I am not a design engineer, but as a quality management professional, I would like to outline some major causes of inverter failures that I’ve encountered:

1. Lack of Phase Loss or Overvoltage Protection: If the circuit design of a three-phase inverter does not take into account input phase loss protection or overvoltage protection, the inverter can easily get damaged during operation.

2. Improper Circuit Design: Poor circuit design is another key reason why inverters are prone to failure.

3. Component Selection in the Early Development Stage: The selection of all electronic components during the design and development stage is crucial. The technical confirmation of all components before production is especially important.

4. Temperature Control in Soldering Processes: Temperature control during reflow soldering, wave soldering, and manual soldering of components is critical. Components that suffer heat damage may not show faults during factory testing but could have a shortened lifespan or fail under high current and voltage conditions once they are in the market.

In summary, aside from failures caused by static electricity, factors such as circuit design integrity, component selection, and temperature control during soldering are major contributors to inverter failures under high current and voltage conditions.