Bidirectional charging and vehicle-to-grid
Turning the on-board charger into a two-way power converter.
You'll learn
- Explain bidirectional charging and vehicle-to-grid at engineering level
- Read the numbers that define the behaviour
- Apply the idea to a real drive system
Overview
A charger built from switching semiconductors is, in principle, no less capable of pushing power out than pulling it in. Bidirectional on-board chargers exploit exactly that symmetry to power homes, appliances and even the grid itself.
In depth
Levels of bidirectional capability
| V2L | V2H | V2G | |
|---|---|---|---|
| Powers | A single plugged-in device | A home's circuits during an outage | Exports to the public grid |
| Typical power | Up to ~3 kW | Up to ~10 kW | Variable, grid-managed |
| Extra hardware needed | Usually none beyond an outlet | Transfer switch / home integration | Grid-certified bidirectional charger and metering |
Enabling any of these modes requires the OBC's DC/DC stage to conduct power in reverse and, for V2G, requires the PFC stage to actively synthesise grid-compliant AC rather than just rectify it — effectively running the front end as a grid-tied inverter.
Key takeaways
Remember this
- Bidirectional charging repurposes the same power electronics to push energy out of the car.
- V2L, V2H and V2G represent increasing levels of integration and grid interaction.
- V2G requires the charger's front end to actively synthesise grid-compliant AC.
Mark this lesson complete
Confirm you've read through and we'll count it toward your progress.
Was this lesson helpful?
Rate this lesson