Power relay aids EV charging designs
The G9KC relay from OMRON is a high-capacity, four-pole power relay designed for demanding industrial, electric vehicle charging and energy management applications.
It excels in switching and controlling large current loads, offering exceptional reliability, safety, and performance. The relay was recognised at the 2024 Elektra awards winning the award for Passive/Interconnection Product of the Year.
With the acceleration of the spread of electric vehicles (EVs), demand has increased for high-performance EV chargers that can use energy more effectively and efficiently. The trend in AC EV chargers include the need for higher output to reduce charging time, increased current, and three-phase compatibility.
In addition, fixed AC EV chargers used in general households and commercial facilities require compact, slim, and lightweight equipment design in terms of installation, design, as well as improved productivity and cost reduction during assembly.
The G9KC relay from OMRON has been designed to address the specific challenges facing designers of AC EV charging equipment.
One of the main challenges in increasing the output of AC EV chargers is the rise in temperature inside the housing due to heat generation of components.
EV chargers are generally installed outdoors, and their housings are sealed to IP standards to prevent water and dirt ingress, in addition, as chargers become smaller and slimmer, their housings become smaller, making it even more likely for the internal temperature to rise. When the internal temperature of the equipment rises, the output charging current reduces resulting in longer charging time and lower efficiency.
Whilst PCB mount relays are much smaller and easier to integrate into EV chargers than contactors, until recently they have tended to have higher contact resistance than contactors, so larger currents generate more heat. TheG9KC has been designed to feature an initial contact resistance of ≤6 mΩ guaranteed reducing heat generation and improving efficiency.
This is lower than that of other 4-pole PCB relays with same/ similar contact ratings in the market.
The relay maintains its lower contact resistance with no critical increase during and after electrical endurance tests.
With low contact resistance, G9KC allows the possibility with good PCB design to generate less heat.
A lower temperature rise inside the equipment maintains high charging performance and extended electrical life.
The relay is available with a 12V or 24V coil and has a normally open, 4 pole, single throw (4PST-NO / 4a) contact configuration, additional models are available featuring an auxiliary contact with normally closed, single pole, single throw (SPST-NC / 1b) contact configuration.
The relay’s auxiliary contact structure (called a mirror contact structure) is fully compliant with IEC 60947-4-1 Annex F (F.7.2), which requires main contacts and auxiliary contacts be mechanically linked and have more than 0.5 mm of contact gap between auxiliary contacts, the auxiliary contact is used as a safety feature to detect if the main contacts have suffered a welding failure.
The G9KC was designed to address specific technical challenges faced in AC EV charger designs, however its high current capability, efficiency and safety features make it suitable for other applications including input and output circuits of uninterruptable power supplies (UPS) and output circuits of inverters used in Solar PV systems.
This relay is a mechanically coupled 4-pole structure.
It has been designed and tested to have a short circuit capability on the conditions of 3 kA conditional rated short current and 32 A rated current specified by IEC 62955.
In addition, the relay is tested to meet 50,000 cycles of electrical endurance required by IEC 61851-1 on the condition of 32 A 277 VAC and the auxiliary contact option is compliant with mirror contact structure specified by IEC 60947-4-1 and is useful to monitor main load contact status specified by IEC 61851-1.
Authorised distributor Anglia is offering customers free samples of the relay.