Hyundai Sonata Hybrid 2011-12, Emergency Response Manual, Page: 14 / 42

Hyundai Sonata Hybrid Page 12
Vehicle Systems Overview
High-Voltage Electrical Isolation:
Unlike the 12V electrical system that is grounded to the vehicle’s chassis, the Sonata Hybrid’s high-
voltage electrical system is designed to be isolated from the vehicle.
Regulation of High-Voltage Electrical Current:
Current from the High-Voltage Battery is
controlled by the Power Relay Assembly (PRA),
which consists of Positive and Negative Main
Relays, a Pre-charge Relay, Pre-charge Resistor,
and the Battery Current Sensor. The PRA is
located inside the High-Voltage Battery Pack
Assembly and controls the high-voltage power
circuit between the High-Voltage Battery and the
Hybrid Power Control Unit.
High-Voltage Safety System:
There are multiple safety systems incorporated
into the Sonata Hybrid. The system that protects
the High-Voltage Electrical System is called the
Battery Management System (BMS). The BMS is
located inside the High-Voltage Battery Assembly
and measures several parameters to maintain the
optimal performance of the High-Voltage Battery.
It controls the battery cooling fan to ensure
proper battery operation. In addition, if a system
fault occurs, the BMS turns off the PRA to protect
the system.
PRA
BMS
Shown with back Seat Removed
Shown with back Seat Removed