Description and Operation — Electric Drive Control — Overview

Overview

The center of the motor control system is a microprocessor called the Inverter System Controller (ISC), also known as the SOBDMC. The Inverter System Controller (ISC) receives inputs from sensors and other electronic components. Based on the information received and programmed in its memory, the Inverter System Controller (ISC) generates output signals to control various relays, solenoids and actuators.

The Inverter System Controller (ISC) can wake up only if an external signal is received from the BCM, BCMC, DCDC, BECM, GWM or ECM. There are three circuits that wake up the Inverter System Controller (ISC): ISP-R from the BCMC, the wake-up circuit from the BCM, and the HEV wake-up circuit from other unique HEV modules. The Inverter System Controller (ISC) will not wake up if the vehicle Battery Power (VBPWR) circuit from the 12V battery is not connected to the module and the module ground wire(s) are not connected. Application of any of the 3 wake-up signals will cause the Inverter System Controller (ISC) to close the power relay built into the BCMC VPWR circuit, which supplies main 12V power to the Inverter System Controller (ISC) and several other components.

Once the Inverter System Controller (ISC) is awake, it can maintain 12V power through the relay. The Inverter System Controller (ISC) can operate for several minutes after the ignition is turned off to perform various system functions. The Inverter System Controller (ISC) can be woken up and operate while the high-voltage battery is charging on a plug-in hybrid electric vehicle, to control the HVAC system for cooling the high-voltage battery.

Some failure modes require a complete power shutdown and restart of the Inverter System Controller (ISC) to recover. To ensure a complete module power shutdown, you must wait several minutes after switching off the power, or monitor the Inverter System Controller (ISC) communication to determine that the module has fully shut down.