| 摘要 |
The invention is concerned with a method for operating inverter-fed rotary current drives for vehicles, in particular for railways, in which during normal operation the rotor frequency of the rotary current asynchronous motor is made to follow its rotational frequency for the purpose of keeping constant a predetermined torque and overspeed or slip processes are compensated by means of the actual vehicle speed, under the influence of the engine characteristic line Md = F(n). The extreme steepness of the natural characteristic line of the asynchronous motor leads to troublesome dynamic processes when the rotor frequency is being fixed. In order to overcome this disadvantage and to make the steepness of the torque/engine speed characteristic line of the rotary current asynchronous motor capable of being matched to the requirements of optimum slip and overspeed protection by means of circuitry: - in each case the difference is formed between the rotational frequency (frot) of the rotary current asynchronous motor and a frequency (fv) assigned to the actual vehicle speed - this frequency difference is reduced by a factor (k) in accordance with a desired flattening of the motor characteristic line and - the reduced frequency difference (1/k . frot-fv) is added to the rotor frequency, formed from the rotational frequency (frot) and set slip frequency (fsset), for the rotary current asynchronous motor depending on whether it is a case of travel mode or braking mode, with the correct sign with the effect of reducing the motor slip frequency. <IMAGE> |
