Electrical Insulation at 800 V Electric Vehicles

Currently, electric vehicles use drive-fed traction motors that rely on 400 V power supplies. But factors such as motor size, operating temperature, power, efficiency, batteries, and charging time are leading a push toward higher voltages. Accordingly, motor and power electronic designers and producers are targeting 800 V. However, this voltage could be a source of electrical stresses on electrical insulation systems. Because the insulation used in low-voltage motors is too thin, the insulation system risks being subjected to the same electrical field strength as with high-voltage motors. This article describes the potential stresses on insulation systems associated with pulse width modulated drives. Solutions for detecting insulation issues and methods of increasing insulation system function will also be presented.