Operation Description

WARNING: This page is about a different car, the 2012 Infiniti M35h. However, it is still accessible from the selected car via links, so may be relevant.

When High-voltage System is Connected

When vehicle is READY, HPCM controls the system main relays and first applies current via the resistor inside the DC/DC converter, protecting the circuit from high-voltage inrush current.

System relay operation

Turns ON the pre-charge relay and system main relay 1, and applies current to the circuit via the resistor. At this time, the capacitors inside the traction motor inverter are charged. (Pre-charge)

Fig 1: HPCM Input/Output Circuit (Relay 1)
Courtesy of NISSAN NORTH AMERICA, INC.
When the capacitors are charged, system main relay 2 turns ON and the pre-charge relay turns OFF, connecting the high-voltage circuit.

Fig 2: HPCM Input/Output Circuit (Relay 2)
Courtesy of NISSAN NORTH AMERICA, INC.

When High-voltage System is Disconnected

When high-voltage system is disconnected, HPCM turns system main relay 2 OFF and discharges the capacitors inside the drive inverter (discharge). When discharge is completed, main relay 1 turns OFF, disconnecting the high-voltage circuit.