General treatment methods for inverter overcurrent problems:
The output side of the inverter is a PWM voltage waveform, and after passing through the motor winding, the output current is approximately a sine wave, and lags behind the voltage by a phase viewpoint, which is determined by the power factor of the motor. The output current of the inverter is detected by a fine resistor or current transformer, and the CPU processes the current signal.
In order to protect the inverter, when the output current is above a certain threshold, the inverter will report an overcurrent problem. The inverter also immediately closes the pulse output. This is an important and necessary way to protect the inverter device from damage. This problem cannot be blocked.
There are many reasons for the formation of inverter overcurrent problems, which should be analyzed according to the actual situation. If you find the right source and then prescribe the right medicine, you can generally deal with it.
The motor cable connects the inverter to the motor. Then analyze the separation from the inverter side and the motor side.
1. The first is the influence from the inverter side.
The common causes of inverter overcurrent on the inverter side are:
The acceleration time is too short. The greater the torque of the motor required at the moment, the torque is proportional to the current, so the current is also large. Extend the acceleration time appropriately.
Improves functionality. If the voltage is raised too high during the start-up process during V/f control, an overcurrent may be formed. Drop the voltage appropriately to increase the value.
The PID parameters are not suitable. If the dynamic response is too high, an overcurrent may be formed. Extend the filtering time, minus P and I.
2. The second is the influence from the motor side.
The common causes of inverter overcurrent on the motor side are:
The motor cable is short-circuited to ground. The cable is not well insulated and has broken skin. The cable insulation can be tested with a shake meter to confirm the quality of the cable.
Motor stalled. At this moment, the inverter will try to use more torque to rotate the motor, which may cause an overcurrent problem.
3. Ultimately, it is a hardware problem.
If the current detection mechanism inside the inverter is not working properly, or there is a problem with the CPU processing mechanism, these cannot be handled by setting parameters, and it needs to be repaired.
If the current of the inverter and the motor does not match, it may also form an overcurrent problem. For example, if a small inverter has a large motor, or the nameplate parameters are written incorrectly, it may form an overcurrent problem.
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