| 摘要 |
<p>The method involves producing saw tooth voltage pulses of variable duration (T7) as a function of the load and voltage conditions of the supply system, with reinforcing pulses (T10) succeeding the variable duration pulse (T7). Each saw tooth pulse (T7) is formed from a train of partial voltage pulses composed of pulse of duration (T1), a pulse of duration (T2) and a train of constant duration pulses (T3). The pulses of duration (T1,T2,T3) are of the same polarity, and the time gaps (T4,T5,T6) separating the partial voltage pulses are variable as a function of load conditions and as a function of the motor voltage supply. The reinforcing pulses (T10) are only supplied when the extreme load condition defined by k1*T4 < k2*T5 appears, k1 and k2 being predetermined constants. During the intervals (T4,T5 and T6) the winding of the motor is short circuited.</p> |
