After over voltage is generated, in order to prevent the internal circuit from being damaged, the over-voltage protection function of the inverter will act so that the inverter will stop running and the equipment can not work normally. Therefore, measures must be taken to eliminate over-voltage and prevent the occurrence of faults. Due to different applications of the inverter and the motor, the causes of over-voltage are not the same, so appropriate measures should be taken according to the specific circumstances.
2. Over-voltage generation and regenerative braking The so-called inverter over-voltage, refers to a variety of reasons caused by the inverter voltage exceeds the rated voltage, concentrated in the inverter DC bus DC voltage. During normal operation, the DC link voltage of the inverter is the average value after three-phase full-wave rectification.
If 380V line voltage calculation, the average DC voltage Ud = 1.35U line = 513V. When the overvoltage occurs, the storage capacitor on the DC bus will be charged. When the voltage rises to about 700V, the inverter will overvoltage protection according to the model. There are two main reasons for overvoltage:
Power over-voltage and over-voltage regeneration. When the inverter three-phase power fluctuations, frequent undervoltage, overvoltage fault, may be appropriate to adjust the "undervoltage operating point setting" "overvoltage operating point set" these two parameters.