| 摘要 |
PROBLEM TO BE SOLVED: To surely enable a detection of a DC bus current corresponding to each phase even if voltage commands of respective phases are near by in a PWM inverter for obtaining a phase current used to feedback control from a DC bus current. SOLUTION: When first voltage command values vv1* and vw1* of a v phase and a w phase are near by, as shown in Fig. (b), a correction in which the third w phase is offset from the vw1* by a vcmp23 in the former half of a PWM period to set a difference from the v phase to a Dmin and the vw1* is offset in a reverse direction by the vcmp23 in the latter half of the period is executed as a second voltage command value, and a PWM pulse is generated. As shown in Fig. (c), falling and rising timing interval ΔT of the PWM pulse between the phases is assured by the above correction, a DC bus current Is during switching can be detected by the respective pulses. As shown in Fig. (d), phase currents iu, iv and iw of the respective phases can be clearly obtained. |
