Theory Of Operation
The Smart Alternator communicates with the Powertrain Control Module (PCM) over a Pulse Width Modulated (PWM) LIN BUS communication circuit. The Smart Alternator contains an Intelligent Voltage Regulator that controls the Alternator overall operation. The Smart Alternator requires Battery supply on the Fused B+ circuit and a good case ground to power up the internal regulator and operate correctly. The PCM sends the Smart Alternator the following messages/commands over the LIN BUS circuit.
- Wake-up signal
- Voltage set point
- Ramp time
- Maximum current output based on operating and environmental conditions
The Smart Alternator controls the charging rate based on the PCM commands. The Smart Alternator also performs diagnostics for electrical and mechanical faults with the Alternator. The Smart Alternator sends the following information/faults regarding diagnostics and Alternator load conditions to the PCM:
- Regulator duty cycle
- Internal Battery voltage
- Measured energizing current
- Integrated circuit temperature
- Pulley rotational speed
- Errors messages for internal mechanical error, electrical error, or over temperature error