The wireless charger has a sending coil arrangement on-shore mounted on a hydraulic arm with y and z axis movement. The sending coil is connected to a nearby power electronic where grid connection and alternatively shore based energy storage can be connected. The input voltage to the power electronics is 690V 50/60Hz.
On the ship side there is a similar coil arrangement where the receiving coil plate is mounted flush with the side of the vessel. The coil arrangement is connected to a rectifier for DC conversion.
The basic principle is following:
- Current in inductive sending coil creates a controlled magnetic field.
- Magnetic field from sending coil creates a current in the receiving coil.
- High frequency current flowing in the inductive coil is converted to DC Power.
- Energy is stored in the ship batteries
This system can transfer more than 2 MW with a distance between the coils of about 4- 500 mm.
Capacity of the Wärtsilä wireless charger
One standard basic unit delivers 2.5MW. Landside and onboard connections are normally 690VAC, but that can be adapted with transformers and there is also the possibility for a common DC bus connection. At 690V, 2.5MW corresponds to 2500Arms three phase. The power rating of the charging system can easily be increased by using several units in parallel, or by specifying a larger unit with an increased active coil area.