Date & Time: October 17th, 09:30-10:00
Location: Seminar Room M 3170-73 in the M-building, LTH
Author: Anes Mehmedagic, Viktor Nyman
Title:  Balancing the operating conditions of dual alternators using a 3-DOF PID controller
Supervisor:  Avo Reinap (IEA LTH), Matilda Andersson (Scania)
Examiner:  Anders Rantzer

Abstract: 
In heavy vehicle applications, the electrical power demand can exceed 
the capacity of a single standard alternator. Installing two or more 
alternators in parallel can be done to satisfy the electrical 
consumption needs without the complexity and cost of developing larger 
alternator units. However, this configuration poses challenges such as 
uneven load distribution, thermal imbalance and premature alternator 
failure. This thesis aims to mitigate these challenges by developing a 
control method that balances the operating conditions of dual 
alternators. The thesis work was carried out at Scania CV AB in 
Södertälje, Sweden. A three degree-of-freedom PID controller was 
developed and implemented in the Scania Engine Management System (EMS). 
This controller balances the thermal operating conditions of dual 
alternators by regulating their excitation current while still meeting 
the electric power demands of the vehicle. Experimental validation of 
the control method was performed using a Scania test vehicle equipped 
with dual LIN-communicating alternators. The results show that the 
controller successfully manages to reduce and control the temperature 
difference between the alternators, thereby mitigating uneven ageing of 
the alternators and achieving more balanced operation. Some non-linear 
behaviors were however observed, such as dead-band effects and 
oscillations near control limits, due implementation choices and system 
characteristics. The presented control method provides a stable and 
effective approach for improving the reliability and lifespan of dual 
alternator systems in heavy vehicles. The findings also form a basis for 
future research such as improved performance of the developed controller 
and enhanced thermal modeling of alternator systems