| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve current detection accuracy by making offset learning of a current sensor high in accuracy. <P>SOLUTION: When the offset learning execution conditions are established (when determined to be YES at S100) and at a second time learning opportunity and thereafter since operation start (when determined to be NO at S120), the present value of a capacitor temperature Tc of a smoothing capacitor for the operating power voltage of the current sensor is compared with the stored capacitor temperature Tc# at the last learning (S130). Only when the present capacitor temperature Tc is higher than that at the last learning Tc# (when determined to be YES at S130), the offset learning is performed (S140). The present capacitor temperature Tc is stored as the temperature Tc# at the last learning. Thereby, even when the equivalent direct current resistance of the smoothing capacitor has temperature dependency, the current detection can be performed using a suitable offset learning value in correspondence to a change in the ripple voltage level accompanying the temperature change. <P>COPYRIGHT: (C)2009,JPO&INPIT |
