Power Electronics: Notes

The hybrid-relevant power electronics of the E72 are divided into two control units:

Auxiliary Power Module APM
Power Electronic Box PEB

Both control units are installed above the combustion engine in the engine compartment. The safety cover protects against touching the high voltage connections directly. Both control units are high voltage components.

There is a bridge on the safety cover, which closes the circuit of the high voltage interlock loop. Four easily accessible screws must first be unscrewed in order to remove the safety cover. The safety cover is still attached via a fifth screw that cannot be seen initially. The bridge must be unlocked and pulled out so that this screw can be unscrewed. This interrupts the circuit of the high voltage interlock loop and de-energizes the high voltage electrical system. Only now, the fifth screw can be unscrewed and the safety cover can be removed.

Fig 1: Identifying Installation Location Of APM And PEB

Courtesy of BMW OF NORTH AMERICA, INC.

APM AND PEB EXPLANATION CHART

Index	Explanation
1	Bridge for high voltage interlock loop
2	Power Electronic Box PEB
3	Safety cover
4	Auxiliary Power Module APM

Fig 2: Identifying Auxiliary Power Module System

Courtesy of BMW OF NORTH AMERICA, INC.