A cooling device for cooling at least two power electronic devices by a working fluid. The cooling device has a heat receiver portion of the Pulsating Heat Pipe circuit system and a pair of thermo-conducting walls provided on mutually opposite sides of the heat receiver arrangement and sandwiching the heat receiver portion between them. These walls are adapted for being thermally connected to a respective one of the power electronic devices. The cooling device further has a heat dissipator arrangement with a heat dissipator portion of the Pulsating Heat Pipe circuit system and a plurality of fins thermally coupled to the heat dissipator portion for transferring heat from the heat dissipator portion to an external cooling fluid for cooling the working fluid in the heat dissipator portion. The Pulsating Heat Pipe circuit system connects the heat receiver portion with the heat dissipator portion for transferring heat from the heat receiver portion to the heat dissipator portion by the Pulsating Heat Pipe action of the working fluid.