OPEN-PHASE DETECTION SYSTEM AND LOAD DRIVE UNIT

摘要

PROBLEM TO BE SOLVED: To constitute an open phase detection system so that input open phase is detected for a short time, when a capacitor of a small capacity value for smoothing is used at a converter portion. SOLUTION: A voltage between busbars is sampled by a voltage detecting portion (S1); and on the condition that the inclination A immediately prior to this timing has as its sampling voltage V less than a predetermined voltage V1 is sharper than a predetermined inclination B (T8:YES), a missing phase detecting portion discriminates (detects) that the phase is the input missing phase (T9). COPYRIGHT: (C)2007,JPO&INPIT