Powertrain Control Module (Pcm)

The PCM contains the EVR software and circuit.

The amount of direct current produced by the generator is controlled by EVR circuitry contained within the PCM. This circuitry is connected in series with the generators second rotor field terminal and its ground.

Voltage is regulated by cycling the battery positive path to control the strength of the rotor magnetic field. The EVR circuitry monitors system line voltage (B(+)) and battery temperature which is provided by the IBS. It then determines a target charging voltage. If sensed battery voltage is 0.5 volts or lower than the target voltage, the PCM grounds the field winding until sensed battery voltage is 0.5 volts above target voltage. A circuit in the PCM cycles the battery positive (high side) of the generator field up to 400 times per second (400Hz), but has the capability to ground the field control wire 100% of the time (full field) to achieve the target voltage. If the charging rate cannot be monitored (limp-in), a duty cycle of 25% is used by the PCM in order to have some generator output