The frequency converter is in use suddenly the speed reduces, then the debugging is out of control, how to do?
The power over voltage means that the DC bus voltage exceeds the rated value because the voltage of the supply is too high. Now, most inverters have an input voltage of up to 460V, so the overvoltage caused by power supply is extremely rare. The main issue discussed in this paper is the regenerative overvoltage. The regenerative overvoltage mainly has the following reasons: when the big GD2 (flywheel moment) load slows down, the inverter deceleration time is set too short;
Among them, overvoltage is the most common phenomenon. After the overvoltage is generated, the inverter will prevent the internal circuit from damaging, and its over-voltage protection function will make the inverter stop running, resulting in the equipment can not work properly. Therefore, measures must be taken to eliminate excessive voltage and prevent the occurrence of faults. As the frequency converter and motor applications are different, the causes of over-voltage are not the same, so we should take appropriate countermeasures according to specific circumstances.
Excessive voltage generation and regenerative braking, the so-called inverter over-voltage, refers to a variety of reasons caused by inverter voltage exceeds the rated voltage, concentrated in the DC bus frequency converter DC voltage. In normal operation, the DC part voltage of converter is the average value after three-phase full wave rectification.
The average DC voltage Ud=1.35U line =513V is calculated by the 380V line voltage. When the overvoltage occurs, the energy storage capacitor on the DC bus will be charged, and when the voltage rises to about 700V, due to different models, the converter will protect the voltage. There are two main causes of over voltage: over voltage and over voltage.
Overvoltage prevention measures: due to over-voltage causes are different, so the countermeasures are not the same. For overvoltage in parking, if there is no special requirement for parking time or position, it can be solved by using extended frequency converter, deceleration time or free parking. The so-called free parking, that is, the frequency converter will switch off the main switch, so that the motor free sliding stop. If the parking time or parking position have certain requirements, then the DC brake (DC brake) function can be used
