1. The engine is inexpensive and lightweight.
2. The working conditions of wind turbines are relatively difficult, with relatively high vibrations. Magnets in motors using permanent magnets are subject to magnet loss. With the improvement of technology, this problem is gradually solved.
3. When using a dual-powered motor, the frequency converter only needs one-third of the frequency conversion. A permanent magnet motor requires frequency conversion at full power, which requires a lot of additional cost. 1.5 MW as an example, the frequency conversion alone must increase. The cost is more than 1 million.
4. There are already permanent magnet wind turbines, such as Goldwind and Xiangdian.
What are the advantages of direct drive motors over dual feed motors?
Hello, there is basically nodifference between doubly fed generators and wirewound asynchronous generators. the principles are the same, the structure is the same, it's basically the same thing with different names. To be precise, doubly fed generators are a special type of wound-type asynchronous generators. The main objectives are slightly different. Double-fed generators are powered by a rotor-side frequency converter. a resistor connected to the side of the rotor to adjust the speed. Since the inverter power supply has high frequency harmonics and impacts, the dual-fed generator will take more care of insulation and growth when designing the motor body than the asynchronous generator with conventional winding. generator. Large inductance is used to improve the filtering effect, and as the frequency converter has a certain voltage levelOn, in order to fully utilize the capacity of the frequency converter, the rotor voltage of the double-fed generator must match the frequency. converter during design. Generally speaking, the doubly fed generator will be larger than the conventional wound type asynchronous generator which is designed to be larger. For example, the rotor voltage of a doubly powered motor used in wind power is 690 V, while that of a conventional wound asynchronous generator is over 300 V.
Essentially, there is no big difference between the two. The main differences in application scenarios lead to some changes in some small places.
There is no speed-increasing gearbox, which completely solves the bottleneck problem of high gearbox failure rate that affects fan reliability; therehas no mechanical parts such as gearboxes in the transmission chain, which have a low failure rate; noise, simple structure and easy to maintain and use. It has greater reliability and higher mechanical efficiency; using permanent magnet synchronous generator, the generator has no excitation loss, which effectively improves the efficiency of the fan, it has no carbon brushes and slip; rings, which solves the problem of high failure rate of slip rings and carbon brushes in double-fed generators. It eliminates the trouble of regular powder cleaning, reduces generator maintenance and improves fan availability, and meanwhile the operating cost is low. 20-year lifespan, total cost of ownership (TCO) is 15% lower than a dual-powered fan with a step-up housingspeed % higher.