Automotive Electronics EMC/EMI Compliance

As the CAN standard does not include tasks of application layer protocols, such as flow control, device addressing, and transportation of data blocks larger than one message, and above all, application data, many implementations of higher layer protocols were created. Several are standardized for a business area, although all can be extended by each manufacturer. For passenger cars, each manufacturer has its own standard. Among these implementations are:

• ARINC 825 (for the aviation industry)

• CANaerospace (for the aviation industry)

• CAN Kingdom

• CANopen (used for industrial automation)

• CCP / XCP

• DeviceNet (used for industrial automation)

• EnergyBus (used for electrical vehicles)

• GMLAN (for General Motors)

• ISO 15765-4

• ISO 11783 or ISOBUS (agriculture)

• ISO 14229

• SAE J1939 (heavy road vehicles)

• ISO 11992 for heavy trailers

• MilCAN

• CAN bus 10

• NMEA 2000 (marine industry)

• RV-C (used for recreational vehicles)

• SafetyBUS p (used for industrial automation)

• SmartCraft

• Smart Distributed System (SDS)

• VSCP (used for building automation)

Christian Rosu

There are several CAN physical layer and other standards:

•ISO 11898-1: CAN Data Link Layer and Physical Signaling

•ISO 11898-2: CAN High-Speed Medium Access Unit

ISO 11898-2 uses a two-wire balanced signaling scheme. It is the most used physical layer in car

Powertrain applications and industrial control networks.

•ISO 11898-3: CAN Low-Speed, Fault-Tolerant, Medium-Dependent Interface

•ISO 11898-4: CAN Time-Triggered Communication

ISO 11898-4 standard defines the time-triggered communication on CAN (TTCAN). It is based on the

CAN data link layer protocol providing a system clock for the scheduling of messages.

•ISO 11898-5: CAN High-Speed Medium Access Unit with Low-Power Mode

•ISO 11898-6: CAN High-speed medium access unit with selective wake-up functionality

•ISO 11992-1: CAN fault-tolerant for truck/trailer communication

•ISO 11783-2: 250 kbit/s, Agricultural Standard

ISO 11783-2 uses four unshielded twisted wires; two for CAN and two for terminating bias circuit

(TBC) power and ground. This bus is used on agricultural tractors. This bus is intended to provide

interconnectivity with any implementation adhering to the standard.

•ISO 15765-2 also called ISO-TP, is a standard for flow control and handling of messages larger than eight bytes.

•SAE J1939-11: 250 Kbit/s, Shielded Twisted Pair (STP)

•SAE J1939-15: 250 Kbit/s, Unshielded Twisted Pair (UTP) (reduced layer)

The SAE J1939 standard uses a two-wire twisted pair, −11 has a shield around the pair while −15 does not. SAE 1939 defines also application data and is widely used in heavy-duty (truck) and autobus industry as well as in agricultural & construction equipment.

See Movie

1) Check mirrors
2) Signal before changing lanes
3) Shoulder check
4) Check mirror again then change lanes

Types of Electromagnetic Coupling: Conducted, Radiation, Magnetic Field, Electric Filed

Electric Field Coupling

The EF lines start on positive charge and end on negative charge from higher voltage conductors to lower voltage conductors. Any two conductors at different potentials (voltages) have electric field lines between them. EF shields are connected to “ground” to maximize their effectiveness.

     The electric field lines are passing through ungrounded metallic planes. 

Grounding a copper enclosure does not increase or decrease its shielding property but it reduces the crosstalk within the product itself. The ungrounded shield allows coupling signals from circuits within the shielded enclosure. If the device is connected via external cable to another module the ungrounded shield can serve to capacitively couple signals from outside the enclosure. 

Stand by and Wake up

The supply device is woken up by a signal from the EV.

Compatibility check

Compatibility of the primary and the secondary devices is checked with the information exchanged at the initialization phase: power classes, operating frequency, magnetic coupling, circuit topology, tuning.

Initial Alignment check

The MF-WPT system will determine that the primary and secondary devices are properly well positioned relative to each other.

Start Power Transfer

The MF-WPT system is capable to transfer the power from the primary device to the secondary device upon the request from the vehicle. The MF-WPT system does not perform power transfer until the command and control communication is properly established and the primary device and secondary device are properly positioned.

Time Scheduled Power Transfer

Perform Power Transfer

MF-WPT system transfers the power from the primary device to the secondary device in accordance with the power demand of the EV. The maximum transferring power of the off-board MF-WPT system must not be exceeded. The vehicle can change the requested transfer power.

Stop Power Transfer

MF-WPT system is able to stop transfer the power from the primary device to the secondary device in accordance with the demand of the EV. The vehicle can requested stop power transfer.

User initiated Stop Power Transfer

MF-WPT system allows the user to terminate of power supply. (e.g. pushing stop button).

Safety monitoring & diagnostics

continuous monitoring of power transfer conditions

continuous monitoring of command & control communication

continuous monitoring of safety conditions

Power Transfer Monitoring: The supply device provide means to verify that the actual output power does not differ from the expected output power by a certain limit; if the limit is exceeded, it shall stop power transfer.

Thermal Monitoring:WPT systems is capable to detect metallic objects and to stop the power transfer.

Live Object Protection: WPT systems provide life object protection by design or may provide means to detect live objects and to stop power transfer.

Failure Conditions:The supply device stops the transfer in case of of power short-circuit, earth leakage, excess temperature, insulation failure, overcurrent, overload conditions.

Ventilation: Verify that the ventilation system of the area is functioning and active.