| 摘要 |
PROBLEM TO BE SOLVED: To more reliably detect two-phase current when a current detection system by one current detection element is applied to a two-phase modulation system.SOLUTION: Current detection means detects a phase current of a motor on the basis of a signal generated by a current detection element connected to a DC side of an inverter circuit in correspondence with a current value and a PWM signal pattern. PWM signal generating means generates any two-phase PWM signal patterns out of three-phase patterns in the way that it follows a rotor position. The PWM signal generating means increases and decreases duty in a first phase of the three phases on both a delay side and an advancing side with an arbitrary phase of a carrier period as a reference, in a second phase on either the delay side or the advancing side, and in the third phase in the opposite direction. Timing adjusting means makes adjustments so that the current detection means detects current at fixed timing with respect to one of the phases within the carrier period and detects current at fixed timing with respect to the other phases or can detect current at variable timing in accordance with magnitude of an output voltage. |
