| 摘要 |
PROBLEM TO BE SOLVED: To enable current detection even when a voltage modulation rate is high.SOLUTION: An electric power conversion system detects a current of each phase on the basis of a voltage drop of a current detecting resistor element connected in series with a lower arm switching element on a lower arm side of each phase of a PWM-controlled three-phase inverter by comparing three-phase duty command values corresponding to three-phase voltage commands with a carrier wave. The electric power conversion system includes a control device for, when the three-phase duty command values are a maximum phase, an intermediate phase, and a minimum phase in the decreasing order, and when a power supply time of the lower arm switching element of the intermediate phase is less than a predetermined value, providing a current detection period which shifts the duty command value of the intermediate phase toward a negative direction and a voltage adjustment period which shifts the duty command value of the intermediate phase toward z a positive direction, to detect the current of each phase in the current detection period. |
