| 摘要 |
PURPOSE:To reduce the current ripple and a motor noise by positively forming freewheeling mode when PWM-controlling an inverter bridge. CONSTITUTION:A pattern generator 16 outputs freewheeling pattern outputs V1- V3 having phase difference of 120 deg. from each other on the basis of the phase signal of electromotive force of a synchronous motor 3 obtained from the output signal of a position detector 5. Adders 17-19 respectively add current references outputted from a current reference generator 8 in the respective phases and freewheeling pattern outputs V1-V3 outputted from the generator 16 to form a corrected current reference, which is inputted as true current reference to comparators 12-14. The outputs of the comparators 12-14 are applied to a drive circuit 15. |
