| 摘要 |
PROBLEM TO BE SOLVED: To reduce switching loss and eddy current loss of a DC brushless motor driven through a two-phase bridge connection three-phase inverter especially during low speed rotation. SOLUTION: When the r.p.m. of a motor is controlled such that the DC power supply voltage V of an inverter is kept constant up to N1, as shown on fig. (b), before the r.p.m. is increased by increasing the on duty of PWM(pulse width modulation), as shown on fig. (a), and then the r.p.m. is increased by increasing the V, as shown in Fig. (b), the relation between speed command value and output voltage command value is switched from conventional one shown by a dot line (a) to one shown by a solid line when two switches on the diagonal of a two-phase bridge connection is subjected to PWM (refer to intervals T1, T4) and when other switches are subjected to PWM. |
