5 kVA Single Phase Frequency Converter Output Voltage Issue

Hello, everybody! Our HZ-50-1105 5 kVA single phase frequency converter has no output voltage. The display for voltage and frequency are both 0. The converter has been working until recently. As we turned the converter on, there would be a warning buzzer. We confirmed there is input voltage and we also tried to replace the fuse but there is no output voltage. Do you have any recommendations on what else we can check?

Alexander wrote:
It sounds like the warning buzzer might indicate a fault with the driver board. I'd suggest checking if the IGBT (Insulated Gate Bipolar Transistor) module is functioning correctly. Sometimes, low or no output voltage can be due to issues with the IGBT or the driver circuitry.

Alexander wrote:
The single phase frequency converter has a warning buzzer, which may be a fault with the driver board. Please now follow the attached troubleshooting document to measure the IGBT module and driver board, and feedback with the measurement results for the next step.

ATO wrote:
Thank you for the response! Below are the measurements following the 5kVA converter troubleshooting document. The N-G2 DC voltage is very low.
Fuse resistance: 0.1 ohm
IGBT module detection:
L-G1: 9.99 KΩ
L-G2: 9.99 KΩ
N-G1: 10.01 KΩ
N-G2: 10 KΩ
Driver board checkers:
J1: 25.22 VAC
J2: 25.2 VAC
J3: 25.22 VAC
J4: 25.17 VAC
L-G1: 1.451
DCV L-G2: 1.288 DCV
N-G1: 1.356 DCV
N-G2: 0.689 DCV
We are currently lining down because of the converter. We would appreciate your help with troubleshooting.

The issue appears to be within the N-G2 cell. I verified that the N-G2 connector was inserted properly and cleaning the contact pins did not make any difference. I could only perform the visible inspection on the top of the PCA and I could not see any burnt spots or components. I would appreciate any additional troubleshooting instructions you can offer.

Alexander wrote:
Based on your feedback and the measurements provided, it appears the driver board is damaged. The voltage discrepancies, particularly in the N-G2 readings, suggest a fault on the board itself. You will need to replace the driver board with a new one to resolve the issue.