Electric Vehicle

Hyundai Mobis develops Bi-directional On Board Charger (OBC) for electric vehicles, crucial for implementation of V2G

Hyundai Mobis has become the first Korean company to develop the Bi-directional On Board Charger (OBC) for electric vehicles, which is key to the implementation  of V2G (Vehicle To Grid).

V2G refers to using the idle power while plug-in environment-friendly cars, such as EV and PHEV, connected to the grid, are parked. The electric vehicle is charged while connected to the grid, and the electricity remaining after the day’s operation is transmitted (and/or discharged) back to the grid. The electric vehicle effectively becomes a moving Energy Storage System (ESS).


The electric power supplied by vehicles can be used as emergency power in households and cities. Four electric vehicles can supply energy that can be used by 20 households in a day. If more vehicles are available, the surplus power can be secured and large-scale blackouts may be prevented. Damages to industries due to blackouts are estimated to be KRW 650 billion a year in Korea.

The industry estimates that if V2G is applied to 100,000 vehicles, 500MW power, equivalent to the power generation of a thermoelectric power plant, will be secured. Experts say that “In general, automobiles are being used less than 20% of the time, and they are parked in the remaining time,” and it will be very effective. Currently, pilot V2G projects are being actively carried out in Japan, Denmark, the US, and China.

The ‘bi-directional OBC’ has bi-directional power control circuits,’ such as the AC?DC converter and the step-up/down converter, for bi-directional conversion of DC/AC. Hyundai Mobis started the vehicle testing according to the virtual power scenario earlier this year, and finished it at the end of last month, while actively commencing with vehicle testing linked to KEPCO’s real-time power data from this month.

The actual vehicle verification begins with a dedicated charging station diagnosing the power state of the vehicle, such as battery efficiency and capacity. The optimal V2G schedule is then created according to the hypothetical scenarios in which the power supply, cost, and load are analyzed. Vehicles receive this data signal, and repeats charging and discharging according to a predetermined schedule.

In future smart cities, many electric vehicles will be charged at the same time. To reduce the resulting power load, V2G is essential. The successful development of the bi-directional OBC enabled Hyundai Mobis to respond more proactively to the global V2X (Vehicle To Everything, including V2G) market, which is expected to grow to KRW30 trillion ($26.7 billion) by 2025.


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