ASYNCHRONOUS THREE-PHASE MACHINES, FED BY FREQUENCY CONVERTERS

摘要

In all operation modes the desired motor thrust is the controlling value and sets the required value of motor current. The actual motor current is controlled by the regulating section. In the lower speed range, tht is when the inverter output voltage is less than maximum, the motor current is controlled by output voltage variation. When the output voltage reaches maximum, that is in the higher speed range, control of the thrust is performed by slip frequency variation. The inverter voltage and frequency output are controlled by the actual speed signal and the required slip frequency value.