| 摘要 |
PURPOSE:To prevent drive switching transistors from mutual short circuit and also to obtain such motor as is less in flutter and satisfactory in operating efficiency by subjecting a stator winding of a three-phase transistor motor to delta connection and carrying current in a given timing thereto. CONSTITUTION:A pulse train P0 of a period T0 generated from a pulse train generating circuit 1 is supplied to a rectangular wave generating circuit 2, through which rectangular wave trains P1-P6 having period 6T0, on-width 120 deg. and phase difference T0 are generated and supplied to bases of transistors TR1TR6 respectively. Assuming, therefore, a full circuit current be i and a switching loss of the transistors TR1-TR6 anglected, there flow currents iU, iV, iW to stator windings U, V, W respectively. From keeping an on-period of the rectangular wave trains P1-P6 at a drive coming in the range of 120 deg.+alpha (alpha=0-3 deg.), such form factor as is more approximate to a sine wave is obtainable in addition to a short circuit preventive effect. |
