Power Electronics Failure with Short Circuit

The most frequent issue within EDU during early phase of the integration would be the inverter failure with short circuit with many reasons but its diagnostics and root case investigation is not that easy compared to other mechanical system due to the dynamics of the complex electrical architecture. This can be mitigated by having correct design review and HiL test.

I can also offer a systemic approach to root cause analysis with a bunch of experience from field failure.

Driveline Oscillation

Motor oscillation at low speed with high torque is well known issue and the driveline system is very prone to extreme vibration and component failure without any clutch elements in BEV when it comes to this oscillation mode and wheel sleep event being exposed to the extreme shock load at low frequency that is not normally considered and tested for driveline component. The oscillation can be mitigated with Anti-oscillation feature within software that was tested in the vehicle as you can see the vibration has been removed effectively with the shudder compensation feature on. This extreme use case also can be considered as requirement for durability.

[Fig 1. Without SW feature]

[Fig 2. With 'Shudder Compensation' on]

Performance Derating and Thermal Management

Normally Motor manufacturer provide two curves for peak(e.g. for 30s or 60s) and continuous(60mins) but OEM is not sure how to translate these characteristics and how the vehicle reacts out of this peak performance and if the derated performance is acceptable for usage. Motor manufacture should be able to present clearly its achievable performance between peak and continuous area and certify with its thermal limit in place and OEM also should be clear about required performance for continuous and peak and test in different use case and environment to make sure how they can protect the customers with its known performance. The EV has got lots of protection layer for Battery, EDU and electrical components that trigger the derating mode and the thermal management system should decide how to prioritise the cooling for which component at its different mode.