Generator Control Module Description and Operation
Generator Control Module Description and Operation
Overview
The generator control module is also referred to as the starter generator control module. The generator control module is located in the generator control and battery module assembly which is located in the trunk directly behind the rear seat.
The generator control module is comprised of the following control modules:
* Hybrid powertrain control module
* 14 volt power module
* Drive motor control module
The generator control module functions as an inverter, inverting high voltage direct current (DC) electrical energy to 3 phase alternating current (AC) electrical energy and vice versa. The generator control module also functions as a DC to DC converter, converting high voltage DC to 14 volts DC. The generator control module is located in the generator control and battery module assembly. The generator control and battery module assembly is air cooled.
High Voltage Circuits
Direct Current (DC)
The generator control module is connected to the positive and negative terminals of the high voltage, (DC) generator battery assembly. Both of the negative and positive high voltage DC battery poles are isolated from the vehicle chassis. The positive high voltage DC cable is switched ON or OFF by a high voltage, high current contactor relay contained within the generator control and battery module assembly. All high voltage DC negative and positive DC cables are orange in color to alert the technician to the potential presence of high voltage.
Three Phase Alternating Current (AC)
Three individual cables connect each phase of the drive motor to the generator control module. Each individually shielded cable is orange in color to alert the technician to the potential presence of high voltage. These three cables are routed from engine compartment to the rear of the vehicle in a single conduit.
Low Voltage Circuits
The 14V power module is an electronic device that converts high voltage (115V) DC to low voltage (14V) DC for operation of all low voltage modules and to charge the 12 volt accessory battery. The 14 volt power module is not serviced separately and is part of the generator control module.
Low Voltage (12V) Direct Current
Low voltage (12V) cables on the hybrid vehicle do not require unique coloring or servicing procedures.
Hybrid Powertrain Control Module
Location
The hybrid powertrain control module is a non-serviceable, flash-programmable micro-processor that is part of the generator control module.
Operating Functions
The hybrid powertrain control module is the main controller of powertrain operation. The hybrid powertrain control module determines when to perform normal operating modes such as auto stop, launch assist mode, and regenerative braking. The hybrid powertrain control module also operates in conjunction with the battery energy control module to determine when to enable and disable the DC high voltage circuits. The motor control module operates the drive motor based upon hybrid powertrain control module commands.
Communication and Hosted Diagnostics
The hybrid powertrain control module is the host controller for DTC and scan tool parameter information for the following control modules:
* 14V power module
* Drive motor control module
* Battery energy control module
These modules diagnose their own operation and determine when a fault condition is present. The 14V power module communicates diagnostic status to the hybrid powertrain control module over serial data.
The drive motor control module and the hybrid powertrain control module exchange information and commands on a serial peripheral interface bus internal communication circuit as well as the hi-speed serial data communication circuit.
In the event the battery energy control module (BECM) communicates a fault condition, the hybrid powertrain control module will determine if one or more operating modes are affected and notify the vehicle operator by requesting the MIL illuminate and/or by displaying a message in the Driver Information Center. In addition, the hybrid powertrain control module will store the associated DTC information for retrieval by a scan tool. Some hosted modules may require an ignition cycle to clear certain DTCs from the hybrid powertrain control module.
Circuit Inputs
In addition to data parameters, the hybrid powertrain control module directly monitors the following signal circuits:
* Engine crankshaft position sensor signal (via serial data message from ECM - not direct)
* High voltage interlock circuit
* Brake Pedal Position
* Drive Motor Temperature (via motor control module)
* Drive Motor Position (via motor control module)
* Hood switch
* Various internal signals (temps, etc.)
Circuit Outputs
In addition to control through other controllers, the hybrid powertrain control module directly controls:
* Cooling Fan
* Auxiliary Transmission fluid pump
* Drive Motor
* Drive Motor Cooling pump
Drive Motor Control Module
Location
The drive motor control module is a flash-programmable micro-processor. The drive motor control module is non serviceable and is part of the generator control module.
Operating Functions
The drive motor control module's main function is to monitor the drive motor input/output circuits and to control the insulated gate bipolar transistors that control the drive motor by inverting the high voltage DC electrical energy to 3 phase AC electrical energy and vice versa.
Communication and Hosted Diagnostics
The hybrid powertrain control module communicates with the drive motor control module using an internal serial data circuit. The drive motor control module does not store its own diagnostic trouble code (DTC) information. The hybrid powertrain control module will store the drive motor control module associated DTC information for retrieval by a scan tool. The scan tool can communicate directly with the drive motor control module in order to retrieve data parameters only.
Circuit Inputs
In addition to data parameters, the drive motor control module monitors the drive motor for:
* Voltage
* Current
* Speed and direction
* Temperature
Additionally, the drive motor control module monitors the insulated gate bipolar transistor components for temperature and proper operation. Some of the drive motor control modules operation data is shared with the hybrid powertrain control module.
Circuit Outputs
The drive motor control module controls the insulated gate bipolar transistor driver board which is located in the drive motor control module, that in-turn controls the drive motor. The drive motor is controlled by the 3-phase alternating current (AC). Three cables connect the drive motor to the drive motor control module which is part of the generator control module.
14 Volt Power Module
Location
The 14 volt power module is a non-serviceable device that is part of the generator control module.
Operating Functions
The 14V power module is the device which converts high voltage (115V) DC to low voltage (12V) DC for accessory electrical operation and to charge the 12 volt accessory battery. The 14 volt power module will typically charge the 12 volt system at approximately 14.5 volts with a max power output of 1600 watts. The 14 volt power module is not programmable.