SLVAF35A February 2021 – July 2024 DRV8714-Q1 , TPS2HB16-Q1
The traction inverter motor control system must integrate a large bank of filter capacitors, typically called DC link capacitors, which generates a huge inrush current once the main contactors are closed while the capacitors are fully discharged. Therefore, a pre-charge function is mandatory to limit the inrush current during the power-up procedure. A contactor combined with a current-limiting resistor is the simplest implementation of the pre-charge function.
A process example during the power-up sequence follows:
Additionally, no contact can be stuck and no insulation leakage failure is allowed before closing the contactors. Contactor status diagnosis and insulation detection must be implemented in the system-level design.