Circuit/System Description

The generator control module also called the starter generator control module is comprised of the following three control modules; the hybrid powertrain control module, 14 volt power module and the drive motor control module. These three control modules are non serviceable and are part of the generator control module.

The drive motor control module operates the starter generator, also referred to as the drive motor, based upon hybrid powertrain control module commands. The drive motor control module controls the speed and output torque of the starter generator through the sequencing actuation of high current switching transistors called insulated gate bipolar transistors. The starter generator operates utilizing 3-phase alternating current (AC) electricity. Each insulated gate bipolar transistors operates a single phase of the starter generator. Each phase is individually identified as U, V and W. The drive motor control module monitors the current of phase U and W. The drive motor control module uses logic to calculate phase V current values. This information is used in order to detect over current conditions.

Because all starter generator phase circuits are electrically joined together, they should each flow about the same amount of current. The drive motor control module performs a mathematical calculation to verify that the phase current sensors are accurate. If the current sensors indicate about the same amount of phase current, the sum of the calculation should be near zero. If the currents are not similar, this DTC will set.