engleski

Accuracy of the stator and rotor voltage frequency measurement (motor speed estimation).

The stator and rotor voltage frequency is determined on the base of the number of cycles counting between two consecutive rotor voltage zero crossing. The sampling frequency of the rotor voltage frequency measurement is 10 kHz, and estimation uncertanty of the time cycle is 0.1ms. The rotor voltage frequency is changing between 0 and 100Hz. It is possible to rich a higher values due to a overrsynchronous mode of operation. It is realistic to expected maximal speed 30% higher than a synchronous, which means that maximum ecpected frequency can be no more then 130Hz. Maximum possible error of estimation is +/-1% for 100Hz signal. The largest rotor voltage frequency estimation error is when motor reversing the speed from oversynchronous lowering to maximal (synchronous) speed hoisting because maximal rotor voltage frequency in the first moment can be 230Hz. Frequency of the rotor voltage is estimated as mean value of all three phases, and output frequency can be filtered with low pass filter. Then error of estimation can be less than calculated, but response is slower.

speed estimation; speed error; speed accuracy; sampling frequency; speed estimation

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