EMC glands support, seal and protect interfaces between HV cables and components. We show you how AGRO provide solutions for protection against EMI for EV’s and their experience in overcoming the engineering challenges in the EV world. We look at how AGRO have examined and understood those in the cable assembly and vehicle manufacturing industry.
AGRO EVolution EMC cable glands are purely designed to protect EV’s against electric magnetic interference (EMI), they also serve to save time during the assembly of commercial EV powertrains.
“The high-level challenge was about properly understanding and interpreting the requirements of vehicle and component manufacturers, and of cable assembly companies,” Mr Halfiger, Innovation Driver for eMobility at AGRO says. “It was also essential to apply our knowhow in electromagnetic compatibility [EMC] and shield current-carrying capacity.”
EV’s are sources of EMI (electromagnetic interference) and this is what they rely on:
Switching electric currents on and off generates RF pulses that will in turn induce unwanted currents through unshielded components, causing glitches and failures.
You can protect the EV as electronic control modules and power electronics devices are housed in boxes made from metal or conductive plastic, while power cables incorporate a conductive sheath.
The boxes and sheaths must form an unbroken faraday cage around the whole HV system to allow any currents induced in them to flow to ground without reaching the components inside.
1. Contact sleeve
AGRO developed a solution centred on a supporting ring with a contact sleeve, this is axially crimped to the table.
This ensures a continuous 360º electrical contact between the contact sleeve and the cable’s shield, and between the supporting ring and the threaded insert in the component enclosure.
2. Silicone sealing ring for protection
Watertight integrity for each connection is provided by a silicone sealing ring, which incorporates a zigzag split, allowing the connection to be changed without disconnecting the cable. The ring is compressed and held in place by a nut that screws onto the threaded insert in the component enclosure.
“Developing the supporting ring and contact sleeve solution in combination with the new axial crimping technology was itself a major challenge,” Mr Halfiger explains.
Agro EMC cable glands can be used in commercial vehicles and construction machinery in the following components:
Other likely applications include auxiliary drives, ancillary equipment and even the actual charging infrastructure, according to AGRO.
“There are two areas that especially require a high-performance EMC cable gland,” Mr Halfiger adds.
“First are the conductors between AC inverters and traction motors, which not only require good EMC shielding but also very high shielding currents to be discharged with low impedance and minimal heating.”
“The second important application is between the DC-DC converter and any ancillary equipment. This is where the demands on EMC safety are highest, owing to the high switching frequencies, requiring a shield connection that offers lifelong reliability.”
“However, the entire HV vehicle electrical system is often subjected to parasitic EMC signals, which is why – depending on the approach taken to earthing across the entire electrical system – demands can be high. This also shows that shielding all the power and signal conductors should be EMC-tight throughout.”
Available for cables with cross-sectional areas between 16 and 120 mm2, EVolution EMC glands can carry shield currents of more than 100 A and meet the IP68 and IP6K9K ingress protection standards, says the AGRO.Blog