principle of the generator theoretically says that as long as there is power to drive the motor, the stator side of the motor can directly emit electrical energy. The working principle of a modern variable-speed doubly-fed wind turbine is to convert wind energy into mechanical torque (i.e., the rotational inertia of the wind wheel) through the impeller, increase the speed through the main shaft transmission chain, and the gearbox, and then drive the generator rotor to rotate to generate electricity.
The semi-direct drive concept was born out of the problems encountered in the development of direct-drive and double-fed wind turbinesin the process of large-scale development. characteristics of both.
The difference between semi-direct drive wind turbine and direct drive wind turbine:
1. The principles of the two are different,
1. A direct-drive wind turbine is a generator directly driven by the wind, also known as a gearless wind turbine. This generator is driven by a multi-pole motor directly connected to the impeller, eliminating the need for a traditional component such as a gearbox.
2. The semi-direct drive wind turbine adopts one-stage or two-stage speed-increasing gearbox, multi-pole synchronous generator, and full-capacity converter. In addition, in order to reduce the weight of the engine room, semi-direct drive wind turbines are mostly compact models, that is, the low-speed shaft is eliminated or the length of the low-speed shaft is reduced, and the output shaft of the speed increase box is directly connected to the main shaft of the generator.
2. The advantages of the two are different
1. The direct-drive wind turbine does not have a gearbox, which reduces transmission losses and improves power generation efficiency, especially in low wind speed environments. , the effect is more significant.
2. The semi-direct drive generator rotates at a high speed. This feature determines that semi-direct drive can improve the reliability and service life of the gearbox on the one hand. At the same time, compared with direct drive generators, it can take into account the corresponding generator design and improve the design and manufacturing conditions of high-power direct drive generators.
3. The structures of the two are different.
1. The direct-drive wind turbine uses a multi-pole motor directly connected to the impeller for driving, eliminating the need for a gearbox. part. Since the gearbox is a component that is easily overloaded and has a high rate of premature damage in megawatt wind turbines, there is no direct-drive wind turbine without a gearbox.
2. The semi-direct drive concept was born out of the problems encountered in the development of large-scale direct drive and doubly-fed wind turbines, taking into account the characteristics of both. Structurally speaking halfDirect drive can be similar to double-fed and has the characteristics of various layout forms. At the same time, the spindle-less structure currently under study also has a similar appearance to direct drive.
The above content refers to Baidu Encyclopedia - Semi-direct drive wind turbine
The above content refers to Baidu Encyclopedia - Direct drive wind turbine