Not until the ______ of Yellowstone Park in the late nineteenth century did the United States have a national park.
People wandering in the fairground or park area()wear a uniform.
People wandering in the fairground or park area()wear a uniform.
三相系统的直流经过Park变换后,转化为d、q轴分量中的基频交流。
Park变换的物理意义是:定子的静止三相绕组被两个同转子一起旋转的等效绕组所代替,并且三相的对称交流变成直流。