发明名称 |
Induction motor drive unit, motor drive system, and elevating system |
摘要 |
A slip frequency is estimated from a current instruction or detected currents in an induction motor. Acceleration impossibility in an induction motor drive unit is determined, when the slip frequency exceeds the maximum torque generating slip frequency for the predetermined interval or the time integrating result exceeds a predetermined value; when the q-axis magnetic flux exceeds the maximum torque generating q-axis magnetic flux or exceeds for a predetermined interval; when the estimated rotational speed is under a predetermined value; when the rotational speed variation rate is negative; and when the rotational speed instruction value or the estimated rotational speed is equal to or smaller than a predetermined value. An induction motor drive system and an elevating system including the induction motor drive unit are also disclosed.
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申请公布号 |
US7902790(B2) |
申请公布日期 |
2011.03.08 |
申请号 |
US20080142002 |
申请日期 |
2008.06.19 |
申请人 |
HITACHI INDUSTRIAL EQUIPMENT SYSTEMS CO., LTD. |
发明人 |
ARAKAWA YOICHIRO;NAGATA KOICHIRO;TOMITA HIROYUKI |
分类号 |
H02P21/14 |
主分类号 |
H02P21/14 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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