System Main Relay Control System Description

SYSTEM

SYSTEM MAIN RELAY CONTROL : System Description


SYSTEM DIAGRAM







HPCM INPUT/OUTPUT SIGNAL CHART

Input Signal Item





Output Signal Item






DESCRIPTION

HPCM controls ON/OFF of the system main relays (system main relays 1 and 2, and pre-charge relay) to connect and disconnect the hybrid system high-voltage circuit.

OPERATION DESCRIPTION

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.
1.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)





2.When the capacitors are charged, system main relay 2 turns ON and the pre-charge relay turns OFF, connecting the high-voltage circuit.





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.

POWER DISCONNECT CONTROL AT TIME OF VEHICLE COLLISION

Because the hybrid system uses high-voltage power, when the air bag activation signal is detected at the time of a vehicle collision, HPCM turns the system main relays OFF.

CONDITIONS FOR SYSTEM MAIN RELAY OFF

HPCM turns OFF the system main relays as per the following conditions.
- When the ignition switch is turned to OFF
- When the air bag activated
- When the interlock switch turned OFF
- When a malfunction is detected in the hybrid system (fail-safe)
- When the 12V battery voltage is low