当采用6脉波三相桥式电路且电网频率为50Hz时，单相交交变频电路的输出上限频率约为30Hz。
查看答案
矩阵式变频电路是一种变频电路。它采用的开关器件是全控器件；控制方式是斩控方式。
A. 对
B. 错
New Yorker Katy Benson wears, other people notice.
A. Whatever
B. Whoever
C. However
D. Never
It might be something she made herself, or a(n) combination of things she has put together.
A. few
B. odd
C. nothing
D. lots
What we are planning is technology never seen in Australia before.
A. outdated
B. out of fashion
C. cutting-edge
D. ancient
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