| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize a low-cost motor controller which can detect an excess state (overcurrent) of power source current to be supplied to a three-phase inverter. <P>SOLUTION: A power consumption P of a motor 3 is presumed according to formula: P≈I<SB>q</SB>×V<SB>q</SB><SP>*</SP>. Here, this formula is available since a d-axis current command value I<SB>d</SB><SP>*</SP>of the motor controller 100 is constantly set to "0". It is assumed that the command value (q-axis voltage V<SB>q</SB><SP>*</SP>) is not abruptly changed largely with respect to a time. For example, in a on-vehicle motor-driven power steering system or the like, such an assumption is always satisfied. Accordingly, a value of the power source current Ib can be presumed by a power source current presuming unit 13 according to formula: Ib=P/(η×Vb) (0<η≤1), here, a value of a power factor η can be empirically obtained as its optimum value. <P>COPYRIGHT: (C)2004,JPO |
