TIDUF23 may 2023
Due to the large amount of energy storage possible in the DC bus capacitors, discharge resistors are required to bring the DC bus to a safe voltage in a reasonable amount of time. The Discharge PCB mounts to the V+ and V- terminals of one of the DC bus capacitors and has high-power surface mount resistors in addition to a board-to-board connector for the DC bus voltage sense measurement on the Controller. The resistors are sized to discharge the bus from a nominal voltage of 800 V to less than 50 V in under a minute. This requires the resistor network to dissipate a maximum of 9.4 W across 9 resistors and it has a working voltage rating of 1500 V.