Hi,
I have a customer who used AMC1301 on inverter products, but there was a problem during the factory test, resulting in failure to deliver normally.
Description of the fault state: The frequency converter is powered on, the three-phase output current detected by the hardware is consistent, while the three-phase output current detected by the software is inconsistent. Maintenance inspection found that the AMC1301 input VINN and VINP collection was incorrect; When detecting the same batch of devices, inconsistency is found at the input end, and the manufacturer is required to provide an analysis report.
After the production feedback was received, the fault information E047 (current imbalance) was detected by oscilloscope, and the actual current was found to be no problem. The current detection signal of the control board was detected, and the output IW signal of the inverter was found to be incorrect, and the test value was too small.
Then the hardware circuit was tested, and IT was found that the resistance value of the front resistor of the AMC1301 isolator was incorrect. The actual test was 18.6Ω, and the resistance value before the IR/IT/IU three-phase current detection of the inverter was respectively 28.1Ω/28.6Ω/28.5Ω. Compared with other normal machines, the R123 resistance at this position is 33Ω, so the AMC1301 is judged to be invalid.
Schematic diagram W -- WHE directly parallel two 6mΩ sampling resistors.
Please help to review this part of the schematic, thank you!
