| 摘要 |
The invention relates to a method of starting an asynchronous machine irrespective of whether the rotor of the machine is rotating or not when the machine is supplied by an inverter provided with a separate moment and flux or moment and magnetizing current control, which is faster than the time constants of the asynchronous machine. According to the invention, zero moment is set as a target for the control, a voltage is supplied to the stator of the machine by the inverter, a stator current vector and a stator flux generated by the voltage is determined, an estimate of that vector or some other quantity comparable to the stator flux is determined, a moment caused by the stator flux vector and the stator current vector is determined and information of the moment is supplied to the control, which tries to zero the caused moment by making the stator flux and a rotor flux generated thereby cophasal, thus synchronizing the supply frequency of the inverter with a possible rotation of the machine rotor. |
