| 摘要 |
PURPOSE:To facilitate self-readhesion by detecting a frequency corresponding to the current of an idling or slipping motor among a plurality of induction motors for driving an electric motor vehicle and then feeding back thus detected frequency through a primary delay element. CONSTITUTION:DC power of a stringing 1 is inverted through an inverter 5 into VVVF power for driving four induction motors 6A-6D and an input current IM is detected through a CT10 at a detecting section 11. Rotational speeds are then detected by means of pulse generators 7A-7D for respective motors at frequency operating sections 8A-8D, and selecting sections 9A, 9B determine a reference rotary frequency fro and a rotary frequency at the time of idling/ slipping based on maximum and minimum values at the time of powering and regeneration. An adding/subtracting section 17 produces a signal fvs based on the difference between fro and frs. The fvs is then compared 12 through a comparing element 20 with the current IM and the current pattern IP thus determining a differential current IM. The fvs is added 15 through a primary delay element 21 to the pattern frequencies fSP, fro and a frequency corresponding to the IM and the result is fed back to the inverter 5. According to the constitution, self readhesion is carried out easily. |
