What are the reasons and protective measures for inverter overcurrent?

“What are the reasons and protective measures for inverter overcurrent? When the inverter is working, the upper and lower tubes of the same bridge arm are always in the alternate conduction state. In this process, due to some reason (for example, the temperature of the environment is too high), the parameter of the component is changed, which leads to the through occurrence.

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The inverter manufacturer talks about the main reasons for inverter overcurrent:

1. Non-short circuit overcurrent, this is mainly because:

a. The motor is seriously overloaded.

b. The reason is that the motor accelerates too fast.

c. Because the U/f ratio (torque compensation) is set too high, but the motor is under light load.

2. Short-circuit overcurrent, the inverter manufacturer said, this is mainly because:

a. Current overcurrent caused by a short circuit on the load side;

b. The load side is grounded

c. As a result of the formation of through-through, the upper and lower transistors of the same bridge arm of the inverter bridge are turned on at the same time. When the inverter is working, the upper and lower tubes of the same bridge arm are always in the alternate conduction state. In this process, due to some reason (for example, the temperature of the environment is too high), the parameter of the component is changed, which leads to the through occurrence.

The inverter manufacturer stated that the following protective measures can be taken against overcurrent:

1. On the premise of meeting the requirements of production equipment and manufacturing process, strive to increase the acceleration or deceleration time to avoid overcurrent during acceleration or deceleration.

2. Check whether the matching between the inverter, motor and production equipment is good enough, the transmission part is not flexible enough, and whether the material is stuck.

3. The inverter manufacturer believes that the integrity of the inverter is also a key link. For example: Whether the three-phase voltage balance meets the requirements, if it does not meet the requirements, check whether the drive waveform of the inverter is normal. In addition, if the inverter main circuit component of the inverter fails, it will also cause the occurrence of overcurrent.

4. When the output cable of the inverter is lengthened, it will increase high-frequency loss, resulting in insufficient output of the inverter, so the following methods can be used to deal with it:

a. Modify some parameters on the inverter. When conditions permit, you can modify the output carrier frequency of the inverter, reduce the output frequency, and reduce the high-frequency loss. In addition, the output torque can be increased to minimize the impact of high-frequency loss.

b. Install an AC reactor at the output end of the inverter to effectively prevent overcurrent. Regarding the choice of reactor, it must be selected according to the opinions of the inverter manufacturer.