| 摘要 |
PURPOSE:To enable necessary rigidity to be applied even at the time of the stopping of a motor, by shifting the phase of one-side voltage between two sorts of output voltage for comparing two sorts of chopping wave voltage with a voltage command value. CONSTITUTION:Steady-state chopping wave voltage T1 and steady-state chopping wave voltage T2 which is shifted by 180 deg. in phase form the voltage T1 in the same shape are compared with voltage command M by operational amplifiers OP1, OP2, to result in the PWM 1 and PWM 2 of PWM signals. In this case, when the signal PWM 2 is delayed by a delay set value Dt with a delay circuit DEL, then the period of base signals BD1 and BD4 put together and the period of base signals BD3 and BD2 put together, namely, a positive voltage application period and a negative voltage application period are alternately found. As a result, to both ends of a motor, positive voltage and negative voltage are alternately applied, and current ripple is reduced and optimum rigidity is obtained at the time of stopping. |
