Designing electrical systems for electric vehicle platforms is much more complicated than designing electrical systems for internal combustion engine (ICE) platforms. To meet the new challenges, system engineers require design tools capable of scaling with EV system complexity. Unlike an ICE platform, which includes a 12 V electrical system, an EV platform typically includes a 400 to 600 V high-voltage power system for propulsion, an intermediate voltage system (e.g., 48 V) for chassis and body applications, and the compulsory 12 V system for infotainment and commodity body and comfort applications. What’s more, EVs include switched-mode DC-DC converters to efficiently translate voltage between systems. The linear contribution to overall system complexity is exacerbated by the fact that these artifacts introduce new pathologies to the system.
Reliability concerns unique to high-voltage systems include arcing, short circuits to ground, loss of common ground, and voltage short circuits. Loss of common ground could flip voltage polarity and destroy electronic systems. To cope with loss of common ground, an electrical system designer may choose to employ separate ground connections. To avoid voltage shorts, the system engineer may decide to separate voltage networks with different connectors and isolated routing.
The switched-mode power converters (and inverter for the traction motor drive) contribute new sources of electromagnetic interference to the system. In particular, harmonics of the high-power switching systems can interfere with vehicle communication networks and electronic systems. Subsequently, the electric system designer must take care to ensure that proper shielding is used in cables, connectors, and components. All the while, size and weight must be minimized to improve performance and reduce cost.
These and other challenges associated with EV design raise the bar for electric system design tools. Tool requirements include tight integration between functional and physical design and powerful simulation capabilities. Tight integration between the functional and physical design enables early design exploration without overcommitting to a particular architecture. For example, with this capability, the system engineer could experiment with different approaches to eliminate the loss of common ground problem. Rich modeling and simulation capabilities enable analysis of voltage drop and EMC effects before physical prototyping is prudent or available.