| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize accurate sensor-less vector control with no increase in shunt resistor in 2-shunt method. <P>SOLUTION: In an inverter main circuit, three arms in which two switching elements are connected in series to a DC power source, for contradictory ON/OFF operation, are connected in three-phase bridge. The three-phase pseudo AC voltage of three-phase PWM method is applied to a motor. A shunt resistor is connected to a DC power source, in series along with at least two arms among the three arms of the inverter main circuit. A control means detects a current flowing to the shunt resistor at a predetermined cycle and controls ON/OFF operation of respective switching elements of the inverter main circuit based on the detected current. The control means uses a current value detected at the time, almost before 180°, corresponding to a predetermined angle range where the ON time of switching element is continuously at a specified value or less, instead of a current value in a predetermined angle range. <P>COPYRIGHT: (C)2010,JPO&INPIT |
