With the growth of electric vehicles (EV), electromagnetic compatibility (EMC) will be a major consideration as more vehicles are manufactured and the need for charging stations increases. Schaffner - the international leader in the development and production of solutions which ensure the efficient and reliable operation of electronic systems - has written a white paper examining some of these issues.

With the regulations set in the EU to have trucks and other vehicles be electric by 2025, the current growth of popularity of electric cars, and the expected demand of 20 million EVs by 2030, Schaffner forecasts a need for a huge increase in charging stations. The white paper postulates that for every million EVs 77,000 charging points will be needed. If there are 20 million electric vehicles by 2030, that would be a need for 1.54 million charging locations.

Electromagnetic compatibility “is concerned with the emission and immunity of products connected to the mains supply. The emitted interference or emission generated by lossy switching operations must not exceed specified limits. If noncompliant products are brought onto the market, problems may arise in operation with other consumers connected to the main power grid. Immunity to interference describes the ability of products to withstand external influences without error. The immunity of products can be verified by various tests, for example by means of the surge, burst or flickr test.

Schaffner develops EMC filters that enable compliance with emission limit standards. These filters are designed to operate in the frequency range between 9 kHz and 30 MHz in order to suppress conducted interference. This prevents other devices in the environment from being negatively affected. All standard filters are designed in accordance with the IEC 60939-3 standard („Passive filter units for electromagnetic interference suppression“) and other international standards and are therefore quickly ready for use in a potential customer system,” the white paper notes.

 Designers of battery and hybrid electric vehicle charging stations will need to take into consideration the safety requirements and EMC limit values that need to be met For  DC charging stations (fast charging stations) the IEC 61851-23 standard defines the general requirements for the control communication between a DC EV charging station and an EV. The requirements for digital communication between a DC EV charging station and an electric vehicle for control of direct current charging are defined in IEC 61851-24.

The complications arise when the location of the charging station is considered. Is it an industrial (Class A) or residential environment (Class B).

“With recent new directives from the European Union pertaining to buses, trucks, agricultural and construction equipment being emission-free by 2025, manufacturers have been investing in the development of fuel-cell and electric vehicles”, as Components in Electronics reports.

The good news is this has increased demand for sensors, connectors, transformers and e-mech components. A demand that will grow well into the 2030s.

Issues with galvanic separation between the input and output side of charging stations is also a requirement to meet safety standards beyond EMC. Here Schaffner notes, “The use of medium-frequency transformers is particularly beneficial for DC fast charging stations, where

inverter technology is anyway required for rectifying the AC mains voltage. Compared to conventional main grid transformers, they can be designed much more compact with the same performance. This means that they can also be placed in constricted charging stations”.

Galvanic separation prevents electric conduction between two electric circuits intended to exchange power and/or signals - in this case, the charging station and the vehicle. Galvanic isolation is a design technique that separates electrical circuits to eliminate stray currents. Signals can pass between galvanically isolated circuits, but stray currents, such as differences in ground potential or currents induced by AC power, are blocked.

As more future-oriented approaches for vehicles, charging systems and forms of mobility are developed new issues will arise and be met. The promising aspect of this large-scale growth and demand for EVs and HEVs (Hybrid Electric Vehicles) is continued demand for various electronic components, but more importantly a global awareness and effort to address climate change.