Real-time power management system for sensorless motor control and short circuit localization

October 19, 2011 // By Eric Fitterer (PSA Peugeot Citroën), Igor Ablaev (Finprom-Resource), Philippe Briot (Briot & Associates)
Integrated mechatronic systems open doors to better diagnosis and better control of actuators. The combination of power line communication and distributed computing offers a smart and low-cost solution for in-car subsystems power management. The implementation of a robust PLC protocol allows drastic harnesses weight reduction. The article describes the practical implementation of distributed power management in seats, doors and lighting subsystems.

I. Car EEA context

In today's vehicles, adding a new function in the pre-existing Electric/Electronic Architecture (EEA) is often accomplished by the incorporation of one ECU connected to its own sensor & actuator components. The increasing number of ECUs in vehicles becomes critical in term of integration into the vehicle since available space for electronic is no longer maintained. In term of complexity it also leads to an increase of wires, communication networks, energy management and so forth. Thus disruptive solutions are required to reduce numerous wires & ECUs and to optimize energy consumption. The introduction of PLС in the vehicles combined with increased use of mechatronics is a possible solution.

Components vs. wire harness

For a middle range or C segment vehicle we can consider a total of 35 embedded ECUs, 20 ECUs for the power train, chassis and HMI & multimedia domains. For the body & comfort domains, 15 ECUs are implemented within around 100 sensors and actuators. Only some integrate an electronic module within the mechanical part we call mechatronic modules and only a few of these ECUs are mechatronic types.

Regarding the diversity of actuators we consider using the PLC solution on the small and medium actuators which are used for mechanical movement in the door and seat areas where, for the sensors, the electronic characteristics do not impact the PLС solution and the mechatronic size. Indeed, the range of the average current for these actuators is from 1 to 10 Amps with a maximum inrush current of 25 Amps in few cases. The command is either very simple or uses a low frequency PWM. The response time of these functional systems is around 200ms within a sensor signal response in the range of 20 to 200Hz maximum.

The wiring harness in this body & cockpit area can count more than 700 wires which means more than 1,3km of wires, 1400 connexions and 25kg. For instance,

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