FEV has developed PD-HVX (Partial Discharge – High Voltage X) for the early detection and prevention of PD in high-voltage electric-drive units (EDUs). PD can cause damage to the insulation in modern EDUs, and in the worst-case scenario this can result in total failure of the vehicle.

PD-HVX uses electromagnetic frequency analysis to measure the electromagnetic fields around a drive unit. The software then uses the results to determine whether PD is occurring within the EDU during operation, which enables customers to take action.

PD is a local, electrical sparkover that can occur at high voltages above 600 V. It is caused by extremely small defects or inhomogeneities in insulation material or soiled surfaces. If it remains unnoticed within an EDU and occurs repeatedly, it can lead to gradual damage of the insulation and to premature stoppage of the vehicle.

“PD has been known for a long time in the field of electrical systems engineering and high-voltage transmission networks, where corresponding tests are common practice,” said Dr Michael Stapelbroek, vice-president, electric powertrain, at FEV.

“In the automotive sector, the phenomenon is just gaining focus with the increasing spread of 800 V batteries. By detecting partial discharge in the EDU at an early stage, possible reasons for insulation damage in the electronics can be eliminated during the development process. This prevents delays due to premature vehicle failure and additional costs during development.”