| 摘要 |
PURPOSE:To reduce current to be supplied to a motor, to reduce in size the transistor of an inverter, and to decrease in size a whole driver by varying an excitation command in response to a torque range. CONSTITUTION:An excitation command to be supplied to a vector calculator 22 is selectively supplied from two excitation instructing circuits 24, 26. The first circuit 24 is used in a relatively low torque range to output an excitation command when an efficiency is seriously considered. The second circuit 26 outputs a torque seriously considered excitation command, and outputs a constant or predetermined excitation command when a required torque becomes high. Thus, when travelling on a flat road at a predetermined speed, the excitation command is so applied that the efficiency becomes maximum, and when a high torque is required at the time of acceleration or climbing on an ascent, the command is reduced to a predetermined value to output a sufficiently high torque. |
