About Power Distribution

This section describes the power wiring networks used in the embedded system design phase and how you can build such a network in Electrical & Electronics Architecture.

This page discusses:

Power Wiring Diagram

A power wiring diagram is represented as a topology with specific elements and specific constraints applied on these elements.

A power wiring network includes:

  • Electrical devices (for example: batteries, fuses, relays, fuse/relay boxes, ground points, lights, shunt)
  • ECUs
  • Wires connecting these ECUs and electrical devices
  • Electrical currents consumed by some components
Note: The architecture of boxes and ECUs can be decomposed with subsystems.

Electrical Devices

The electrical devices contain the following properties:

  • Device type: Battery, Box, Fuse, Ground, PowerModule, Relay, Shunt, or Other.
  • Rating: only for fuses, relays, and shunts.
  • Derating factor: only for fuses. Each derating factor has a correction coefficient Ci. The effective rating is computed as follows: Effective Rating = Rating / (Product of the Ci).
  • Cost.
  • Currency.

Relay

A relay has four or five ports connected by four or five connections (four for a single-throw and five for a double-throw).

Among these ports:

  • Two ports are controlled ports. The connector type for these ports should not be Power.
  • Two or three ports are used for the electrical current. The connector type for these ports must be Power.

However, if you assign Power connector type to all ports, the port for the current has to be ignored during the current consumption calculation. To do so, select Is ignored in current consumption synthesis in the Electrical tab of relay In ports.

Power Module

A power module consumes an electrical current and provides a current to another electrical device.

Consuming Hardware Components

The consuming hardware components (that is the components, which consume electricity) correspond to:

  • ECUs
  • Electrical devices of device type PowerModule or Other

Ports

The ports of consuming hardware components have specific properties.

Ports Properties Description
In Current name For example: operating current, standby current.
Current value Current intensity in Ampere.
Load usage A value of load percentage specified for an electrical current.
Is current sink Boolean property to define the port as an electrical current sink.
Out Is current source Boolean property to define the port as an electrical current source. If the property is False, the port is ignored.
Max current value Maximum current intensity in Ampere, if the port is a current source.

For example:

  • An ECU can be a current converter, so it can consume a current of 5A in input, and can reply another current of 50mA to an output marked as IsCurrentSource = True.
  • The output for a battery is always defined as a current source.

Building Process

You have to create and define several topology elements to build your power distribution network.

For this, one process is the following:

  1. Creating electrical devices.
  2. Creating ECUs.
  3. Creating a topology containing subsystems, electrical devices, and ECUs.
  4. Defining electrical properties on electrical devices and on ports.
You can also create the elements in another order.